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《A Short History of Nearly Everything》
ACKNOWLEDGMENTS
As I sit here, in early 2003, I have before me several pages of manuscript bearing majesticallyencing and tactful notes from Ian Tattersal of the Ameri Museum of Natural Historypointing out, inter alia, that Perigueux is not a wineprodug region, that it is iive but atouorthodox of me to italicize taxonomic divisions above the level of genus and species,that I have persistently misspelled esaille, a place that I retly visited, and so on insimilar vein through two chapters of text c his area of expertise, early humans.
Goodness knows how many other inky embarrassments may lurk in these pages yet, but itis thanks to Dr. Tattersall and all of those whom I am about to mention that there arent manyhundreds more. I ot begin to thank adequately those who helped me in the preparation ofthis book. I am especially ied to the following, who were uniforml99lib.t>y generous and kindlyand showed the most heroic reserves of patien answering one simple, endlessly repeatedquestion: "Im sorry, but you explain that again?"In the Uates: Ian Tattersall of the Ameri Museum of Natural History in NewYork; John Thorstensen, Mary K. Hudson, and David Blanchflower of Dartmouth College inHanover, Neshire; Dr. William Abdu and Dr. Bryan Marsh of Dartmouth-Hitedical ter in Lebanon, Neshire; Ray Anderson and Brian Witzke of the Ioartment of Natural Resources, Iowa city; Mike Voorhies of the Uy of Nebraskaand Ashfall F9９ｌiｂ.ossil Beds State Park near Orchard, Nebraska; Chuck Offenburger of BuenaVista Uy, Storm Lake, Iowa; Ken Rancourt, director of research, Mount Washingtoorham, Neshire; Paul Doss, geologist of Yellowstoional Park,and his wife, Heidi, also of the National Park; Frank Asara of the Uy of California atBerkeley; Oliver Payne and Lynn Addison of the National Geographic Society; James O.
Farlow, IndianaPurdue Uy; Roger L. Larson, professor of marine geophysiiversity of Rhode Island; Jeff Guinn of the Fort Worth Star-Telegram neer; Jerry Kasten of Dallas, Texas; and the staff of the Iowa Historical Society in DesMoines.
In England: David Caplin of Imperial College, London; Richard Fortey, Les Elli９９lｉｂ?s, and KathyWay of the Natural History Museum; Martin Raff of Uy College, London; RosalindHarding of the Institute of Biological Anthropology in Oxford; Dr. Laurence Smaje, formerlyof the Welle Institute; ah Blackmore of The Times.
In Australia: the Reverend Robert Evans of Hazelbrook, New South Wales; Alan Thorneand Victoria Be of the Australian National Uy in berra; Louise Burke andJohn Hawley of berra; Anne Milne of the Sydney M Herald; Ian Nowak, formerlyof the Geological Society of Western Australia; Thomas H. Riuseum Victoria; TimFlannery, director of the South Australian Museum in Adelaide; and the very helpful staff ofthe State Library of New South Wales in Sydney.
And elsewhere: Sue Superville, informatioer ma the Museum of New Zealandin Wellington, and Dr. Emma Mbua, Dr. Koen Maes, and Jillani Ngalla of the Kenya NationalMuseum in Nairobi.
I am also deeply and variously ied to Patrick Janson-Smith, Gerald Howard, MarianneVelma99lｉb?ns, Alison Tulett, Larry Finlay, Steve Rubin, Jed Mattes, Carol Heaton, Charles Elliott,David Bryson, Felicity Bryson, Dan M, Nick Southern, Patrick Gallagher, LarryAshmead, and the staff of the peerless and ever-cheery Howe Library in Hanover, Neshire.
Above all, and as always, my profouhanks to my dear wife, thia.
CONTENTS
AOWLEDGMENTS
INTRODU
PART I LOST IN THE OS
1 How to Build a Universe
2 Wele to the Solar System
3 The Reverend Evanss Universe
PART II THE SIZE OF THE EARTH
4 The Measure of Things
5 The Stone-Breakers
6 Sce Red in Tooth and Claw
7 Elemental Matters
PART III ANEW AGE DAWNS
8 Einsteins Universe
9 The Mighty Atom
10 Getting the Lead Out
11 Muster Marks Quarks
12 The Earth Moves
PART IV DANGEROUS PLA
13 Bang!
14 The Fire Below
15 Dangerous Beauty
PART V LIFE ITSELF
16 Lonely Pla
17 Into the Troposphere
18 The Bounding Main
19 The Rise of Life
20 Small World
21 Life Goes On
22 Good-bye to All> That
23 The Riess of Being
24 Cells
25 Darwins Singular Notion
26 The Stuff of Life
PART VI THE ROAD TO US
27 Ice Time
28 The Mysterious Biped
29 The Restless Ape
30 Good-bye
NOTES
BIBLIOGRAPHY
INDEX
The physicist Leo Szilard onnouo his friend Hahe that he was thinking of keeping a diary: "I dont io publish. Iam merely going to record the facts for the information of God.""Dont you think God knows the fa９９lｉb?cts?" Bethe asked.
"Yes," said Szilard.
"He knows the facts, but He does not know this version of the facts."
-Hans Christian von Baeyer,Taming the Atom
INTRODUCTION
Wele. And gratulations. I am delighted that you could make it. Getting here wasnteasy, I know. In fact, I suspect it was a little tougher than you realize.
To begin with, for you to be here now trillions of drifting atoms had somehow to assemblein an intricate and intriguingly obliging mao create you. Its an arra sospecialized and particular that it has never been tried before and will o this once. Forthe many years (we hope) these tiny particles will unplainingly engage in all thebillions of deft, cooperative efforts necessary to keep you intad let you experiehesupremely agreeable but generally underappreciated state known as existence.
Why atoms take this trouble is a bit of a puzzle. Being you is not a gratifying experiehe atomic level. For all their devoted attention, your atoms dont actually care about you-indeed, dont even know that you are there. They dont even know that they are there. They aremindless particles, after all, and not even themselves alive. (It is a slightly arresting notionthat if you were to pick yourself apart with tweezers, oom at a time, you would produce amound ..of fiomic dust, none of which had ever been alive but all of which had once beenyou.) Yet somehow for the period of your existehey will ao a single overargimpulse: to keep you you.
The bad news is that atoms are fickle and their time of devotion is fleeting-fleeting indeed.
Even a long human life adds up to only about 650,000 hours. And when that modestmilestone flashes past, or at some other point thereabouts, for reasons unknown your atomswill shut you down, silently disassemble, and go off to be other things. And thats it for you.
Still, you may rejoice that it happens at all. Generally speaking in the universe it doesnt, sofar as we tell. This is decidedly odd because the atoms that so liberally and geniallyflock together to form living things oh are exactly the same atoms that dee to do itelsewhere. Whatever else it may be, at the level of chemistry life is curiously mundane:
carbon, hydrogen, oxygen, and nitrogen, a little calcium, a dash of sulfur, a light dusting ofother very ordinary elements-nothing you wouldnt find in any ordinary drugstore-and thatsall you he only thing special about the atoms that make you is that they make you.
That is of course the miracle of life.
Whether or not atoms make life in other ers of the universe, they make plenty else;ihey make everything else. Without them there would be no water or air or rocks, nostars and plas, no distant gassy clouds or swirling nebulae or any of the other things thatmake the universe so usefully material. Atoms are so numerous and necessary that we easilyoverlook that they actually exist at all. There is no law that requires the universe to fillitself with small particles of matter or to produce light and gravity and the other physicalproperties on which our existence hihere actually be a universe at all. For theloime there wasnt. There were no atoms and no universe for them to float about in.
There was nothing-nothing at all anywhere.
So thank goodness for atoms. But the fact that you have atoms and that they assemble insuch a willing manner is only part of what got you here. To be here now, alive iwenty-first tury and smart enough to know it, you also had to be the beneficiary of araordinary string of biological good fortune. Survival oh is a surprisingly trickybusiness. Of the billions and billions of species of living thing that have existed sihedawn of time, most-99.99 pert-are no longer around. Life oh, you see, is not onlybrief but dismayingly tenuous. It is a curious feature of our existehat we e from aplahat is very good at promoting life but eveer at extinguishing it.
The average species oh lasts for only about four million years, so if you wish to bearound for billions of years, you must be as fickle as the atoms that made you. You must beprepared to ge everything about yourself-shape, size, color, species affiliatiohing-and to do so repeatedly. Thats much easier said than done, because the process ofge is random. To get from "protoplasmal primordial atomic globule" (as the Gilbert andSullivan song put it) to se upright modern human has required you to mutate raitsover and over in a precisely timely manner for an exceedingly long while. So at variousperiods over the last 3.8 billion years you have abhorred oxygen and then doted on it, grownfins and limbs and jaunty sails, laid eggs, flicked the air with a forked tongue, been sleek,been furry, lived underground, lived in trees, been as big as a deer and as small as a mouse,and a million things more. The ti deviation from any of these evolutionary shifts, and youmight now be lig algae from cave walls or lolling walrus-like on some stony shore air through a blowhole iop of your head before diving sixty feet for amouthful of delicious sandworms.
Not only have you been lucky enough to be attached siime immemorial to a favoredevolutionary line, but you have also beeremely-make that miraculously-fortunate in yourpersonal ary. sider the fact that for 3.8 billion years, a period of time older thahs mountains and rivers and os, every one of your forebears on both sides has beenattractive enough to find a mate, healthy enough to reproduce, and suffitly blessed by fateand circumstao live long enough to do so. Not one of your perti aors wassquashed, devoured, drowned, starved, stranded, stuck fast, untimely wounded, or otherwisedeflected from its lifes quest of delivering a tiny charge of geic material to the rightpart the right moment in order to perpetuate the only possible sequence of hereditarybinations that could result-eventually, astoundingly, and all too briefly-in you.
This is a book about how it happened-in particular hoent from there being nothing atall to there being something, and then how a little of that something turned into us, and alsosome of what happened iween and sihats a great deal to cover, of course, which iswhy the book is called A Short History of Nearly Everything, even though it isnt really. Itcouldnt be. But with luck by the time we finish it will feel as if it is.
My own starting point, for what its worth, was an illustrated sce book that I had as aclassroom text when I was in fourth or fifth grade. The book was a standard-issue 1950sschoolbookbattered, unloved, grimly hefty-but he front it had an illustration that justcaptivated me: a cutaway diagram showing the Earths interior as it would look if you cut intothe pla with a large knife and carefully withdrew a wedge representing about a quarter ofits bulk.
Its hard to believe that there was ever a time when I had not seen su illustrationbefore, but evidently I had not for I clearly remember being transfixed. I suspect, in hoy,my initial i was based on a private image of streams of unsuspeg eastboundmotorists in the Ameri plains states plunging over the edge of a sudden 4,000-mile-highcliff runniweeral Amerid the North Pole, but gradually my attention did turnin a more scholarly mao the stific import of the drawing and the realization that theEarth sisted of discrete layers, ending in the ter with a glowing sphere of iron andnickel, which was as hot as the surface of the Sun, acc to the caption, and I rememberthinking with real wonder: "How do they know that?"I didnt doubt the correess of the information for an instant-I still tend to trust thepronous of stists in the way I trust those of surgeons, plumbers, and otherpossessors of are and privileged information-but I couldnt for the life of me ceive howany human mind could work out aces thousands of miles below us, that no eye hadever seen and no X ray could pee, could look like and be made of. To me that was just amiracle. That has been my position with sce ever since.
Excited, I took the book home that night and ope before dinner-an a that I expepted my mother to feel my forehead and ask if I was all right-and, starting with the firstpage, I read.
And heres the thing. It wasing at all. It wasnt actually altogether prehensible.
Above all, it didnt answer any of the questions that the illustration stirred up in a normalinquiring mind: How did we end up with a Sun in the middle of our pla? And if it isburning away down there, why isnt the ground under our feet hot to the touch? And why isntthe rest of the interior melting-or is it? And when the core at last burns itself out, will some ofthe Earth slump into the void, leaving a giant sinkhole on the surface? And how do you knowthis? How did you figure it out?
But the author was strangely silent on such details-indeed, silent ohing butanties, synes, axial faults, and the like. It was as if he wao keep the good stuffsecret by making all of it soberly unfathomable. As the years passed, I began to suspect thatthis was not altogether a private impulse. There seemed to be a mystifying universalspiracy amobook authors to make certaierial they dealt with rayedtoo he realm of the mildly iing and was always at least a longdistance phone callfrom the frankly iing.
I now know that there is a happy abundance of sce writers who pen the most lucid andthrilling prose-Timothy Ferris, Richard Fortey, and Tim Flannery are three that jump out froma siation of the alphabet (and thats not even to mentioe but godlike RichardFeynman)-but sadly none of them wrote abook I ever used. All mine were written bymen (it was always men) who held the iing notion that everything became clear whenexpressed as a formula and the amusingly deluded belief that the children of America wouldappreciate having chapters end with a se of questions they could mull over in their owntime. So I grew up vihat sce was supremely dull, but suspeg that it be, and not really thinking about it at all if I could help it. This, too, became my position for along time.
Then much later-about four or five years ago-I was on a long flight across the Pacific,staring idly out the window at moonlit o, when it occurred to me w9９ｌib?ith a certainunfortable forcefulhat I didnt know the first thing about the only pla I was evergoing to live on. I had no idea, for example, why the os were salty but the Great Lakeswerent. Didnt have the fai idea. I didnt know if the os were growing more saltywith time or less, and whether o salinity levels was something I should be edabout or not. (I am very pleased to tell you that until the late 1970s stists didnt know theao these questioher. They just didnt talk about it very audibly.)And o salinity of course represented only the merest sliver of my ignorance. I didntknow what a proton was, or a protein, didnt know a quark from a quasar, didnt uandhow geologists could look at a layer of ro a yon wall and tell you how old it was,didnt know anything really. I became gripped by a quiet, unwonted urge to know a littleabout these matters and to uand how people figured them out. That to me remaihegreatest of all amazements-how stists work things out. How does anybody know howmuch the Earth weighs or how old its rocks are or what really is way down there ier? How they know how and when the universe started and what it was like when itdid? How do they know what goes on inside an atom? And how, e to that-or perhapsabove all- stists so ofteo know nearly everything but then still t prediearthquake or even tell us whether we should take an umbrella with us to the raextWednesday?
So I decided that I would devote a portion of my life-three years, as it now turns out-toreading books and journals and finding saintly, patient experts prepare??o answer a lot ofoutstandingly dumb questions. The idea was to see if it isnt possible to uand andappreciate-marvel at, enjoy even-the wonder and aplishments of sce at a level thatisnt too teical or demanding, but isirely superficial either.
That was my idea and my hope, and that is what the book that follows is inteo be.
Anyway, we have a great deal of ground to cover and much less than 650,000 hours in whichto do it, so lets begin.
PART I LOST IN THE COSMOS
They.’re all in the same plane.
They’re all going around in the same dire. . . .
It’s perfect, you know.
It’s geous.
It’s almost uny.
-As99liｂ?roneoffrey Marcy
describing the solar system
1 HOW TO BUILD A UNIVERSENO MATTER
HOW hard you try you will never be able to grasp just how tiny, how spatiallyunassuming, is a proton. It is just way too small.
A proton is an infinitesimal part of an atom, which is itself of course an insubstantial thing.
Protons are so small that a little dib of ink like the dot on this i hold something in theregion of 500,000,000,000 of them, rather more than the number of seds tained in halfa million years. So protons are exceedingly microscopic, to say the very least.
Now imagine if you (and of course you ’t) shrinking one of those protons down to abillionth of its normal size into a spaall that it would make a proton look enormous.
Now pato that tiny, tiny space about an ounatter. Excellent. You are ready to starta universe.
I’m assuming of course that you wish to build an inflationary universe. If you’d preferio build a more old-fashioned, standard Big Bang universe, you’ll need additionalmaterials. In fact, you will o gather up everything there is every last mote and partiatter between here and the edge of creation and squeeze it into a spot so infinitesimallypact that it has no dimensions at all. It is known as a singularity.
Iher case, get ready for a really big bang. Naturally, you will wish to retire to a safeplace to observe the spectacle. Unfortunately, there is o retire to because outside thesingularity there is no where. When the universe begins to expand, it won’t be spreading outto fill a larger emptiness. The only space that exists is the space it creates as it goes.
It is natural but wrong to visualize the singularity as a kind nant dot hanging in adark, boundless void. But there is no spao darkness. The singularity has no “around”
around it. There is no space for it to occupy, no place for it to be. We ’t even ask how longit has been there—whether it has just lately popped into being, like a good idea, or whether ithas been there forever, quietly awaiting the right moment. Time does. There is no pastfor it to emerge from.
And so, from nothing, our universe begins.
In a single blinding pulse, a moment of glory much too swift and expansive for any form ofwords, the singularity assumes heavenly dimensions, space beyond ception. In the firstlively sed (a sed that many ologists will devote careers to shaving into ever-finerwafers) is produced gravity and the other forces that govern physics. Ihan a miheuniverse is a million billion miles across and growing fast. There is a lot of heat now, tenbillion degrees of it, enough to begin the nuclear reas that create the lighter elements—principally hydrogen and helium, with a dash (about oom in a hundred million) oflithium. In three minutes, 98 pert of all the matter there is or will ever be has beenproduced. We have a universe. It is a place of the most wondrous and gratifying possibility,aiful, too. And it was all done in about the time it takes to make a sandwich.
When this moment happened is a matter of some debate. ologists have long arguedover whether the moment of creation was 10 billion years ago or twice that or something iween. The sensus seems to be heading for a figure of about 13.7 billion years, but thesethings are notoriously difficult to measure, as we shall see further on. All that really besaid is that at some ierminate point in the very distant past, for reasons unknown, therecame the moment known to sce as t = 0. We were on our way.
There is of course a great deal we don’t know, and much of what we think we know wehaven’t known, or thought we’ve known, for long. Eveion of the Big Bang is quite aret ohe idea had been kig around sihe 1920s, when Gees Lema?tre, aBelgian priest-scholar, first tentatively proposed it, but it didn’t really bee an activenotion in ology until the mid-1960s when two young radio astronomers made araordinary and ient discovery.
Their names were Arno Penzias and Robert Wilson. In 1965, they were trying to make useof a large unications antenna owned by Bell Laboratories at Holmdel, New Jersey, butthey were troubled by a persistent background noise—a steady, steamy hiss that made anyexperimental work impossible. The noise was uing and unfocused. It came from everypoint in the sky, day and night, through every season. For a year the young astronomers dideverything they could think of to track down and elimihe hey tested everyelectrical system. They rebuilt instruments, checked circuits, wiggled wires, dusted plugs.
They climbed into the dish and placed duct tape over every seam and rivet. They climbedbato the dish with brooms and scrubbing brushes and carefully swept it of whatthey referred to in a later paper as “white dielectric material,” or what is known moreonly as bird shit. Nothing they tried worked.
Unknown to them, just thirty miles arion Uy, a team of stists led byRobert Dicke was w on how to find the very thing they were trying so diligently to getrid of. The Prion researchers were pursuing ahat had been suggested in the 1940sby the Russian-born astrophysicist Geamow that if you looked deep enough into spaceyou should find some ic background radiatio over from the Big Bang. Gamowcalculated that by the time it crossed the vastness of the os, the radiation would reachEarth in the form of microwaves. In a more ret paper he had even suggested an instrumentthat might do the job: the Bell antenna at Holmdel. Unfortunately, her Penzias andWilson, nor any of the Prion team, had read Gamow’s paper.
The hat Penzias and Wilson were hearing was, of course, the hat Gamoostulated. They had found the edge of the universe, or at least the visible part of it, 90 billiontrillion miles away. They were “seeing” the first photons—the most a light in theuniverse—though time and distance had verted them to microwaves, just as Gamoredicted. In his book The Inflationary Universe , Alan Guth provides an analogy that helps toput this finding in perspective. If you think of peering into the depths of the universe as likelooking down from the huh floor of the Empire State Building (with the huh floorrepresenting now and street level representing the moment of the Big Bang), at the time ofWilson and Penzias’s discovery the most distant galaxies anyone had ever detected were onabout the sixtieth floor, and the most distant things—quasars—were on about the tweh.
Penzias and Wilson’s finding pushed our acquaintah the visible universe to within halfan inch of the sidewalk.
Still unaware of what caused the noise, Wilson and Penzias phoned Dicke at Prion anddescribed their problem to him in the hope that he might suggest a solution. Dicke realized atonce what the two young men had found. “Well, boys, we’ve just been scooped,” he told hiscolleagues as he hung up the phone.
Soon afterward the Astrophysical Journal published two articles: one by Penzias andWilson describing their experieh the hiss, the other by Dicke’s team explaining itsnature. Although Penzias and Wilson had not been looking for ic background radiation,didn’t know what it was when they had found it, and hadn’t described or interpreted itscharacter in any paper, they received the 1978 Nobel Prize in physics. The Prionresearchers got only sympathy. Acc to Dennis Overbye in Lonely Hearts of the os, her Penzias nor Wilson altogether uood the significe of what they had founduntil they read about it in the New York Times .
Ially, disturbance from ic background radiation is something we have allexperieune your television to any el it doesn’t receive, and about 1 pert of thedang static you see is ated for by this a remnant of the Big Bang. The imeyou plain that there is nothing on, remember that you always watch the birth of theuniverse.
Although everyone calls it the Big Bang, many books caution us not to think of it as anexplosion in the ventional se was, rather, a vast, sudden expansion on a whoppingscale. So what caused it?
Oion is that perhaps the singularity was the relic of an earlier, collapsed universe—that we’re just one of aernal cycle of expanding and collapsing universes, like the bladderon an oxygen mae. Others attribute the Big Bang to what they call “a false vacuum” or “ascalar field” or “vacuum energy”—some quality or thing, at any rate, that introduced ameasure of instability into the nothihat was. It seems impossible that you could getsomething from nothing, but the fact that ohere was nothing and now there is a universeis evident proof that you . It may be that our universe is merely part of many largeruniverses, some in different dimensions, and that Big Bangs are going on all the time all overthe place. Or it may be that spad time had some other forms altogether before the BigBang—forms too alien for us to imagine—and that the Big Bang represents some sort oftransition phase, where the universe went from a form we ’t uand to one we almost. “These are very close tious questions,” Dr. Andrei Linde, a ologist atStanford, told the New York Times in 2001.
The Big Bang theory isn’t about the bang itself but about what happened after the bang.
Not long after, mind you. By doing a lot of math and watg carefully what goes on inparticle accelerators, stists believe they look back to 10-43seds after the moment ofcreation, when the universe was still so small that you would have needed a microscope tofind it. We mustn’t swoon over every extraordinary hat es before us, but it isperhaps worth latg on to one from time to time just to be reminded of their ungraspableand amazing breadth. Thus 10-43is 0.0000000000000000000000000000000000000000001, orone 10 million trillion trillion trillionths of a sed.
**A word on stifiotation: Since very large numbers are cumbersome to write and nearly impossible to read, stistsuse a shorthand involving powers (or multiples) of ten in which, for instance, 10,000,000,000 is written 1010 and 6,500,000bees 6.5 x 106. The principle is based very simply on multiples of ten: 10 x 10 (or 100) bees 102; 10 x 10 x 10 (or1,000) is 103; and so on, obviously and indefinitely. The little superscript number sighe number of zeroes followingthe larger principal number. ive notations provide latter in print (especially essentially a mirror image, with thesuperscript number indig the number of spaces to the right of the decimal point (so 10-4 means 0.0001). Though I salutethe principle, it remains an amazement to me that anyone seeing "1.4 x 109 km3’ would see at ohat that signifies 1.4Most of what we know, or believe we know, about the early moments of the universe isthanks to an idea called inflation theory first propounded in 1979 by a junior particlephysicist, then at Stanford, now at MIT, named Alan Guth. He was thirty-two years old and,by his own admission, had never done anything much before. He would probably never havehad his great theory except that he happeo attend a lecture on the Big Bang given byher than Robert Dicke. The lecture inspired Guth to take an i in ology, andin particular in the birth of the universe.
The eventual result was the inflation theory, which holds that a fra of a moment afterthe dawn of creation, the universe underwent a sudden dramatic expansion. It inflated—i ran away with itself, doubling in size every 10-34seds. The whole episode may havelasted no more than 10-30seds—that’s one million million million million millionths of ased—but it ged the universe from something you could hold in your hand tosomething at least 10,000,000,000,000,000,000,000,000 times bigger. Inflation theoryexplains the ripples and eddies that make our universe possible. Without it, there would be noclumps of matter and thus no stars, just drifting gas and everlasting darkness.
Acc to Guth’s theory, at oen-millionth of a trillionth of a trillionth of a trillionthof a sed, gravity emerged. After another ludicrously brief interval it was joined byeleagism and the strong and weak nuclear forces—the stuff of physics. These werejoined an instant later by swarms of elementary particles—the stuff of stuff. From nothing atall, suddenly there were swarms of photons, protorons, rons, and much else—between 1079and 1089of each, acc to the standard Big Bang theory.
Such quantities are of course ungraspable. It is enough to know that in a single craginstant we were endowed with a universe that was vast—at least a hundred billion light-yearsacross, acc to the theory, but possibly any size up to infinite—and perfectly arrayed forthe creation of stars, galaxies, and other plex systems.
What is extraordinary from our point of view is how well it turned out for us. If theuniverse had formed just a tiny bit differently—if gravity were fraally stronger orweaker, if the expansion had proceeded just a little more slowly or swiftly—then there mightnever have been stable elements to make you and me and the grouand on. Had gravitybeen a trifle strohe universe itself might have collapsed like a badly erected tent,without precisely the right values to give it the right dimensions ay and poparts. Had it been weaker, however, nothing would have coalesced. The universe would haveremained forever a dull, scattered void.
This is one reason that some experts believe there may have been many bangs,perhaps trillions and trillions of them, spread through the mighty span of eternity, and that thereason we exist in this particular one is that this is one we could exist in. As Ed. Tryonof bia Uy o it: “In ao the question of why it happened, I offer themodest proposal that our Universe is simply one of those things which happen from time tobillion cubic kilometers, and no less a wohat they would choose the former over the in a book designed for the generalreader, where the example was found). On the assumption that many general readers are as unmathematical as I am, I will usethem sparingly, though they are occasionally unavoidable, not least in a chapter dealing with things on a ic scale.
time.” To which adds Guth: “Although the creation of a universe might be very uryon emphasized that no one had ted the failed attempts.”
Martin Rees, Britain’s astronomer royal, believes that there are many universes, possibly aninfinite number, each with different attributes, in different binations, and that we simplylive ihat bihings in the way that allows us to exist. He makes an analogy witha very large clothing store: “If there is a large stock of clothing, you’re not surprised to find asuit that fits. If there are many universes, each governed by a differi of numbers, therewill be one where there is a particular set of numbers suitable to life. We are in that one.”
Rees maintains that six numbers in particular govern our universe, and that if any of thesevalues were ged even very slightly things could not be as they are. For example, for theuniverse to exist as it does requires that hydrogen be verted to helium in a precise butparatively stately manner—specifically, in a way that verts sevehousandths ofits mass to energy. Lower that value very slightly—from 0.007 pert to 0.006 pert,say—and no transformation could take place: the universe would sist of hydrogen andnothing else. Raise the value very slightly—to 0.008 pert—and bonding would be sowildly prolific that the hydrogen would long since have been exhausted. Iher case, withthe slightest tweaking of the he universe as we know and would not be here.
I should say that everything is just right so far. In the long term, gravity may turn out to be alittle to, and one day it may halt the expansion of the universe and bring it collapsingin upon itself, till it crushes itself down into another singularity, possibly to start the wholeprocess ain. Oher hand it may be too weak and the universe will keep ragaway forever until everything is so far apart that there is no aterial iions, sothat the universe bees a place that is i and dead, but very roomy. The third option isthat gravity is just right—“critical density” is the ologists’ term for it—and that it willhold the universe together at just the right dimensions藏书网 to allow things to go on indefinitely.
ologists in their lighter moments sometimes call this the Goldilocks effect—thateverything is just right. (For the record, these three possible universes are known respectivelyas closed, open, and flat.)Now the question that has occurred to all of us at some point is: what would happen if youtraveled out to the edge of the universe and, as it were, put your head through the curtains?
Where would your head be if it were no longer in the universe? What would you find beyond?
The answer, disappointingly, is that you ever get to the edge of the universe. That’s notbecause it would take too long to get there—though of course it would—but because even ifyou traveled outward and outward in a straight line, indefinitely and pugnaciously, you wouldnever arrive at an outer boundary. Instead, you would e back to where you began (atwhich point, presumably, you would rather lose heart in the exercise and give up). The reasonfor this is that the universe bends, in a way we ’t adequately imagine, in ahEinstein’s theory of relativity (which we will get to in due course). For the moment it isenough to know that we are not adrift in some large, ever-expanding bubble. Rather, spacecurves, in a way that allows it to be boundless but finite. Space ot even properly be saidto be expanding because, as the physicist and Nobel laureate Steven Weinberg notes, “solarsystems and galaxies are not expanding, and space itself is not expanding.” Rather, thegalaxies are rushing apart. It is all something of a challeo intuition. Or as the biologist J.
B. S. Haldane once famously observed: “The universe is not only queerer than we suppose; itis queerer than we suppose.”
The analogy that is usually given for explaining the curvature of space is to try to imaginesomeone from a universe of flat surfaces, who had never seen a sphere, being brought toEarth. No matter how far he roamed across the pla’s surface, he would never find an edge.
He might eventually return to the spot where he had started, and would of course be utterlyfouo explain how that had happened. Well, we are in the same position in space asour puzzled flatlander, only we are flummoxed by a higher dimension.
Just as there is no place where you find the edge of the universe, so there is no placewhere you stand at the ter and say: “This is where it all began. This is the termostpoint of it all.” We are all at the ter of it all. Actually, we don’t know that for sure; we’t prove it mathematically. Stists just assume that we ’t really be the ter of theuniverse—think what that would imply—but that the phenomenon must be the same for allobservers in all places. Still, we don’t actually know.
For us, the universe goes only as far as light has traveled in the billions of years siheuniverse was formed. This visible universe—the universe we know and talk about—is amillion million million million (that’s 1,000,000,000,000,000,000,000,000) miles across. Butacc to most theories the universe at large—the meta-universe, as it is sometimescalled—is vastly roomier still. Acc to Rees, the number of light-years to the edge ofthis larger, unseen universe would be written not “with ten zeroes, not even with a hundred,but with millions.” In short, there’s more space than you imagine already without going tothe trouble to envision some additional beyond.
For a long time the Big Bang theory had one gaping hole that troubled a lot of people—hat it couldn’t begin to explain how we got here. Although 98 pert of all thematter that exists was created with the Big Bang, that matter sisted exclusively of lightgases: the helium, hydrogen, and lithium that we mentioned earlier. Not one particle of theheavy stuff so vital to our own being—carbon, nitrogen, oxygen, and all the rest—emergedfrom the gaseous brew of creation. But—and here’s the troubling point—te these heavyelements, you he kind of heat and energy of a Big Bang. Yet there has been only oneBig Bang and it didn’t produce them. So where did they e from?
Iingly, the man who found the ao that question was a ologist whoheartily despised the Big Bang as a theory and ed the term “Big Bang” sarcastically, as away of mog it. We’ll get to him shortly, but before we turn to the question of how we gothere, it might be worth taking a few mio sider just where exactly “here” is.
2 WELCOME TO THE SOLAR SYSTEMAS
TROHESE DAYS do the most amazing things. If someoruck a mat the Moon, they could spot the flare. From the tihrobs and wobbles of distant starsthey ihe size and character and even potential habitability of plas muote to be seen—plas so distant that it would take us half a million years in a spaceshipto get there. With their radio telescopes they capture wisps of radiation so preposterouslyfaint that the total amount of energy collected from outside the solar system by all of themtogether since colleg began (in 1951) is “less than the energy of a single snowflakestriking the ground,” in the words of Carl Sagan.
In short, there isn’t a great deal that goes on in the universe that astronomers ’t fihey have a mind to. Which is why it is all the more remarkable to reflect that until 1978no one had ever noticed that Pluto has a moon. In the summer of that year, a youngastronomer named James Christy at the U.S. Naval Observatory in Flagstaff, Arizona, wasmaking a routine examination of photographic images of Pluto when he saw that there wassomething there—something blurry and uain but definitely other than Pluto. sulting acolleague named Robert Harrington, he cluded that what he was looking at was a moon.
And it wasn’t just any mooive to the pla, it was the biggest moon in the solarsystem.
This was actually something of a blow to Pluto’s status as a pla, which had never beenterribly robust anyway. Since previously the space occupied by the moon and the spaceoccupied by Pluto were thought to be one and the same, it meant that Pluto was much smallerthan anyone had supposed—smaller even than Mercury. Indeed, seven moons in the solarsystem, including our own, are larger.
Now a natural question is why it took so long for ao find a moon in our own solarsystem. The answer is that it is partly a matter of where astronomers point their instrumentsand partly a matter of what their instruments are desigo detect, and partly it’s just Pluto.
Mostly it’s where they point their instruments. In the words of the astronomer ClarkChapman: “Most people think that astronet out at night in observatories and s theskies. That’s not true. Almost all the telescopes we have in the world are desigo peer atvery tiny little pieces of the sky way off in the distao see a quasar or hunt for black holesor look at a distant galaxy. The only real work of telescopes that ss the skies has beendesigned and built by the military.”
We have been spoiled by artists’ renderings into imagining a clarity of resolution thatdoes in actual astronomy. Pluto in Christy’s photograph is faint and fuzzy—a piece ofit—and its moon is not the romantically backlit, crisply delied panion orbyou would get in a National Geographic painting, but rather just a tiny aremelyindistinct hint of additional fuzziness. Such was the fuzziness, in fact, that it took seven yearsfor ao spot the moon again and thus indepely firm its existence.
One ouch about Christy’s discovery was that it happened in Flagstaff, for it was therein 1930 that Pluto had been found in the first place. That semi in astronomy waslargely to the credit of the astronomer Percival Lowell. Lowell, who came from one of theoldest ahiest Boston families (the one in the famous ditty about Boston being thehome of the bean and the cod, where Lowells spoke only to Cabots, while Cabots spoke onlyto God), ehe famous observatory that bears his name, but is most indeliblyremembered for his belief that Mars was covered with als built by industrious Martians forpurposes of veying water from pions to the dry but productive lands heequator.
Lowell’s other abiding vi was that there existed, somewhere out beyoune,an undiscovered ninth pla, dubbed Pla X. Lowell based this belief ularities hedetected in the orbits of Uranus aune, aed the last years of his life t tofind the gassy giant he was certain was out there. Unfortunately, he died suddenly in 1916, atleast partly exhausted by his quest, and the search fell into abeyance while Lowell’s heirssquabbled over his estate. However, in 1929, partly as a way of defleg attention awayfrom the Mars al saga (which by now had bee a serious embarrassment), the LowellObservatory directors decided to resume the seard to that end hired a young man fromKansas named Clyde Tombaugh.
Tombaugh had no formal training as an astronomer, but he was diligent and he was astute,and after a year’s patient searg he somehow spotted Pluto, a faint point of light in aglittery firmament. It was a miraculous find, and what made it all the more striking was thatthe observations on which Lowell had predicted the existence of a pla beyouneproved to be prehensively erroneous. Tombaugh could see at ohat the new plawas nothing like the massive gasball Lowell had postulated, but any reservations he or anyoneelse had about the character of the new pla were soo aside in the delirium thatattended almost any big news story in that easily excited age. This was the first Ameri-discovered pla, and no one was going to be distracted by the thought that it was really justa distant icy dot. It was named Pluto at least partly because the first two letters made amonogram from Lowell’s initials. Lowell osthumously hailed everywhere as a genius ofthe first order, and Tombaugh was largely fotten, except among plaary astronomers,who tend to revere him.
A few astronomers tio think there may be a Pla X out there—a real whopper,perhaps as much as ten times the size of Jupiter, but so far out as to be invisible to us. (Itwould receive so little sunlight that it would have almost o reflect.) The idea is that itwouldn’t be a ventional pla like Jupiter or Saturn—it’s much too far away for that;we’re talking perhaps 4.5 trillion miles—but more like a sun that never quite made it. Moststar systems in the os are binary (double-starred), which makes our solitary sun a slightoddity.
As for Pluto itself, nobody is quite sure how big it is, or what it is made of, what kind ofatmosphere it has, or even what it really is. A lot of astronomers believe it isn’t a pla all,but merely the largest object so far found in a zone of galactic debris known as the Kuiperbelt. The Kuiper belt was actually theorized by an astronomer named F. C. Leonard in 1930,but the name herard Kuiper, a Dutative w in America, who expaheidea. The Kuiper belt is the source of what are known as short-period ets—those thate past pretty regularly—of which the most famous is Halley’s et. The more reclusivelong-period ets (among them the ret visitors Hale-Bopp and Hyakutake) e fromthe much more distant Oort cloud, about which more presently.
It is certainly true that Pluto doesn’t act much like the other plas. Not only is it runty andobscure, but it is so variable in its motions that no one tell you exactly where Pluto will bea tury hence. Whereas the other plas orbit on more or less the same plane, Pluto’sorbital path is tipped (as it were) out of alig at an angle of seventeen degrees, like thebrim of a hat tilted rakishly on someone’s head. Its orbit is sular that for substantialperiods on each of its lonely circuits around the Sun it is closer to us thaune is. Formost of the 1980s and 1990s, une was in fact the solar system’s most far-flung pla.
Only on February 11, 1999, did Pluto return to the outside lahere to remain for the 228 years.
So if Pluto really is a pla, it is certainly an odd o is very tiny: just one-quarter of 1pert as massive as Earth. If you set it down on top of the Uates, it would cover notquite half the lower forty-eight states. This alone makes it extremely anomalous; it means thatour plaary system sists of four rocky inner plas, fassy iants, and a tiny,solitary iceball. Moreover, there is every reason to suppose that we may soon begin to findother even larger icy spheres in the same portion of space. Then we will have problems. AfterChristy spotted Pluto’s moon, astronomers began tard that se of the oreattentively and as of early December 2002 had found over six hundred additional Traunian Objects, or Plutinos as they are alternatively called. One, dubbed Varuna, is nearlyas big as Pluto’s moon. Astronomers now think there may be billions of these objects. Thedifficulty is that many of them are awfully dark. Typically they have an albedo, orreflectiveness, of just 4 pert, about the same as a lump of charcoal—and of course theselumps of charcoal are about four billion miles away.
And how far is that exactly? It’s almost beyond imagining. Space, you see, is justenormous—just enormous. Let’s imagine, for purposes of edification aertai, thatwe are about to go on a journey by rocketship. We won’t go terribly far—just to the edge ofour own solar system—but we o get a fix on how big a place space is and what a smallpart of it we occupy.
Now the bad news, I’m afraid, is that we won’t be home for supper. Even at the speed oflight, it would take seven hours to get to Pluto. But of course we ’t travel at anything likethat speed. We’ll have to go at the speed of a spaceship, and these are rather more lumbering.
The best speeds yet achieved by any human object are those of the Voyager 1 and2 spacecraft,which are now flying away from us at about thirty-five thousand miles an hour.
The reason the Voyager craft were launched when they were (in August aember1977) was that Jupiter, Saturn, Uranus, aune were aligned in a way that happens onlyonce every 175 years. This ehe two Voyagers to use a “gravity assist” teique inwhich the craft were successively flung from one gassy giant to the in a kind of icversion of “crack the whip.” Even so, it took them nine years to reach Uranus and a dozen tocross the orbit of Pluto. The good news is that if we wait until January 2006 (which is whenNASA’s New Horizons spacecraft is tentatively scheduled to depart for Pluto) we takeadvantage of favorable Jovian positioning, plus some advances in teology, ahere inonly a decade or so—though getting home again will take rather longer, I’m afraid. At allevents, it’s going to be a long trip.
Now the first thing you are likely to realize is that space is extremely well named and ratherdismayingly uful. Our solar system may be the liveliest thing for trillions of miles, butall the visible stuff in it—the Sun, the plas and their moons, the billion or so tumblingrocks of the asteroid belt, ets, and other miscellaneous driftius—fills less than atrillionth of the available space. You also quickly realize that none of the maps you have everseen of the solar system were remotely drawn to scale. Most schoolroom charts show theplas ing oer the other at neighborly intervals—the iants actually castshadows over each other in many illustrations—but this is a necessary deceit to get them allon the same piece of paper. une iy isn’t just a little bit beyond Jupiter, it’s waybeyond Jupiter—five times farther from Jupiter than Jupiter is from us, so far out that itreceives only 3 pert as much sunlight as Jupiter.
Such are the distances, in fact, that it isn’t possible, in any practical terms, to draw the solarsystem to scale. Even if you added lots of fold-out pages to your textbooks or used a reallylong sheet of poster paper, you wouldn’t e close. On a diagram of the solar system toscale, with Earth reduced to about the diameter of a pea, Jupiter would be over a thousaaluto would be a mile and a half distant (and about the size of a bacterium, so youwouldn’t be able to see it anyway). On the same scale, Proxima tauri, our star,would be almost ten thousand miles away. Even if you shrank dowhing so that Jupiterwas as small as the period at the end of this sentence, and Pluto was no bigger than amolecule, Pluto would still be over thirty-five feet away.
So the solar system is really quite enormous. By the time we reach Pluto, we have e sofar that the Sun—our dear, warm, skin-tanning, life-giving Sun—has shrunk to the size of apinhead. It is little more than a bright star. In such a lonely void you begin to uandhow even the most signifit objects—Pluto’s moon, for example—have escaped attention.
In this respect, Pluto has hardly been alone. Until the Voyager expeditions, une wasthought to have two moons; Voyager found six more. When I was a boy, the solar system wasthought to tain thirty moons. The total now is “at least y,” about a third of which havebeen found in just the last ten years.
The point to remember, of course, is that when sidering the universe at large we don’tactually know what is in our own solar system.
Now the other thing you will notice as we speed past Pluto is that we are speeding pastPluto. If you check your itinerary, you will see that this is a trip to the edge of our solarsystem, and I’m afraid we’re not there yet. Pluto may be the last object marked onschoolroom charts, but the system doeshere. In fact, it isn’t even close to endingthere. We won’t get to the solar system’s edge until assed through the Oort cloud, avast celestial realm of drifting ets, and we won’t reach the Oort cloud for another—I’m sosorry about this—ten thousand years. Far from marking the e of the solar system, asthose schoolroom maps so cavalierly imply, Pluto is barely one-fifty-thousandth of the way.
Of course we have no prospect of such a journey. A trip of 240,000 miles to the Moon stillrepresents a very big uaking for us. A manned mission to Mars, called for by the firstPresident Bush in a moment of passing giddiness, was quietly dropped when someone workedout that it would cost $450 billion and probably result in the deaths of.. all the crew (their DNAtorn to tatters by high-energy solar particles from which they could not be shielded).
Based on what we know now and reasonably imagihere is absolutely no prospectthat any human being will ever visit the edge of our own solar system—ever. It is just too far.
As it is, even with the Hubble telescope, we ’t see even into the Oort cloud, so we don’tactually know that it is there. Its existence is probable but entirely hypothetical.
*About all that be said with fidence about the Oort cloud is that it starts somewherebeyond Pluto and stretches some two light-years out into the os. The basiit ofmeasure in the solar system is the Astronomical Unit, or AU, representing the distance from*Properly called the Opik-Oort cloud, it is named for the Estonian astronomer Ernst Opik, who hypothesized itsexisten 1932, and for the Dutch astronomer Jan Oort, who refihe calculatioeen years later.
the Sun to the Earth. Pluto is about forty AUs from us, the heart of the Oort cloud about fiftythousand. In a word, it is remote.
But let’s pretend again that we have made it to the Oort cloud. The first thing you mightnotice is how very peaceful it is out here. We’re a long way from anywhere now—so far fromour own Sun that it’s not even the brightest star in the sky. It is a remarkable thought that thatdistant tiny twinkle has enough gravity to hold all these ets in orbit. It’s not a very strongbond, so the ets drift in a stately manner, moving at only about 220 miles an hour. Fromtime to time some of these lonely ets are nudged out of their normal orbit by some slightgravitational perturbation—a passing star perhaps. Sometimes they are ejected into theemptiness of spaever to be seen again, but sometimes they fall into a long orbit aroundthe Sun. About three or four of these a year, known as long-period ets, pass through theinner solar system. Just occasionally these stray visitors smato something solid, likeEarth. That’s why we’ve e out here now—because the et we have e to see hasjust begun a long fall toward the ter of the solar system. It is headed for, of all places,Manson, Iowa. It is going to take a long time to get there—three or four million years atleast—so we’ll leave it for now, aurn to it much later iory.
So that’s your solar system. And what else is out there, beyond the solar system? Well,nothing and a great deal, depending on how you look at it.
In the short term, it’s nothing. The most perfect vacuum ever created by humans is not asempty as the emptiness of iellar space. And there is a great deal of this nothingness untilyou get to the bit of something. Our neighbor in the os, Proxima tauri,which is part of the three-star cluster known as Alpha tauri, is 4.3 light-years away, a sissyskip in galactic terms, but that is still a hundred million times farther than a trip to the Moon.
To reach it by spaceship would take at least twenty-five thousand years, and even if you madethe trip you still wouldn’t be anywhere except at a lonely clutch of stars in the middle of avast nowhere. To reach the landmark of sequence, Sirius, would involve another 4.6light-years of travel. And so it would go if you tried to star-hop your way across the os.
Just reag the ter of our own galaxy would take far lohan we have existed asbeings.
Space, let me repeat, is enormous. The average distaween stars out there is 20million million miles. Even at speeds approag those of light, these are fantasticallychallenging distances for any traveling individual. Of course, it is possible that alien beingstravel billions of miles to amuse themselves by planting crop circles in Wiltshire htening the daylights out of some puy in a pickup tru a lonely road in Arizona(they must have teenagers, after all), but it does seem unlikely.
Still, statistically the probability that there are other thinking beings out there is good.
Nobody knows how many stars there are in the Milky Way—estimates range from 100 billionor so to perhaps 400 billion—and the Milky Way is just one of 140 billion or so alaxies, many of them even larger than ours. In the 1960s, a professor at ell namedFrank Drake, excited by such whopping numbers, worked out a famous equation desigocalculate the ces of advanced life in the os based on a series of diminishingprobabilities.
Under Drake’s equation you divide the number of stars in a selected portion of the universeby the number of stars that are likely to have plaary systems; divide that by the number ofplaary systems that could theoretically support life; divide that by the number on whichlife, having arisen, advao a state of intelligence; and so on. At each such division, thenumber shrinks colossally—yet even with the most servative inputs the number ofadvanced civilizations just in the Milky Way always works out to be somewhere in themillions.
What an iing aing thought. We may be only one of millions of advancedcivilizations. Unfortunately, space being spacious, the average distaween any two ofthese civilizations is reed to be at least two hundred light-years, which is a great dealmore than merely saying it makes it sound. It means for a start that even if these beings knowwe are here and are somehow able to see us ielescopes, they’re watg light that leftEarth two hundred years ago. So they’re not seeing you ahey’re watg the FrenchRevolution and Thomas Jefferson and people in silk stogs and powdered wigs—peoplewho don’t know what an atom is, ene, and who make their electricity by rubbing a rodof amber with a piece of fur and think that’s quite a trick. Any message we receive from themis likely to begin “Dear Sire,” and gratulate us on the handsomeness of our horses and ourmastery of whale oil. Two hundred light-years is a distance so far beyond us as to be, well,just beyond us.
So even if we are not really alone, in all practical terms we are. Carl Sagan calculated thenumber of probable plas in the universe at large at 10 billion trillion—a number vastlybeyond imagining. But what is equally beyond imagining is the amount of space throughwhich they are lightly scattered. “If we were randomly ied into the universe,” Saganwrote, “the ces that you would be on or near a pla would be less than one in a billiontrillion trillion.” (That’s 1033, or a one followed by thirty-three zeroes.) “Worlds are precious.”
Which is why perhaps it is good hat in February 1999 the Iional Astronomiion ruled officially that Pluto is a plahe universe is a big and lonely place. We dowith all the neighbors we get.
3 THE REVEREND EVANS’S UNIVERSE
WHEN THE SKIES are clear and the Moon is not tht, the Reverend Robert Evans, aquiet and cheerful man, lugs a bulky telescope onto the back deck of his home in the BlueMountains of Australia, about fifty miles west of Sydney, and does araordinary thing. Helooks deep into the past and finds dying stars.
Looking into the past is of course the easy part. Gla the night sky and what you see ishistory and lots of it—the stars not as they are now but as they were when their light leftthem. For all we know, the North Star, our faithful panion, might actually have bur last January or in 1854 or at any time sihe early fourteenth tury and news of it justhasn’t reached us yet. The best we say— ever say—is that it was still burning on thisdate 680 years ago. Stars die all the time. What Bob Evans does better than anyone else whohas ever tried is spot these moments of celestial farewell.
By day, Evans is a kindly and now semiretired minister in the Uniting Chur Australia,who does a bit of freelance work and researches the history of eenth-tury religiousmovements. But by night he is, in his unassuming way, a titan of the skies. He huntssupernovae.
Supernovae occur when a giant star, one much bigger than our own Sun, collapses and theacularly explodes, releasing in an instant the energy of a hundred billion suns, burningfor a time brighter than all the stars in its galaxy. “It’s like a trillion hydrogen bombs going offat once,” says Evans. If a supernova explosion happened within five hundred light-years of us,we would be goners, acc to Evans—“it would wreck the show,” as he cheerfully puts it.
But the universe is vast, and supernovae are normally much too far away to harm us. In fact,most are so unimaginably distant that their light reaches us as no more than the faiwinkle. For the month or so that they are visible, all that distinguishes them from the otherstars in the sky is that they occupy a point of space that wasn’t filled before. It is theseanomalous, very occasional pricks in the crowded dome of the night sky that the ReverendEvans finds.
To uand what a feat this is, imagine a standard dining room table covered in a blacktablecloth and someohrowing a handful of salt across it. The scattered grains bethought of as a galaxy. Now imagine fifteen hundred more tables like the first one—enough tofill a Wal-Mart parking lot, say, or to make a single liwo miles long—each with a randomarray of salt across it. Now add one grain of salt to any table a Bob Evans walk amongthem. At a glance he will spot it. That grain of salt is the supernova.
Evans’s is a talent so exceptional that Oliver Sacks, in An Anthropologist on Mars, devotesa passage to him in a chapter on autistic savants—quickly adding that “there is no suggestionthat he is autistic.” Evans, who has not met Sacks, laughs at the suggestion that he might beeither autistic or a savant, but he is powerless to explain quite where his talent es from.
“I just seem to have a knaemorizing star fields,” he told me, with a franklyapologetic look, when I visited him and his wife, Elaine, in their picture-book bungalow on atranquil edge of the village of Hazelbrook, out where Sydney finally ends and the boundlessAustralian bush begins. “I’m not particularly good at other things,” he added. “I don’tremember names well.”
“Or where he’s put things,” called Elaine from the kit.
He nodded frankly again and grihen asked me if I’d like to see his telescope. I hadimagihat Evans would have a proper observatory in his backyard—a scaled-downversion of a Mount Wilson or Palomar, with a sliding domed roof and a meized chair thatwould be a pleasure to maneuver. In fact, he led me not outside but to a crowded storeroomoff the kit where he keeps his books and papers and where his telescope—a whiteder that is about the size and shape of a household hot-water tas in a homemade,swiveling plywood mount. When he wishes to observe, he carries them in two trips to a smalldeck off the kit. Between the of the roof and the feathery tops of eucalyptustrees growing up from the slope below, he has only a letter-box view of the sky, but he says itis more than good enough for his purposes. And there, when the skies are clear and the Moonnot tht, he finds his supernovae.
The term supernova was ed in the 1930s by a memorably odd astrophysicist namedFritz Zwicky. Born in Bulgaria and raised in Switzerland, Zwicky came to the CaliforniaInstitute of Te藏书网ology in the 1920s and there at once distinguished himself by his abrasivepersonality aic talents. He didn’t seem to be outstandingly bright, and many of hiscolleagues sidered him little more than “an irritating buffoon.” A fitness buff, he wouldoften drop to the floor of the Caltech dining hall or other public areas and do one-armedpushups to demonstrate his virility to anyone who seemed ined to doubt it. He wasnotoriously aggressive, his manually being so intimidating that his closestcollaborator, a gentle man named Walter Baade, refused to be left aloh him. Amongother things, Zwicky accused Baade, who was German, of being a Nazi, which he was not. Onat least one occasion Zwicky threateo kill Baade, who worked up the hill at the MountWilson Observatory, if he saw him on the Caltech campus.
But Zwicky was also capable of insights of the most startling brilliance. In the early 1930s,he turned his attention to a question that had long troubled astronomers: the appearan thesky of occasional unexplained points of light, ars. Improbably he wondered if theron—the subatomic particle that had just been discovered in England by JamesChadwick, and was thus both novel and rather fashionable—might be at the heart of things. Itoccurred to him that if a star collapsed to the sort of densities found in the core of atoms, theresult would be an unimaginably pacted core. Atoms would literally be crushed together,their eles forced into the nucleus, f rons. You would have a ron star.
Imagine a million really weighty onballs squeezed down to the size of a marble and—well, you’re still not even close. The core of a ron star is so dehat a single spoonfulof matter from it would weigh 200 billion pounds. A spoonful! But there was more. Zwickyrealized that after the collapse of such a star there would be a huge amount of energy leftover—enough to make the biggest bang in the universe. He called these resultant explosionssuperhey would be—they are—the biggest events iion.
On January 15, 1934, the journal Physical Review published a very cise abstract of apresentation that had been ducted by Zwicky and Baade the previous month at StanfordUy. Despite its extreme brevity—one paragraph of twenty-four lihe abstratained an enormous amount of new sce: it provided the first refereo supernovaeand to ron stars; vingly explaiheir method of formation; correctly calculatedthe scale of their explosiveness; and, as a kind of cluding bonus, ected supernovaexplosions to the produ of a mysterious new phenomenon called ic rays, which hadretly been found swarming through the universe. These ideas were revolutionary to say theleast. ron stars wouldn’t be firmed for thirty-four years. The ic rays notion,though sidered plausible, hasn’t been verified yet. Altogether, the abstract was, in thewords of Caltech astrophysicist Kip S. Thorne, “one of the most prest dots iory of physid astronomy.”
Iingly, Zwicky had almost no uanding of why any of this would happen.
Acc to Thorne, “he did not uand the laws of physics well enough to be able tosubstantiate his ideas.” Zwicky’s talent was f ideas. Others—Baade mostly—were leftto do the mathematical sweeping up.
Zwicky also was the first that there wasn’t nearly enough visible mass in theuniverse to hold galaxies together and that there must be some ravitational influence—what we now call dark matter. Ohing he failed to see was that if a ron star shrankenough it would bee so dehat even light couldn’t escape its immense gravitationalpull. You would have a black hole. Unfortunately, Zwicky was held in such disdain by mostof his colleagues that his ideas attracted almost no notice. When, five years later, the greatRobert Oppenheimer turned his attention to ron stars in a landmark paper, he made not asingle refereo any of Zwicky’s work even though Zwicky had been w for years onthe same problem in an office just down the hall. Zwicky’s dedus ing dark matterwouldn’t attract serious attention for nearly four decades. We only assume that he did alot of pushups in this period.
Surprisingly little of the universe is visible to us when we ine our heads to the sky. Onlyabout 6,000 stars are visible to the naked eye from Earth, and only about 2,000 be seenfrom any one spot. With binoculars the number of stars you see from a single locatioo about 50,000, and with a small two-inch telescope it leaps to 300,000. With a sixteen-inch telescope, such as Evans uses, you begin to t not in stars but in galaxies. From hisdeck, Evans supposes he see between 50,000 and 100,000 galaxies, each taining tensof billions of stars. These are of course respectable numbers, but even with so much to take in,supernovae are extremely rare. A star burn for billions of years, but it dies just ondquickly, and only a few dying stars explode. Most expire quietly, like a campfire at dawn. In atypical galaxy, sisting of a hundred billion stars, a supernova will occur on average onceevery two or three hundred years. Finding a supernova therefore was a little bit like standingon the observation platform of the Empire State Building with a telescope and seargwindows around Manhattan in the hope of finding, let us say, someone lighting a twenty-first-birthday cake.
So when a hopeful and softspoken minister got in touch to ask if they had any usable fieldcharts for hunting superhe astronomical unity thought he was out of his mind.
At the time Evans had a ten-inch telescope—a very respectable size for amateur stargazingbut hardly the sort of thing with which to do serious ology—and he roposing tofind one of the universe’s rarer phenomena. In the whole of astronomical history before Evansstarted looking in 1980, fewer than sixty supernovae had been found. (At the time I visitedhim, in August of 2001, he had just recorded his thirty-fourth visual discovery; a thirty-fifthfollowed three months later and a thirty-sixth in early 2003.)Evans, however, had certain advantages. Most observers, like most people generally, are inthe northern hemisphere, so he had a lot of sky largely to himself, especially at first. He alsohad speed and his uny memory. Large telescopes are cumbersome things, and much oftheir operational time is ed with being maneuvered into position. Evans could swinghis little sixteen-inch telescope around like a tail gunner in a dogfight, spending no more thana couple of seds on any particular point in the sky. In sequence, he could observeperhaps four hundred galaxies in an evening while a large professional telescope would belucky to do fifty or sixty.
Looking for supernovae is mostly a matter of not finding them. From 1980 to 1996 heaveraged two discoveries a year—not a huge payoff for hundreds of nights of peering andpeering. Once he found three in fifteen days, but aime he went three years withoutfinding any at all.
“There is actually a certain value in not finding anything,” he said. “It helps ologists towork out the rate at which galaxies are evolving. It’s one of those rare areas where theabsence of evidenceis evidence.”
On a table beside the telescope were stacks of photos and papers relevant to his pursuits,and he showed me some of them now. If you have ever looked through popular astronomicalpublications, and at some time you must have, you will know that they are generally full ofric..hly luminous color photos of distant nebulae and the like—fairy-lit clouds of celestial lightof the most delicate and moving splendor. Evans’s w images are nothing like that. Theyare just blurry blad-white photos with little points of haloed brightness. One he showedme depicted a swarm of stars with a trifling flare that I had to put close to my face to see.
This, Evans told me, was a star in a stellation called Fornax from a galaxy known toastronomy as NGC1365. (NGC stands for New General Catalogue, where these things arerecorded. O was a heavy book on someone’s desk in Dublin; today, needless to say, it’sa database.) For sixty million silent years, the light from the star’s spectacular demise traveledunceasingly through spatil one night in August of 2001 it arrived at Earth in the form ofa puff of radiahe ti brightening, in the night sky. It was of course Robert Evans onhis eucalypt-sted hillside who spotted it.
“There’s something satisfying, I think,” Evans said, “about the idea of light traveling formillions of years through spad just at the right moment as it reaches Earth someonelooks at the right bit of sky and sees it. It just seems right that a of that magnitudeshould be witnessed.”
Supernovae do much more than simply impart a sense of wohey e in severaltypes (one of them discovered by Evans) and of these one in particular, known as a Iasupernova, is important to astronomy because it always explodes in the same way, with thesame critical mass. For this reason it be used as a standard dle to measure theexpansion rate of the universe.
In 1987 Saul Perlmutter at the Lawrence Berkeley lab in California, needing more Iasuperhan visual sightings were providing, set out to find a more systematic method ofsearg for them. Perlmutter devised a nifty system using sophisticated puters andcharge-coupled devices—in essence, really good digital cameras. It automated supernovahunting. Telescopes could now take thousands of pictures a a puter detect thetelltale bright spots that marked a supernova explosion. In five years, with the eique,Perlmutter and his colleagues at Berkeley found forty-two supernovae. Now even amateursare finding superh charge-coupled devices. “With CCDs you aim a telescope atthe sky and go watch television,” Evans said with a touch of dismay. “It took all the roma of it.”
I asked him if he was tempted to adopt the eology. “Oh, no,” he said, “I enjoy myway too much. Besides”—he gave a nod at the photo of his latest supernova and smiled—“I still beat them sometimes.”
The question that naturally occurs is “What would it be like if a star exploded nearby?” Our stellar neighbor, as we have seen, is Alpha tauri, 4.3 light-years away. I hadimagihat if there were an explosion there we would have 4.3 years to watch the light ofthis magnifit event spreading across the sky, as if tipped from a giant . What would itbe like if we had four years and four months to wat inescapable doom advang towardus, knowing that when it finally arrived it would blow the skin right off our bones? Wouldpeople still go to work? Would farmers plant crops? Would anyone deliver them to the stores?
Weeks later, ba the town in Neshire where I live, I put these questions to JohnThorstensen, an astro Dartmouth College. “Oh no,” he said, laughing. “The news ofsu event travels out at the speed of light, but so does the destructiveness, so you’d learnabout it and die from it in the same instant. But don’t worry because it’s not going to happen.”
For the blast of a supernova explosion to kill you, he explained, you would have to be“ridiculously close”—probably within ten light-years or so. “The danger would be varioustypes of radiation—ic rays and so on.” These would produce fabulous auroras,shimmering curtains of spooky light that would fill the whole sky. This would not be a goodthing. Anything potent enough to put on such a show could well blow away themagosphere, the magie high above the Earth that normally protects us fromultraviolet rays and other ic assaults. Without the magosphere anyone unfortunateenough to step into sunlight would pretty quickly take on the appearance of, let us say, anovercooked pizza.
The reason we be reasonably fident that su event won’t happen in our erof the galaxy, Thorstensen said, is that it takes a particular kind of star to make a supernova inthe first place. A didate star must be ten to twenty times as massive as our own Sun and“we don’t have anything of the requisite size that’s that close. The universe is a mercifully bigplace.” The likely didate he added, is Betelgeuse, whose various sputterings havefor years suggested that something iingly unstable is going on there. But Betelgeuse isfifty thousand light-years away.
Only half a dozen times in recorded history have supernovae been close enough to bevisible to the naked eye. One was a blast in 1054 that created the Crab Nebula. Another, in1604, made a star bright enough to be seen during the day for over three weeks. The mostret was in 1987, when a supernova flared in a zone of the os known as the LargeMagellanic Cloud, but that was only barely visible and only in the southern hemisphere—andit was a fortably safe 169,000 light-years away.
Supernovae are signifit to us iher decidedly tral way. Without them wewouldn’t be here. You will recall the ological drum with which we ehe firstchapter—that the Big Bang created lots of light gases but no heavy elements. Those camelater, but for a very long time nobody could figure out how they came later. The problem wasthat you needed something really hot—hotter even than the middle of the hottest stars—te carbon and iron and the other elements without which we would be distressinglyimmaterial. Supernovae provided the explanation, and it was an English ologist almostas singular in manner as Fritz Zwicky who figured it out.
He was a Yorkshireman named Fred Hoyle. Hoyle, who died in 2001, was described in anobituary in Nature as a “ologist and troversialist” and both of those he most certainlywas. He was, acc to Nature ’s obituary, “embroiled in troversy for most of his life”
and “put his o much rubbish.” He claimed, for instance, and without evidehat theNatural History Museum’s treasured fossil of an Archaeopteryx was a fery along the linesof the Piltdown hoax, causing much exasperation to the museum’s paleontologists, who had tospend days fielding phone calls from journalists from all over the world. He also believed thatEarth was not only seeded by life from space but also by many of its diseases, such asinfluenza and bubonic plague, and suggested at one point that humans evolved projegnoses with the nostrils underh as a way of keeping ic pathogens from falling intothem.
It was he who ed the term “Big Bang,” in a moment of facetiousness, for a radiobroadcast in 1952. He pointed out that nothing in our uanding of physics could atfor why everything, gathered to a point, would suddenly and dramatically begin to expand.
Hoyle favored a steady-state theory in which the universe was stantly expanding andtinually creating new matter as it went. Hoyle also realized that if stars imploded theywould liberate huge amounts of heat—100 million degrees or more, enough to begin togee the heavier elements in a process known as nucleosynthesis. In 1957, w withothers, Hoyle showed how the heavier elements were formed in supernova explosions. Forthis work, W. A. Fowler, one of his collaborators, received a Nobel Prize. Hoyle, shamefully,did not.
Acc to Hoyle’s theory, an exploding star would gee enough heat to create all thenew elements and spray them into the os where they would faseous clouds—theiellar medium as it is known—that could eventually coalesto new solar systems.
With the heories it became possible at last to struct plausible sarios for how wegot here. What we now think we know is this:
About 4.6 billion years ago, a great swirl of gas and dust some 15 billion miles acrossaccumulated in space where we are now and began to aggregate. Virtually all of it—99.9pert of the mass of the solar system—went to make the Sun. Out of the floating materialthat was left over, two microscopic grains floated close enough together to be joined byelectrostatic forces. This was the moment of ception for our pla. All over the inchoatesolar system, the same was happening. Colliding dust grains formed larger and larger clumps.
Eventually the clumps grew large enough to be called plaesimals. As these endlesslybumped and collided, they fractured or split or rebined in endless random permutations,but in every enter there was a winner, and some of the winners grew big enough todomihe orbit around which they traveled.
It all happened remarkably quickly. To grow from a tiny cluster of grains to a baby plasome hundreds of miles across is thought to have taken only a few tens of thousands of years.
In just 200 million years, possibly less, the Earth was essentially formed, though still moltenand subject to stant bombardment from all the debris that remained floating about.
At this point, about 4.5 billion years ago, an object the size of Mars crashed ih,blowing out enough material to form a panion sphere, the Moon. Within weeks, it isthought, the flung material had reassembled itself into a single clump, and within a year it hadformed into the spherical rock that panions us yet. Most of the lunar material, it isthought, came from the Earth’s crust, not its core, which is why the Moon has so little ironwhile we have a lot. The theory, ially, is almost alresented as a ret one, butin fact it was first proposed in the 1940s by Reginald Daly of Harvard. The only ret thingabout it is people paying any attention to it.
Wheh was only about a third of its eventual size, it robably already beginning toform an atmosphere, mostly of carbon dioxide, nitrogehane, and sulfur. Hardly the sortof stuff that we would associate with life, a from this noxious stew life formed. Carbondioxide is a powerful greenhouse gas. This was a good thing because the Sun wassignifitly dimmer back then. Had we not had the be of a greenhouse effect, the Earthmight well have frozen over permaly, and life might never have gotten a toehold. Butsomehow life did.
For the 500 million years the youh tio be pelted relentlessly byets, meteorites, and alactic debris, which brought water to fill the os and thepos necessary for the successful formation of life. It was a singularly hostileenviro a somehow life got going. Some tiny bag of chemicals twitched andbecame animate. We were on our way.
Four billion years later people began to wonder how it had all happened. And it is there thatour story akes us.
PART II THE SIZE OF THE EARTHNature and Nature’s laws lay hid innight;God said, Let on be! And allwas light.
-Alexander Pope
4 THE MEASURE OF THINGS
IF YOU HAD to select the least vivial stific field trip of all time, you could certainlydo worse than the French Royal Academy of Sces’ Peruvian expedition of 1735. Led by ahydrologist named Pierre Bouguer and a soldier-mathemati named Charles Marie de Lai arty of stists and adventurers who traveled to Peru with the purposeulating distahrough the Andes.
At the time people had lately bee ied with a powerful desire to uand theEarth—to determine how old it was, and how massive, where it hung in space, and how it hade to be. The French party’s goal was to help settle the question of the circumferehe pla by measuring the length of one degree of meridian (or 1/360 of the distance aroundthe pla) along a line reag from Yarouqui, near Quito, to just beyond what isnow Ecuador, a distance of about two hundred miles.
1Almost at ohings began to g, sometimes spectacularly so. In Quito, the visitorssomehow provoked the locals and were chased out of town by a mob armed with stones. Soohe expedition’s doctor was murdered in a misuanding over a woman. Thebotanist became deranged. Others died of fevers and falls. The third most senior member ofthe party, a man named Pierre Godin, ran off with a thirteen-year-old girl and could not beio return.
At one point the group had to suspend work fht months while La ine rode off toLima to sort out a problem with their permits. Eventually he and Bouguer stopped speakingand refused to work together. Everywhere the dwindling party went it was met with thedeepest suspis from officials who found it difficult to believe that a group of Frenchstists would travel halfway around the world to measure the world. That made no seall. Two and a half turies later it still seems a reasonable question. Why didn’t the Frenchmake their measurements in Frand save themselves all the bother and disfort of theirAndean adventure?
The answer lies partly with the fact that eighteenth-tury stists, the Fren particular,seldom did things simply if an absurdly demanding alternative was available, and partly ractical problem that had first arisen with the English astronomer Edmond Halley manyyears before—long before Bouguer and La ine dreamed of going to South America,much less had a reason for doing so.
* Triangulation, their chosehod, ular teique based on the geometric fact that if you know thelength of one side of a triangle and the angles of two ers, you work out all its other dimensions withoutleaving your chair. Suppose, by way of example, that you and I decided we wished to know how far it is to theMoon. Using triangulation, the first thing we must do is put some distaween us, so lets say fumentthat you stay in Paris and I go to Moscow ah look at the Moon at the same time. Now if you imagine aline eg the three principals of this exercise-that is, you and I and the Moon-it forms a triangle. Measurethe length of the baseliween you and me and the angles of our two ers and the rest be simplycalculated. (Because the interiles of a triangle always add up to 180 degrees, if you know the sum of twoof the angles you instantly calculate the third; and knowing the precise shape of a triangle and the length ofone side tells you the lengths of the other sides.) This was in fact the method use by a Greek astronomer,Hipparchus of Nicaea, in 150 B.C. to work out the Moons distance from Earth. At ground level, the principles ulatiohe same, except that the triangles dont reato space but rather are laid side to side on amap. In measuring a degree of meridian, the surveyors would create a sort of les marg acrossthe landscape.
Halley was an exceptional figure. In the course of a long and productive career, he was asea captain, a cartographer, a professor of geometry at the Uy of Oxford, deputytroller of the Royal Mint, astronomer royal, and ior of the deep-sea diving bell. Hewrote authoritatively on magism, tides, and the motions of the plas, and fondly on theeffects of opium. He ied the weather map and actuarial table, proposed methods f out the age of the Earth and its distance from the Sun, even devised a practicalmethod for keeping fish fresh out of season. The ohing he didn’t do, iingly enough,was discover the et that bears his name. He merely reized that the et he saw in1682 was the same ohat had been seen by others in 1456, 1531, and 1607. It didn’tbee Halley’s et until 1758, some sixteen years after his death.
For all his achievements, however, Halley’s greatest tribution to human knowledge maysimply have been to take part in a modest stific wager with two other worthies of his day:
Robert Hooke, who is perhaps best remembered now as the first person to describe a cell, andthe great and stately Sir Christopher Wren, who was actually an astronomer first and architectsed, though that is not often generally remembered now. In 1683, Halley, Hooke, andWren were dining in Londohe versation turo the motions of celestial objects.
It was known that plas were ined to orbit in a particular kind of oval known as anellipse—“a very specifid precise curve,” to quote Richard Feynman—but it wasn’tuood why. Wren generously offered a prize worth forty shillings (equivalent to a coupleof weeks’ pay) to whichever of the men could provide a solution.
Hooke, ell known for taking credit for ideas that weren’t necessarily his own,claimed that he had solved the problem already but deed now to share it oerestingand iive grounds that it would rob others of the satisfa of disc the answer forthemselves. He would instead “ceal it for some time, that others might know how to valueit.” If he thought any more oter, he left no evidence of it. Halley, however, becameed with finding the ao the point that the following year he traveled toCambridge and boldly called upon the uy’s Lucasian Professor of Mathematics, Isaaewton, in the hope that he could help.
on was a decidedly odd figure—brilliant beyond measure, but solitary, joyless, pricklyto the point of paranoia, famously distracted (upon swinging his feet out of bed in the mhe would reportedly sometimes sit for hours, immobilized by the sudden rush of thoughts tohis head), and capable of the most riveting strangeness. He built his own laboratory, the firstat Cambridge, but then engaged in the most bizarre experiments. Once he ied a bodkin—a long needle of the sort used for sewiher—into his eye socket and rubbed it arouwixt my eye and the bone as o [the] backside of my eye as I could” just to see whatwould happen. What happened, miraculously, was nothing—at least nothing lasting. Onanother occasioared at the Sun for as long as he could bear, to determine what effect itwould have upon his vision. Again he escaped lasting damage, though he had to spend somedays in a darkened room before his eyes fave him.
Set atop these odd beliefs and quirky traits, however, was the mind of a supreme genius—though even when w in ventional els he often showed a tendency topeculiarity. As a student, frustrated by the limitations of ventional mathematics, heied airely new form, the calculus, but then told no one about it for twenty-sevenyears. In like manner, he did work in optics that transformed our uanding of light andlaid the foundation for the sce of spectroscopy, and again chose not to share the results forthree decades.
For all his brilliance, real sce ated for only a part of his is. At least half hisw life was giveo alchemy and wayward religious pursuits. These were not meredabblings but wholehearted devotions. He was a secret adherent of a dangerously hereticalsect called Arianism, whose principal te was the belief that there had been no Holy Trinity(slightly ironiewton’s college at Cambridge was Trinity). He spent endless hoursstudying the floor plan of the lost Temple of King Solomon in Jerusalem (teag himselfHebrew in the process, the better to s inal texts) in the belief that it held mathematicalclues to the dates of the sed ing of Christ and the end of the world. His attat toalchemy was no less ardent. In 1936, the eist John Maynard Keynes bought a trunk ofon’s papers at au and discovered with astonishment that they were overwhelminglypreoccupied not with optics or plaary motions, but with a single-minded quest to turn basemetals into precious ones. An analysis of a strand of on’s hair in the 1970s found ittained mercury—a of io alchemists, hatters, and thermometer-makersbut almost no one else—at a tration some forty times the natural level. It is perhapslittle wohat he had trouble remembering to rise in the m.
Quite what Halley expected to get from him when he made his unannounced visit in August1684 we only guess. But thanks to the later at of a on fidant, AbrahamDeMoivre, we do have a record of one of sce’s most historiters:
In 1684 DrHalley came to visit at Cambridge [and] after they had some timetogether the Drasked him what he thought the curve would be that would bedescribed by the Plas supposing the force of attra toward the Sun to bereciprocal to the square of their distance from it.
This was a refereo a pieathematiown as the inverse square law, which Halleywas vinced lay at the heart of the explanation, though he wasn’t sure exactly how.
SrIsaac replied immediately that it would be an [ellipse]. The Doctor, struck withjoy & amazement, asked him how he k. ‘Why,’ saith he, ‘I have calculatedit,’ whereupon DrHalley asked him for his calculation without farther delay,SrIsaac looked among his papers but could not find it.
This was astounding—like someone saying he had found a cure for cer but couldn’tremember where he had put the formula. Pressed by Halley, on agreed to redo thecalculations and produce a paper. He did as promised, but then did much more. He retired fortwo years of intensive refle and scribbling, and at length produced his masterwork: thePhilosophiae Naturalis Principia Mathematiathematical Principles of NaturalPhilosophy, better known as the Principia .
On a great while, a few times in history, a human mind produces an observation soacute and ued that people ’t quite decide which is the more amazing—the fact orthe thinking of it. Principia was one of those moments. It made on instantly famous. Forthe rest of his life he would be draped with plaudits and honors, being, among much else,the first person in Britain knighted for stific achievement. Even the great Germanmathemati Gottfried von Leibniz, with whom on had a long, bitter fight over priorityfor the iion of the calculus, thought his tributions to mathematics equal to all theaccumulated work that had preceded him. “he gods no mortal may approach,” wroteHalley in a sehat was endlessly echoed by his poraries and by many otherssince.
Although the Principia has been called “one of the most inaccessible books ever written”
(on iionally made it difficult so that he wouldn’t be pestered by mathematical“smatterers,” as he called them), it was a bea to those who could follow it. It not onlyexplained mathematically the orbits of heavenly bodies, but also identified the attractive forcethat got them moving in the first place—gravity. Suddenly every motion in the universe madesense.
At Principia ’s heart were on’s three laws of motion (which state, very baldly, that athing moves in the dire in which it is pushed; that it will keep moving in a straight liil some other force acts to slow or deflect it; and that every a has an opposite andequal rea) and his universal law of gravitation. This states that every obje theuniverse exerts a tug on every other. It may not seem like it, but as you sit here now you arepulling everything around you—walls, ceiling, lamp, pet cat—toward you with your own little(indeed, very little) gravitational field. And these things are also pulling on you. It wason who realized that the pull of any two objects is, to quote Feynman again,“proportional to the mass of ead varies inversely as the square of the distaweenthem.” Put another way, if you double the distaween two objects, the attrabetween them bees four times weaker. This be expressed with the formulaF = GmmR2which is of course way beyond anything that most of us could make practical use of, but atleast preciate that it is elegantly pact. A couple of brief multiplications, a simpledivision, and, bingo, you know yravitational position wherever you go. It was the firstreally universal law of nature ever propounded by a human mind, which is why on isregarded with suiversal esteem.
Principia’s produ was not without drama. To Halley’s horror, just as work wasnearing pletioon and Hooke fell into dispute over the priority for the inversesquare law aon refused to release the crucial third volume, without which the firsttwo made little sense. Only with some frantic shuttle diplomad the most liberalapplications of flattery did Halley manage finally to extract the cluding volume from theerratic professor.
Halley’s traumas were not yet quite over. The Royal Society had promised to publish thework, but now pulled out, g financial embarrassment. The year before the society hadbacked a costly flop called The History of Fishes , and they now suspected that the market fora book on mathematical principles would be less than clamorous. Halley, whose means werenot great, paid for the book’s publication out of his own pocket. on, as was his ,tributed nothing. To make matters worse, Halley at this time had just accepted a positionas the society’s clerk, and he was informed that the society could no longer afford to providehim with a promised salary of ￡50 per annum. He was to be paid instead in copies of TheHistory of Fishes .
on’s laws explained so many things—the slosh and roll of o tides, the motions ofplas, why onballs trace a particular trajectory before thudding back to Earth, why wearen’t flung into space as the pla spih us at hundreds of miles an hour2—that ittook a while for all their implications to seep in. But one revelation became almostimmediately troversial.
This was the suggestion that the Earth is not quite round. Acc to on’s theory,the trifugal force of the Earth’s spin should result in a slight flattening at the poles and abulging at the equator, which would make the pla slightly oblate. That meant that thelength of a degree wouldn’t be the same in Italy as it was in Scotland. Specifically, the lengthwould shorten as you moved away from the poles. This was not good news for those peoplewhose measurements of the Earth were based on the assumption that the Earth erfectsphere, which was everyone.
For half a tury people had been trying to work out the size of the Earth, mostly bymaking very exag measurements. One of the first such attempts was by an Englishmathemati named Richard Norwood. As a young man Norwood had traveled to Bermudawith a diving bell modeled on Halley’s device, intending to make a fortune scooping pearlsfrom the seabed. The scheme failed because there were no pearls and anyway Norwood’s belldidn’t work, but Norwood was not oo waste an experience. In the early sevehtury Bermuda was well known among ships’ captains for being hard to locate. Theproblem was that the o was big, Bermuda small, and the navigational tools for dealingwith this disparity hopelessly ie. There wasn’t eve an agreed length for anautical mile. Over the breadth of ahe smallest miscalculations would beagnified so that ships often missed Bermuda-sized targets by dismaying margins. Norwood,whose first love was trigory and thus angles, decided t a little mathematical rigorto navigation and to that eermio calculate the length of a degree.
Starting with his back against the Tower of London, Norwood spent two devoted yearsmarg 208 miles north to York, repeatedly stretg and measuring a length of ashe went, all the while making the most meticulous adjustments for the rise and fall of the landand the meanderings of the road. The final step was to measure the angle of the Sun at York atthe same time of day and on the same day of the year as he had made his first measurement inLondon. From this, he reasoned he could determihe length of one degree of the Earth’smeridian and thus calculate the distance around the whole. It was an almost ludicrouslyambitious uaking—a mistake of the slightest fra of a degree would throw the wholething out by miles—but in fact, as Norwood proudly declaimed, he was accurate to “within astling”—or, more precisely, to within about six hundred yards. Iric terms, his figureworked out at 110.72 kilometers per degree of arc.
In 1637, Norwood’s masterwork of navigation, The Seaman’s Practice , ublished andfound an immediate following. It went through seventeeions and was still in priy-five years after his death. Norwood returo Bermuda with his family, being a2How fast you are spinning depends on where you are. The speed of the Earth’s spin varies from a little over1,000 miles an hour at the equator to 0 at the poles.
successful planter aing his leisure hours to his first love, trigory. He survivedthere for thirty-eight years and it would be pleasing to report that he passed this span inhappiness and adulation. In fact, he didn’t. On the crossing from England, his two young sonswere placed in a with the Reverend Nathaniel White, and somehow so successfullytraumatized the young vicar that he devoted much of the rest of his career to persegNorwood in any small way he could think of.
Norwood’s two daughters brought their father additional pain by making poor marriages.
One of the husbands, possibly incited by the vicar, tinually laid small charges againstNorwood in court, causing him much exasperation and atied trips acrossBermuda to defend himself. Finally in the 1650s witch trials came to Bermuda and Norwoodspent his final years in severe uhat his papers ory, with their aresymbols, would be taken as unications with the devil and that he would be treated to adreadful execution. So little is known of Norwood that it may in fact be that he deserved hisunhappy deing years. What is certainly true is that he got them.
Meanwhile, the momentum for determining the Earth’s circumference passed to France.
There, the astronomer Jean Picard devised an impressively plicated method ulation involving quadrants, pendulum clocks, zenith sectors, and telescopes (for the motions of the moons of Jupiter). After two years of trundling and triangulatinghis way across France, in 1669 he announced a more accurate measure of 110.46 kilometersfor one degree of arc. This was a great source of pride for the French, but it redicated onthe assumption that the Earth erfect sphere—whiewton now said it was not.
To plicate matters, after Picard’s death the father-and-son team of Giovanni andJacques Cassied Picard’s experiments over a larger area and came up with results thatsuggested that the Earth was fatter not at the equator but at the poles—that on, in otherwords, was exactly wrong. It was this that prompted the Academy of Sces to dispatchBouguer and La io South America to take new measurements.
They chose the Andes because they o measure he equator, to determihere really was a differen sphericity there, and because they reasohat mountainswould give them good sightlines. In fact, the mountains of Peru were so stantly lost incloud that the team often had to wait weeks for an hour’s clear surveying. On top of that, theyhad selected one of the most nearly impossible terrains oh. Peruvians refer to theirlandscape as muy actado —“much acted”—and this it most certainly is. TheFrench had not only to scale some of the world’s most challenging mountains—mountainsthat defeated even their mules—but to reach the mountains they had to ford wild rivers, hacktheir way through jungles, and iles of high, sto, nearly all of it uncharted andfar from any source of supplies. But Bouguer and La ine were nothing if nottenacious, and they stuck to the task for nine and a half long, grim, sun-blistered years.
Shortly before cluding the project, they received word that a sed French team, takingmeasurements in northern Sdinavia (and fag notable disforts of their own, fromsquelg bogs to dangerous ice floes), had found that a degree was in fact longer hepoles, as on had promised. The Earth was forty-three kilometers stouter when measuredequatorially than when measured from top to bottom around the poles.
Bouguer and La ihus had spent nearly a decade w toward a result theydidn’t wish to find only to learn now that they weren’t even the first to find it. Listlessly, theypleted their survey, which firmed that the first French team was correct. Then, still notspeaking, they returo the coast and took separate ships home.
Something else jectured by on in the Principia was that a plumb bob hung near amountain would ine very slightly toward the mountain, affected by the mountain’sgravitational mass as well as by the Earth’s. This was more than a curious fact. If youmeasured the defle accurately and worked out the mass of the mountain, you couldcalculate the universal gravitational stant—that is, the basic value of gravity, known asG—and along with it the mass of the Earth.
Bouguer and La ine had tried this on Peru’s Mount Chimborazo, but had beeed by both the teical difficulties and their own squabbling, and so the notion laydormant for ahirty years until resurrected in England by Nevil Maskelyheastronomer royal. In Dava Sobel’s popular book Longitude, Maskelyne is presented as a ninnyand villain for failing to appreciate the brilliance of the aker John Harrison, and thismay be so, but we are ied to him in other ways not mentioned in her book, not least forhis successful scheme to weigh the Earth. Maskelyne realized that the nub of the problem laywith finding a mountain of suffitly regular shape to judge its mass.
At his urging, the Royal Society agreed to engage a reliable figure to tour the British Islesto see if such a mountain could be found. Maskelyne knew just such a persoronomer and surveyor Charles Mason. Maskelyne and Mason had bee friends elevenyears earlier while engaged in a projeeasure an astronomical event of great importance:
the passage of the pla Venus across the face of the Sun. The tireless Edmond Halley hadsuggested years before that if you measured one of these passages from selected points oh, you could use the principles ulation to work out the distao the Sun, andfrom that calibrate the distao all the other bodies in the solar system.
Unfortunately, transits of Venus, as they are known, are an irregular occurreheye in pairs eight years apart, but then are absent for a tury or more, and there were nonein Halley’s lifetime.
3But the idea simmered and when the ransit came due in 1761,nearly two decades after Halley’s death, the stific world was ready—indeed, more readythan it had been for an astronomical event before.
With the instinct for ordeal that characterized the age, stists set off for more than ahundred locations around the globe—to Siberia, a, South Africa, Indonesia, and thewoods of Wissin, among many others. France dispatched thirty-two observers, Britaieen more, and still others set out from Sweden, Russia, Italy, Germany, Ireland, andelsewhere.
It was history’s first cooperative iional stifiture, and almost everywhere itran into problems. Many observers were waylaid by war, siess, or shipwreck. Others madetheir destinations but opeheir crates to find equipment broken or ed by tropical heat.
Once again the French seemed fated to provide the most memorably unlucky partits.
Jean Chappe spent months traveling to Siberia by coach, boat, and sleigh, nursing his delicateinstruments over every perilous bump, only to find the last vital stretch blocked by swollen3The ransit will be on June 8, 2004, with a sed in 2012. There were none iweh tury.
rivers, the result of unusually heavy spring rains, which the locals were swift to blame on himafter they saw him pointing strange instruments at the sky. Chappe mao escape withhis life, but with no useful measurements.
Unluckier still was Guillaume Le Gentil, whose experiences are wonderfully summarizedby Timothy Ferris in ing of Age in the Milky Way . Le Gentil set off from France a yearahead of time to observe the transit from India, but various setbacks left him still at sea on theday of the transit—just about the worst place to be sieady measurements wereimpossible on a pitg ship.
Undaunted, Le Gentil tinued on to India to await the ransit in 1769. With eightyears to prepare, he erected a first-rate viewing statioed aed his instruments,and had everything in a state of perfect readiness. On the m of the sed transit, June4, 1769, he awoke to a fine day, but, just as Venus began its pass, a cloud slid in front of theSun and remaihere for almost exactly the duration of the transit: three hours, fourteenminutes, and seven seds.
Stoically, Le Gentil packed up his instruments a off for the port, but en routehe tracted dysentery and wabbr>s laid up for nearly a year. Still weakened, he finally made itonto a ship. It was nearly wrecked in a hurrie off the Afri coast. When at last hereached home, eleven and a half years after setting off, and having achieved nothing, hediscovered that his relatives had had him declared dead in his absend hadenthusiastically plundered his estate.
In parison, the disappois experienced by Britaieen scattered observerswere mild. Mason found himself paired with a young surveyor named Jeremiah Dixon andapparently they got along well, for they formed a lasting partnership. Their instrus wereto travel to Sumatra and chart the transit there, but after just one night at sea their ship wasattacked by a French frigate. (Although stists were in an iionally cooperativemood, nations weren’t.) Mason and Dixo a o the Royal Society that itseemed awfully dangerous on the high seas and w if perhaps the whole thingoughtn’t to be called off. In reply they received a swift and chilly rebuke, noting that they hadalready been paid, that the nation and stifiunity were ting on them, and thattheir failure to proceed would result in the irretrievable loss of their reputations. Chastehey sailed on, but en route word reached them that Sumatra had fallen to the Frend sothey observed the transit inclusively from the Cape of Good Hope. On the way home theystopped on the lonely Atlantic outcrop of St. Helena, where they met Maskelyne, whoseobservations had been thwarted by cloud cover. Mason and Maskelyne formed a solidfriendship and spent several happy, and possibly even mildly useful, weeks charting tidalflows.
Soon afterward, Maskelyuro England where he became astronomer royal, andMason and Dixon—now evidently more seasoned—set off for four long and often perilousyears surveying their way through 244 miles of dangerous Ameri wildero settle aboundary dispute betweeates of William Penn and Lord Baltimore and theirrespective ies of Pennsylvania and Maryland. The result was the famous Mason andDixon line, which later took on symbolic importance as the dividing liween the slaveand free states. (Although the line was their principal task, they also tributed severalastronomical surveys, including one of the tury’s most accurate measurements of a degreeof meridian—an achievement that brought them far more acclaim in England thatlingof a boundary dispute between spoiled aristocrats.)Ba Europe, Maskelyne and his terparts in Germany and France were forced to theclusion that the transit measurements of 1761 were essentially a failure. One of theproblems, ironically, was that there were too many observations, which when broughttogether often proved tradictory and impossible to resolve. The successful charting of aVenusian transit fell io a little-known Yorkshire-born sea captain named James Cook,who watched the 1769 transit from a sunny hilltop in Tahiti, and the on to chart andclaim Australia for the British . Upon his return there was now enough information forthe French astronomer Joseph Lalao calculate that the mean distance from the Earth tothe Sun was a little over 150 million kilometers. (Two further transits in the eeury allowed astroo put the figure at 149.59 million kilometers, where it hasremained ever sihe precise distance, we now know, is 149.597870691 millionkilometers.) The Earth at last had a position in space.
As for Mason and Dixon, they returo England as stific heroes and, for reasonsunknown, dissolved their partnership. sidering the frequency with which they turn up atsemis ieenth-tury sce, remarkably little is known about either man. Nolikenesses exist and few written references. Of Dixon the Diary of National Biographynotes intriguingly that he was “said to have been born in a ine,” but then leaves it to thereader’s imagination to supply a plausible explanatory circumstance, and adds that he died atDurham in 1777. Apart from his name and long association with Mason, nothing more isknown.
Mason is only slightly less shadowy. We know that in 1772, at Maskelyne’s behest, heaccepted the ission to find a suitable mountain for the gravitational defleexperiment, at length rep back that the mountain they needed was in the tral ScottishHighlands, just above Loch Tay, and was called Schiehallion. Nothing, however, wouldinduce him to spend a summer surveying it. He never returo the field again. His known movement was in 1786 when, abruptly and mysteriously, he turned up in Philadelphiawith his wife a children, apparently on the verge of destitution. He had not been baerica sinpleting his survey there eighteen years earlier and had no known reasonfor being there, or any friends or patrons to greet him. A few weeks later he was dead.
With Mason refusing to survey the mountain, the job fell to Maskelyne. So for four monthsin the summer of 1774, Maskelyne lived in a tent in a remote Scottish glen and spent his daysdireg a team of surveyors, who took hundreds of measurements from every possibleposition. To find the mass of the mountain from all these numbers required a great deal oftedious calculating, for which a mathemati named Charles Hutton was ehesurveyors had covered a map with scores of figures, each marking aion at some pointon or around the mountain. It was essentially just a fusing mass of numbers, but Huttonnoticed that if he used a pencil to ect points of equal height, it all became much moreorderly. Indeed, one could instantly get a sense of the overall shape and slope of the mountain.
He had ied tour lines.
Extrapolating from his Schiehallion measurements, Hutton calculated the mass of the Earthat 5,000 million million tons, from which could reasonably be deduced the masses of all theother major bodies in the solar system, including the Sun. So from this one experiment welearhe masses of the Earth, the Sun, the Moon, the other plas and their moons, and gottour lines into the bargain—not bad for a summer’s work.
Not everyone was satisfied with the results, however. The shorting of the Schiehallionexperiment was that it was not possible to get a truly accurate figure without knowing theactual density of the mountain. For venience, Hutton had assumed that the mountain hadthe same density as ordinary stone, about 2.5 times that of water, but this was little more thanan educated guess.
One improbable-seeming person who turned his mind to the matter was a try parsonnamed John Michell, who resided in the lonely Yorkshire village of Thornhill. Despite hisremote and paratively humble situation, Michell was one of the great stific thinkers ofthe eighteenth tury and much esteemed for it.
Among a great deal else, he perceived the wavelike nature of earthquakes, ducted muchinal researto magism and gravity, and, quite extraordinarily, envisiohepossibility of black holes two hundred years before anyone else—a leap of intuitive deduthat not eveon could make. When the German-born musi William Herscheldecided his real i in life was astronomy, it was Michell to whom he turned forinstru in making telescopes, a kindness for which plaary sce has been in his debtever since.
4But of all that Michell aplished, nothing was more ingenious or had greater impactthan a mae he designed and built for measuring the mass of the Earth. Unfortunately, hedied before he could duct the experiments and both the idea and the necessary equipmentwere passed on to a brilliant but magnifitly retiring London stist named Henrydish.
dish is a book in himself. Born into a life of sumptuous privilege—his grandfatherswere dukes, respectively, of Devonshire a—he was the most gifted English stistof his age, but also the stra. He suffered, in the words of one of his few biographers,from shyo a “degree b on disease.” Any human tact was for him a source ofthe deepest disfort.
Once he opened his door to find an Austrian admirer, freshly arrived from Vienna, on thefront step. Excitedly the Austrian began to babble out praise. For a few moments dishreceived the pliments as if they were blows from a blunt objed then, uo takeany more, fled dowh and out the gate, leaving the front door wide open. It was somehours before he could be coaxed back to the property. Even his housekeeper unicatedwith him by letter.
Although he did sometimes veo society—he articularly devoted to the weeklystific soirées of the great naturalist Sir Joseph Banks—it was always made clear to theuests that dish was on no at to be approached or even looked at. Thosewho sought his views were advised to wander into his viity as if by act and to “talk as4In 1781 Herschel became the first person in the modero discover a pla. He wao call it Gee,after the British monarch, but was overruled. Instead it became Uranus.
it were into vacy.” If their remarks were stifically worthy they might receive amumbled reply, but more often than not they would hear a peeved squeak (his voice appearsto have been high pitched) and turn to find an actual vad the sight of dishfleeing for a more peaceful er.
His wealth and solitary inations allowed him to turn his house in Clapham into a largelaboratory where he could range undisturbed through every er of the physical sces—electricity, heat, gravity, gases, anything to do with the position of matter. The sedhalf of the eighteenth tury was a time when people of a stifit grew intenselyied in the physical properties of fual things—gases aricity inparticular—and began seeing what they could do with them, often with more enthusiasm thansense. In America, Benjamin Franklin famously risked his life by flying a kite in aricalstorm. In France, a chemist named Pilatre de Rozier tested the flammability of hydrogen bygulping a mouthful and blowing across an open flame, proving at a stroke that hydrogen isindeed explosively bustible and that eyebrows are not necessarily a perma feature ofone’s face. dish, for his part, ducted experiments in which he subjected himself tograduated jolts of electrical current, diligently noting the increasing levels of agony until hecould keep hold of his quill, and sometimes his sciousness, no longer.
In the course of a long life dish made a string of signal discoveries—among muchelse he was the first person to isolate hydrogen and the first to bine hydrogen and oxygento form water—but almost nothing he did was entirely divorced from strangeness. To thetinuing exasperation of his fellow stists, he often alluded in published work to theresults of ti experiments that he had not told anyone about. In his secretiveness hedidn’t merely resemble on, but actively exceeded him. His experiments with electricalductivity were a tury ahead of their time, but unfortunately remained undiscovereduntil that tury had passed. Ihe greater part of what he did wasn’t known until thelate eenth tury when the Cambridge physicist James Clerk Maxwell took oaskof editing dish’s papers, by which time credit had nearly always been given to others.
Among much else, and without telling anyone, dish discovered or anticipated the lawof the servation of energy, Ohm’s law, Dalton’s Law of Partial Pressures, Richter’s Lawof Reciprocal Proportions, Charles’s Law of Gases, and the principles of electricalductivity. That’s just some of it. Acc to the sce historian J. G. Crowther, he alsoforeshadowed “the work of Kelvin and G. H. Darwin on the effect of tidal fri on slowiation of the earth, and Larmor’s discovery, published in 1915, on the effect of localatmospheric cooling . . . the work of Pickering on freezing mixtures, and some of the work ofRooseboom oerogeneous equilibria.” Finally, he left clues that led directly to thediscovery of the group of elements known as the noble gases, some of which are so elusivethat the last of them wasn’t found until 1962. But our i here is in dish’s lastknown experiment when ie summer of 1797, at the age of sixty-seveurned hisattention to the crates of equipment that had beeo him—evidently out of simplestific respect—by John Michell.
When assembled, Michell’s apparatus looked like nothing so much as aeenth-tury version of a Nautilus weight-training mae. It incorporated weights,terweights, pendulums, shafts, and torsion wires. At the heart of the mae were two350-pound lead balls, which were suspended beside two smaller spheres. The idea was tomeasure the gravitational defle of the smaller spheres by the larger ones, which wouldallow the first measurement of the elusive forown as the gravitational stant, and fromwhich the weight (strictly speaking, the mass)5of the Earth could be deduced.
Because gravity holds plas in orbit and makes falling objects land with a bang, we tendto think of it as a powerful force, but it is not really. It is only powerful in a kind of collectivesense, when one massive object, like the Sun, holds on to another massive object, like theEarth. At aal level gravity is extraordinarily unrobust. Each time you pick up a bookfrom a table or a dime from the floor you effortlessly overe the bined gravitatioion of aire pla. What dish was trying to do was measure gravity at thisextremely featherweight level.
Delicacy was the key word. Not a whisper of disturbance could be allowed into the roomtaining the apparatus, so dish took up a position in an adjoining room and made hisobservations with a telescope aimed through a peephole. The work was incredibly exagand involved seventeen delicate, interected measurements, which together took nearly ayear to plete. When at last he had finished his calculations, dish annouhat theEarth weighed a little over 13,000,000,000,000,000,000,000 pounds, or six billion trillioris, to use the modern measure. (A metri is 1,000 kilograms or 2,205 pounds.)Today, stists have at their disposal maes so precise they detect the weight of asingle bacterium and so sensitive that readings be disturbed by someone yawniy-five feet away, but they have not signifitly improved on dish’s measurements of1797. The curre estimate for Earth’s weight is 5.9725 billion trillioris, adifference of only about 1 pert from dish’s finding. Iingly, all of this merelyfirmed estimates made by on 110 years before dish without any experimentalevide all.
So, by the late eighteenth tury stists knew very precisely the shape and dimensionsof the Earth and its distance from the Sun and plas; and now dish, without evenleaving home, had gives weight. So you might think that determining the age of theEarth would be relatively straightforward. After all, the necessary materials were literally attheir feet. But no. Human beings would split the atom and ielevision, nylon, and instantcoffee before they could figure out the age of their own pla.
To uand why, we must travel north to Scotland and begin with a brilliant and genialman, of whom few have ever heard, who had just ied a new sce called geology.
5To a physicist, mass a are two quite different things. Your mass stays the same wherever you go, butyour weight varies depending on how far you are from the ter of some other massive object like a pla.
Travel to the Moon and you will be much lighter but no less massive. Oh, for all practical purposes, massa are the same and so the terms be treated as synonymous. at least outside the classroom.
5 THE STONE-BREAKERS
AT JUST THE time that Henry dish was pleting his experiments in London, fourhundred miles away in Edinburgh another kind of cluding moment was about to take placewith the death of James Hutton. This was bad news for Hutton, of course, but good news forsce as it cleared the way for a man named John Playfair to rewrite Hutton’s work withoutfear of embarrassment.
Hutton was by all ats a man of the kee insights and liveliest versation, a delightin pany, and without rival when it came to uanding the mysterious slow processesthat shaped the Earth. Unfortunately, it was beyond him to set down his notions in a form thatanyone could begin to uand. He was, as one biographer observed with an all but audiblesigh, “almost entirely i of rhetorical aplishments.” Nearly every line he pennedwas an invitation to slumber. Here he is in his 1795 masterwork, A Theory of the Earth withProofs and Illustrations , discussing . . . something:
The world which we inhabit is posed of the materials, not of the earth whichwas the immediate predecessor of the present, but of the earth which, in asdingfrom the present, we sider as the third, and which had preceded the land thatwas above the surface of the sea, while our present land was yet beh the waterof the o.
Yet almost singlehandedly, and quite brilliantly, he created the sce of geology andtransformed our uanding of the Earth. Hutton was born in 1726 into a prosperousScottish family, and ehe sort of material fort that allowed him to pass much of hislife in a genially expansive round of light work and intellectual betterment. He studiedmedie, but found it not to his liking and turned i, which he followed in arelaxed and stific way on the family estate in Berwickshire. Tiring of field and flock, in1768 he moved to Edinburgh, where he founded a successful business produg salammonia coal soot, and busied himself with various stific pursuits. Edinburgh atthat time was a ter of intellectual vigor, and Hutton luxuriated in its enrig possibilities.
He became a leading member of a society called the Oyster Club, where he passed hisevenings in the pany of men such as the eist Adam Smith, the chemist JosephBlack, and the philosopher David Hume, as well as such occasional visiting sparks asBenjamin Franklin and James Watt.
Iradition of the day, Hutton took an i in nearly everything, from mineralogy tometaphysics. He ducted experiments with chemicals, iigated methods of iningand al building, toured salt mines, speculated on the meisms of heredity, collectedfossils, and propouheories on rain, the position of air, and the laws of motion,among much else. But his particular i was geology.
Among the questions that attracted i in that fanatically inquisitive age was ohathad puzzled people for a very long time—namely, why a clamshells and other marinefossils were so often found on mountaintops. How oh did they get there? Those whothought they had a solution fell into two opposing camps. One group, known as theunists, was vihat everything oh, including seashells in improbably loftyplaces, could be explained by rising and falling sea levels. They believed that mountains,hills, and other features were as old as the Earth itself, and were ged only when watersloshed over them during periods of global flooding.
Opposing them were the Plutonists, who hat voloes ahquakes, amongother enlivening agents, tinually ged the face of the pla but clearly owed nothing towayward seas. The Plutonists also raised awkward questions about where all the water we wasn’t in flood. If there was enough of it at times to cover the Alps, then where, pray,was it during times of tranquility, such as now? Their belief was that the Earth was subject toprofound internal forces as well as surfaes. However, they couldn’t vingly explainhow all those clamshells got up there.
It was while puzzling over these matters that Hutton had a series of exceptional insights.
From looking at his own farmland, he could see that soil was created by the erosion of rod that particles of this soil were tinually washed away and carried off by streams andrivers and redeposited elsewhere. He realized that if such a process were carried to its naturalclusion theh would eventually be worn quite smooth. Yet everywhere around himthere were hills. Clearly there had to be some additional process, some form of renelift, that created new hills and mountains to keep the cycle going. The marine fossils onmountaintops, he decided, had not been deposited during floods, but had risen along with themountains themselves. He also deduced that it was heat within the Earth that created newrocks and tis and thrust up mountain s. It is not too much to say that geologistswouldn’t grasp the full implications of this thought for two hundred years, when finally theyadopted plate teics. Above all, what Hutton’s theories suggested was that Earth processesrequired huge amounts of time, far more than anyone had ever dreamed. There were enoughinsights here to transform utterly our uanding of the Earth.
In 1785, Hutton worked his ideas up into a long paper, which was read at secutivemeetings of the Royal Society of Edinburgh. It attracted almost no notice at all. It’s not hardto see why. Here, in part, is how he prese to his audience:
In the one case, the f cause is in the body which is separated; for, after thebody has been actuated by heat, it is by the rea of the proper matter of thebody, that the chasm which stitutes the vein is formed. Iher case, again,the cause is extrinsi relation to the body in which the chasm is formed. Therehas been the most violent fracture and divulsion; but the cause is still to seek; andit appears not in the vein; for it is not every fracture and dislocation of the solidbody of our earth, in which minerals, or the proper substanineral veins,are found.
Needless to say, almost no one in the audience had the fai idea what he was talkingabout. Enced by his friends to expand his theory, ioug hope that he mightsomehow stumble onto clarity in a more expansive format, Huttohe en yearspreparing his magnum opus, which ublished in two volumes in 1795.
Together the two books ran to nearly a thousand pages and were, remarkably, worse thaneven his most pessimistic friends had feared. Apart from anything else, nearly half thepleted work now sisted of quotations from French sources, still in the inal French.
A third volume was so uig that it wasn’t published until 1899, more than a turyafter Hutton’s death, and the fourth and cluding volume was never published at all.
Hutton’s Theory of the Earth is a strong didate for the least read important book in sce(or at least would be if there weren’t so many others). Even Charles Lyell, the greatestgeologist of the followiury and a man who read everything, admitted he couldn’t getthrough it.
Luckily Hutton had a Boswell in the form of John Playfair, a professor of mathematics atthe Uy of Edinburgh and a close friend, who could not only write silken prose but—thanks to many years at Hutton’s elbow—actually uood what Hutton was trying to say,most of the time. In 1802, five years after Hutton’s death, Playfair produced a simplifiedexposition of the Huttonian principles, entitled Illustrations of the Huttonian Theory of theEarth. The book was gratefully received by those who took an active i in geology,whi 1802 was not a large hat, however, was about to ge. And how.
In the winter of 1807, thirteen like-minded souls in London got together at the FreemasonsTavern at Long Acre, in t Garden, to form a dining club to be called the GeologicalSociety. The idea was to meet once a month to s geologiotions lass or two ofMadeira and a vivial dihe price of the meal was set at a deliberately hefty fifteenshillings to disce those whose qualifications were merely cerebral. It soon becameapparent, however, that there was a demand for something more properly institutional, with aperma headquarters, where people could gather to share and discuss new findings. Inbarely a decade membership grew to four huill all gentlemen, of course—and theGeological was threatening to eclipse the Royal as the premier stific society in thetry.
The members met twice a month from November until June, when virtually all of themwent off to spend the summer doing fieldwork. These weren’t people with a peiary iin minerals, you uand, or even academics for the most part, but simply gentlemen withthe wealth and time to indulge a hobby at a more or less professional level. By 1830, therewere 745 of them, and the world would never see the like again.
It is hard to imagine now, but geology excited the eenth tury—positively grippedit—in a way that no sce ever had before or would again. In 1839, when RoderickMurchison published The Silurian System, a plump and ponderous study of a type of rockcalled greywacke, it was an instaseller, rag through four editions, even though it costeight guineas a copy and was, in true Huttonian style, unreadable. (As even a Murchisonsupporter ceded, it had “a total want of literary attractiveness.”) And when, in 1841, thegreat Charles Lyell traveled to America to give a series of lectures in Boston, selloutaudiences of three thousand at a time packed into the Lowell Institute to hear his tranquilizingdescriptions of maries and seismic perturbations in Campania.
Throughout the modern, thinking world, but especially in Britain, men of learniuredinto the tryside to do a little “stone-breaking,” as they called it. It ursuit takenseriously, and they teo dress with appropriate gravity, in top hats and dark suits, exceptfor the Reverend William Bud of Oxford, whose habit it was to do his fieldwork in anacademic gown.
The field attracted maraordinary figures, not least the aforementioned Murchison,who spent the first thirty or so years of his life galloping after foxes, verting aeronauticallychallenged birds into puffs of driftihers with buckshot, and showing al agilitywhatever beyond that o read The Times or play a hand of cards. Then he discoveredan i in rocks and became with rather astounding swiftness a titan of geologicalthinking.
Then there was Dr. James Parkinson, who was also an early socialist and author of manyprovocative pamphlets with titles like “Revolution without Bloodshed.” In 1794, he licated in a faintly lunatic-sounding spiracy called “the Pop-gun Plot,” in which it lao shoot King Gee III in the neck with a poisoned dart as he sat in his box at thetheater. Parkinson was hauled before the Privy cil for questioning and came within anace of being dispatched in irons to Australia before the charges against him were quietlydropped. Adopting a more servative approach to life, he developed an i in geologyand became one of the founding members of the Geological Society and the author of animportant geological text, anic Remains of a Former World, which remained in print forhalf a tury. He never caused trouble again. Today, however, we remember him for hislandmark study of the affli then called the “shaking palsy,” but known ever since asParkinson’s disease. (Parkinson had oher slight claim to fame. In 1785, he becamepossibly the only person in history to win a natural history museum in a raffle. The museum,in London’s Leicester Square, had been founded by Sir Ashton Lever, who had driven himselfbankrupt with his urained colleg of natural wonders. Parkinsohe museum until1805, when he could no longer support it and the colle was broken up and sold.)Not quite as remarkable in character but more iial than all the others bined wasCharles Lyell. Lyell was born in the year that Hutton died and only seventy miles away, in thevillage of Kinnordy. Though Scottish by birth, he grew up in the far south of England, in theNew Forest of Hampshire, because his mother was vihat Scots were feckless drunks.
As was generally the pattern with eenth-tury gentlemen stists, Lyell came from abackground of fortable wealth and intellectual vigor. His father, also named Charles, hadthe unusual distin of being a leading authority on the poet Dante and on mosses.
(Orthotricium lyelli, which most visitors to the English tryside will at some time have saton, is named for him.) From his father Lyell gained an i in natural history, but it was atOxford, ..where he fell uhe spell of the Reverend William Bud—he of the flowinggowns—that the young Lyell began his lifeloion to geology.
Bud was a bit of a charming oddity. He had some real achievements, but he isremembered at least as much for his etricities. He articularly noted for a menagerieof wild animals, some large and dangerous, that were allowed to roam through his house andgarden, and for his desire to eat his way through every animal iion. Depending onwhim and availability, guests to Bud’s house might be served baked guinea pig, mibatter, roasted hedgehog, or boiled Southeast Asian sea slug. Bud was able to fiin them all, except the on garden mole, which he declared disgusting. Almostiably, he became the leading authority on coprolites—fossilized feces—and had a tablemade entirely out of his colle of spes.
Even when dug serious sce his manner was generally singular. Once Mrs.
Bud found herself being shaken awake in the middle of the night, her husband g iement: “My dear, I believe that Cheirotherium ’s footsteps are undoubtedly testudinal.”
Together they hurried to the kit in their nightclothes. Mrs. Bud made a flour paste,which she spread across the table, while the Reverend Bud fetched the family tortoise.
Plunking it onto the paste, they goaded it forward and discovered to their delight that itsfootprints did indeed match those of the fossil Bud had been studying. Charles Darwinthought Bud a buffoon—that was the word he used—but Lyell appeared to find himinspiring and liked him well enough to go t with him in Scotland in 1824. It was soohis trip that Lyell decided to abandon a career in law ae himself to geology full-time.
Lyell was extremely shhted ahrough most of his life with a pained squint,which gave him a troubled air. (Eventually he would lose his sight altogether.) His other slightpeculiarity was the habit, when distracted by thought, of taking up improbable positions onfurniture—lying across two chairs at once or “resting his head on the seat of a chair, whilestanding up” (to quote his friend Darwin). Often when lost in thought he would slink so lowin a chair that his buttocks would all but touch the floor. Lyell’s only real job in life rofessor of geology at King’s College in London from 1831 to 1833. It was around this timethat he produced The Principles of Geology, published in three volumes between 1830 and1833, whi many ways solidated and elaborated upohoughts first voiced byHutton a geion earlier. (Although Lyell never read Hutton in the inal, he was a keenstudent of Playfair’s reworked versioween Hutton’s day and Lyell’s there arose a new geological troversy, which largelysuperseded, but is often fused with, the old unian–Plutonian dispute. The new battlebecame an argumeween catastrophism and uniformitarianism—unattractive terms for animportant and very long-running dispute. Catastrophists, as you might expect from the name,believed that the Earth was shaped by abrupt cataclysmic events—floods principally, which iswhy catastrophism aunism are often wrongly buogether. Catastrophism articularly f to clerics like Bud because it allowed them to incorporate thebiblical flood of Noah into serious stific discussions. Uniformitarians by trast believedthat ges oh were gradual and that nearly all Earth processes happened slowly, overimmense spans of time. Hutton was much more the father of the notion than Lyell, but it wasLyell most people read, and so he became in most people’s minds, then and now, the father ofmeological thought.
Lyell believed that the Earth’s shifts were uniform and steady—that everything that hadever happened in the past could be explained by events still going on today. Lyell and hisadherents didn’t just disdain catastrophism, they detested it. Catastrophists believed thatextins were part of a series in whiimals were repeatedly wiped out and replacedwith new sets—a belief that the naturalist T. H. Huxley mogly likeo “a succession ofrubbers of whist, at the end of which the players upset the table and called for a new pack.” Itwas too ve a way to explain the unknown. “Never was there a dogma more calculatedto foster indolence, and to blunt the keen edge of curiosity,” sniffed Lyell.
Lyell’s hts were not insiderable. He failed to explain vingly howmountain ranges were formed and overlooked glaciers as a of ge. He refused toaccept Louis Agassiz’s idea of ice ages—“the refrigeration of the globe,” as he dismissivelytermed it—and was fident that mammals “would be found in the oldest fossiliferousbeds.” He rejected the notion that animals and plants suffered sudden annihilations, andbelieved that all the principal animal groups—mammals, reptiles, fish, and so on—hadcoexisted sihe dawn of time. On all of these he would ultimately be proved wrong.
Yet it would be nearly impossible to overstate Lyell’s influehe Principles of Geologywent through twelve editions in Lyell’s lifetime and tained notions that shaped geologicalthinking far into the tweh tury. Darwin took a first edition with him on theBeaglevoyage and wrote afterward that “the great merit of the Principles was that it altered thewhole tone of one’s mind, and therefore that, when seeing a thing never seen by Lyell, osaw it partially through his eyes.” In short, he thought him nearly a god, as did many of hisgeion. It is a testament to the strength of Lyell’s sway that in the 1980s when geologistshad to abandon just a part of it to aodate the impact theory of extins, it nearlykilled them. But that is another chapter.
Meanwhile, geology had a great deal of s out to do, and not all of it went smoothly.
From the outset geologists tried to categorize rocks by the periods in which they were laiddown, but there were often bitter disagreements about where to put the dividing lines—nonemore so than a long-runnie that became known as the Great Devonian troversy.
The issue arose when the Reverend Adam Sedgwick of Cambridge claimed for the Cambrianperiod a layer of rock that Roderick Murchison believed belonged rightly to the Silurian. Thedispute raged for years and grew extremely heated. “De la Beche is a dirty dog,” Murchisonwrote to a friend in a typical outburst.
Some sense of the strength of feeling be gained by glang through the chapter titlesof Martin J. S. Rudwick’s excellent and somber at of the issue, The Great Devoniantroversy. These begin innocuously enough with headings such as “Arenas of Gentlemae” and “Unraveling the Greywacke,” but then proceed on to “The Greywacke Defendedand Attacked,” “Reproofs and Recriminations,” “The Spread of Ugly Rumors,” “WeaverRets His Heresy,” “Putting a Provincial in His Place,” and (in case there was any doubtthat this was war) “Murchisohe Rhineland Campaign.” The fight was finally settledin 1879 with the simple expedient of ing up with a new period, the Ordovi, to beied betweewo.
Because the British were the most active in the early years, British names are predominantin the geological lexi. Devonian is of course from the English ty of Devon. Cambrianes from the Roman name for Wales, while Ordovi and Silurian recall a Welshtribes, the Ordovices and Silures. But with the rise of geological prospeg elsewhere,names began to creep in from all over.Jurassic refers to the Jura Mountains on the border ofFrand Switzerland.Permian recalls the former Russian province of Perm in the UralMountains. ForCretaceous (from the Latin for “chalk”) we are ied to a Belgian geologistwith the perky name of J. J. d’Omalius d’Halloy.
inally, geological history was divided into four spans of time: primary, sedary,tertiary, and quaternary. The system was too o last, and soon geologists weretributing additional divisions while eliminating others. Primary and sedary fell out ofuse altogether, while quaternary was discarded by some but kept by others. Today oiary remains as a on designation everywhere, even though it no longer represents athird period of anything.
Lyell, in his Principles, introduced additional units knoochs or series to cover theperiod sihe age of the dinosaurs, among them Pleistoe (“most ret”), Plioe(“more ret”), Mioe (“moderately ret”), and the rather endearingly vague Oligoe(“but a little ret”). Lyell inally inteo employ “-synous” for his endings,giving us such chy designations as Meiosynous and Pleiosynous. TheReverend William Whewell, an iial man, objected oymological grounds andsuggested instead an “-eous” pattern, produg Meioneous, Pleioneous, and so on. The “-e” terminatiohus something of a promise.
Nowadays, and speaking very generally, geological time is divided first into freatks known as eras: Precambrian, Paleozoic (from the Greek meaning “old life”),Mesozoic (“middle life”), and ozoic (“ret life”). These four eras are further dividedinto anywhere from a dozen to twenty subgroups, usually called periods though sometimesknown as systems. Most of these are also reasonably well known: Cretaceous, Jurassic,Triassic, Silurian, and so on.
1Then e Lyell’s epochs—the Pleistoe, Mioe, and so on—which apply only to themost ret (but paleontologically busy) sixty-five million years, and finally we have a massof finer subdivisions known as stages es. Most of these are named, nearly alwaysawkwardly, after places: Illinoian, Desmoinesian, Croixian, Kimmeridgian, and so on in likevein. Altogether, acc to John McPhee, these number iens of dozens.”
Fortunately, unless you take up geology as a career, you are unlikely ever to hear any of themagain.
Further fusing the matter is that the stages es in North America have differentnames from the stages in Europe and often only roughly interse time. Thus the NorthAmeri atian stage mostly corresponds with the Ashgillian stage in Europe, plus atiny bit of the slightly earlier Carado stage.
Also, all this ges from textbook to textbook and from person to person, so that someauthorities describe seve epochs, while others are tent with four. In some books,too, you will find the tertiary and quaternary taken out and replaced by periods of differehs called the Palaeogene and Neogehers divide the Precambrian into two eras, thevery a Ar and the more ret Proterozoietimes too you will see the termPhanerozoic used to describe the span enpassing the ozoic, Mesozoid Paleozoiceras.
Moreover, all this applies only to units of time . Rocks are divided into quite separate unitsknown as systems, series, and stages. A distin is also made between late and early(referring to time) and upper and lower (referring to layers of rock). It all get terriblyfusing to nonspecialists, but to a geologist these be matters of passion. “I have seengrown men glow indest with rage over this metaphorical millised in life’s history,”
the British paleontologist Richard Fortey has written with regard to a long-running tweh-tury dispute over where the boundary lies between the Cambrian and Ordovi.
At least today we bring some sophisticated dating teiques to the table. For most ofthe eenth tury geologists could draw on nothing more than the most hopefulguesswork. The frustrating position then was that although they could place the various rod fossils in order by age, they had no idea how long any of those ages were. WhenBud speculated oiquity of an Ichthyosaurus skeleton he could do er thansuggest that it had lived somewhere betweehousand, or more thahousand timesten thousand” years earlier.
Although there was no reliable way of dating periods, there was no she of peoplewilling to try. The most well known early attempt was in 1650 when Archbishop JamesUssher of the Church of Ireland made a careful study of the Bible and other historical sourd cluded, in a hefty tome called Annals of the Old Testament , that the Earth had been1There will be ing here, but if you are ever required to memorize them you might wish to remember JohnWilfords helpful advice to think of the eras (Precambrian, Paleozoic, Mesozoi( ozoic) as seasons in ayear and the periods (Permian, Triassic Jurassic, etc.) as the months.
created at midday on October 23, 4004B.C. , an assertion that has amused historians abook writers ever since.
2There is a persistent myth, ially—and one propounded in many serious books—thatUssher’s views dominated stific beliefs well into the eenth tury, and that it wasLyell who put everyoraight. Stephen Jay Gould, in Time’s Arrow, cites as a typicalexample this sentence from a popular book of the 1980s: “Until Lyell published his book,most thinking people accepted the idea that the earth was young.” In fao. As Martin J. S.
Rudwick puts it, “No geologist of any nationality whose work was taken seriously by eologists advocated a timescale fined within the limits of a literalistic exegesis ofGenesis.” Even the Reverend Bud, as pious a soul as the eenth tury produoted that nowhere did the Bible suggest that God made Heaven ah on the first day,but merely “in the beginning.” That beginning, he reasoned, may have lasted “millions uponmillions of years.” Everyone agreed that the Earth was a. The question was simply howa.
One of the better early attempts at dating the pla came from the ever-reliable EdmondHalley, who in 1715 suggested that if you divided the total amount of salt in the world’s seasby the amount added each year, you would get the number of y.９9ｌｉｂ?ears that the os had beeence, which would give you a rough idea of Earth’s age. The logic ealing, butunfortunately no one knew how much salt was in the sea or by how much it increased eachyear, which rehe experiment impracticable.
The first attempt at measurement that could be called remotely stific was made by theFren Gees-Louis Leclerte de Buffon, in the 1770s. It had long been knownthat the Earth radiated appreciable amounts of heat—that arent to anyone who wentdown a i there wasn’t any way of estimating the rate of dissipation. Buffon’sexperiment sisted of heating spheres until they glowed white hot and theimating therate of heat loss by toug them (presumably very lightly at first) as they cooled. From thishe guessed the Earth’s age to be somewhere between 75,000 and 168,000 years old. This wasof course a wild uimate, but a radiotion heless, and Buffon found himselfthreatened with exunication for expressing it. A practical man, he apologized at oncefor his thoughtless heresy, then cheerfully repeated the assertions throughout his subsequentwritings.
By the middle of the eenth tury most learned people thought the Earth was at leasta few million years old, perhaps even some tens of millions of years old, but probably notmore than that. So it came as a surprise when, in 1859 in On the in of Species , CharlesDarwin annouhat the geological processes that created the Weald, an area of southernEngland stretg across Kent, Surrey, and Sussex, had taken, by his calculations,306,662,400 years to plete. The assertion was remarkable partly for being so arrestinglyspecific but even more for flying in the face of accepted wisdom about the age of the Earth.
3Itproved so tentious that Darwin withdrew it from the third edition of the book. The2Although virtually all books find a space for him, there is a striking variability iails associated withUssher. Some books say he made his pronou in 1650, others in 1654, still others in 1664. Many cite thedate of Earths reputed beginning as October 26. At least one book of note spells his name "Usher." The matter isiingly surveyed in Stephen Jay Goulds Eight Little Piggies.
3Darwin loved a number. In a later work, he annouhat the number of worms to be found in anaverage acre of English try soil was 53,767.
problem at its heart remained, however. Darwin and his geological friends he Earth tobe old, but no one could figure out a way to make it so.
Unfortunately for Darwin, and fress, the question came to the attention of the greatLord Kelvin (who, though indubitably great, was then still just plain William Thomson; hewouldn’t be elevated to the peerage until 1892, when he was sixty-eight years old and nearingthe end of his career, but I shall follow the vention here of using the roactively).
Kelvin was one of the most extraordinary figures of the eenth tury—indeed of aury. The German stist Hermann von Helmholtz, no intellectual slouch himself, wrotethat Kelvin had by far the greatest “intelligend lucidity, and mobility of thought” of anyman he had ever met. “I felt quite wooden beside him sometimes,” he added, a bit dejectedly.
The se is uandable, for Kelvin really was a kind of Victorian superman. Hewas born in 1824 in Belfast, the son of a professor of mathematics at the Royal Academistitution who soon after transferred to Glasgow. There Kelvin proved himself such aprodigy that he was admitted to Glasgow Uy at the exceedingly tender age of ten. Bythe time he had reached his early twenties, he had studied at institutions in London and Paris,graduated from Cambridge (where he won the uy’s top prizes for rowing andmathematics, and somehow found time to launch a musical society as well), beeed afellow of Peterhouse, and written (in Frend English) a dozen papers in pure and appliedmathematics of such dazzling inality that he had to publish them anonymously for fear ofembarrassing his superiors. At the age of twenty-two he returo Glasgow Uy totake up a professorship in natural philosophy, a position he would hold for the fifty-threeyears.
In the course of a long career (he lived till 1907 and the age of eighty-three), he wrote 661papers, accumulated 69 patents (from which he grew abundantly wealthy), and gained renownin nearly every branch of the physical sces. Among much else, he suggested the methodthat led directly to the iion of refrigeration, devised the scale of absolute temperaturethat still bears his name, ied the boosting devices that allowed telegrams to be sentacross os, and made innumerable improvements to shipping and navigation, from theiion of a popular marine pass to the creation of the first depth sounder. And thosewere merely his practical achievements.
His theoretical work, iromagism, thermodynamics, and the wave theory of light,was equally revolutionary.
4He had really only one flaw and that was an inability to calculatethe correct age of the Earth. The question occupied much of the sed half of his career, buthe never came anywhere near getting it right. His first effort, in 1862 for an article in apopular magazine called Macmillan’s , suggested that the Earth was 98 million years old, butcautiously allowed that the figure could be as low as 20 million years or as high as 400million. With remarkable prudence he aowledged that his calculations could be wrong if4In particular he elaborated the Sed Law of Thermodynamics. A discussion of these laws would be a book initself, but I offer here this crisp summation by the chemist P. W Atkins, just to provide a sense of them: "Thereare four Laws. The third of them, the Sed Law, was reized first; the first, the Zeroth Law, wasformulated last; the First Law was sed; the Third Law might not even be a law in the same sense as theothers." In briefest terms, the sed la states that a little energy is always wasted. You t have a perpetualmotion device because no matter how effit, it will always lose energy aually run down. The first lawsays that you t create energy and the third that you t reduce temperatures to absolute zero; there willalways be some residual warmth. As Dennis Overbye he three principal laws are sometimes expressedjocularly as (1) you t win, (2) you t break even, and (3) you t get out of the game.
“sourow unknown to us are prepared in the great storehouse of creation”—but it wasclear that he thought that unlikely.
With the passage of time Kelvin would beore fht in his assertions and lesscorrect. He tinually revised his estimates downward, from a maximum of 400 millionyears, to 100 million years, to 50 million years, and finally, in 1897, to a mere 24 millionyears. Kelvin wasn’t being willful. It was simply that there was nothing in physics that couldexplain how a body the size of the Sun could burn tinuously for more than a few tens ofmillions of years at most without exhausting its fuel. Therefore it followed that the Sun and itsplas were relatively, but inescapably, youthful.
The problem was that nearly all the fossil evidence tradicted this, and suddenly in theeenth tury there was a lot of fossil evidence.
6 SCIENCE RED IN TOOTH AND CLAW
IN 1787, SOMEONE in New Jersey—exactly who now seems to be fotten—found anenormous thighboig out of a stream bank at a place called Woodbury Creek. Thebone clearly didn’t belong to any species of creature still alive, certainly not in New Jersey.
From what little is known now, it is thought to have beloo a hadrosaur, a large duck-billed dinosaur. At the time, dinosaurs were unknown.
The bone was sent to Dr. Caspar Wistar, the nation’s leading anatomist, who described it ata meeting of the Ameri Philosophical Society in Philadelphia that autumn. Unfortunately,Wistar failed pletely the bone’s signifid merely made a few cautiousand uninspired remarks to the effect that it was indeed a whopper. He thus missed the ce,half a tury ahead of anyone else, to be the discoverer of dinosaurs. Ihe boed so little ihat it ut in a storeroom aually disappeared altogether.
So the first dinosaur bone ever found was also the first to be lost.
That the bone didn’t attract greater i is more than a little puzzling, for its appearancecame at a time when America was in a froth of excitement about the remains of large, aanimals. The cause of this froth was a strange assertion by the great Frenaturalist thete de Buffon—he of the heated spheres from the previous chapter—that living things inthe New World were inferior in nearly every way to those of the Old World. America, Buffonwrote in his vast and much-esteemed Histoire Naturelle , was a land where the water wasstagnant, the soil unproductive, and the animals without size or, their stitutionsweakened by the “noxious vapors” that rose from its rotting ss and sunless forests. Insu enviro eveive Indians lacked virility. “They have no beard or bodyhair,” Buffon sagely fided, “and no ardor for the female.” Their reproductive ans were“small and feeble.”
Buffon’s observations found surprisingly eager support among other writers, especiallythose whose clusions were not plicated by actual familiarity with the try. ADut named eille de Pauw announced in a popular work called RecherchesPhilosophiques sur les Améris that native Ameri males were not only reproductivelyunimposing, but “so lag in virility that they had milk in their breasts.” Such viewsenjoyed an improbable durability and could be foued or echoed in Europeas tillhe end of the eenth tury.
Not surprisingly, such aspersions were indignantly met in America. Thomas Jeffersonincorporated a furious (and, uhe text is uood, quite bewildering) rebuttal in hisNotes oate of Virginia , and induced his Neshire friend General John Sullivanto send twenty soldiers into the northern woods to find a bull moose to present to Buffon asproof of the stature and majesty of Ameri quadrupeds. It took the men two weeks to trackdown a suitable subject. The moose, when shot, unfortunately lacked the imposing horns thatJefferson had specified, but Sullivan thoughtfully included a rack of antlers from an elk with the suggestion that these be attached instead. Who in France, after all, would know?
Meanwhile in Philadelphia—Wistar’s city—naturalists had begun to assemble the bones ofa giant elephant-like creature known at first as “the great Ameri initum” but lateridentified, not quite correctly, as a mammoth. The first of these bones had been discovered ata place called Big Bone Li Kentucky, but soon others were turning up all over. America,it appeared, had once been the home of a truly substantial creature—ohat would surelydisprove Buffon’s foolish Gallitentions.
In their keeo demonstrate the initum’s bulk and ferocity, the Ameriaturalists appear to have bee slightly carried away. They overestimated its size by afactor of six and gave it frightening claws, whi fact came from a Megalonyx, iantground sloth, found nearby. Rather remarkably, they persuaded themselves that the animalhad ehe agility and ferocity of the tiger,” and portrayed it in illustrations as poungwith feline grato prey from boulders. When tusks were discovered, they were forced intothe animal’s head in any number of iive ways. Oorer screwed the tusks in upsidedown, like the fangs of a saber-toothed cat, which gave it a satisfyingly aggressive aspect.
Another arrahe tusks so that they curved backwards on the engaging theory that thecreature had been aquatid had used them to anchor itself to trees while dozing. The mostperti sideration about the initum, however, was that it appeared to be extinct—afact that Buffon cheerfully seized upon as proof of its intestably degee nature.
Buffon died in 1788, but the troversy rolled on. In 1795 a sele of bones made theirway to Paris, where they were examined by the rising star of paleontology, the youthful andaristocratic Gees Cuvier. Cuvier was already dazzling people with his genius for takingheaps of disarticulated bones and whipping them into shapely forms. It was said that he coulddescribe the look and nature of an animal from a siooth or scrap of jaw, and often he species and genus into the bargain. Realizing that no one in America had thought to writea formal description of the lumberi, Cuvier did so, and thus became its officialdiscoverer. He called it a mastodon (which means, a touexpectedly, “nipple-teeth”).
Inspired by the troversy, in 1796 Cuvier wrote a landmark paper, Note on the Species ofLiving and Fossil Elephants, in which he put forward for the first time a formal theory ofextins. His belief was that from time to time the Earth experienced global catastrophes inwhich groups of creatures were wiped out. Fious people, including Cuvier himself, theidea raised unfortable implications si suggested an unatable casualness o of Provideo what end would God create species only to wipe them out later? Thenotion was trary to the belief in the Great of Being, which held that the world wascarefully ordered and that every living thing within it had a plad purpose, and always hadand always would. Jefferson for one couldn’t abide the thought that whole species would everbe permitted to vanish (or, e to that, to evolve). So when it ut to him that theremight be stifid political value in sending a party to explore the interior of Americabeyond the Mississippi he leapt at the idea, hoping the intrepid adventurers would find herdsof healthy mastodons and other outsized creatures grazing on the bounteous plains.
Jefferson’s personal secretary and trusted friend Meriwether Lewis was chosen co-leader andchief naturalist for the expedition. The persoed to advise him on what to look out forwith regard to animals living and deceased was her than Caspar Wistar.
In the same year—in fact, the same month—that the aristocratid celebrated Cuvier ropounding his extin theories in Paris, oher side of the English el a rathermore obscure Englishman was having an insight into the value of fossils that would also havelasting ramifications. William Smith was a young supervisor of stru on the SomersetCoal al. On the evening of January 5, 1796, he was sitting in a coag inn in Somersetwheted dowion that would eventually make his reputation. To interpret rocks,there o be some means of correlation, a basis on which you tell that thosecarboniferous rocks from Devon are youhan these Cambrian rocks from Wales. Smith’sinsight was to realize that the answer lay with fossils. At every ge in rock strata certainspecies of fossils disappeared while others carried on into subsequent levels. By noting whichspecies appeared in which strata, you could work out the relative ages of rocks wherever theyappeared. Drawing on his knowledge as a surveyor, Smith began at oo make a map ofBritain’s rock strata, which would be published after many trials in 1815 and would bee aerstone of meology. (The story is prehensively covered in SimonWier’s popular book The Map That ged the World .)Unfortunately, having had his insight, Smith was curiously ued in uandingwhy rocks were laid down in the way they were. “I have left off puzzling about the in ofStrata and tent myself with knowing that it is so,” he recorded. “The whys and whereforesot e within the Province of a Mineral Surveyor.”
Smith’s revelatiarding strata heightehe moral awkwardness iins. To begin with, it firmed that God had wiped out creatures not occasionally butrepeatedly. This made Him seem not so much careless as peculiarly hostile. It also made itinvely necessary to explain how some species were wiped out while others tinuedunimpeded into succeeding eons. Clearly there was more to extins than could beated for by a single Noa deluge, as the Biblical flood was known. Cuvie99ｌｉb?r resolvedthe matter to his own satisfa by suggesting that Genesis applied only to the most retinundation. God, it appeared, hadn’t wished to distract or alarm Moses with news of earlier,irrelevains.
So by the early years of the eenth tury, fossils had taken on a certain inescapableimportance, which makes Wistar’s failure to see the significe of his dinosaur bone all themore unfortunate. Suddenly, in any case, bones were turning up all over. Several otheropportunities arose for Ameris to claim the discovery of dinosaurs but all were wasted. In1806 the Lewis and Clark expedition passed through the Hell Creek formation in Montana, anarea where fossil hunters would later literally trip over dinosaur bones, and even examinedwhat was clearly a dinosaur bone embedded in rock, but failed to make anything of it. Otherbones and fossilized footprints were found in the ecticut River Valley of New Englandafter a farm boy named Plinus Moody spied aracks on a rock ledge at South Hadley,Massachusetts. Some of these at least survive—notably the bones of an Anchisaurus, whichare in the colle of the Peabody Museum at Yale. Found in 1818, they were the firstdinosaur boo be examined and saved, but unfortunately weren’t reized for what theywere until 1855. In that same year, 1818, Caspar Wistar died, but he did gain a certainued immortality when a botanist homas Nuttall named a delightful climbingshrub after him. Some botanical purists still insist on spelling it wistaria .
By this time, however, paleontological momentum had moved to England. In 1812, atLyme Regis on the Dorset coast, araordinary child named Mary Anning—aged eleven,twelve, or thirteen, depending on whose at you read—found a strange fossilized seamonster, seventee long and now known as the ichthyosaurus, embedded ieep anddangerous cliffs along the English el.
It was the start of a remarkable career. Anning would spend the hirty-five yearsgathering fossils, which she sold to visitors. (She is only held to be the source for thefamous towister “She sells seashells on the seashore.”) She would also find the firstplesiosaurus, another marine monster, and one of the first a pterodactyls. Though hese was teically a dinosaur, that wasn’t terribly relevant at the time sinobody thenknew what a dinosaur was. It was enough to realize that the world had once held creaturesstrikingly unlike anything we might now find.
It wasn’t simply that Anning was good at spotting fossils—though she was unrivalled atthat—but that she could extract them with the greatest delicad without damage. If youever have the ce to visit the hall of a mariiles at the Natural History Museumin London, I urge you to take it for there is no other way to appreciate the scale ay ofwhat this young woman achieved w virtually unaided with the most basic tools innearly impossible ditions. The plesiosaur aloook her ten years of patient excavation.
Although untrained, Anning was also able to provide petent drawings and descriptions forscholars. But even with the advantage of her skills, signifit finds were rare and she passedmost of her life in poverty.
It would be hard to think of a more overlooked person in the history of paleontology thanMary Anning, but in fact there was one who came painfully close. His name was GideonAlgernon Mantell and he was a try doctor in Sussex.
Mantell was a lanky assemblage of shortings—he was vain, self-absorbed, priggish,ful of his family—but never was there a more devoted amateur paleontologist. He wasalso lucky to have a devoted and observant wife. In 1822, while he was making a house callon a patient in rural Sussex, Mrs. Mantell went for a stroll down a nearby lane and in a pile ofrubble that had beeo fill potholes she found a curious object—a curved brown stone,about the size of a small walnut. Knowing her husband’s i in fossils, and thinking itmight be one, she took it to him. Mantell could see at o was a fossilized tooth, and aftera little study became certain that it was from an animal that was herbivorous, reptiliaremely large—tens of feet long—and from the Cretaceous period. He was right on allts, but these were bold clusions sihing like it had been seen before or evenimagined.
Aware that his finding would entirely upend what was uood about the past, and urgedby his friend the Reverend William Bud—he of the gowns and experimental appetite—to proceed with caution, Mantell devoted three painstaking years to seeking evideosupport his clusions. He sent the tooth to Cuvier in Paris for an opinion, but the greatFren dismissed it as being from a hippopotamus. (Cuvier later apologized handsomelyfor this uncharacteristic error.) One day while doing research at the Hunterian Museum inLondon, Mantell fell into versation with a fellow researcher who told him the tooth lookedvery like those of animals he had been studying, South Ameri iguanas. A hastyparison firmed the resemblance. And so Mantell’s creature became Iguanodon , aftera basking tropical lizard to which it was not in any manner related.
Mantell prepared a paper for delivery to the Royal Society. Unfortunately it emerged thatanother dinosaur had been found at a quarry in Oxfordshire and had just been formallydescribed—by the Reverend Bud, the very man who had urged him not to work in haste.
It was the Megalosaurus, and the name was actually suggested to Bud by his friend Dr.
James Parkinson, the would-be radical and eponym for Parkinson’s disease. Bud, it maybe recalled, was foremost a geologist, and he showed it with his work on Megalosaurus. In hisreport, for the Transas of the Geological Society of London , he hat the creature’steeth were not attached directly to the jawbone as in lizards but placed in sockets in themanner of crocodiles. But having noticed this much, Bud failed to realize what it meant:
Megalosaurus was airely ype of creature. So although his report demonstrated littleacuity or insight, it was still the first published description of a dinosaur, and so to him ratherthan the far more deserving Mantell goes the credit for the discovery of this a line ofbeings.
Unaware that disappoi was going to be a tinuiure of his life, Mantelltinued hunting for fossils—he found aniant, the Hylaeosaurus, in 1833—andpurchasing others from quarrymen and farmers until he had probably the largest fossilcolle in Britain. Mantell was an excellent doctor and equally gifted bone hunter, but hewas uo support both his talents. As his colleg mania grew, he ed his medicalpractice. Soon fossils filled nearly the whole of his house in Brighton and ed much ofhis ine. Much of the rest went to underwriting the publication of books that few cared toown. Illustrations of the Geology of Sussex , published in 1827, sold only fifty copies ahim ￡300 out of pocket—an unfortably substantial sum for the times.
In some desperation Mantell hit on the idea of turning his house into a museum andcharging admission, theedly realized that such a merary act would ruin his standingas a gentleman, not to mention as a stist, and so he allowed people to visit the house forfree. They came in their hundreds, week after week, disrupting both his practice and his homelife. Eventually he was forced to sell most of his colle to pay off his debts. Soon after, hiswife left him, taking their four children with her.
Remarkably, his troubles were only just beginning.
In the district of Sydenham in south London, at a place called Crystal Palace Park, therestands a strange and fotten sight: the world’s first life-sized models of dinosaurs. Not manypeople travel there these days, but ohis was one of the most popular attras inLondon—in effect, as Richard Fortey has he world’s first theme park. Quite a lotabout the models is not strictly correct. The iguanodon’s thumb has been placed on its nose,as a kind of spike, and it stands on four sturdy legs, making it look like a rather stout andawkwardly rown dog. (In life, the iguanodon did not crou all fours, but edal.) Looking at them now you would scarcely guess that these odd and lumberiscould cause great rancor and bitterness, but they did. Perhaps nothing in natural history hasbeen at the ter of fiercer and more enduring hatreds than the line of a beasts knownas dinosaurs.
At the time of the dinosaurs’ stru, Sydenham was on the edge of London and itsspacious park was sidered an ideal place to re-erect the famous Crystal Palace, the glassand cast-iron structure that had been the terpiece of the Great Exhibition of 1851, and fromwhich the new park naturally took its he dinosaurs, built of crete, were a kind ofbonus attra. On New Year’s Eve 1853 a famous dinner for twenty-one promistists was held ihe unfinished iguanodon. Gideon Mantell, the man who had foundand identified the iguanodon, was not among them. The person at the head of the table wasthe greatest star of the young sce of paleontology. His name was Richard Owen and bythis time he had already devoted several productive years to making Gideon Mantell’s lifehell.
Owen had grown up in Lancaster, in the north of England, where he had trained as a doctor.
He was a born anatomist and so devoted to his studies that he sometimes illicitly borrowedlimbs, ans, and other parts from cadavers and took them home for leisurely disse.
Once while carrying a sack taining the head of a black Afri sailor that he had justremoved, Owen slipped on a wet cobble and watched in horror as the head bounced awayfrom him down the lane and through the open doorway of a cottage, where it came to rest inthe front parlor. What the octs had to say upon finding an unattached head rolling to ahalt at their feet only be imagined. One assumes that they had not formed any terriblyadvanced clusions when, an instant later, a fraught-looking young man rushed in,wordlessly retrieved the head, and rushed out again.
In 1825, aged just twenty-one, Owen moved to London and soon after was engaged by theRoyal College of Surgeons to help aheir extensive, but disordered, colles ofmedical and anatomical spes. Most of these had beeo the institution by JohnHunter, a distinguished surgeon and tireless collector of medical curiosities, but had neverbeen catalogued anized, largely because the paperwork explaining the significe ofeach had gone missing soon after Hunter’s death.
Owen swiftly distinguished himself with his powers anization aion. At thesame time he showed himself to be a peerless anatomist with instincts for restruost on a par with the great Cuvier in Paris. He bee su expert on the anatomy ofanimals that he was granted first refusal on any animal that died at the London ZoologicalGardens, and these he would invariably have delivered to his house for examination. Once hiswife returned home to find a freshly deceased rhinoceros filling the front hallway. He quicklybecame a leading expert on all kinds of animals living ainct—from platypuses,eas, and other newly discovered marsupials to the hapless dodo and the extinct giantbirds called moas that had roamed New Zealand until eaten out of existence by the Maoris. Hewas the first to describe the archaeopteryx after its discovery in Bavaria in 1861 and the firstto write a formal epitaph for the dodo. Altogether he produced some six hundred anatomicalpapers, a prodigious output.
But it was for his work with dinosaurs that Owen is remembered. He ed the termdinosauria in 1841. It means “terrible lizard” and was a curiously inapt name. Dinosaurs, aswe now know, weren’t all terrible—some were no bigger than rabbits and probably extremelyretiring—and the ohing they most emphatically were not was lizards, which are actually ofa much older (by thirty million years) lineage. Oell aware that the creatures werereptilian and had at his disposal a perfectly good Greek word, herpeton, but for some reasonchose not to use it. Another, more excusable erriven the paucity of spes at the time)was that dinosaurs stitute not o two orders of reptiles: the bird-hipped ornithissand the lizard-hipped sauriss.
Owen was not an attractive person, in appearance or in temperament. A photograph fromhis late middle years shows him as gaunt and sinister, like the villain in a Victorianmelodrama, with long, lank hair and bulging eyes—a face thten babies. In manner hewas cold and imperious, and he was without scruple in the furtherance of his ambitions. Hewas the only person Charles Darwin was ever known to hate. Even Owen’s son (who soonafter killed himself) referred to his father’s “lamentable ess of heart.”
His undoubted gifts as an anatomist allowed him to get away with the most barefaceddishoies. In 1857, the naturalist T. H. Huxley was leafing through a ion ofChurchill’s Medical Directory wheiced that Owen was listed as Professor ofparative Anatomy and Physiology at the Gover School of Mines, which rathersurprised Huxley as that was the position he held. Upon inquiring how Churchill’s had madesu elemental error, he was told that the information had been provided to them by Dr.
Owen himself. A fellow naturalist named Hugh Faler, meanwhile, caught Owen taki for one of his discoveries. Others accused him of borrowing spes, then denyinghe had done so. Owen even fell into a bitter dispute with the Queen’s dentist over the creditfor a theory ing the physiology of teeth.
He did not hesitate to persecute those whom he disliked. Early in his career Owen used hisinflue the Zoological Society to blackball a young man named Rrant whose onlycrime was to have shown promise as a fellow anatomist. Grant was astoo discover thathe was suddenly denied access to the anatomical spes he o duct hisresearch. Uo pursue his work, he sank into an uandably dispirited obscurity.
But no one suffered more from Owen’s unkindly attentions than the hapless andincreasingly tragic Gideon Mantell. After losing his wife, his children, his medical practid most of his fossil colleantell moved to London. There in 1841—the fateful yearin which Owen would achieve his greatest glory for naming and identifying the dinosaurs—Mantell was involved in a terrible act. While crossing Clapham on in a carriage,he somehow fell from his seat, grew entangled in the reins, and was dragged at a gallop h ground by the panicked horses. The act left him bent, crippled, and in i, with a spine damaged beyond repair.
Capitalizing on Mantell’s enfeebled state, Owe about systematically expungingMantell’s tributions from the record, renaming species that Mantell had named yearsbefore and claiming credit for their discovery for himself. Mantell tio try to dinal research but Owen used his influe the Royal Society to ehat most of hispapers were rejected. In 1852, uo bear any more pain or perseaook hisown life. His deformed spine was removed ao the Royal College of Surgeonswhere—and now here’s an irony for you—it laced in the care of Richard Owen, directorof the college’s Hunterian Museum.
But the insults had not quite finished. Soon after Mantell’s death an arrestingly uncharitableobituary appeared ierary Gazette. In it Mantell was characterized as a medioatomist whose modest tributions to paleontology were limited by a “want of exaowledge.” The obituary even removed the discovery of the iguanodon from him aed it io Cuvier and Owen, among others. Though the piece carried no bylihestyle was Owen’s and no one in the world of the natural sces doubted the authorship.
By this stage, however, Owen’s transgressions were beginning to catch up with him. Hisundoing began when a ittee of the Royal Society—a ittee of which he happeo be chairman—decided to award him its highest honor, the Royal Medal, for a paper he hadwritten on ainct mollusc called the belemnite. “However,” as Deborah Cadbury notes inher excellent history of the period, Terrible Lizard, “this piece of work was not quite asinal as it appeared.” The belem turned out, had been discovered four years earlierby an amateur naturalist named ing Pearce, and the discovery had been fully reported ata meeting of the Geological Society. Owen had been at that meeting, but failed to mentionthis when he presented a report of his own to the Royal Society—in whiot ially,he rechristehe creature Belemnites owenii in his own honor. Although Owen was allowedto keep the Royal Medal, the episode left a permaarnish on his reputation, even amonghis few remaining supporters.
Eventually Huxley mao do to Owen what Owen had doo so many others: he hadhim voted off the cils of the Zoological and Royal societies. As a final insult Huxleybecame the new Hunterian Professor at the Royal College of Surgeons.
Owen would never again do important research, but the latter half of his career was devotedto one uionable pursuit for which we all be grateful. In 1856 he became head ofthe natural history se of the British Museum, in which capacity he became the drivingforce behind the creation of London’s Natural History Museum. The grand and belovedGothic heap in South Kensington, opened in 1880, is almost entirely a testament to his vision.
Before Owen, museums were designed primarily for the use and edification of the elite, ahen it was difficult to gain access. In the early days of the British Museum, prospectivevisitors had to make a written application and undergo a brief interview to determine if theywere fit to be admitted at all. They then had to return a sed time to pick up a ticket—that isassuming they had passed the interview—and finally e back a third time to view themuseum’s treasures. Evehey were whisked through in groups and not allowed tolinger. Owen’s plan was to wele everyone, even to the point of encing wmento visit in the evening, and to devote most of the museum’s space to public displays. He evenproposed, very radically, to put informative labels on each display so that people couldappreciate what they were viewing. In this, somewhat uedly, he posed by T. H.
Huxley, who believed that museums should be primarily researstitutes. By making theNatural History Museum an institution for everyone, Owen transformed our expectations ofwhat museums are for.
Still, his altruism in general toward his fellow man did not deflect him from more personalrivalries. One of his last official acts was to lobby against a proposal to erect a statue inmemory of Charles Darwin. In this he failed—though he did achieve a certaied,ient triumph. Today his statue ands a masterly view from the staircase of themain hall iural History Museum, while Darwin and T. H. Huxley are signedsomewhat obscurely to the museum coffee shop, where they stare gravely over peoplesnag on cups of tea and jam doughnuts.
It would be reasoo suppose that Richard Owen’s petty rivalries marked the low pointof eenth-tury paleontology, but in fact worse was to e, this time from overseas. InAmeri the closing decades of the tury there arose a rivalry even more spectacularlyvenomous, if not quite as destructive. It was between twe and ruthless men, EdwardDrinker Cope and Othniel Charles Marsh.
They had mu on. Both were spoiled, driven, self-tered, quarrelsome, jealous,mistrustful, and ever unhappy. Betweehey ged the world of paleontology.
They began as mutual friends and admirers, even naming fossil species after each other,and spent a pleasaogether in 1868. However, something the wroweenthem—nobody is quite sure what—and by the followihey had developed aythat would grow into ing hatred over the hirty years. It is probably safe to saythat no two people iural sces have ever despised each other more.
Marsh, the elder of the two by eight years, was a retiring and bookish fellow, with a trimbeard and dapper manner, who spent little time in the field and was seldom very good atfinding things when he was there. On a visit to the famous dinosaur fields of o Bluff,Wyoming, he failed to notice the bohat were, in the words of one historian, “lyingeverywhere like logs.” But he had the means to buy almost anything he wanted. Although hecame from a modest background—his father was a farmer in upstate New York—his unclewas the supremely rid extraordinarily indulgent financier Gee Peabody. When Marshshowed an i in natural history, Peabody had a museum built for him at Yale andprovided funds suffit for Marsh to fill it with almost whatever took his fancy.
Cope was born more directly into privilege—his father was a rich Philadelphiabusinessman—and was by far the more adventurous of the two. In the summer of 1876 inMontana while Gee Armstrong Custer and his troops were being cut down at Little BigHorn, Cope was out hunting for bones nearby. When it ointed out to him that this robably not the most prudent time to be taking treasures from Indian lands, Cope thought fora minute and decided to press on anyway. He was having too good a season. At one point heran into a party of suspicious Crow Indians, but he mao win them over by repeatedlytaking out and replag his false teeth.
For a decade or so, Marsh and Cope’s mutual dislike primarily took the form of quietsniping, but in 1877 it erupted into grandiose dimensions. In that year a Coloradoschoolteacher named Arthur Lakes found bones near Morrison while out hiking with a friend.
Reizing the bones as ing from a “gigantic saurian,” Lakes thoughtfully dispatchedsome samples to both Marsh and Cope. A delighted Cope sent Lakes a hundred dollars for histrouble and asked him not to tell anyone of his discovery, especially Marsh. fused, Lakesnow asked Marsh to pass the bones on to Cope. Marsh did so, but it was an affront that hewould never fet.
It also marked the start of a war betweewo that became increasingly bitter,underhand, and often ridiculous. They sometimes stooped to oeam’s diggers throwingrocks at the other team’s. Cope was caught at one point jimmying open crates that belooMarsh. They insulted each other in print and each poured s oher’s results.
Seldom—perhaps never—has sce been driven forward more swiftly and successfully byanimosity. Over the several years the two meween them increased the number ofknown dinosaur species in America from 9 to almost 150. Nearly every dinosaur that theaverage person ame—stegosaurus, brontosaurus, diplodocus, triceratops—was found byone or the other of them.
1Unfortunately, they worked in such reckless haste that they oftenfailed to hat a new discovery was something already knowweeheymao “discover” a species calledUintatheres anceps no fewer thay-two times. Ittook years to sort out some of the classifiesses they made. Some are not sorted outyet.
Of the two, Cope’s stific legacy was much the more substantial. In a breathtakinglyindustrious career, he wrote some 1,400 learned papers and described almost 1,300 newspecies of fossil (of all types, not just dinosaurs)—more than double Marsh’s output in bothcases. ight have done even more, but unfortunately he went into a rather precipitatedest in his later years. Having ied a fortune in 1875, he ied unwisely in silverand lost everything. He ended up living in a single room in a Philadelphia b house,surrounded by books, papers, and bones. Marsh by trast finished his days in a splendidmansion in New Haven. Cope died in 1897, Marsh two years later.
In his final years, Cope developed oher iing obsession. It became his earwish to be declared the type spe forHomo sapiens —that is, that his bones would be theofficial set for the human raormally, the type spe of a species is the first set of1The notable exception being the Tyrannosaurus rex, which was found by Barnum Brown in 1902.
bones found, but sino first set of Homo sapiens bos, there was a vacy, whichCope desired to fill. It was an odd and vain wish, but no one could think of any grounds tooppose it. To that end, Cope willed his boo the Wistar Institute, a learned society inPhiladelphia endowed by the desdants of the seemingly inescapable Caspar Wistar.
Unfortunately, after his bones were prepared and assembled, it was found that they showedsigns of incipient syphilis, hardly a feature one would wish to preserve iype spefor one’s own race. So Cope’s petition and his bones were quietly shelved. There is still notype spe for modern humans.
As for the other players in this drama, Owen died in 1892, a few years before Cope orMarsh. Bud ended up by losing his mind and finished his days a gibbering wre alunatic asylum in Clapham, not far from where Mantell had suffered his crippling act.
Mantell’s twisted spine remained on display at the Hunterian Museum for nearly a turybefore being mercifully obliterated by a German bomb in the Blitz. What remained ofMantell’s colle after his death passed on to his children, and much of it was taken to NewZealand by his son Walter, who emigrated there in 1840. Walter became a distinguished Kiwi,eventually attaining the offiinister of Native Affairs. In 1865 he dohe primespes from his father’s colle, including the famous iguanodon tooth, to the ialMuseum (now the Museum of New Zealand) in Wellington, where they have remained eversihe iguanodon tooth that started it all—arguably the most important tooth iology—is no longer on display.
Of course dinosaur hunting didn’t end with the deaths of the great eenth-tury fossilhunters. Io a surprisient it had only just begun. In 1898, the year that fellbetween the deaths of Cope and Marsh, a trove greater by far than anything found before wasdiscovered—noticed, really—at a place called Bone Quarry, only a few miles fromMarsh’s prime hunting ground at o Bluff, Wyoming. There, hundreds and hundreds offossil bones were to be fouhering out of the hills. They were so numerous, in fact, thatsomeone had built a out of them—hehe name. In just the first two seasons, 100,000pounds of a bones were excavated from the site, and tens of thousands of pounds morecame in each of the half dozen years that followed.
The upshot is that by the turn of the tweh tury, paleontologists had literally tons ofold boo pick over. The problem was that they still didn’t have any idea how old any ofthese bones were. Worse, the agreed ages for the Earth couldn’t fortably support thenumbers of eons and ages and epochs that the past obviously tained. If Earth were reallyonly twenty million years old or so, as the great Lord Kelvin insisted, then whole orders ofa creatures must have e into being and go again practically in the samegeological instant. It just made no sense.
Other stists besides Kelvin turheir minds to the problem and came up with resultsthat only deepehe uainty. Samuel Haughton, a respected geologist at Trinity Collegein Dublin, announced aimated age for the Earth of 2,300 million years—way beyondanything anybody else was suggesting. When this was drawn to his attention, he recalculatedusing the same data and put the figure at 153 million years. John Joly, also of Trinity, decidedto give Edmond Halley’s o salts idea a whirl, but his method was based on so manyfaulty assumptions that he was hopelessly adr..
ift. He calculated that the Earth was 89 millionyears old—ahat fit ly enough with Kelvin’s assumptions but unfortunately not withreality.
Such was the fusion that by the close of the eenth tury, depending on whichtext you sulted, you could learn that the number of years that stood between us and thedawn of plex life in the Cambrian period was 3 million, 18 million, 600 million, 794million, or 2.4 billion—or some other number within that range. As late as 1910, one of themost respected estimates, by the Ameri Ge?e Becker, put the Earth’s age at perhaps aslittle as 55 million years.
Just when matters seemed most intractably fused, along came another extraordinaryfigure with a novel approach. He was a bluff and brilliant New Zealand farm boy namedEr Rutherford, and he produced pretty well irrefutable evidehat the Earth was at leastmany hundreds of millions of years old, probably rather more.
Remarkably, his evidence was based on alchemy—natural, spontaneous, stificallycredible, and wholly non-occult, but alchemy heless. on, it turned out, had not beens after all. Aly how that came to be is of course aory.
7 ELEMENTAL MATTERSCHEMISTRY
AS AN ear and respectable sce is often said to date from 1661, whe Boyle of Oxford published The Sceptical Chymist —the first work to distinguishbetwees and alchemists—but it was a slow and ofteic transition. Into theeighteenth tury scholars could feel oddly fortable in both camps—like the GermanJohann Becher, who produced an uionable work on mineralogy called PhysicaSubterranea , but who also was certain that, given the right materials, he could make himselfinvisible.
Perhaps nothier typifies the strange and often actal nature of chemical s its early days than a discovery made by a German named Hennig Brand in 1675. Brandbecame vihat gold could somehow be distilled from human urihe similarity ofcolor seems to have been a factor in his clusion.) He assembled fifty buckets of humanurine, which he kept for months in his cellar. By various redite processes, he verted theurine first into a noxious paste and then into a translut waxy substanone of it yieldedgold, of course, but a strange and iing thing did happen. After a time, the substancebegan to glow. Moreover, when exposed to air, it often spontaneously burst into flame.
The ercial potential for the stuff—which soon became knohosphorus, fromGreek and Latin roots meaning “light bearing”—was not lost on eager businesspeople, but thedifficulties of manufacture made it too costly to exploit. An ounce of phosphorus retailed forsix guineas—perhaps five hundred dollars in today’s money—or more than gold.
At first, soldiers were called on to provide the raw material, but su arra washardly ducive to industrial-scale produ. In the 1750s a Swedish chemist named Karl(or Carl) Scheele devised a way to manufacture phosphorus in bulk without the slop or smellof uri was largely because of this mastery of phosphorus that Sweden became, andremains, a leading produatches.
Scheele was both araordinary araordinarily luckless fellooor pharmacistwith little in the way of advanced apparatus, he discovered eight elements—chlorine, fluorine,manganese, barium, molybdenum, tungsten, nitrogen, and oxygen—and got credit for hem. In every case, his finds were either overlooked or made it into publication aftersomeone else had made the same discovery indepely. He also discovered many usefulpounds, among them ammonia, gly, and tannic acid, and was the first to see theercial potential of chlorine as a bleach—all breakthroughs that made other peopleextremely wealthy.
Scheele’s oable shorting was a curious insisten tasting a little of everythinghe worked with, including suotoriously disagreeable substances as mercury, prussic acid(another of his discoveries), and hydroic acid—a pound so famously poisonous that150 years later Erwin Schr?dinger chose it as his toxin of choi a famous thoughtexperiment (see page 146). Scheele’s rashness eventually caught up with him. In 1786, agedjust forty-three, he was found dead at his workbench surrounded by an array of toxicchemicals, any one of which could have ated for the stunned and terminal look on hisface.
Were the world just and Swedish-speaking, Scheele would have enjoyed universal acclaim.
Instead credit has teo lodge with more celebrated chemists, mostly from the English-speaking world. Scheele discovered oxygen in 1772, but for various heartbreakinglyplicated reasons could not get his paper published in a timely manner. Instead credit wentto Joseph Priestley, who discovered the same element indepely, but latterly, in thesummer of 1774. Even more remarkable was Scheele’s failure to receive credit for thediscovery of chlorine. Nearly all textbooks still attribute chlorine’s discovery to HumphryDavy, who did indeed find it, but thirty-six years after Scheele had.
Although chemistry had e a long way in the tury that separated on and Boylefrom Scheele and Priestley and Henry dish, it still had a long way to ght up to theclosing years of the eighteenth tury (and in Priestley’s case a little beyond) stistseverywhere searched for, and sometimes believed they had actually found, things that justweren’t there: vitiated airs, dephlogisticated marine acids, phloxes, calxes, terraqueousexhalations, and, above all, phlogiston, the substahat was thought to be the active agentin bustion. Somewhere in all this, it was thought, there also resided a mysterious élanvital, the force that brought inanimate objects to life. No one knew where this ethereal essencelay, but two things seemed probable: that you could e with a jolt of electricity (anotion Mary Shelley exploited to full effe her novel Fraein ) and that it existed insome substances but not others, which is why we ended up with two branches of chemistry:
anic (for those substahat were thought to have it) and inanic (for those that didnot).
Someone of insight was o thrust chemistry into the me, and it was theFrench who provided him. His name was Antoine-Laurent Lavoisier. Born in 1743, Lavoisierwas a member of the minor nobility (his father had purchased a title for the family). In 1768,he bought a practig share in a deeply despised institution called the Ferme Générale (eneral Farm), which collected taxes and fees on behalf of the gover. AlthoughLavoisier himself was by all ats mild and fair-mihe pany he worked for washer. For ohing, it did not tax the rich but only the poor, and then often arbitrarily. ForLavoisier, the appeal of the institution was that it provided him with the wealth to follow hisprincipal devotion, sce. At his peak, his personal earnings reached 150,000 livres a year—perhaps $20 million in today’s money.
Three years after embarking on this lucrative career path, he married the fourteen-year-olddaughter of one of his bosses. The marriage was a meeting of hearts and minds both. MadameLavoisier had an incisive intelled soon was w productively alongside her husband.
Despite the demands of his job and busy social life, they mao put in five hours ofsost days—two in the early m and three in the evening—as well as thewhole of Sunday, which they called their jour de bonheur (day of happiness). SomehowLavoisier also found the time to be issioner of gunpowder, supervise the building of awall around Paris to deter smugglers, help found the metric system, and coauthor thehandbook Méthode de Nomenclature Chimique , which became the bible freeing on thenames of the elements.
As a leading member of the Académie Royale des Sces, he was also required to take aninformed and active i in whatever was topical—hypnotism, prison reform, therespiration of is, the water supply of Paris. It was in such a capacity in 1780 thatLavoisier made some dismissive remarks about a heory of bustion that had beensubmitted to the academy by a hopeful young stist. The theory was indeed wrong, but thestist never fave him. His name was Jean-Paul Marat.
The ohing Lavoisier never did was discover a. At a time when it seemed as ifalmost anybody with a beaker, a flame, and some iing powders could discoversomething new—and when, not ially, some two-thirds of the elements were yet to befound—Lavoisier failed to uncover a single o certainly wasn’t for want of beakers.
Lavoisier had thirteen thousand of them in what was, to an almost preposterous degree, thefi private laboratory ience.
Instead he took the discoveries of others and made sense of them. He threw out phlogistonaic airs. He identified oxygen and hydrogen for what they were and gave them boththeir modern names. In short, he helped t rigor, clarity, ahod to chemistry.
And his fancy equipment did in fae in very handy. For years, he and MadameLavoisier occupied themselves with extremely exag studies requiring the fimeasurements. They determined, for instahat a rusting object doesn’t lose weight, aseveryone had long assumed, but gai—araordinary discovery. Somehow as itrusted the object was attrag elemental particles from the air. It was the first realization thatmatter be transformed but not eliminated. If you burhis book now, its matter wouldbe ged to ash and smoke, but the amount of stuff in the universe would be the same.
This became known as the servation of mass, and it was a revolutionary cept.
Unfortunately, it cided with aype of revolution—the Frene—and for this oneLavoisier was entirely on the wrong side.
Not only was he a member of the hated Ferme Générale, but he had enthusiastically builtthe wall that enclosed Paris—an edifice so loathed that it was the first thing attacked by therebellious citizens. Capitalizing on this, in 1791 Marat, now a leading voi the NationalAssembly, denounced Lavoisier and suggested that it was well past time for his hanging.
Soon afterward the Ferme Générale was shut down. Not long after this Marat was murderedin his bath by an aggrieved young woman named Charlotte Corday, but by this time it was toolate for Lavoisier.
In 1793, the Reign of Terror, already intense, ratcheted up to a higher gear. In Oarie Antoie was sent to the guillotihe following month, as Lavoisier and his wifewere making tardy plans to slip away to Scotland, Lavoisier was arrested. In May he andthirty-one fellow farmers-general were brought before the Revolutionary Tribunal (in acourtroom presided over by a bust of Marat). Eight were granted acquittals, but Lavoisier ahers were taken directly to the Place de la Revolution (now the Place de la corde),site of the b９9lｉb?usiest of French guillotines. Lavoisier watched his father-in-law beheaded, thenstepped up and accepted his fate. Less than three months later, on July 27, Robespierrehimself was dispatched in the same way and in the same place, and the Reign of Terrorswiftly ended.
A hundred years after his death, a statue of Lavoisier was erected in Paris and muchadmired until someone pointed out that it looked nothing like him. Under questioning thesculptor admitted that he had used the head of the mathemati and philosopher the Marquisde dorcet—apparently he had a spare—in the hope that no one would notice or, havingnoticed, would care. In the sed regard he was correct. The statue of Lavoisier-cum-dorcet was allowed to remain in place for another half tury until the Sed WorldWar when, one m, it was taken away aed down for scrap.
In the early 1800s there arose in England a fashion for inhaling nitrous oxide, or laughinggas, after it was discovered that its use “was attended by a highly pleasurable thrilling.” Forthe half tury it would be the drug of choice for young people. One learned body, theAskesian Society, was for a time devoted to little else. Theaters put on “laughing gasevenings” where volunteers could refresh themselves with a robust inhalation and theain the audieh their ical staggerings.
It wasn’t until 1846 that a around to finding a practical use for nitrous oxide, asahetic. Goodness knows how many tens of thousands of people suffered unnecessaryagonies uhe surgeon’s knife because no ohought of the gas’s most obvious practicalapplication.
I mention this to make the point that chemistry, having e so far in the eighteeury, rather lost its bearings in the first decades of the eenth, in much the way thatgeology would in the early years of the tweh. Partly it was to do with the limitations ofequipment—there were, for instano trifuges until the sed half of the tury,severely restrig many kinds of experiments—and partly it was social. Chemistry was,generally speaking, a sce for businesspeople, for those who worked with coal and potashand dyes, and not gentlemen, who teo be drawn to geology, natural history, and physics.
(This was slightly less true in tial Europe than in Britain, but only slightly.) It isperhaps telling that one of the most important observations of the tury, Brownian motion,which established the active nature of molecules, was made not by a chemist but by a Scottishbotanist, Robert Brown. (What Brown noticed, in 1827, was that tiny grains of pollensuspended in water remained indefinitely in motion no matter how long he gave them tosettle. The cause of this perpetual motion—he as of invisible molecules—waslong a mystery.)Things might have been worse had it not been for a splendidly improbable character namedt von Rumford, who, despite the grandeur of his title, began life in Woburn,Massachusetts, in 1753 as plain Benjamin Thompson. Thompson was dashing and ambitious,“handsome iure and figure,” occasionally ceous and exceedingly bright, butuntroubled by anything so invenieng as a scruple. At een he married a rich widowfourteen years his senior, but at the outbreak of revolution in the ies he unwisely sidedwith the loyalists, for a time spying on their behalf. Ieful year of 1776, fag arrest“for lukewarmness in the cause of liberty,” he abandoned his wife and child and fled justahead of a mob of anti-Royalists armed with buckets of hot tar, bags of feathers, and anear desire to adorn him with both.
He decamped first to England and then to Germany, where he served as a military advisorto the gover of Bavaria, so impressing the authorities that in 1791 he was named tvon Rumford of the Holy Roman Empire. While in Munich, he also designed and laid out thefamous park known as the English Garden.
Iween these uakings, he somehow found time to duct a good deal of solidsce. He became the world’s foremost authority on thermodynamid the first toelucidate the principles of the ve of fluids and the circulation of o currents. Healso ied several useful objects, including a drip coffeemaker, thermal underwear, and atype e still known as the Rumford fireplace. In 1805, during a sojourn in France, hewooed and married Madame Lavoisier, widow of Antoine-Laurent. The marriage was not asuccess and they soon parted. Rumford stayed on in France, where he died, universallyesteemed by all but his former wives, in 1814.
But our purpose iioning him here is that in 1799, during a paratively briefinterlude in London, he fouhe Royal Institutio another of the many learnedsocieties that popped into being all over Britain ie eighteenth and early eeuries. For a time it was almost the only institution of standing to actively promote theyoung sce of chemistry, and that was thanks almost eo a brilliant young mannamed Humphry Davy, who oihe institution’s professor of chemistry shortlyafter its iion and rapidly gained fame as an outstandiurer and productiveexperimentalist.
Soon after taking up his position, Davy began to bang out new elements oeranother—potassium, sodium, magnesium, calcium, strontium, and aluminum or aluminium,depending on which branch of English you favor.
1He discovered so many elements not somuch because he was serially astute as because he developed an ingenious teique ofapplyiricity to a molten substarolysis, as it is known. Altogether hediscovered a dozes, a fifth of the known total of his day. Davy might have done farmore, but unfortunately as a young man he developed an abiding attat to the buoyantpleasures of nitrous oxide. He grew so attached to the gas that he drew on it (literally) three orfour times a day. Eventually, in 1829, it is thought to have killed him.
Fortunately more sober types were at work elsewhere. In 1808, a dour Quaker named JohnDalton became the first person to intimate the nature of an atom (progress that will bediscussed more pletely a little further on), and in 1811 an Italian with the splendidlyoperatiame of Lorenzo Romano Amadeo Carlo Avogadro, t of Quarequa ao,made a discovery that would prove highly signifit in the long term—namely, that twoequal volumes of gases of any type, if kept at the same pressure and temperature, will taiiumbers of molecules.
Two things were notable about Avogadro’s Principle, as it became known. First, itprovided a basis for more accurately measuring the size a of atoms. UsingAvogadro’s mathematics, chemists were eventually able to work out, for instahat atypical atom had a diameter of 0.00000008 timeters, which is very little indeed. Andsed, almost no one knew about Avogadro’s appealingly simple principle for almost fiftyyears.
2Partly this was because Avogadro himself was a retiring fellow—he worked alone,corresponded very little with fellow stists, published feers, and attended ings—but also it was because there were ings to attend and few chemicaljournals in which to publish. This is a fairly extraordinary fact. The Industrial Revolution was1The fusiohe aluminum/aluminium spelling arose b cause of some uncharacteristidecisiveness onDavys part. When he first isolated the element in 1808, he called it alumium. For son reasohought better ofthat and ged it to aluminum four years later. Ameris dutifully adopted the erm, but mai Britishusers disliked aluminum, pointing out that it disrupted the -ium patterablished by sodium, calcium, andstrontium, so they added a vowel and syllable.
2The principle led to the much later adoption of Avogadros number, a basiit of measure iry, whichwas named for Avogadro long after his death. It is the number of molecules found in 2.016 grams of hydrogengas (or an equal volume of any as). Its value is placed at 6.0221367 x 1023, which is an enormously largenumber. Chemistry students have long amused themselves by puting just how large a is, so I report that it is equivalent to the number of pop kernels o cover the Uates to a depth of ninemiles, or cupfuls of water in the Pacific O, or soft drink s that would, evenly stacked, cover the Earth to adepth of 200 miles. An equivalent number of Ameri pennies would be enough to make every person oha dollar trillio is a big number.
driven in large part by developments iry, a as an anized sce chemistrybarely existed for decades.
The Chemical Society of London was not founded until 1841 and didn’t begin to produce aregular journal until 1848, by which time most learned societies in Britain—Geological,Geographical, Zoological, Horticultural, and Linnaean (for naturalists and botanists)—were atleast twenty years old and often much more. The rival Institute of Chemistry didn’t e intobeing until 1877, a year after the founding of the Ameri Chemical Society. Becausechemistry was so slow to get anized, news of Avogadro’s important breakthrough of 1811didn’t begin to bee general until the first iional chemistry gress, in Karlsruhe,in 1860.
Because chemists for so long worked in isolation, ventions were slow to emerge. Untilwell into the sed half of the tury, the formula H2O2might mean water to one chemistbut hydrogen peroxide to another. C2H4could signify ethylene or marsh gas. There was hardlya molecule that was uniformly represented everywhere.
Chemists also used a bewildering variety of symbols and abbreviations, often self-ied.
Sweden’s J. J. Berzelius brought a mueeded measure of order to matters by decreeing thatthe elements be abbreviated on the basis of their Greek or Latin names, which is why theabbreviation for iron is Fe (from the Latin ferrum ) and that for silver is Ag (from the Latium ). That so many of the other abbreviations accord with their English names (N fornitrogen, O for Oxygen, H for hydrogen, and so on) reflects English’s Latiure, not itsexalted status. To indicate the number of atoms in a molecule, Berzelius employed asuperscript notation, as in H2O. Later, for no special reason, the fashion became to rehenumber as subscript: H2O.
Despite the occasional tidyings-up, chemistry by the sed half of the eenth turywas in something of a mess, which is why everybody was so pleased by the rise toprominen 1869 of an odd and crazed-looking professor at the Uy of St. Petersburgnamed Dmitri Ivanovich Mendeleyev.
Mendeleyev (also sometimes spelled Mendeleev or Mendeléef) was born in 1834 atTobolsk, in the far west of Siberia, into a well-educated, reasonably prosperous, and verylarge family—se, in fact, that history has lost track of exactly how many Mendeleyevsthere were: some sources say there were fourteen children, some say seventeen. All agree, atany rate, that Dmitri was the you. Luck was not always with the Mendeleyevs. WhenDmitri was small his father, the headmaster of a local school, went blind and his mother hadto go out to work. Clearly araordinary woman, she eventually became the manager of asuccessful glass factory. All went well until 1848, when the factory burned down and thefamily was reduced to penury. Determio get her you child an education, theindomitable Mrs. Mendeleyev hitchhiked with young Dmitri four thousand miles to St.
Petersburg—that’s equivalent to traveling from London to Equatorial Guinea—and depositedhim at the Institute of Pedagogy. Worn out by her efforts, she died soon after.
Mendeleyev dutifully pleted his studies aually landed a position at the loiversity. There he was a petent but not terribly outstanding chemist, known more forhis wild hair and beard, which he had trimmed just once a year, than for his gifts in thelaboratory.
However, in 1869, at the age of thirty-five, he began to toy with a way te theelements. At the time, elements were normally grouped in two ways—either by atomic weight(using Avogadro’s Principle) or by on properties (whether they were metals ases,for instance). Mendeleyev’s breakthrough was to see that the two could be bined in asiable.
As is often the way in sce, the principle had actually been anticipated three yearspreviously by an amateur chemist in England named John Newlands. He suggested that whes were arranged by weight they appeared to repeat certain properties—in a seoharmo every eighth place along the scale. Slightly unwisely, for this was an ideawhose time had not quite yet e, Newlands called it the Law of Octaves and likehearrao the octaves on a piano keyboard. Perhaps there was something in Newlands’smanner of presentation, but the idea was sidered fually preposterous and widelymocked. At gatherings, droller members of the audience would sometimes ask him if he couldget his elements to play them a little tune. Disced, Newlands gave up pushing the ideaand soon dropped from view altogether.
Mendeleyev used a slightly different approach, plag his elements into groups of seven,but employed fually the same principle. Suddenly the idea seemed brilliant andwondrously perceptive. Because the properties repeated themselves periodically, the iionbecame known as the periodic table.
Mendeleyev was said to have been inspired by the card game known as solitaire in NorthAmerid patience elsewhere, wherein cards are arranged by suit horizontally and bynumber vertically. Using a broadly similar cept, he arrahe elements in horizontalrows called periods aical ns called groups. This instantly showed o ofrelationships when read up and down and another when read from side to side. Specifically,the vertical ns put together chemicals that have similar properties. Thus copper sits ontop of silver and silver sits on top of gold because of their chemical affinities as metals, whilehelium, neon, and argon are in a n made up of gases. (The actual, formal determinant inthe is something called their ele valences, for which you will have to enroll innight classes if you wish an uanding.) The horizontal rows, meanwhile, arrahechemicals in asding order by the number of protons in their nuclei—what is known as theiratomiumber.
The structure of atoms and the significe of protons will e in a following chapter, sofor the moment all that is necessary is to appreciate the anizing principle: hydrogen hasjust one proton, and so it has an atomiumber of one and es first on the chart; uraniumhas wo protons, and so it es he end and has an atomiumber of wo.
In this sense, as Philip Ball has pointed out, chemistry really is just a matter of ting.
(Atomiumber, ially, is not to be fused with atomic weight, which is the numberof protons plus the number of rons in a give.) There was still a great deal thatwasn’t known or uood. Hydrogen is the most o in the universe, ano one would guess as much for ahirty years. Helium, the seost abunda, had only been found the year before—its existence hadn’t even been suspectedbefore that—and then not oh but in the Sun, where it was found with a spectroscopeduring a solar eclipse, which is why it honors the Greek sun god Helios. It wouldn’t beisolated until 1895. Even so, thanks to Mendeleyev’s iion, chemistry was now on a firmfooting.
For most of us, the periodic table is a thing of beauty in the abstract, but for chemists itestablished an immediate orderliness and clarity that hardly be overstated. “Without adoubt, the Periodic Table of the Chemical Elements is the most elegant anizational chartever devised,” wrote Robert E. Krebs in The History and Use of Our Earth’s ChemicalElements, and you find similar ses in virtually every history of chemistry in print.
Today we have “120 or so” knows—wo naturally ones plus acouple of dozen that have beeed in labs. The actual number is slightly tentiousbecause the heavy, synthesized eleme for only millionths of seds and chemistssometimes argue over whether they have really beeed or not. In Mendeleyev’s dayjust sixty-three elements were known, but part of his cleverness was to realize that theelements as then known didn’t make a plete picture, that many pieces were missing. Histable predicted, with pleasing accuracy, where new elements would slot ihey werefound.
No one knows, ially, how high the number of elements might go, though anythingbeyond 168 as an atomic weight is sidered “purely speculative,” but what is certain is thatanything that is found will fit ly into Mendeleyev’s great scheme.
The eenth tury held one last great surprise for chemists. It began in 1896 whenHenri Becquerel in Paris carelessly left a packet of uranium salts on a ed photographicplate in a drawer. Wheook the plate out some time later, he was surprised to discoverthat the salts had burned an impression in it, just as if the plate had been exposed to light. Thesalts were emitting rays of some sort.
sidering the importance of what he had found, Becquerel did a very strahing: heturhe matter over to a graduate student for iigation. Fortuhe student was aret émigré from Poland named Marie Curie. W with her new husband, Pierre, Curiefound that certain kinds of rocks poured out stant araordinary amounts of energy,yet without diminishing in size or ging in aable way. What she and her husbandcouldn’t know—what no one could know until Einstein explaihings the followingdecade—was that the rocks were verting mass into energy in an exceedingly effit way.
Marie Curie dubbed the effect “radioactivity.” In the process of their work, the Curies alsofound two new elements—polonium, which they named after her native try, and radium.
In 1903 the Curies and Becquerel were jointly awarded the Nobel Pribbr>ze in physics. (MarieCurie would win a sed prize, iry, in 1911, the only person to win in bothchemistry and physics.)At McGill Uy in Mohe young New Zealand–born Er Rutherford becameied in the new radioactive materials. With a colleague named Frederick Soddy hediscovered that immense reserves of energy were bound up in these small amounts of matter,and that the radioactive decay of these reserves could at for most of the Earth’s warmth.
They also discovered that radioactive elements decayed into other elements—that one dayyou had an atom of uranium, say, and the you had an atom of lead. This was trulyextraordinary. It was alchemy, pure and simple; no one had ever imagihat such a thingcould happen naturally and spontaneously.
Ever the pragmatist, Rutherford was the first to see that there could be a valuable practicalapplication in this. He noticed that in any sample of radioactive material, it always took thesame amount of time for half the sample to decay—the celebrated half-life—and that thissteady, reliable rate of decay could be used as a kind of clock. By calculating backwards fromhow much radiation a material had now and how swiftly it was deg, you could work outits age. He tested a piece of pitchblehe principal ore of uranium, and found it to be 700million years old—very much older than the age most people were prepared to grant theEarth.
In the spring of 1904, Rutherford traveled to London to give a lecture at the RoyalInstitution—the august anization founded by t von Rumford only 105 years before,though that powdery and periwigged age now seemed a distant eon pared with the roll-your-sleeves-up robustness of the late Victorians. Rutherford was there to talk about his newdisiion theory of radioactivity, as part of which he brought out his piece of pitchblende.
Tactfully—for the aging Kelvin resent, if not always fully awake—Rutherford hat Kelvin himself had suggested that the discovery of some other source of heat wouldthrow his calculations out. Rutherford had found that other source. Thanks to radioactivity theEarth could be—and self-evidently was—much older thawenty-four million yearsKelvin’s calculations allowed.
Kelvin beamed at Rutherford’s respectful presentation, but was in famoved. He neveraccepted the revised figures and to his dying day believed his work on the age of the Earth hismost astute and important tribution to sce—far greater than his work onthermodynamics.
As with most stific revolutions, Rutherford’s new findings were not universallyaccepted. John Joly of Dublin strenuously insisted well into the 1930s that the Earth was nomore thay-nine million years old, and was stopped only then by his owh. an to worry that Rutherford had now giveoo much time. But even withradiometric dating, as decay measurements became known, it would be decades before we gotwithin a billion years or so of Earth’s actual age. Sce was on the right track, but still wayout.
Kelvin died in 1907. That year also saw the death of Dmitri Mendeleyev. Like Kelvin, hisproductive work was far behind him, but his deing years were notably less serene. As heaged, Mendeleyev became increasingly etric—he refused to aowledge the existenceof radiation or the ele or anything else much that was new—and difficult. His finaldecades were spent mostly st out of labs aure halls all across Europe. In 1955,element 101 was named mendelevium in his honor. “Appropriately,” notes Paul Strathern, “itis an unstable element.”
Radiation, of course, went on and on, literally and in ways nobody expected. In the early1900s Pierre Curie began to experience clear signs of radiation siess—notably dull achesin his bones and ic feelings of malaise—which doubtless would have progressedunpleasantly. We shall never know for certain because in 1906 he was fatally run over by acarriage while crossing a Paris street.
Marie Curie spent the rest of her life w with distin in the field, helping to foundthe celebrated Radium Institute of the Uy of Paris in 1914. Despite her two NobelPrizes, she was never elected to the Academy of Sces, in large part because after the deathof Pierre she ducted an affair with a married physicist that was suffitly indiscreet tosdalize even the French—or at least the old men who ran the academy, which is perhapsanother matter.
For a long time it was assumed that anything so miraculously eic as radioactivitymust be beneficial. For years, manufacturers of toothpaste and laxatives put radioactivethorium in their products, and at least until the late 1920s the Glen Springs Hotel in the FingerLakes region of New York (and doubtless others as well) featured with pride the therapeuticeffects of its “Radioactive mineral springs.” Radioactivity wasn’t banned in erproducts until 1938. By this time it was much too late for Madame Curie, who died ofleukemia in 1934. Radiation, in fact, is so pernicious and long lasting that even now herpapers from the 1890s—even her cookbooks—are too dangerous to handle. Her lab books arekept in lead-lined boxes, and those who wish to see them must don protective clothing.
Thanks to the devoted and unwittingly high-risk work of the first atomic stists, by theearly years of the tweh tury it was being clear that Earth was uionablyvenerable, though another half tury of sce would have to be done before anyone couldfidently say quite how venerable. Sce, meanwhile, was about to get a new age of itsowomie.
PART III A NEW AGE DAhysicist is the atoms’ way of thinking about atoms.
-Anonymous
8 EINSTEIN’S UNIVERSEAS
THE EENTH tury drew to a close, stists could reflect with satisfa thatthey had pinned down most of the mysteries of the physical world: electricity, magism,gases, optics, acoustics, kiics, and statistical meics, to name just a few, all had falleninto order before them. They had discovered the X ray, the cathode ray, the ele, andradioactivity, ied the ohm, the watt, the Kelvin, the joule, the amp, and the little erg.
If a thing could be oscillated, accelerated, perturbed, distilled, bined, weighed, or madegaseous they had do, and in the process produced a body of universal laws so weightyand majestic that we still tend to write them out in capitals: the Eleagic Field Theoryof Light, Richter’s Law of Reciprocal Proportions, Charles’s Law of Gases, the Law ofbining Volumes, the Zeroth Law, the Valence cept, the Laws of Mass As, andothers beyond ting. The whole world ged and chuffed with the maery andinstruments that their iy had produced. Many wise people believed that there wasnothing much left for sce to do.
In 1875, when a young German in Kiel named Max Planck was deg whether to devotehis life to mathematics or to physics, he was urged most heartily not to choose physicsbecause the breakthroughs had all been made there. The iury, he was assured,would be one of solidation and refi, not revolution. Planck didn’t listeudiedtheoretical physid threw himself body and soul into work oropy, a process at theheart of thermodynamics, which seemed to hold much promise for an ambitious young man.
1In 1891 he produced his results and learo his dismay that the important work oropyhad in fact been done already, in this instance by a retiring scholar at Yale Uy namedJ. Willard Gibbs.
Gibbs is perhaps the most brilliant person that most people have never heard of. Modest tothe point of near invisibility, he passed virtually the whole of his life, apart from three yearsspent studying in Europe, within a three-block area bounded by his house and the Yalecampus in New Haven, ecticut. For his first ten years at Yale he didn’t even bother todraw a salary. (He had indepe means.) From 1871, when he joihe uy as aprofessor, to his death in 1903, his courses attracted an average of slightly over oudent asemester. His written work was difficult to follow and employed a private form of notationthat many found inprehensible. But buried among his are formulations were insightsof the loftiest brilliance.
In 1875–78, Gibbs produced a series of papers, collectively titledOn the Equilibrium ofHeterogeneous Substances , that dazzlingly elucidated the thermodynamic principles of, well,1Specifically it is a measure of randomness or disorder in a system. Darrell Ebbing, iextbook GeneralChemistry, very usefully suggests thinking of a deck of cards. A new pack fresh out of the box, arranged by suitand in sequence from ace to king, be said to be in its ordered state. Shuffle the cards and you put them in adisordered state. Entropy is a way of measuring just how disordered that state is and of determining thelikelihood of particular outes with further shuffles. Of course, if you wish to have any observationspublished in a respectable journal you will need also to uand additional cepts such as thermalnonuniformities, lattice distances, and stoietric relationships, but thats the general idea.
nearly everything—“gases, mixtures, surfaces, solids, phase ges . . . chemical reas,eleical cells, sedimentation, and osmosis,” to quote William H. Cropper. In esse Gibbs did was show that thermodynamics didn’t apply simply to heat and energy at thesort of large and noisy scale of the steam engine, but was also present and iial at theatomic level of chemical reas. Gibbs’s Equilibrium has been called “the Principia ofthermodynamics,” but for reasons that defy speculation Gibbs chose to publish theselandmark observations iransas of the ecticut Academy of Arts and Sces,a journal that mao be obscure even in ecticut, which is why Planck did not hearof him until too late.
Undaunted—well, perhaps mildly daunted—Planck turo other matters.
2We shall turnto these ourselves in a moment, but first we must make a slight (but relevant!) detour toCleveland, Ohio, and an institution then known as the Case School of Applied Sce. There,in the 1880s, a physicist of early middle years named Albert Michelson, assisted by his friendthe chemist Edward Morley, embarked on a series of experiments that produced curious anddisturbis that would have great ramifications for much of what followed.
What Michelson and Morley did, without actually intending to, was undermine alongstanding belief in something called the luminiferous ether, a stable, invisible, weightless,friless, and unfortunately wholly imaginary medium that was thought to permeate theuniverse. ceived by Descartes, embraced by on, and veed by nearly everyoneever sihe ether held a position of absolute trality in eenth-tury physics as away of explaining how light traveled across the emptiness of space. It was especially neededin the 1800s because light aromagism were now seen as waves, which is to saytypes of vibrations. Vibrations must occur in something; hehe need for, and lastiion to, aher. As late as 1909, the great British physicist J. J. Thomson was insisting:
“The ether is not a fantastic creation of the speculative philosopher; it is as essential to us asthe air we breathe”—this more than four years after it retty intestably establishedthat it did. People, in short, were really attached to the ether.
If you o illustrate the idea of eenth-tury America as a land of opportunity,you could hardly improve on the life of Albert Michelson. Born in 1852 on the German–Polish border to a family of poor Jewish merts, he came to the Uates with hisfamily as an infant and grew up in a mining camp in California’s gold rush try, where hisfather ran a dry goods business. Too poor to pay for college, he traveled to Washington, D.d took to l by the front door of the White House so that he could fall in besidePresident Ulysses S. Grant when the President emerged for his daily stitutional. (It wasclearly a more i age.) In the course of these walks, Michelson so ingratiated himself tothe President that Grant agreed to secure for him a free place at the U.S. Naval Academy. Itwas there that Michelson learned his physics.
Ten years later, by norofessor at the Case School in Cleveland, Michelson becameied in trying to measure something called the ether drift—a kind of head windproduced by moving objects as they plowed through space. One of the predis ofonian physics was that the speed of light as it pushed through the ether should vary with2Planck was often unlucky in life. His beloved first wife died early, in 1909, and the younger of his two sonswas killed in the First World War. He also had twin daughters whom he adored. One died giving birth. Thesurviving twio look after the baby and fell in love with her sisters husband. They married and two yearslater she died in childbirth. In 1944, when Planck was eighty-five, an Allied bomb fell on his house and he losteverything-papers, diaries, a lifetime of accumulations. The following year his surviving son was caught in aspiracy to assassiler and executed.
respect to an observer depending oher the observer was moving toward the source oflight or away from it, but no one had figured out a way to measure this. It occurred toMichelson that for half the year the Earth is traveling toward the Sun and for half the year it ismoving away from it, and he reasohat if you took careful enough measurements atopposite seasons and pared light’s travel time betweewo, you would have youranswer.
Michelson talked Alexander Graham Bell, newly enriched ior of the telephone, intoproviding the funds to build an ingenious aive instrument of Michelson’s owndevising called an interferometer, which could measure the velocity of light with greatprecision. Then, assisted by the genial but shadowy Morley, Michelson embarked on years offastidious measurements. The work was delicate and exhausting, and had to be suspended fora time to permit Michelson a brief but prehensive nervous breakdown, but by 1887 theyhad their results. They were not at all what the two stists had expected to find.
As Caltech astrophysicist Kip S. Thorne has written: “The speed of light turned out to bethe same inall dires and at all seasons.” It was the first hint in two hundred years—ily two hundred years, in fact—that on’s laws might not apply all the timeeverywhere. The Michelson-Morley oute became, in the words of William H. Cropper,“probably the most famous ive result in the history of physics.” Michelson was awardeda Nobel Prize in physics for the work—the first Ameri so honored—but not for twentyyears. Meanwhile, the Michelson-Morley experiments would hover unpleasantly, like a mustysmell, in the background of stific thought.
Remarkably, ae his findings, wheweh tury dawned Michelsonted himself among those who believed that the work of sce was nearly at an end,with “only a few turrets and pino be added, a few roof bosses to be carved,” in thewords of a writer in Nature.
In fact, of course, the world was about to enter a tury of sce where many peoplewouldn’t uand anything and none would uand everything. Stists would soonfind themselves adrift in a bewildering realm of particles and antiparticles, where things popin and out of existen spans of time that make nanoseds look plodding and uful,where everything is strange. Sce was moving from a world of macrophysics, whereobjects could be seen and held and measured, to one of microphysics, where events transpirewith unimaginable swiftness on scales far below the limits of imagining. We were about toehe quantum age, and the first person to push on the door was the so-far unfortunateMax Planck.
In 1900, now a theoretical physicist at the Uy of Berlin and at the somewhatadvanced age of forty-two, Planveiled a new “quantum theory,” which posited thatenergy is not a tinuous thing like flowing water but es in individualized packets,which he called quanta. This was a novel cept, and a ?good one. In the short term it wouldhelp to provide a solution to the puzzle of the Michelson-Morley experiments in that itdemonstrated that light be a wave after all. In the loerm it would lay thefoundation for the whole of modern physics. It was, at all events, the first clue that the worldwas about to ge.
But the landmark event—the dawn of a new age—came in 1905, when there appeared inthe German physics journal Annalen der Physik a series of papers by a young Swissbureaucrat who had no uy affiliation, no access to a laboratory, and the regular use ofno library greater than that of the national patent offi Bern, where he was employed as ateical examihird class. (An application to be promoted to teical examiner sedclass had retly beeed.)His name was Albert Einstein, and in that oful year he submitted to Annalen derPhysik five papers, of which three, acc to C. P. Snow, “were among the greatest iory of physics”—one examining the photoelectric effect by means of Planck’s newquantum theory, one on the behavior of small particles in suspension (what is known asBrownian motion), and olining a special theory of relativity.
The first won its author a Nobel Prize and explaihe nature of light (and also helped tomake television possible, among other things).
3The sed provided proof that atoms doindeed exist—a fact that had, surprisingly, been in some dispute. The third merely gedthe world.
Einstein was born in Ulm, in southern Germany, in 1879, but grew up in Munich. Little inhis early life suggested the greato e. Famously he didn’t learn to speak until he wasthree. In the 1890s, his father’s electrical business failing, the family moved to Milan, butAlbert, by now a teenager, went to Switzerland to tinue his education—though he failedhis college entrance exams on the first try. In 1896 he gave up his German citizenship toavoid military scription aered the Zurich Polyteistitute on a four-year coursedesigo out high school sce teachers. He was a bright but not outstandingstudent.
In 1900 he graduated and within a few months was beginning to tribute papers toAnnalen der Physik. His very first paper, on the physics of fluids in drinking straws (of allthings), appeared in the same issue as Planck’s quantum theory. From 1902 to 1904 heproduced a series of papers on statistical meily to discover that the quietlyproductive J. Willard Gibbs in ecticut had dohat work as well, in his ElementaryPrinciples of Statistical Meics of 1901.
At the same time he had fallen in love with a fellow student, a Hungarian named MilevaMari 1901 they had a child out of wedlock, a daughter, who was discreetly put up foradoptioein never saw his child. Two years later, he and Maric were married. Iween these events, in 1902, Eiook a job with the Swiss patent office, where hestayed for the seven years. He ehe work: it was challenging enough to engage hismind, but not so challenging as to distract him from his physics. This was the backgroundagainst which he produced the special theory of relativity in 1905.
Called “On the Electrodynamioving Bodies,” it is one of the most extraordinarystific papers ever published, as much for how it resented as for what it said. It hadno footnotes or citations, tained almost no mathematics, made ion of any workthat had influenced or preceded it, and aowledged the help of just one individual, a3Einstein was honored, somewhat vaguely, "for services to theoretical physics." He had to wait sixteen years, till1921, to receive the award-quite a long time, all things sidered, but nothing at all pared with FrederickReines, who detected the rino in 1957 but wasnt honored with a Nobel until 1995, thirty-eight years later, orthe Germa Ruska, who ied the eleicroscope in 1932 and received his Nobel Prize in 1986,more than half a tury after the fact. Sinobel Prizes are never awarded posthumously, loy be asimportant a factor as iy for prizewinners.
colleague at the patent offiamed Michele Besso. It was, wrote C. P. Snow, as if Einstein“had reached the clusions by pure thought, unaided, without listening to the opinions ofothers. To a surprisingly large extent, that is precisely what he had done.”
His famous equation, E =mc2, did not appear with the paper, but came in a brief supplementthat followed a few months later. As you will recall from school days, E in the equation standsfor energy, m for mass, and c2for the speed of light squared.
In simplest terms, what the equation says is that mass and energy have an equivalence.
They are two forms of the same thing: energy is liberated matter; matter is energy waiting tohappen. Since c2(the speed of light times itself) is a truly enormous number, what theequation is saying is that there is a huge amount—a really huge amount—of energy bound upin every material thing.
4You may not feel outstandingly robust, but if you are an average-sized adult you willtain within your modest frame han 7 x 1018joules of potential energy—enough toexplode with the force of thirty very large hydrogen bombs, assuming you knew how toliberate it and really wished to make a point. Everything has this kind of energy trappedwithin it. We’re just not very good at getting it out. Even a uranium bomb—the mosteic thing roduced yet—releases less than 1 pert of the energy it couldrelease if only we were more ing.
Among much else, Einstein’s theory explained how radiation worked: how a lump ofuranium could throw out stant streams of high-level energy without melting away like anice cube. (It could do it by verting mass to energy extremely effitly à laE =mc2.) Itexplained how stars could burn for billions of years without rag through their fuel. (Ditto.)At a stroke, in a simple formula, Einstein endowed geologists and astronomers with theluxury of billions of years. Above all, the special theory showed that the speed of light wasstant and supreme. Nothing could overtake it. It brought light (no pun intended, exactly) tothe very heart of our uanding of the nature of the universe. Not ially, it alsosolved the problem of the luminiferous ether by making it clear that it did. Einsteingave us a universe that didn’t .
Physicists as a rule are not overatteo the pronous of Swiss patent officeclerks, and so, despite the abundance of useful tidings, Einstein’s papers attracted little notice.
Having just solved several of the deepest mysteries of the universe, Einstein applied for a jobas a uy lecturer and was rejected, and then as a high school teacher and was rejectedthere as well. So he went back to his job as an examihird class, but of course he keptthinking. He hadn’t even e close to finishi.
When the poet Paul Valéry once asked Einstein if he kept a notebook to record his ideas,Einstein looked at him with mild but genuine surprise. “Oh, that’s not necessary,” he replied.
“It’s so seldom I have one.” I need hardly point out that when he did get o teo begood. Einstein’s idea was one of the greatest that anyone has ever had—indeed.he verygreatest, acc to Boorse, Motz, and Weaver ihoughtful history of atomic sce.
4How c came to be the symbol for the speed of light is something of a mystery, but David Bodanis suggests itprobably came from the Latin celeritas, meaning swiftness. The relevant volume of the Oxford EnglishDiary, piled a decade before Einsteins theory, reizes c as a symbol for many things, from carbonto cricket, but makes ion of it as a symbol fht or swiftness.
“As the creation of a single mind,” they write, “it is undoubtedly the highest intellectualachievement of humanity,” which is of course as good as a pliment get.
In 1907, or so it has sometimes been written, Albert Einstein saw a workman fall off a roofand began to think about gravity. Alas, like many good stories this one appears to beapocryphal. Acc to Einstein himself, he was simply sitting in a chair when the problemof gravity occurred to him.
Actually, what occurred to Einstein was something more like the beginning of a solution tothe problem of gravity, si had been evident to him from the outset that ohing missingfrom the special theory was gravity. What was “special” about the special theory was that itdealt with things moving in an essentially unimpeded state. But what happened when a thingin motion—light, above all—entered an obstacle such as gravity? It was a question thatwould occupy his thoughts for most of the decade ao the publication in early1917 of a paper entitled “ological siderations on the General Theory of Relativity.”
The special theory of relativity of 1905 rofound and important piece of work, ofcourse, but as C. P. Snow once observed, if Einstein hadn’t thought of it when he did someoneelse would have, probably within five years; it was an idea waiting to happen. But the geheory was something else altogether. “Without it,” wrote Snow in 1979, “it is likely that weshould still be waiting for the theory today.”
With his pipe, genially self-effag manner, arified hair, Einstein was too splendida figure to remain permaly obscure, and in 1919, the war over, the world suddenlydiscovered him. Almost at once his theories of relativity developed a reputation for beingimpossible for an ordinary person to grasp. Matters were not helped, as David Bodanis pointsout in his superb book E=mc2, when the New York Times decided to do a story, and—forreasons that ever fail to excite wonder—sent the paper’s golfing correspo, oneHenry Crouch, to duct the interview.
Crouch was hopelessly out of his depth, and got nearly everything wrong. Among the morelasting errors in his report was the assertion that Einstein had found a publisher daring enoughto publish a book that only twelve men “in all the world could prehend.” There was nosuch book, no such publisher, no such circle of learned men, but the notion stuyway.
Soon the number of people who could grasp relativity had been reduced even further in thepopular imagination—and the stific establishment, it must be said, did little to disturb themyth.
When a journalist asked the British astronomer Sir Arthur Eddington if it was true that hewas one of only three people in the world who could uaein’s relativity theories,Eddington sidered deeply for a moment and replied: “I am trying to think who the thirdperson is.” In fact, the problem with relativity wasn’t that it involved a lot of differentialequations, Lorentz transformations, and other plicated mathematics (though it did—eveein needed help with some of it), but that it was just so thhly nonintuitive.
In essence what relativity says is that spad time are not absolute, but relative to boththe observer and to the thing being observed, and the faster one moves the more pronouhese effects bee. We ever accelerate ourselves to the speed of light, and the harderwe try (and faster we go) the more distorted we will bee, relative to an outside observer.
Almost at once popularizers of sce tried to e up with ways to make these ceptsaccessible to a general audience. One of the more successful attempts—ercially atleast—was The ABC of Relativity by the mathemati and philosopher Bertrand Russell. Init, Russell employed an image that has been used many times since. He asked the reader toenvision a train one hundred yards long moving at 60 pert of the speed of light. Tosomeoanding on a platform watg it pass, the train would appear to be oyyards long and everything on it would be similarly pressed. If we could hear thepassengers orain speak, their voices would sound slurred and sluggish, like a recordplayed at too sloeed, and their movements would appear similarly ponderous. Even theclocks orain would seem to be running at only four-fifths of their normal speed.
However—and here’s the thing—people orain would have no sense of thesedistortions. To them, everything orain would seem quite normal. It would be we oform who looked weirdly pressed and slowed down. It is all to do, you see, with yourpositioive to the moving object.
This effect actually happens every time you move. Fly across the Uates, and youwill step from the plane a quinzillionth of a sed, or something, youhan those you leftbehind. Even in walking across the room you will very slightly alter your own experieime and space. It has been calculated that a baseball thrown at a hundred miles an hour willpick up 0.000000000002 grams of mass on its way to home plate. So the effects of relativityare real and have been measured. The problem is that such ges are muall tomake the ti detectable differeo us. But for other things in the universe—light,gravity, the universe itself—these are matters of sequence.
So if the ideas of relativity seem weird, it is only because we don’t experiehese sorts ofiions in normal life. However, to turn to Bodanis again, we all only enterother kinds of relativity—for instah regard to sound. If you are in a park and someoneis playing annoying music, you know that if you move to a more distant spot the music willseem quieter. That’s not because the musicis quieter, of course, but simply that your positioive to it has ged. To something too small or sluggish to duplicate this experience—asnail, say—the idea that a boom box could seem to two observers to produce two differentvolumes of music simultaneously might seem incredible.
The most challenging and nonintuitive of all the cepts in the general theory of relativityis the idea that time is part of space. Our instinct is tard time as eternal, absolute,immutable—nothing disturb its steady tick. In fact, acc to Einstein, time is variableand ever ging. It even has shape. It is bound up—“iricably interected,” inStephen Hawking’s expression—with the three dimensions of spa a curious dimensionknoacetime.
Spacetime is usually explained by asking you to imagine something flat but pliant—amattress, say, or a sheet of stretched rubber—on which is resting a heavy round object, suchas an iron ball. The weight of the iron ball causes the material on which it is sitting to stretd sag slightly. This is roughly analogous to the effect that a massive object such as the Sun(the iron ball) has on spacetime (the material): it stretches and curves and s it. Now ifyou roll a smaller ball across the sheet, it tries to go in a straight line as required by on’slaws of motion, but as it nears the massive objed the slope of the sagging fabric, it rollsdownward, iably drawn to the more massive object. This is gravity—a product of thebending of spacetime.
Every object that has mass creates a little depression in the fabric of the os. Thus theuniverse, as Dennis Overbye has put it, is “the ultimate sagging mattress.” Gravity on thisview is no longer so much a thing as an oute—“not a ‘force’ but a byproduct of theing of spacetime,” in the words of the physicist Michio Kaku, who goes on: “In somesense, gravity does ; what moves the plas and stars is the distortion of spadtime.”
Of course the sagging mattress analogy take us only so far because it doesn’tincorporate the effect of time. But then our brains take us only so far because it is sonearly impossible to envision a dimension prising three parts space to one part time, allinterwoven like the threads in a plaid fabric. At all events, I think we agree that this wasan awfully big thought for a young man staring out the window of a patent offi thecapital of Switzerland.
Among much else, Einstein’s general theory of relativity suggested that the universe mustbe either expanding or trag. But Einstein was not a ologist, and he accepted theprevailing wisdom that the universe was fixed aernal. More or less reflexively, hedropped into his equations something called the ological stant, which arbitr.arilyterbalahe effects of gravity, serving as a kind of mathematical pause button. Bookson the history of sce always five Eihis lapse, but it was actually a fairlyappalling piece of sd he k. He called it “the biggest blunder of my life.”
tally, at about the time that Einstein was affixing a ological stant to histheory, at the Lowell Observatory in Arizona, an astronomer with the cheerily intergalaame of Vesto Slipher (who was in fact from Indiana) was taking spectrographic readings ofdistant stars and disc that they appeared to be moving away from us. The universewasn’t static. The stars Slipher looked at showed unmistakable signs of a Doppler shift5—thesame meism behind that distinctive stretched-out yee-yummm sound cars make as theyflash past on a racetrack. The phenomenon also applies to light, and in the case of reggalaxies it is known as a red shift (because light moving away from us shifts toward the redend of the spectrum; approag light shifts to blue).
Slipher was the first to notice this effect with light and to realize its potential importancefor uanding the motions of the os. Unfortunately no one muoticed him. TheLowell Observatory, as you will recall, was a bit of an oddity thanks to Percival Lowell’sobsession with Martian als, whi the 1910s made it, in every sense, an outpost ofastronomical endeavor. Slipher was unaware of Einstein’s theory of relativity, and the worldwas equally unaware of Slipher. So his finding had no impact.
Glory instead would pass to a large mass of ego named Edwin Hubble. Hubble was born in1889, ten years after Einstein, in a small Missouri town on the edge of the Ozarks and grewup there and ion, Illinois, a suburb of Chicago. His father was a successful insuranceexecutive, so life was always fortable, and Edwin enjoyed a wealth of physidowments, too. He was a strong and gifted athlete, charming, smart, and immensely good-looking—“handsome almost to a fault,” in the description of William H. Cropper, “an5Named for Johann Christian Doppler, an Austrian physicist, who first noticed the effe 1842. Briefly, pens is that as a moving object approaches a stationary os sound waves bee bunched up as they cramup against whatever device is receiving them (your ears, say), just as you would expect of anything that is beingpushed from behind toward an immobile object. This bung is perceived by the listener as a kind of pinchedand elevated sound (the yee). As the sound source passes, the sound waves spread out ahen, causing thepitch to drop abruptly (the yummm).
Adonis” in the words of another admirer. Acc to his own ats, he also maofit into his life more or less stant acts of valor—resg drowning swimmers, leadingfrightened men to safety across the battlefields of France, embarrassing world-championboxers with knockdown punches in exhibition bouts. It all seemed too good to be true. It was.
For all his gifts, Hubble was also an ie liar.
This was more than a little odd, for Hubble’s life was filled from an early age with a levelof distin that was at times almost ludicrously golden. At a single high school track meetin 1906, he won the pole vault, shot put, discus, hammer throw, standing high jump, andrunning high jump, and was on the winning mile-relay team—that is seven first places i—and came in third in the broad jump. In the same year, he set a state record for the highjump in Illinois.
As a scholar he was equally profit, and had no trouble gaining admission to studyphysid astronomy at the Uy of Chicago (where, tally, the head of thedepartment was now Albert Michelson). There he was selected to be one of the first Rhodesscholars at Oxford. Three years of English life evidently turned his head, for he returoWheaton in 1913 wearing an Inverness cape, smoking a pipe, and talking with a peculiarlyorotund at—not quite British but not quite not—that would remain with him for life.
Though he later claimed to have passed most of the sed decade of the tury practiglaw iucky, in fact he worked as a high school teacher and basketball coa NewAlbany, Indiana, before belatedly attaining his doctorate and passing briefly through theArmy. (He arrived in Franonth before the Armistid almost certainly never hearda shot fired in anger.)In 1919, now aged thirty, he moved to California and took up a position at the MountWilson Observatory near Los Angeles. Swiftly, and more than a little uedly, hebecame the most outstanding astronomer of the tweh tury.
I藏书网t is worth pausing for a moment to sider just how little was known of the os at thistime. Astrooday believe there are perhaps 140 billion galaxies in the visible universe.
That’s a huge number, much bigger than merely saying it would lead you to suppose. Ifgalaxies were frozen peas, it would be enough to fill a large auditorium—the old BostonGarden, say, or the Royal Albert Hall. (An astrophysicist named Bruce Gregory has actuallyputed this.) In 1919, when Hubble first put his head to the eyepiece, the number of thesegalaxies that were known to us was exactly ohe Milky Way. Everything else was thoughtto be either part of the Milky Way itself or one of many distant, peripheral puffs of gas.
Hubble quickly demonstrated h that belief was.
Over the decade, Hubble tackled two of the most fual questions of theuniverse: how old is it, and how big? To answer both it is necessary to know two things—howfar away certain galaxies are and how fast they are flying away from us (what is known astheir recessional velocity). The red shift gives the speed at which galaxies are retiring, butdoesn’t tell us how far away they are to begin with. For that you need what are known as“standard dles”—stars whose brightness be reliably calculated and used asbenchmarks to measure the brightness (and hence relative distance) of other stars.
Hubble’s luck was to e along soon after an ingenious woman named Hea Swat had figured out a way to do so. Leavitt worked at the Harvard College Observatory asa puter, as they were known. puters spent their lives studying photographic plates ofstars and making putations—hehe was little more than drudgery by anothername, but it was as close as women could get to real astronomy at Harvard—or indeed prettymuywhere—in those days. The system, however unfair, did have certain uedbes: it meant that half the fi minds available were directed to work that wouldotherwise have attracted little reflective attention, and it ehat women ended up with anappreciation of the firucture of the os that often eluded their male terparts.
One Harvard puter, Annie Jump on, used her repetitive acquaintah thestars to devise a system of stellar classifications so practical that it is still ioday.
Leavitt’s tribution was even more profound. She noticed that a type of star known as aCepheid variable (after the stellation Cepheus, where it first was identified) pulsated witha regular rhythm—a kind of stellar heartbeat. Cepheids are quite rare, but at least one of themis well known to most of us. Polaris, the Pole Star, is a Cepheid.
We now know that Cepheids throb as they do because they are elderly stars that havemoved past their “main sequence phase,” in the parlance of astronomers, and bee redgiants. The chemistry iants is a little weighty for our purposes here (it requires anappreciation for the properties of singly ionized helium atoms, among quite a lot else), but putsimply it means that they burn their remaining fuel in a way that produces a very rhythmic,very reliable brightening and dimming. Leavitt’s genius was to realize that by paring therelative magnitudes of Cepheids at different points in the sky you could work out where theywere iion to each other. They could be used as “standard dles”—a term she edand still in universal use. The method provided only relative distances, not absolute distances,but even so it was the first time that anyone had e up with a usable way to measure thelarge-scale universe.
(Just to put these insights into perspective, it is perhaps worth noting that at the time Leavittand on were inferring fual properties of the os from dim smudges onphotographic plates, the Harvard astronomer William H. Pickering, who could of course peerinto a first-class telescope as often as he wanted, was developing his seminal theory that darkpatches on the Moon were caused by swarms of seasonally migrating is.)binit’s ic yardstick with Vesto Slipher’s handy red shifts, Edwin Hubblenow began to measure selected points in space with a fresh eye. In 1923 he showed that a puffof distant gossamer in the Andromeda stellation known as M31 wasn’t a gas cloud at allbut a blaze of stars, a galaxy in its ht, a huhousand light-years across and atleast nine huhousand light-years away. The universe was vaster—vastly vaster—thananyone had ever supposed. In 1924 he produced a landmark paper, “Cepheids in SpiralNebulae” (nebulae,from the Latin for “clouds,” was his word falaxies), showing that theuniverse sisted not just of the Milky Way but of lots of indepe galaxies—“islanduniverses”—many of them bigger than the Milky Way and much more distant.
This finding alone would have ensured Hubble’s reputation, but he now turo thequestion of w out just how much vaster the universe was, and made an even morestriking discovery. Hubble began to measure the spectra of distant galaxies—the busihatSlipher had begun in Arizona. Using Mount Wilson’s new hundred-inch Hooker telescopeand some clever inferences, he worked out that all the galaxies in the sky (except for our ownlocal cluster) are moving away from us. Moreover, their speed and distance were lyproportional: the further away the galaxy, the faster it was moving.
This was truly startling. The universe was expanding, swiftly and evenly in all dires. Itdidn’t take a huge amount of imagination to read backwards from this and realize that it musttherefore have started from some tral point. Far from being the stable, fixed, eternal voidthat everyone had always assumed, this was a universe that had a beginning. It mighttherefore also have an end.
The wonder, as Stephen Hawking has noted, is that no one had hit on the idea of theexpanding universe before. A statiiverse, as should have been obvious to on ahinking astronomer since, would collapse in upon itself. There was also the problemthat if stars had been burning indefinitely in a statiiverse they’d have made the wholeintolerably hot—certainly much too hot for the likes of us. An expanding universe resolvedmuch of this at a stroke.
Hubble was a much better observer than a thinker and didn’t immediately appreciate thefull implications of what he had found. Partly this was because he was woefully ignorant ofEinstein’s General Theory of Relativity. This was quite remarkable because, for ohiein and his theory were world famous by now. Moreover, in 1929 Albert Michelson—now in his twilight years but still one of the world’s most alert aeemed stists—accepted a position at Mount Wilson to measure the velocity of light with his trustyinterferometer, and must surely have at least mentioo him the applicability of Einstein’stheory to his own findings.
At all events, Hubble failed to make theoretical hay when the ce was there. Instead, itwas left to a Belgian priest-scholar (with a Ph.D. from MIT) named Gees Lema?tre t together the two strands in his own “fireworks theory,” which suggested that theuniverse began as a geometrical point, a “primeval atom,” which burst into glory and hadbeen moving apart ever si was ahat very ly anticipated the modernception of the Big Bang but was so far ahead of its time that Lema?tre seldom gets morethan the sentence or two that we have given him here. The world would need additionaldecades, and the ient discovery of ic background radiation by Penzias and Wilsonat their hissing antenna in New Jersey, before the Big Bang would begin to move fromiing idea to established theory.
her Hubble ein would be much of a part of that big story. Though no onewould have guessed it at the time, both men had done about as much as they were ever goingto do.
In 1936 Hubble produced a popular book called The Realm of the Nebulae, whichexplained in flattering style his own siderable achievements. Here at last he showed thathe had acquainted himself with Einstein’s theory—up to a point anyway: he gave it fesout of about two hundred.
Hubble died of a heart atta 1953. One last small oddity awaited him. For reasonscloaked in mystery, his wife deed to have a funeral and never revealed what she did withhis body. Half a tury later the whereabouts of the tury’s greatest astronomer remainunknown. For a memorial you must look to the sky and the Hubble Space Telescope,launched in 1990 and named in his honor.
9 THE MIGHTY ATOM
WHILE EINSTEIN AND Hubble were productively unraveling the large-scale structure ofthe os, others were struggling to uand something closer to hand but in its way justas remote: the tiny and ever- mysterious atom.
The great Caltech physicist Richard Feynman once observed that if you had to reducestific history to one important statement it would be “All things are made of atoms.” Theyare everywhere and they stitute every thing. Look around you. It is all atoms. Not just thesolid things like walls and tables and sofas, but the air iween. And they are there inhat you really ot ceive.
The basic w arra of atoms is the molecule (from the Latin for “little mass”).
A molecule is simply two or more atoms w together in a more or less stablearra: add two atoms of hydrogen to one of oxygen and you have a molecule of water.
Chemists tend to think in terms of molecules rather thas in much the way thatwriters tend to think in terms of words and not letters, so it is molecules they t, and theseare numerous to say the least. At sea level, at a temperature of 32 degrees Fahre, onecubitimeter of air (that is, a space about the size of a sugar cube) will tain 45 billionbillion molecules. And they are in every single cubitimeter you see around you. Thinkhow many cubitimeters there are in the world outside your window—how many sugarcubes it would take to fill that view. Then think how many it would take to build a universe.
Atoms, in short, are very abundant.
They are also fantastically durable. Because they are so long lived, atoms really get around.
Every atom you possess has almost certainly passed through several stars and been part ofmillions anisms on its way to being you. We are each so atomically numerous andso vigorously recycled at death that a signifit number of our atoms—up to a billion foreach of us, it has been suggested—probably once beloo Shakespeare. A billion moreeach came from Buddha and Genghis Khan ahoven, and any other historical figureyou care to he personages have to be historical, apparently, as it takes the atomssome decades to bee thhly redistributed; however muay wish it, you arenot yet oh Elvis Presley.)So we are all reinations—though short-lived ones. When we die our atoms willdisassemble and move off to find new uses elsewhere—as part of a leaf or other human beingor drop of dew. Atoms, however, go on practically forever. Nobody actually knows how longan atom survive, but acc to Marti is probably about 1035years—a numberso big that even I am happy to express it in notation.
Above all, atoms are tiiny indeed. Half a million of them lined up shoulder toshoulder could hide behind a human hair. On such a scale an individual atom is essentiallyimpossible to imagine, but we of course try.
Start with a millimeter, which is a lihis long: -. Now imagihat line divided into athousand equal widths. Each of those widths is a mi. This is the scale of micranisms.
A typical paramecium, for instance, is about two mis wide, 0.002 millimeters, which isreally very small. If you wao see with your naked eye a paramecium swimming in adrop of water, you would have to enlarge the drop until it was some forty feet across.
However, if you wao see the atoms in the same drop, you would have to make the dropfifteen miles across.
Atoms, in other words, exist on a scale of minuteness of another order altogether. To getdown to the scale of atoms, you would o take eae of those mi slices and shaveit into ten thousand finer widths. That’s the scale of an atom: oen-millionth of amillimeter. It is a degree of slenderness way beyond the capacity of our imaginations, but you get some idea of the proportions if you bear in mind that oom is to the width of amillimeter line as the thiess of a sheet of paper is to the height of the Empire StateBuilding.
It is of course the abundand extreme durability of atoms that makes them so useful,and the tihat makes them so hard to deted uand. The realization that atomsare these three things—small, numerous, practically iructible—and that all things aremade from them first occurred not to Antoine-Laure藏书网nt Lavoisier, as you might expect, or evento Henry dish or Humphry Davy, but rather to a spare and lightly educated EnglishQuaker named John Dalton, whom we first entered in the chapter ory.
Dalton was born in 1766 on the edge of the Lake Distriear Cockermouth to a family ofpoor but devout Quaker weavers. (Four years later the poet William Wordsworth would alsojoin the world at Cockermouth.) He was an exceptionally bright student—so very brightihat at the improbably youthful age of twelve he ut in charge of the local Quakerschool. This perhaps says as much about the school as about Dalton’s precocity, but perhapsnot: we know from his diaries that at about this time he was readion’s Principia in theinal Latin and other works of a similarly challenging nature. At fifteen, stillsastering, he took a job in the nearby town of Kendal, and a decade after that hemoved to Maer, scarcely stirring from there for the remaining fifty years of his life. InMaer he became something of an intellectual whirlwind, produg books and paperson subjects ranging from metey to grammar. Color blindness, a dition from whichhe suffered, was for a long time called Daltonism because of his studies. But it lumpbook called A New System of Chemical Philosophy, published in 1808, that established hisreputation.
There, in a short chapter of just five pages (out of the book’s more than nine hundred),people of learning first entered atoms in something approag their modernception. Dalton’s simple insight was that at the root of all matter are exceedingly tiny,irreducible particles. “We might as well attempt to introduce a new pla into the solarsystem or annihilate one already ience, as to create or destroy a particle of hydrogen,”
he wrote.
her the idea of atoms nor the term itself was exactly new. Both had been developed bythe a Greeks. Dalton’s tribution was to sider the relative sizes and characters ofthese atoms and how they fit together. He knew, for instahat hydrogen was the lightestelement, so he gave it an atomic weight of one. He believed also that water sisted of sevenparts of oxygen to one of hydrogen, and so he gave oxygen an atomic weight of seven. Bysuch means was he able to arrive at the relative weights of the knows. He wasn’talways terribly accurate—oxygen’s atomic weight is actually sixteen, not seven—but theprinciple was sound and formed the basis for all of moderry and much of the rest ofmodern sce.
The work made Dalton famous—albeit in a low-key, English Quaker sort of way. In 1826,the French chemist P .J. Pelletier traveled to Maer to meet the atomic hero. Pelletierexpected to find him attached to some grand institution, so he was astouo discover himteag elementary arithmetic to boys in a small school on a back street. Acc to thestific historian E. J. Holmyard, a fused Pelletier, upon beholding the great man,stammered:
“Est-ce que j’ai l’honneur de m’addresser à Monsieur Dalton?” for he couldhardly believe his eyes that this was the chemist of European fame, teag a boyhis first four rules. “Yes,” said the matter-of-fact Quaker. “Wilt thou sit downwhilst I put this lad right about his arithmetic?”
Although Dalton tried to avoid all honors, he was elected to the Royal Society against hiswishes, showered with medals, and given a handsome gover pension. When he died in1844, forty thousand people viewed the coffin, and the funeral ce stretched for twomiles. His entry in the Diary of National Biography is one of the lo, rivaled ih only by those of Darwin and Lyell among eenth-tury men of sce.
For a tury after Dalton made his proposal, it remaiirely hypothetical, and a fewemi stists—notably the Viennese physicist Ernst Mach, for whom is he speedof sound—doubted the existence of atoms at all. “Atoms ot be perceived by the senses . .
. they are things of thought,” he wrote. The existence of atoms was so doubtfully held in theGerman-speaking world in particular that it was said to have played a part in the suicide of thegreat theoretical physicist, and atomithusiast, Ludwig Boltzmann in 1906.
It was Einstein who provided the first introvertible evidence of atoms’ existehhis paper on Brownian motion in 1905, but this attracted little attention and in any caseEinstein was soon to bee ed with his wor藏书网k on general relativity. So the first realhero of the atomic age, if not the first personage on the se, was Er Rutherford.
Rutherford was born in 1871 in the “back blocks” of New Zealand to parents who hademigrated from Scotland to raise a little flax and a lot of children (to paraphrase StevenWeinberg). Growing up in a remote part of a remote try, he was about as far from themainstream of sce as it ossible to be, but in 1895 he won a scholarship that took himto the dish Laboratory at Cambridge Uy, which was about to bee the hottestpla the world to do physics.
Physicists are notoriously sful of stists from other fields. When the wife of thegreat Austrian physicist Wolfgang Pauli left him for a chemist, he was staggered withdisbelief. “Had she taken a bullfighter I would have uood,” he remarked in woo afriend. “But a chemist . . .”
It was a feeling Rutherford would have uood. “All sce is either physics or stampcolleg,” he once said, in a lihat has been used many times sihere is a certainengaging irony therefore that when he won the Nobel Prize in 1908, it was iry, notphysics.
Rutherford was a lucky man—lucky to be a genius, but even luckier to live at a time whenphysid chemistry were so exg and so patible (his owimentsnotwithstanding). Never again would they quite so fortably overlap.
For all his success, Rutherford was not an especially brilliant man and was actually prettyterrible at mathematics. Often duriures he would get so lost in his owions thathe would give up halfway through ahe students to work it out for themselves.
Acc to his longtime colleague James Chadwick, discoverer of the ron, he wasn’teven particularly clever at experimentation. He was simply tenacious and open-minded. Forbrilliance he substituted shrewdness and a kind of daring. His mind, in the words of onebiographer, was “always operating out towards the frontiers, as far as he could see, and thatwas a great deal further than most other men.” fronted with an intractable problem, herepared to work at it harder and lohan most people and to be more receptive tounorthodox explanations. His greatest breakthrough came because he repared to spendimmeedious hours sitting at a s ting alpha particle stillations, as they wereknown—the sort of work that would normally have been farmed out. He was one of the firstto see—possibly the very first—that the power i iom could, if harnessed, makebombs powerful enough to “make this old world vanish in smoke.”
Physically he was big and booming, with a voice that made the timid shrink. Once whentold that Rutherford was about to m藏书网ake a radio broadcast across the Atlantic, a colleague drilyasked: “Why use radio?” He also had a huge amount of good-natured fidence. Whensomeone remarked to him that he seemed always to be at the crest of a wave, he responded,“Well, after all, I made the wave, didn’t I?” C. P. Snow recalled how on a Cambridgetailor’s he overheard Rutherford remark: “Every day I grow in girth. And iality.”
But both girth and fame were far ahead of him in 1895 wheched up at thedish.
1It was a singularly eventful period in sce. In the year of his arrival inCambridge, Wilhelm Roentgen discovered X rays at the Uy of Würzburg in Germany,and the year Henri Becquerel discovered radioactivity. And the dish itself wasabout to embark on a long period of greatness. In 1897, J. J. Thomson and colleagues woulddiscover the ele there, in 1911 C. T. R. Wilson would produce the first particle detectorthere (as we shall see), and in 1932 James Chadwick would discover the ron there.
Further still iure, James Watson and Francis Crick would discover the structure ofDNA at the dish in 1953.
In the beginning Rutherford worked on radio waves, and with some distin—hemao transmit a crisp signal more than a mile, a very reasonable achievement for thetime—but gave it up when he ersuaded by a senior colleague that radio had little future.
On the whole, however, Rutherford didn’t thrive at the dish. After three years there,feeling he was going nowhere, he took a post at McGill Uy in Montreal, and there hebegan his long and steady rise to greatness. By the time he received his Nobel Prize (for“iigations into the disiion of the elements, and the chemistry of radioactivesubstances,” acc to the official citation) he had moved on to Maer Uy,and it was there, in fact, that he would do his most important work iermining thestructure and nature of the atom.
1The name es from the same dishes who producery. This one was William dish, seventhDuke of Devonshire, who was a gifted mathemati and steel baron in Victland. In 1870, he gave theuy ￡6,300 to build an experimental lab.
By the early tweh tury it was known that atoms were made of parts—Thomson’sdiscovery of the ele had established that—but it wasn’t known hoarts therewere or how they fit together or what shape they took. Some physicists thought that atomsmight be cube shaped, because cubes be packed together so ly without any wastedspace. The meneral view, however, was that an atom was more like a currant bun or aplum pudding: a dense, solid object that carried a positive charge but that was studded withively charged eles, like the currants in a currant bun.
In 1910, Rutherford (assisted by his student Hans Geiger, who would later iheradiatioor that bears his name) fired ionized helium atoms, or alpha particles, at asheet of gold foil.
2To Rutherford’s astonishment, some of the particles bounced back. It wasas if, he said, he had fired a fifteen-inch shell at a sheet of paper and it rebounded into his lap.
This was just not supposed to happen. After siderable refle he realized there could beonly one possible explanation: the particles that bounced back were striking something smalland de the heart of the atom, while the other particles sailed through unimpeded. Anatom, Rutherford realized, was mostly empty space, with a very dense nucleus at the ter.
This was a most gratifying discovery, but it presented one immediate problem. By all the lawsof ventional physics, atoms shouldn’t therefore exist.
Let us pause for a moment and sider the structure of the atom as we know it now. Everyatom is made from three kinds of elementary particles: protons, which have a positiveelectrical charge; eles, which have a ive electrical charge; arons, which haveno charge. Protons arons are packed into the nucleus, while eles spin aroundoutside. The number of protons is what gives an atom its chemical identity. An atom with oon is an atom of hydrogen, oh two protons is helium, with three protons is lithium,and so on up the scale. Each time you add a proton you get a new element. (Because thenumber of protons in an atom is always balanced by an equal number of eles, you willsometimes see it written that it is the number of eles that defines a; it es tothe same thing. The way it was explaio me is that protons give an atom its identity,eles its personality.)rons don’t influen atom’s identity, but they do add to its mass. The number ofrons is generally about the same as the number of protons, but they vary up and downslightly. Add a ron or two and you get an isotope. The terms you hear in refereodating teiques in archeology refer to isotopes—carbon-14, for instance, which is an atomof carbon with six protons a rons (the fourteen being the sum of the two).
rons and protons occupy the atom’s nucleus. The nucleus of an atom is tiny—only onemillionth of a billionth of the full volume of the atom—but fantastically dense, sitains virtually all the atom’s mass. As Cropper has put it, if an atom were expao thesize of a cathedral, the nucleus would be only about the size of a fly—but a fly manythousands of times heavier thahedral. It was this spacioushis resounding,ued roomihat had Rutherford scratg his head in 1910.
It is still a fairly astounding notion to sider that atoms are mostly empty space, and thatthe solidity we experience all around us is an illusion. When two objects e together in the2Geiger would also later bee a loyal Nazi, uatingly betraying Jewish colleagues, including many whohad helped him.
real world—billiard balls are most often used for illustration—they don’t actually strike eachother. “Rather,” as Timothy Ferris explains, “the ively charged fields of the two ballsrepel each other . . . were it not for their electrical charges they could, like galaxies, pass rightthrough each other unscathed.” When you sit in a chair, you are not actually sitting there, butlevitating above it at a height of one angstrom (a hundred millionth of a timeter), youreles and its eles implacably opposed to any closer intimacy.
The picture that nearly everybody has in mind of an atom is of aron or two flyingaround a nucleus, like plas orbiting a sun. This image was created in 1904, based on littlemore than clever guesswork, by a Japanese physicist named Hantaro Nagaoka. It ispletely wrong, but durable just the same. As Isaac Asimov liked to inspiredgeions of sce fi writers to create stories of worlds within worlds, in which atomsbee tiny inhabited solar systems or our solar system turns out to be merely a mote in somemuch larger scheme. Even now , the European anization for Nuclear Research, usesNagaoka’s image as a logo on its website. In fact, as physicists were soon to realize, elesare not like orbiting plas at all, but more like the blades of a spinning fan, managing to fillevery bit of spa their orbits simultaneously (but with the crucial differehat the bladesof a fan only seem to be everywhere at once; eles are ).
Needless to say, very little of this was uood in 1910 or for many years afterward.
Rutherford’s finding presented some large and immediate problems, not least that ronshould be able to orbit a nucleus without crashing. ventiorodynamic theorydemahat a flyiron should very quickly run out of energy—in only an instant orso—and spiral into the nucleus, with disastrous sequences for both. There was also theproblem of how protons with their positive charges could buogether ihe nucleuswithout blowing themselves and the rest of the atom apart. Clearly whatever was going ondown there in the world of the very small was not governed by the laws that applied in themacro world where our expectations reside.
As physicists began to delve into this subatomic realm, they realized that it wasn’t merelydifferent from anything we knew, but different from anything ever imagined. “Becauseatomic behavior is so unlike ordinary experience,” Richard Feynman once observed, “it isvery difficult to get used to and it appears peculiar and mysterious to everyone, both to thenovid to the experienced physicist.” When Feynman made that ent, physicists hadhad half a tury to adjust to the strangeness of atomic behavior. So think how it must havefelt to Rutherford and his colleagues in the early 1910s when it was all brand new.
One of the people w with Rutherford was a mild and affable young Dane namedNiels Bohr. In 1913, while puzzling over the structure of the atom, Bohr had an idea soexg that he postponed his honeymoon to write what became a landmark paper. Becausephysicists couldn’t see anything so small as an atom, they had to try to work out its structurefrom how it behaved when they did things to it, as Rutherford had done by firing alphaparticles at foil. Sometimes, not surprisingly, the results of these experiments were puzzling.
One puzzle that had been around for a long time had to do with spectrum readings of thewavelengths of hydrogen. These produced patterns showing that hydrogen atoms emittedenergy at certain wavelengths but not others. It was rather as if someone under surveillaurning up at particular locations but was never observed traveliween them. No onecould uand why this should be.
It was while puzzling over this problem that Bohr was struck by a solution and dashed offhis famous paper. Called “On the stitutions of Atoms and Molecules,” the paper explainedhow eles could keep from falling into the nucleus by suggesting that they could occupyonly certain well-defined orbits. Acc to the heory, aron moviweenorbits would disappear from one and reappear instantaneously in another without visiting thespace between. This idea—the famous “quantum leap”—is of course utterly strange, but itwas too good not to be true. It not only kept eles from spiraling catastrophically into thenucleus; it also explained hydrogen’s bewildering wavelengths. The eles only appearediain orbits because they oed iain orbits. It was a dazzling insight, and itwon Bohr the 1922 Nobel Prize in physics, the year after Einstein received his.
Meanwhile the tireless Rutherford, now back at Cambridge as J. J. Thomson’s successor ashead of the dish Laboratory, came up with a model that explained why the nuclei didn’tblow up. He saw that they must be offset by some type of ralizing particles, which hecalled rons. The idea was simple and appealing, but not easy to prove. Rutherford’sassociate, James Chadwick, devoted eleven intensive years to hunting for rons beforefinally succeeding in 1932. He, too, was awarded with a Nobel Prize in physics, in 1935. AsBoorse and his colleagues point out in their history of the subject, the delay in discovery robably a very good thing as mastery of the ron was essential to the development of theatomib. (Because rons have no charge, they aren’t repelled by the electrical fields atthe heart of an atom and thus could be fired like tiny torpedoes into an atomiucleus, settingoff the destructive process known as fission.) Had the ron been isolated in the 1920s, they is “very likely the atomib would have been developed first in Europe,undoubtedly by the Germans.”
As it was, the Europeans had their hands full trying to uand the strange behavior ofthe ele. The principal problem they faced was that the ele sometimes behaved like aparticle and sometimes like a wave. This impossible duality drove physicists nearly mad. Forthe decade all across Europe they furiously thought and scribbled and offered petinghypotheses. In France, Prince Louis-Victor de Broglie, the s of a ducal family, found thatcertain anomalies in the behavior of eles disappeared when arded them as waves.
The observatioed the attention of the Austrian Erwin Schr?dinger, who made some deftrefis and devised a handy system called wave meics. At almost the same time theGerman physicist Werner Heisenberg came up with a peting theory called matrixmeics. This was so mathematically plex that hardly anyone really uood it,including Heisenberg himself (“I do not even know what a matrix is ,” Heisenberg despairedto a friend at one point), but it did seem to solve certain problems that Schr?dinger’s wavesfailed to explain. The upshot is that physics had two theories, based on flig premises,that produced the same results. It was an impossible situation.
Finally, in 1926, Heisenberg came up with a celebrated promise, produg a newdisciplihat came to be known as quantum meics. At the heart of it was Heisenberg’sUainty Principle, which states that the ele is a particle but a particle that bedescribed in terms of waves. The uainty around which the theory is built is that we ow the path aron takes as it moves through a space or we know where it is at agiven instant, but we ot know both.
3Any attempt to measure one will unavoidably3There is a little uainty about the use of the word uainty in regard to Heisenbergs principle. MichaelFrayn, in an afterword to his play hagen, hat several words in German-Unsicherheit, Unscharfe,Uimmtheit-have been used by various translators, but that none quite equates to the English uainty.
Frayn suggests that ierminacy would be a better word for the principle and ierminability would be betterstill.
disturb the other. This isn’t a matter of simply needing more precise instruments; it is animmutable property of the universe.
What this means in practice is that you ever predict where aron will be at anygiven moment. You only list its probability of being there. In a sense, as Dennis Overbyehas put it, aro exist until it is observed. Or, put slightly differently, until it isobserved aron must be regarded as being “at once everywhere and nowhere.”
If this seems fusing, you may take some fort in knowing that it was fusing tophysicists, too. Overbye notes: “Bohr onehat a person who wasn’t ed onfirst hearing about quantum theory didn’t uand what had been said.” Heisenberg, whenasked how one could envision an atom, replied: “Don’t try.”
So the atom turned out to be quite uhe image that most people had created. Theele doesn’t fly around the nucleus like a pla around its sun, but iakes on themore amorphous aspect of a cloud. The “shell” of an atom isn’t some hard shiny g, asillustrations sometimes ence us to suppose, but simply the outermost of these fuzzyele clouds. The cloud itself is essentially just a zone of statistical probability marking thearea beyond which the ele only very seldom strays. Thus an atom, if you could see it,would look more like a very fuzzy tennis ball than a hard-edged metallic sphere (but not muchlike either or, indeed, like anything you’ve ever seen; we are, after all, dealing here with aworld very different from the one we see around us).
It seemed as if there was no end of strangeness. For the first time, as James Trefil has put it,stists had entered “an area of the universe that our brains just aren’t wired touand.” Or as Feynman expressed it, “things on a small scale behave nothing like thingson a large scale.” As physicists delved deeper, they realized they had found a world where notonly could eles jump from one orbit to another without traveling across any interveningspace, but matter could pop ience from nothing at all—“provided,” in the words ofAlan Lightman of MIT, “it disappears again with suffit haste.”
Perhaps the most arresting of quantum improbabilities is the idea, arising from WolfgangPauli’s Exclusion Principle of 1925, that the subatomic particles iain pairs, even whenseparated by the most siderable distances, eastantly “know” what the other isdoing. Particles have a quality knoin and, acc to quantum theory, the momentyou determihe spin of one part?99lｉｂ?icle, its sister particle, no matter how distant away, willimmediately begin spinning in the opposite dire and at the same rate.
It is as if, in the words of the sce writer Lawrence Joseph, you had two identical poolballs, one in Ohio and the other in Fiji, and the instant you sent one spinning the other wouldimmediately spin in a trary dire at precisely the same speed. Remarkably, thephenomenon roved in 1997 when physicists at the Uy of Geneva sent photonsseven miles in opposite dires and demonstrated that interfering with one provoked aninstantaneous response iher.
Things reached such a pitch that at one ference Bohr remarked of a heory that thequestion was not whether it was crazy, but whether it was crazy enough. To illustrate thenonintuitive nature of the quantum world, Schr?dinger offered a famous thought experimentin which a hypothetical cat laced in a box with oom of a radioactive substaached to a vial of hydroic acid. If the particle degraded within an hour, it would triggera meism that would break the vial and poiso. If not, the cat would live. But wecould not know which was the case, so there was no choice, stifically, but tard thecat as 100 pert alive and 100 pert dead at the same time. This means, as StephenHawking has observed with a touch of uandable excitement, that one ot “predictfuture evely if one ot even measure the present state of the universe precisely!”
Because of its oddities, many physicists disliked quantum theory, or at least certain aspectsof it, and none more so thaein. This was more than a little ironice it was he, in hisannus mirabilis of 1905, who had so persuasively explained how photons of light couldsometimes behave like particles and sometimes like waves—the notion at the very heart of thenew physics. “Quantum theory is very worthy ard,” he observed politely, but he reallydidn’t like it. “God doesn’t play dice,” he said.
4Einstein couldn’t bear the notion that God could create a universe in whie thingswere forever unknowable. Moreover, the idea of a at a distahat one particle couldinstantaneously influenother trillions of miles away—was a stark violation of the specialtheory of relativity. This expressly decreed that nothing could outrace the speed of light a here were physicists insisting that, somehow, at the subatomic level, information could.
(No one, ially, has ever explained how the particles achieve this feat. Stists havedealt with this problem, acc to the physicist Yakir Aharanov, “by not thinking aboutit.”)Above all, there was the problem that quantum physitroduced a level of untidihathadn’t previously existed. Suddenly you wo sets of laws to explain the behavior ofthe universe—quantum theory for the world of the very small aivity for the largeruniverse beyond. The gravity of relativity theory was brilliant at explaining why plasorbited suns or why galaxies teo cluster, but turned out to have no influe all at theparticle level. To explain what kept atoms together, other forces were needed, and in the1930s two were discovered: the strong nuclear ford weak nuclear force. The strong fords atoms together; it’s what allows protons to bed down together in the nucleus. The weakforgages in more miscellaneous tasks, mostly to do with trolling the rates of certainsorts of radioactive decay.
The weak nuclear force, despite its name, is ten billion billion billion times strohangravity, and the strong nuclear force is more powerful still—vastly so, in fact—but theirinflueends to only the ti distahe grip of the strong force reaches out only toabout 1/100,000 of the diameter of an atom. That’s why the nuclei of atoms are so pactedand dense and why elements with big, crowded end to be so unstable: the strong forcejust ’t hold on to all the protons.
The upshot of all this is that physided up with two bodies of laws—one for the worldof the very small, one for the universe at large—leading quite separate lives. Einstein dislikedthat, too. He devoted the rest of his life to searg for a way to tie up these loose ends byfinding a grand uheory, and always failed. From time to time he thought he had it, butit always unraveled on him in the end. As time passed he became increasingly marginalizedand even a little pitied. Almost without exception, wrote Snow, “his colleagues thought, andstill think, that he wasted the sed half of his life.”
4Or at least that is how it is nearly always rehe actual quote was: “It seems hard to sneak a look atGod’s cards. But that He plays did uses ‘telepathic’ methods. . . is something that I ot believe for asingle moment.”
Elsewhere, however, real progress was being made. By the mid-1940s stists hadreached a point where they uood the atom at aremely profound level—as they alltoo effectively demonstrated in August 1945 by exploding a pair of atomibs over Japan.
By this point physicists could be excused for thinking that they had just about queredthe atom. In fact, everything in particle physics was about to get a whole lot moreplicated. But before we take up that slightly exhausting story, we must bring araw of our history up to date by sidering an important and salutary tale of avarice, deceit,bad sce, several needless deaths, and the final determination of the age of the Earth.
10 GETTING THE LEAD OUT
IE 1940s, a graduate student at the Uy of Chied Clair Patterson(who was, first withstanding, an Iowa farm boy by in) was using a new methodof lead isotope measurement to try to get a definitive age for the Earth at last. Unfortunatelyall his samples came up inated—usually wildly so. Most tained something like twohuimes the levels of lead that would normally be expected to occur. Many years wouldpass before Patterson realized that the reason for this lay with a regrettable Ohio iorhomas Midgley, Jr.
Midgley was an engineer by training, and the world would no doubt have been a safer placeif he had stayed so. Instead, he developed an i in the industrial applications ofchemistry. In 1921, while w for the General Motors Research Corporation in Dayton,Ohio, he iigated a pound called tetraethyl lead (also known, fusingly, as leadtetraethyl), and discovered that it signifitly reduced the juddering dition known asengine knock.
Even though lead was widely known to be dangerous, by the early years of the twehtury it could be found in all manner of er products. Food came in s sealed withlead solder. Water was often stored in lead-lianks. It rayed onto fruit as a pesticidein the form of lead arse even came as part of the packaging of toothpaste tubes. Hardlya product existed that didn’t bring a little lead into ers’ lives. However, nothing gave ita greater and more lasting intimacy than its addition to gasoline.
Lead is a oxioo much of it and you irreparably damage the brain aral nervous system. Among the many symptoms associated with overexposure areblindness, insomnia, kidney failure, hearing loss, cer, palsies, and vulsions. In its mostacute form it produces abrupt and terrifying halluations, disturbing to victims andonlookers alike, which generally then give way to a ah. You really don’t want toget too much lead into your system.
Oher hand, lead was easy to extrad work, and almost embarrassingly profitableto produdustrially—araethyl lead did indubitably stop engines from knog. So in1923 three of America’s largest corporations, General Motors, Du Pont, and Standard Oil ofNew Jersey, formed a joierprise called the Ethyl Gasoline Corporation (later shorteo simply Ethyl Corporation) with a view to making as much tetraethyl lead as the world waswilling to buy, and that proved to be a very great deal. They called their additive “ethyl”
because it sounded friendlier aoxic than “lead” and introduced it for publiption (in more ways than most people realized) on February 1, 1923.
Almost at once produ workers began to exhibit the staggered gait and fusedfaculties that mark the retly poisoned. Also almost at ohe Ethyl Corporationembarked on a policy of calm but unyielding denial that would serve it well for decades. AsSharosch McGrayes in her abs history of industrial chemistry,Prometheans in the Lab, when employees at one plant developed irreversible delusions, aspokesman blandly informed reporters: “These men probably went insane because theyworked too hard.” Altogether at least fifteen workers died in the early days of produ ofleaded gasoline, and untold numbers of others became ill, often violently so; the exaumbers are unknown because the pany nearly always mao hush up news ofembarrassing leakages, spills, and poisonings. At times, however, suppressing the newsbecame impossible, most notably in 1924 when in a matter of days five produ workersdied and thirty-five more were turned into perma staggering wrecks at a single ill-ventilated facility.
As rumors circulated about the dangers of the new product, ethyl’s ebullient ior,Thomas Midgley, decided to hold a demonstration for reporters to allay their s. As hechatted away about the pany’s itment to safety, he poured tetraethyl lead over hishands, then held a beaker of it to his nose for sixty seds, claiming all the while that hecould repeat the procedure daily without harm. In fact, Midgley knew only too well the perilsof lead poisoning: he had himself been made seriously ill from overex藏书网posure a few monthsearlier and now, except when reassuring journalists, never wehe stuff if he could helpit.
Buoyed by the success of leaded gasoline, Midgley now turo aeologicalproblem of the age. Refrigerators in the 1920s were often appallingly risky because they useddangerous gases that sometimes leaked. One leak from a refrigerator at a hospital inCleveland, Ohio, in 1929 killed more than a hundred people. Midgley set out to create a gasthat was stable, nonflammable, noncorrosive, and safe to breathe. With an instinct for theregrettable that was almost uny, he ied chlorofluorocarbons, or CFCs.
Seldom has an industrial product been more swiftly or unfortunately embraced. CFCs wentinto produ in the early 1930s and found a thousand applications ihing from carair ditioo deodorant sprays before it was noticed, half a tury later, that they weredev the ozone iratosphere. As you will be aware, this was not a good thing.
Ozone is a form of oxygen in which each molecule bears three atoms of oxygen instead oftwo. It is a bit of a chemical oddity in that at ground level it is a pollutant, while iratosphere it is beneficial, si soaks up dangerous ultraviolet radiation. Beneficial ozoneis not terribly abundant, however. If it were distributed evenly throughout the stratosphere, itwould form a layer just oh of an inch or so thick. That is why it is so easily disturbed,and why such disturbances don’t take long to bee critical.
Chlorofluorocarbons are also not very abundant—they stitute only about one part perbillion of the atmosphere as a whole—but they are extravagantly destructive. One pound ofCFCs capture and annihilate seventy thousand pounds of atmospheric ozone. CFCs alsohang around for a long time—about a tury on average—wreaking havoc all the while.
They are also great heat sponges. A single CFC molecule is about ten thousand times moreeffit at exacerbating greenhouse effects than a molecule of carbon dioxide—and carbondioxide is of course no slouch itself as a greenhouse gas. In short, chlorofluoroayultimately prove to be just about the worst iion of the tweh tury.
Midgley never khis because he died long before anyone realized how destructiveCFCs were. His death was itself memorably unusual. After being crippled with polio,Midgley ied a traption involving a series of motorized pulleys that automaticallyraised or turned him in bed. In 1944, he became entangled in the cords as the mae wentinto a and was strangled...
If you were ied in finding out the ages of things, the Uy of Chicago in the1940s was the place to be. Willard Libby was in the process of iing radiocarbon dating,allowing stists to get an accurate reading of the age of bones and anic remains,something they had never been able to do before. Up to this time, the oldest reliable dateswent bao further than the First Dynasty i from about 3000B.o one couldfidently say, for instance, when the last ice sheets had retreated or at what time in the pastthe agnon people had decorated the caves of Lascaux in France.
Libby’s idea was so useful that he would be awarded a Nobel Prize for it in 1960. It wasbased on the realization that all living things have within them an isotope of carbon calledcarbon-14, which begins to decay at a measurable rate the instant they die. Carbon-14 has ahalf-life—that is, the time it takes for half of any sample to disappear1—of about 5,600 years,so by w out how much a given sample of carbon had decayed, Libby could get a goodfix on the age of an object—though only up to a point. After eight half-lives, only 1/256 of theinal radioactive carbon remains, which is too little to make a reliable measurement, soradiocarbon dating works only for objects up to forty thousand or so years old.
Curiously, just as the teique was being widespread, certain flaws within it becameapparent. To begin with, it was discovered that one of the basipos of Libby’sformula, known as the decay stant, was off by about 3 pert. By this time, however,thousands of measurements had been taken throughout the world. Rather thae everyone, stists decided to keep the inaccurate stant. “Thus,” Tim Flannery notes, “everyraw radiocarbon date you read today is given as too young by around 3 pert.” Theproblems didn’t quite stop there. It was also quickly discovered that carbon-14 samples beeasily inated with carbon from other sources—a tiny scrap of vegetable matter, forinstahat has been collected with the sample and not noticed. For younger samples—those uwenty thousand years or so—slight ination does not always matter somuch, but for older samples it be a serious problem because so few remaining atoms arebeing ted. In the first instao borrow from Flannery, it is like misting by a dollarwhen ting to a thousand; in the sed it is more like misting by a dollar when youhave only two dollars to t.
Libby’s method was also based on the assumption that the amount of carbon-14 imosphere, and the rate at which it has been absorbed by living things, has been sistentthroughout history. In fact it hasn’t been. We now know that the volume of atmosphericcarbon-14 varies depending on how well or h’s magism is defleg ic rays,and that that vary signifitly over time. This means that some carbon-14 dates are more1If you have ever wondered how the atoms determine which 50 pert will die and which 50 pert willsurvive for the session, the answer is that the half-life is really just a statistical venience-a kind ofactuarial table for elemental things. Imagine you had a sample of material with a half-life of 30 seds. It isntthat every atom in the sample will exist for exactly 30 seds or 60 seds or 90 seds or some other tidilyordained period. Each atom will in fact survive for airely random length of time that has nothing to do withmultiples of 30; it might last until two seds from now or it might oscillate away for years or decades orturies to e. No one say. But what we say is that for the sample as a whole the rate ofdisappearance will be such that half the atoms will disappear every 30 seds. Its an average rate, in otherwords, and you apply it to any large sampling. Someone once worked out, for instahat dimes have ahalf-life of about 30 years.
dubious than others. This is particularly so with dates just around the time that people firstcame to the Americas, which is one of the reasons the matter is so perennially in dispute.
Finally, and perhaps a little uedly, readings be thrown out by seeminglyued external factors—such as the diets of those whose bones are beied. O case involved the long-runnie over whether syphilis inated in the NewWorld or the Old. Archeologists in Hull, in the north of England, found that monks in amonastery graveyard had suffered from syphilis, but the initial clusion that the monks haddone so before bus’s voyage was cast into doubt by the realization that they had eaten alot of fish, which could make their bones appear to be older than in fact they were. The monksmay well have had syphilis, but how it got to them, and when, remain tantalizinglyunresolved.
Because of the accumulated shortings of carbon-14, stists devised other methods ofdating a materials, among them thermoluminesence, which measures eles trappedin clays, aron spin resonance, whivolves b a sample witheleagic waves and measuring the vibrations of the eles. But even the best ofthese could not date anything older than about 200,000 years, and they couldn’t date inanicmaterials like rocks at all, which is of course what you need if you wish to determihe ageof your pla.
The problems of dating rocks were such that at one point almost everyone in the world hadgiven up on them. Had it not been for a determined English professor named Arthur Holmes,the quest might well have fallen into abeyaogether.
Holmes was heroic as much for the obstacles he overcame as for the results he achieved.
By the 1920s, when Holmes was in the prime of his career, geology had slipped out offashion—physics was the ement of the age—and had bee severely underfunded,particularly in Britain, its spiritual birthplace. At Durham Uy, Holmes was for manyyears the entire geology department. Often he had to borrow or patch together equipment io pursue his radiometric dating of rocks. At one point, his calculations were effectivelyheld up for a year while he waited for the uy to provide him with a simple addingmae. Occasionally, he had to drop out of academic life altogether to earn enough tosupport his family—for a time he ran a curio shop in Newcastle upon Tyne—and sometimeshe could not even afford the ￡5 annual membership fee for the Geological Society.
The teique Holmes used in his work was theoretically straightforward and arose directlyfrom the process, first observed by Er Rutherford in 1904, in whie atoms decayfrom one element into a a rate predictable enough that you use them as clocks. Ifyou know how long it takes for potassium-40 to bee argon-40, and you measure theamounts of ea a sample, you work out how old a material is. Holmes’s tributionwas to measure the decay rate of uranium into lead to calculate the age of rocks, and thus—hehoped—of the Earth.
But there were many teical difficulties to overe. Holmes also needed—or at leastwould very much have appreciated—sophisticated gadgetry of a sort that could make veryfine measurements from tiny samples, and as we have seen it was all he could do to get asimple adding mae. So it was quite an achievement when in 1946 he was able toannouh some fidehat the Earth was at least three billion years old and possiblyrather more. Unfortunately, he now met yet another formidable impediment to acceptaheservativeness of his fellow stists. Although happy to praise his methodology, manymaintaihat he had found not the age of the Earth but merely the age of the materials fromwhich the Earth had been formed.
It was just at this time that Harrison Brown of the Uy of Chicago developed a hod for ting lead isotopes in igneous rocks (which is to say those that were createdthrough heating, as opposed to the laying down of sediments). Realizing that the work wouldbe exceedingly tedious, he assig to young Clair Patterson as his dissertation project.
Famously he promised Patterson that determining the age of the Earth with his new methodwould be “duck soup.” In fact, it would take years.
Patterson began work on the proje 1948. pared with Thomas Midgley’s colorfultributions to the march ress, Patterson’s discovery of the age of the Earth feelsmore than a touticlimactic. For seven years, first at the Uy of Chicago and then atthe California Institute of Teology (where he moved in 1952), he worked in a sterile lab,making very precise measurements of the lead/uranium ratios in carefully selected samples ofold rock.
The problem with measuring the age of the Earth was that you needed rocks that wereextremely a, taining lead- and uranium-bearing crystals that were about as old as theplaself—anything much younger would obviously give you misleadingly youthfuldates—but really a rocks are only rarely found oh. Ie 1940s no oogether uood why this should be. Indeed, and rather extraordinarily, we would bewell into the space age before anyone could plausibly at for where all the Earth’s oldrocks went. (The answer late teics, which we shall of cet to.) Pattersoime, was left to try to make sense of things with very limited materials. Eventually, adingeniously, it occurred to him that he could circumvent the rock she by using rocksfrom beyoh. He turo meteorites.
The assumption he made—rather a large one, but correct as it turned out—was that maeorites are essentially leftover building materials from the early days of the solar system,and thus have mao preserve a more or less pristierior chemistry. Measure the ageof these wandering rocks and you would have the age also (near enough) of the Earth.
As always, however, nothing was quite as straightforward as such a breezy descriptio sound. Meteorites are not abundant aeoritic samples not especially easy to gethold of. Moreover, Brown’s measurement teique proved finicky ireme andneeded much refi. Above all, there was the problem that Patterson’s samples weretinuously and unatably inated with large doses of atmospheric lead whehey were exposed to air. It was this that eventually led him to create a sterile laboratory—theworld’s first, acc to at least one at.
It took Patterson seven years of patient work just to assemble suitable samples for fiing. In the spring of 1953 he traveled to the Argoional Laboratory in Illinois,where he was graime on a late-model mass spectrograph, a mae capable of detegand measuring the minute quantities of uranium and lead locked up in a crystals. Whenat last he had his results, Patterson was so excited that he drove straight to his boyhood homein Iowa and had his mother check him into a hospital because he thought he was having aheart attack.
Soon afterward, at a meeting in Wissin, Patterson announced a definitive age for theEarth of 4,550 million years (plus or minus 70 million years)—“a figure that standsunged 50 years later,” as McGrayne admiringly notes. After two hundred years ,the Earth finally had an age.
His main work done, Patterson now turned his attention to the nagging question of all thatlead imosphere. He was astouo find that what little was known about the effectsof lead on humans was almost invariably wrong or misleading—and not surprisingly, hediscovered, since for forty years every study of lead’s effects had been funded exclusively bymanufacturers of lead additives.
In one such study, a doctor who had no specialized training in chemical pathologyuook a five-year program in which volunteers were asked to breathe in or swallow leadied quantities. Then their urine and feces were tested. Unfortunately, as the doctorappears not to have known, lead is not excreted as a waste product. Rather, it accumulates inthe bones and blood—that’s what makes it so dangerous—aher bone nor blood wastested. In sequence, lead was given a bill of ?
health.
Patterson quickly established that we had a lot of lead imosphere—still do, in fact,since lead never goes away—and that about 90 pert of it appeared to e fromautomobile exhaust pipes, but he couldn’t prove it. What he needed was a way to parelead levels imosphere now with the levels that existed before 1923, wheraethyllead was introduced. It occurred to him that ice cores could provide the answer.
It was known that snowfall in places like Greenland accumulates into discrete annual layers(because seasonal temperature differences produce slight ges in coloration from wiosummer). By ting back through these layers and measuring the amount of lead in each, hecould work out global lead trations at any time for hundreds, or even thousands, ofyears. The notion became the foundation of ice core studies, on which much modernclimatological work is based.
atterson found was that before 1923 there was almost no lead imosphere, andthat sihat time its level had climbed steadily and dangerously. He now made it his life’squest to get lead taken out of gasolio that end, he became a stant and often vocalcritic of the lead industry and its is.
It would prove to be a hellish campaighyl owerful global corporation withmany friends in high places. (Among its directors have been Supreme Court Justice LewisPowell and Gilbert Grosvenor of the National Geographic Society.) Patterson suddenly foundresearch funding withdrawn or difficult to acquire. The Ameri Petroleum Instituteceled a research tract with him, as did the Uates Public Health Service, asupposedly ral gover institution.
As Patterson increasingly became a liability to his institution, the school trustees wererepeatedly pressed by lead industry officials to shut him up or let him go. Acc to JamieLin Kitman, writing iion in 2000, Ethyl executives allegedly offered to endow achair at Caltech “if Patterson was sent pag.” Absurdly, he was excluded from a 1971National Research cil panel appoio iigate the dangers of atmospheric leadpoisoning even though he was by now uionably the leading expert on atmospheric lead.
To his great credit, Patterson never wavered or buckled. Eventually his efforts led to theintrodu of the Air Act of 1970 and finally to the removal from sale of all leadedgasoline in the Uates in 1986. Almost immediately lead levels in the blood ofAmeris fell by 80 pert. But because lead is forever, those of us alive today have about625 times more lead in our blood than people did a tury ago. The amount of lead imosphere also tio grow, quite legally, by about a huhousaris ayear, mostly from mining, smelting, and industrial activities. The Uates also bannedlead in indoor paint, “forty-four years after most of Europe,” as McGrayes.
Remarkably, sidering its startling toxicity, lead solder was not removed from Amerifood tainers until 1993.
As for the Ethyl Corporation, it’s still going strong, though GM, Standard Oil, and Du Pontno longer have stakes in the pany. (They sold out to a pany called Albemarle Paper in1962.) Acc to McGrayne, as late as February 2001 Ethyl tio tend “thatresearch has failed to show that leaded gasoline poses a threat to humah or theenviro.” On its website, a history of the pany makes ion of lead—or indeedof Thomas Midgley—but simply refers to the inal product as taining “a certainbination of chemicals.”
Ethyl no longer makes leaded gasoline, although, acc to its 2001 pany ats,tetraethyl lead (or TEL as it calls it) still ated for $25.1 million in sales in 2000 (out ofoverall sales of $795 million), up from $24.1 million in 1999, but down from $117 million in1998. In its report the pany stated its determination to “maximize the cash geed byTEL as its usage tio phase down around the world.” Ethyl markets TEL through anagreement with Associated Octel of England.
As for the other sce left to us by Thomas Midgley, chlorofluorocarbons, they werebanned in 1974 in the Uates, but they are tenacious little devils and any that youloosed into the atmosphere before then (in your deodorants or hair sprays, for instance) willalmost certainly be around and dev ozone long after you have shuffled off. Worse, weare still introdug huge amounts of CFto the atmosphere every year. Acc toWayne Biddle, 60 million pounds of the stuff, worth $1.5 billion, still finds its way onto themarket every year. So who is making it? We are—that is to say, many of our largecorporations are still making it at their plants overseas. It will not be banned in Third Worldtries until 2010.
Clair Patterson died in 1995. He didn’t win a Nobel Prize for his weologists neverdo. Nor, more puzzlingly, did he gain any fame or even much attention from half a tury ofsistent and increasingly selfless achievement. A good case could be made that he was themost iial geologist of the tweh tury. Yet who has ever heard of Clair Patterson?
Most geology textbooks don’t mention him. Two ret popular books on the history of thedating of Earth actually mao misspell his name. In early 2001, a reviewer of ohese books in the journal Nature made the additional, rather astounding error of thinkingPatterson was a woman.
At all events, thanks to the work of Clair Patterson by 1953 the Earth at last had an ageeveryone could agree on. The only problem now was it was older than the universe thattai.
11 MUSTER MARK’S QUARKS
IN 1911, A British stist named C. T. R. Wilson was studying cloud formations bytramping regularly to the summit of Ben Nevis, a famously damp Scottish mountain, when itoccurred to him that there must be an easier way to study clouds. Ba the dish Labin Cambridge he built an artificial cloud chamber—a simple devi which he could cooland moisten the air, creating a reasonable model of a cloud in laboratory ditions.
The device worked very well, but had an additional, ued be. When heaccelerated an alpha particle through the chamber to seed his make-believe clouds, it left avisible trail—like the trails of a passing airliner. He had just ied the particle detector.
It provided ving evidehat subatomic particles did indeed exist.
Eventually two other dish stists ied a more powerful proton-beam device,while in California Er Lawre Berkeley produced his famous and impressivecyclotron, or atom smasher, as such devices were loingly known. All of thesetraptions worked—and iill work—on more or less the same principle, the ideabeing to accelerate a proton or other charged particle to aremely high speed along a traetimes circular, sometimes linear), then bang it into another particle and see what fliesoff. That’s why they were called atom smashers. It wasn’t sce at its subtlest, but it wasgenerally effective.
As physicists built bigger and more ambitious maes, they began to find or postulateparticles or particle families seemingly without number: muons, pions, hyperons, mesons, K-mesons, Higgs bosons, intermediate vector bosons, baryons, tas. Even physicists beganto grow a little unfortable. “Young man,” Enrico Fermi replied when a student asked himthe name of a particular particle, “if I could remember the names of these particles, I wouldhave been a botanist.”
Today accelerators have hat sound like something Flash Gordon would use inbattle: the Super Proton Synchrotron, the Large Ele-Positron Collider, the Large HadronCollider, the Relativistic Heavy Ion Collider. Using huge amounts of energy (some operateonly at night so that people in neighb towns don’t have to witheir lights fadihe apparatus is fired up), they whip particles into such a state of livelihat asingle ele do forty-seven thousand laps around a four-mile tunnel in a sed. Fearshave been raised that in their enthusiasm stists might iently create a black hole oreven something called “strange quarks,” which could, theoretically, i with othersubatomic particles and propagate untrollably. If you are reading this, that hasn’thappened.
Finding particles takes a certain amount of tration. They are not just tiny and swiftbut also often tantalizingly eva. Particles e into being and be gone again in aslittle as 0.000000000000000000000001 sed (10-24). Even the most sluggish of unstableparticles hang around for no more than 0.0000001 sed (10-7).
Some particles are almost ludicrously slippery. Every sed the Earth is visited by 10,000trillion trillion tiny, all but massless rinos (mostly shot out by the nuclear broilings of theSun), and virtually all of them pass right through the pla and everything that is on it,including you and me, as if it weren’t there. To trap just a few of them, stists anksholding up to 12.5 million gallons of heavy water (that is, water with a relative abundance ofdeuterium in it) in underground chambers (old mines usually) where they ’t be interferedwith by other types of radiation.
Very occasionally, a passirino will bang into one of the atomiuclei ierand produce a little puff of energy. Stists t the puffs and by such means take us veryslightly closer to uanding the fual properties of the universe. In 1998, Japaneseobservers reported that rinos do have mass, but not a great deal—about oen-millionththat of aron.
What it really takes to find particles these days is money and lots of it. There is a curiousinverse relationship in modern physics betweeininess of the thing being sought and thescale of facilities required to do the searg. , the European anization for NuclearResearch, is like a little city. Straddling the border of Frand Switzerland, it employsthree thousand people and occupies a site that is measured in square miles. boasts astring of maghat weigh more than the Eiffel Tower and an underground tunnel oversixteen miles around.
Breaking up atoms, as James Trefil has noted, is easy; you do it each time you swit afluorest light. Breaking up atomiuclei, however, requires quite a lot of money and agenerous supply of electricity. Getting down to the level of quarks—the particles that make upparticles—requires still more: trillions of volts of electricity and the budget of a small tralAmeriation. ’s new Large Hadron Collider, scheduled to begiions in 2005,will achieve fourteen trillion volts of energy and cost something over $1.5 billion tostruct.
1But these numbers are as nothing pared with what could have been achieved by, a upon, the vast and now unfortunately o-be Superdug Supercollider, whichbegan being structed near Waxahachie, Texas, in the 1980s, before experieng asupercollision of its own with the Uates gress. The iion of the collider was tolet stists probe “the ultimate nature of matter,” as it is alut, by re-creating as nearlyas possible the ditions in the universe during its first ten thousand billionths of a sed.
The plan was to fling particles through a tunnel fifty-two miles long, achieving a trulystaggering y-rillion volts of energy. It was a grand scheme, but would also havecost $8 billion to build (a figure that eventually rose to $10 billion) and hundreds of millionsof dollars a year to run.
In perhaps the fi example in history of p money into a hole in the ground,gress spent $2 billion on the project, then celed it in 1993 after fourteen miles oftunnel had been dug. So Texas now boasts the most expensive hole in the universe. The siteis, I am told by my friend Jeff Guinn of the Fort Worth Star-Telegram, “essentially a vast,cleared field dotted along the circumference by a series of disappointed small towns.”
1There are practical side effects to all this costly effort. The World Wide Web is a offshoot. It wasied by a stist, Tim Berners-Lee, in 1989.
Sihe supercollider debacle particle physicists have set their sights a little lower, buteven paratively modest projects be quite breathtakingly costly when pared with,well, almost anything. A proposed rino observatory at the old Homestake Mine in Lead,South Dakota, would cost $500 million to build—this in a mihat is already dug—beforeyou even look at the annual running costs. There would also be $281 million of “generalversion costs.” A particle accelerator at Fermilab in Illinois, meanwhile, cost $260 millioo refit.
Particle physics, in short, is a hugely expeerprise—but it is a productive one.
Today the particle t is well over 150, with a further 100 or so suspected, butunfortunately, in the words of Richard Feynman, “it is very difficult to uand therelationships of all these particles, and what nature wants them for, or what the esare from oo another.” Iably each time we mao unlock a box, we find that thereis another locked box inside. Some people think there are particles called tas, which travel faster than the speed of light. Others long to find gravitons—the seat of gravity. Atoint we reach the irreducible bottom is not easy to say. Carl Sagan in os raised thepossibility that if you traveled downward into aron, you might find that it tained auniverse of its own, recalling all those sce fi stories of the fifties. “Within it,anized into the local equivalent of galaxies and smaller structures, are an immense numberof other, much tinier elementary particles, which are themselves universes at the leveland so on forever—an infinite downward regression, universes within universes, endlessly.
And upward as well.”
For most of us it is a world that surpasses uanding. To read even aary guideto particle physiowadays you must now find your way through lexical thickets such asthis: “The charged pion and antipion decay respectively into a muon plus arino and anantimuon plus rino with an average lifetime of 2.603 x 10-8seds, the ral piondecays into two photons with an average lifetime of about 0.8 x 10-16seds, and the muonand antimuon decay respectively into . . .” And so it runs on—and this from a book for thegeneral reader by one of the (normally) most lucid of interpreters, Steven Weinberg.
In the 1960s, in an attempt t just a little simplicity to matters, the Caltech physicistMurray Gell-Mann ied a new class of particles, essentially, in the words of StevenWeinberg, “to restore some ey to the multitude of hadrons”—a collective term used byphysicists for protons, rons, and other particles governed by the strong nuclear force.
Gell-Mann’s theory was that all hadrons were made up of still smaller, even morefual particles. His colleague Richard Feynman wao call these nearticles partons, as in Dolly, but was overruled. Ihey became known as quarks.
Gell-Mann took the name from a line in Finnegans Wake: “Three quarks for MusterMark!” (Discriminating physicists rhyme the word with storks, not larks, even though thelatter is almost certainly the pronunciation Joyce had in mind.) The fual simplicity ofquarks was not long lived. As they became better uood it was necessary to introducesubdivisions. Although quarks are muall to have color or taste or any other physicalcharacteristics we would reize, they became clumped into six categories—up, down,strange, charm, top, and bottom—which physicists oddly refer to as their “flavors,” and theseare further divided into the colors red, green, and blue. (One suspects that it was not altogethertal that these terms were first applied in California during the age of psychedelia.)Eventually out of all this emerged what is called the Standard Model, which is essentially asort of parts kit for the subatomic world. The Standard Model sists of six quarks, sixleptons, five known bosons and a postulated sixth, the Higgs boson (named for a Scottishstist, Peter Higgs), plus three of the four physical forces: the strong and weak nuclearforces aromagism.
The arra essentially is that among the basic building bloatter are quarks;these are held together by particles called gluons; and together quarks and gluons formprotons arons, the stuff of the atom’s nucleus. Leptons are the source of eles arinos. Quarks aons together are called fermions. Bosons (named for the Indianphysicist S. N. Bose) are particles that produd carry forces, and include photons andgluons. The Higgs boson may or may not actually exist; it was ied simply as a way ofendowing particles with mass.
It is all, as you see, just a little unwieldy, but it is the simplest model that explainall that happens in the world of particles. Most particle physicists feel, as Leon Ledermanremarked in a 1985 PBS dotary, that the Standard Model lacks elegand simplicity.
“It is too plicated. It has too many arbitrary parameters,” Lederman said. “We don’t reallysee the creator twiddling twenty knobs to set twenty parameters to create the universe as weknow it.” Physics is really nothing more than a search for ultimate simplicity, but so far all wehave is a kind of elegant messiness—or as Lederman put it: “There is a deep feeling that thepicture is not beautiful.”
The Standard Model is not only ungainly but inplete. For ohing, it has nothing at allto say about gravity. Search through the Standard Model as you will, and you won’t findanything to explain why when you place a hat on a table it doesn’t float up to the ceiling. Nor,as we’ve just noted, it explain mass. In order to give particles any mass at all we have tointroduce the notional Higgs boson; whether it actually exists is a matter for twenty-first-tury physics. As Feynman cheerfully observed: “So we are stuck with a theory, and we donot know whether it is right , but we do know that it is a little wrong, or at leastinplete.”
In an attempt to draw everything together, physicists have e up with something calledsuperstring theory. This postulates that all those little things like quarks aons that reviously thought of as particles are actually “strings”—vibrating strands of energy thatoscillate in eleven dimensions, sisting of the three we know already plus time and sevenother dimensions that are, well, unknowable to us. The strings are very tiny—tiny enough topass for point particles.
By introdug extra dimensions, superstring theory enables physicists to pull togetherquantum laws and gravitational ones into one paratively tidy package, but it also meansthat anything stists say about the theory begins to sound wly like the sort ofthoughts that would make you edge away if veyed to you by a stranger on a park bench.
Here, for example, is the physicist Michio Kaku explaining the structure of the universe froma superstring perspective: “The heterotic string sists of a closed string that has two types ofvibrations, clockwise and terclockwise, which are treated differently. The clockwisevibrations live in a ten-dimensional space. The terclockwise live in a twenty-six-dimensional space, of which sixteen dimensions have been pactified. (We recall that inKaluza’s inal five-dimensional, the fifth dimension was pactified by being edup into a circle.)” And so it goes, for some 350 pages.
String theory has further spawned something called “M theory,” whicorporatessurfaces known as membranes—or simply “brao the hipper souls of the world ofphysics. I’m afraid this is the stop on the knowledge highway where most of us must get off.
Here is a sentence from the New York Times, explaining this as simply as possible to a generalaudiehe ekpyrotic process begins far in the indefinite past with a pair of flat emptybranes sitting parallel to each other in a ed five-dimensional space. . . . The two branes,whi the walls of the fifth dimension, could have popped out of nothingness as aquantum fluctuation in the even more distant past and then drifted apart.” Nuing withthat. No uanding it either. Ekpyrotitally, es from the Greek word for“flagration.”
Matters in physics have now reached.９9lｉb? such a pitch that, as Paul Davies noted in Nature, it is“almost impossible for the non-stist to discrimiween the legitimately weird aright crackpot.” The question came iingly to a head in the fall of 2002 when twoFrench physicists, twin bror and Grickha Bogdanov, produced a theory of ambitiousdensity involving such cepts as “imaginary time” and the “Kubo-Sger-Martindition,” and purp to describe the nothihat was the universe before the BigBang—a period that was always assumed to be unknowable (si predated the birth ofphysid its properties).
Almost at ohe Bogdanov paper excited debate among physicists as to whether it wastwaddle, a work of genius, or a hoax. “Stifically, it’s clearly more or less pletenonsense,” bia Uy physicist Peter Woit told the New York Times, “but thesedays that doesn’t much distinguish it from a lot of the rest of the literature.”
Karl Popper, whom Steven Weinberg has called “the dean of modern philosophers ofsce,” once suggested that there may not be an ultimate theory for physics—that, rather,every explanation may require a further explanation, produg “an infinite of more andmore fual principles.” A rival possibility is that suowledge may simply bebeyond us. “So far, fortunately,” writes Weinberg in Dreams of a Final Theory, “we do o be ing to the end of our intellectual resources.”
Almost certainly this is ahat will see further developments of thought, and almostcertainly these thoughts will again be beyond most of us.
While physicists in the middle decades of the tweh-tury were looking perplexedlyinto the world of the very small, astronomers were finding no less arresting an inpletenessof uanding in the universe at large.
When we last met Edwin Hubble, he had determihat nearly all the galaxies in our fieldof view are flying away from us, and that the speed and distance of this retreat are lyproportional: the farther away the galaxy, the faster it is moving. Hubble realized that thiscould be expressed with a simple equation, Ho = v/d (where Ho is the stant, v is therecessional velocity of a flying galaxy, andd its distance away from us). Ho has been knownever since as the Hubble stant and the whole as Hubble’s Law. Using his formula, Hubblecalculated that the universe was about two billion years old, which was a little awkwardbecause even by the late 1920s it was fairly obvious that many things within the universe—not least Earth itself—were probably older than that. Refining this figure has been an ongoingpreoccupation of ology.
Almost99lｉb?t> the only thing stant about the Hubble stant has been the amount ofdisagreement over what value to give it. In 1956, astronomers discovered that Cepheidvariables were more variable than they had thought; they came in two varieties, not ohisallowed them to rework their calculations and e up with a new age for the universe offrom 7 to 20 billion years—not terribly precise, but at least old enough, at last, to embrace theformation of the Earth.
In the years that followed there erupted a long-running dispute between Allan Sandage, heirto Hubble at Mount Wilson, and Gérard de Vaucouleurs, a French-born astronomer based atthe Uy of Texas. Sandage, after years of careful calculations, arrived at a value for theHubble stant of 50, giving the universe an age of 20 billion years. De Vaucouleurs wasequally certain that the Hubble stant was 100.
2This would mean that the universe wasonly half the size and age that Sandage believed—ten billion years. Matters took a furtherlurto uainty when in 1994 a team from the egie Observatories in California,using measures from the Hubble space telescope, suggested that the universe could be as littleas eight billion years old—an age even they ceded was youhan some of the starswithin the universe. In February 2003, a team from NASA and the Goddard Space Flightter in Maryland, using a new, far-reag type of satellite called the WilkinsonMicrowave Anistropy Probe, announced with some fidehat the age of the universe is13.7 billion years, give or take a hundred million years or so. There matters rest, at least forthe moment.
The difficulty in making final determinations is that there are often acres of room forinterpretation. Imagianding in a field at night and trying to decide how far away twodistaric lights are. Using fairly straightforward tools of astronomy you easilyenough determihat the bulbs are of equal brightness and that one is, say, 50 pert moredistant thaher. But what you ’t be certain of is whether the nearer light is, let ussay, a 58-watt bulb that is 122 feet away or a 61-watt light that is 119 feet, 8 inches away. Ontop of that you must make allowances for distortions caused by variations in the Earth’satmosphere, by intergalactic dust, inating light from fround stars, and many otherfactors. The upshot is that your putations are necessarily based on a series of edassumptions, any of which could be a source of tention. There is also the problem thataccess to telescopes is always at a premium and historically measuring red shifts has beennotably costly in telescope time. It could take all night to get a single exposure. Insequence, astronomers have sometimes been pelled (or willing) to base clusionson notably sty evidence. In ology, as the journalist Geoffrey Carr has suggested, wehave “a mountain of theory built on a molehill of evidence.” Or as Martin Rees has put it:
“Our present satisfa [with our state of uanding] may reflect the paucity of the datarather than the excellence of the theory.”
This uainty applies, ially, to relatively nearby things as much as to the distantedges of the universe. As Donald Goldsmith notes, when astronomers say that the galaxy M87is 60 million light-years away, what they really mean (“but do not often stress to the generalpublic”) is that it is somewhere between 40 million and 90 million light-years away—not2You are of course entitled to wonder what is mealy by "a stant of 50" or "a stant of 100." Theanswer lies in astronomical units of measure. Except versationally, astronomers dont use light-years. Theyuse a distance called the parsec 藏书网(a tra of parallax and sed), based on a universal measure called thestellar parallax and equivalent to 3.26 light-years. Really big measures, like the size of a universe, are measuredin megaparsecs: a million parsecs. The stant is expressed in terms of kilometers per sed per megaparsec.
Thus when astronomers refer to a Hubble stant of 50, what they really mean is "50 kilometers per sed permegaparsec." For most of us that is of course an utterly meaningless measure, but then with astronomicalmeasures most distances are so huge as to be utterly meaningless.
quite the same thing. For the universe at large, matters are naturally magnified. Bearing allthat in mind, the best bets these days for the age of the universe seem to be fixed on a range ofabout 12 billion to 13.5 billion years, but we remain a long way from unanimity.
Oerestily suggested theory is that the universe is not nearly as big as wethought, that when we peer into the distane of the galaxies we see may simply berefles, ghost images created by rebounded light.
The fact is, there is a great deal, even at quite a fual level, that we don’t know— what the universe is made of. When stists calculate the amount of matter ohold things together, they always e up desperately short. It appears that at least 90 pertof the universe, and perhaps as much as 99 pert, is posed of Fritz Zwicky’s “darkmatter”—stuff that is by its nature invisible to us. It is slightly galling to think that we live ina universe that, for the most part, we ’t even see, but there you are. At least the names forthe tossible culprits are eaining: they are said to be either WIMPs (for WeaklyIing Massive Particles, which is to say specks of invisible matter left over from the BigBang) or MACHOs (for MAssive pact Halo Objects—really just another name for blackholes, brown dwarfs, and other very dim stars).
Particle physicists have teo favor the particle explanation of WIMPs, astrophysiciststhe stellar explanation of MACHOs. For a time MACHOs had the upper hand, but not nearlyenough of them were found, so se swung back toward WIMPs but with the problemthat no WIMP has ever been found. Because they are weakly iing, they are (assumingthey eve) very hard to detect. ic rays would cause too muterference. Sostists must go deep underground. One kilometer underground ibardmentswould be one millionth what they would be on the surface. But even when all these are addedin, “two-thirds of the universe is still missing from the balance sheet,” as one entatorhas put it. For the moment we might very well call them DUNNOS (for Dark UnknownNonreflective able Objects Somewhere).
Ret evidence suggests that not only are the galaxies of the universe rag away fromus, but that they are doing so at a rate that is accelerating. This is ter to all expectations. Itappears that the universe may not only be filled with dark matter, but with dark energy.
Stists sometimes also call it vacuum energy or, more exotically, quintessence. Whatever itis, it seems to be driving an expansion that no one altogether at for. The theory isthat empty space isn’t so empty at all—that there are particles of matter and antimatterpopping iend popping out again—and that these are pushing the universeoutward at an accelerating rate. Improbably enough, the ohing that resolves all this isEinstein’s ological stant—the little pieath he dropped into the general theoryof relativity to stop the universe’s presumed expansion, and called “the biggest blunder of mylife.” It noears that he may have gotten things right after all.
The upshot of all this is that we live in a universe whose age we ’t quite pute,surrounded by stars whose distances we don’t altogether know, filled with matter we ’tidentify, operating in ah physical laws whose properties we don’t trulyuand.
And on that rather uling note, let’s return to Plah and sider something thatwe do uand—though by now you perhaps won’t be surprised to hear that we don’tuand it pletely and what we do uand we haven’t uood for long.
12 THE EARTH MOVES
IN ONE OF his last professional acts before his death in 1955, Albert Einstein wrote a shortbut glowing foreword to a book by a geologist named Charles Hapgood entitled Earth’sShifting Crust: A Key to Some Basis of Earth Sce. Hapgood’s book was asteady demolition of the idea that tis were in motion. In a tohat all but ihereader to join him in a tolerant chuckle, Hapgood observed that a few gullible souls hadnoticed “an apparent corresponden shape betweeain tis.” It would appear,he went on, “that South America might be fitted together with Africa, and so on. . . . It is evenclaimed that roations on opposite sides of the Atlantic match.”
Mr. Hapgood briskly dismissed any suotions, noting that the geologists K. E. Casterand J. C. Mendes had doensive fieldwork on both sides of the Atlantid hadestablished beyond question that no such similarities existed. Goodness knows what outessrs. Caster and Mendes had looked at, beacuse in fact many of the roations onboth sides of the Atlanticare the same—not just very similar but the same.
This was not ahat flew with Mr. Hapgood, or many eologists of his day. Thetheory Hapgood alluded to was one first propounded in 1908 by an amateur Amerigeologist named Frank Bursley Taylor. Taylor came from a wealthy family and had both themeans and freedom from academistraints to pursue unventional lines of inquiry. Hewas one of those struck by the similarity in shape between the fag coastlines of AfridSouth America, and from this observation he developed the idea that the tis had onceslid around. He suggested—prestly as it turned out—that the g together oftis could have thrust up the world’s mountain s. He failed, however, to producemu the way of evidence, and the theory was sidered too crackpot to merit seriousattention.
In Germany, however, Taylor’s idea icked up, and effectively appropriated, by atheorist named Alfred Wegener, a meteist at the Uy of Marburg. Wegeneriigated the many plant and fossil anomalies that did not fit fortably into the standardmodel of Earth history and realized that very little of it made sense if ventionallyinterpreted. Animal fossils repeatedly turned up on opposite sides of os that were clearlytoo wide to swim. How, he wondered, did marsupials travel from South America to Australia?
How did identical snails turn up in Sdinavia and New England? And how, e to that,did one at for coal seams and other semi-tropical remnants in frigid spots likeSpitsbergen, four hundred miles north of Norway, if they had not somehow migrated therefrom warmer climes?
Wegener developed the theory that the world’s tis had one together in asingle landmass he called Pangaea, where flora and fauna had been able to mingle, before thetis had split apart and floated off to their present positions. All this he put together in abook called Die Entstehung der Koe und Ozeane, or The in of tis andOs, which ublished in German in 1912 ae the outbreak of the FirstWorld War in the meantime—in English three years later.
Because of the war, Wegener’s theory didn’t attract muotice at first, but by 1920, whenhe produced a revised and expanded edition, it quickly became a subject of discussion.
Everyone agreed that tis moved—but up and down, not sideways. The process ofvertical movement, known as isostasy, was a foundation of geological beliefs feions,though no one had any good theories as to how or why it happened. One idea, which remainedibooks well into my own school days, was the baked apple theory propounded by theAustrian Eduard Suess just before the turn of the tury. This suggested that as the molteh had cooled, it had bee wrinkled in the manner of a baked apple, creating obasins and mountain ranges. Never mind that James Hutton had shown long before that anysuch static arra would eventually result in a featureless spheroid as erosion leveledthe bumps and filled in the divots. There was also the problem, demonstrated by Rutherfordand Soddy early in the tury, that Earthly elements hold huge reserves of heat—muuch to allow for the sort of cooling and shrinking Suess suggested. And anyway, if Suess’stheory was correct then mountains should be evenly distributed across the face of the Earth,which patently they were not, and of more or less the same ages; yet by the early 1900s it wasalready evident that ses, like the Urals and Appalas, were hundreds of millionsof years older than others, like the Alps and Rockies. Clearly the time was ripe for a heory. Unfortunately, Alfred Wegener was not the man that geologists wished to provide it.
For a start, his radiotions questiohe foundations of their discipline, seldom aive way to gee warmth in an audience. Such a challenge would have been painfulenough ing from a geologist, but Wegener had no background in geology. He was ameteist, foodness sake. A weatherman—a Germaherman. These were notremediable deficies.
And so geologists took every pain they could think of to dismiss his evidend belittlehis suggestions. To get around the problems of fossil distributions, they posited a “landbridges” wherever they were needed. When an a horse named Hipparion was found tohave lived in Frand Florida at the same time, a land bridge was drawn across theAtlantic. When it was realized that aapirs had existed simultaneously in SouthAmerid Southeast Asia a land bridge was drawn there, too. Soon maps of prehistoricseas were almost solid with hypothesized land bridges—from North America to Europe, fromBrazil to Africa, from Southeast Asia to Australia, from Australia to Antarctica. Theseective tendrils had not only vely appeared whe was necessary to move aliving anism from one landmass to another, but then obligingly vanished without leaving atrace of their former existenone of this, of course, was supported by so much as a grainof actual evidehing s could be—yet it was geological orthodoxy for the half tury.
Even land bridges couldn’t explain some things. One species of trilobite that was wellknown in Europe was also found to have lived on Newfoundland—but only on one side. Noone could persuasively explain how it had mao cross two thousand miles of hostileo but then failed to find its way around the er of a 200-mile-wide island. Even moreawkwardly anomalous was another species of trilobite found in Europe and the Pacifiorthwest but nowhere iween, which would have required not so much a land bridge as aflyover. Yet as late as 1964 when the Encyclopaedia Britannica discussed the rival theories, itwas Wegener’s that was held to be full of “numerous grave theoretical difficulties.”
To be sure, Wegener made mistakes. He asserted that Greenland is drifti by about amile a year, which is clearly nonsense. (It’s more like half an inch.) Above all, he could offerno ving explanation for how the landmasses moved about. To believe in his theory youhad to accept that massive tis somehow pushed through solid crust, like a plh soil, without leaving any furrow in their wake. Nothing then known could plausiblyexplain what motored these massive movements.
It was Arthur Holmes, the English geologist who did so much to determihe age of theEarth, who suggested a possible way. Holmes was the first stist to uand thatradioactive warming could produce ve currents within the Earth. In theory thesecould be powerful enough to slide tis around on the surface. In his popular andiial textbook Principles of Physical Geology , first published in 1944, Holmes laid outa tial drift theory that was in its fuals the theory that prevails today. It wasstill a radical proposition for the time and widely criticized, particularly in the Uates,where resistao drift lasted lohan elsewhere. One reviewer there fretted, without anyevident sense of irony, that Holmes presented his arguments so clearly and pellingly thatstudents might actually e to believe them.
Elsewhere, however, the heory drew steady if cautious support. In 1950, a vote at theannual meeting of the British Association for the Adva of Sce showed that abouthalf of those present now embraced the idea of tial drift. (Hapgood soon after citedthis figure as proof of hically misled British geologists had bee.) Curiously,Holmes himself sometimes wavered in his vi. In 1953 he fessed: “I have neversucceeded in freeing myself from a nagging prejudice against tial drift; in mygeological bones, so to speak, I feel the hyp?hesis is a fantastie.”
tial drift was irely without support in the Uates. Reginald Daly ofHarvard spoke for it, but he, you may recall, was the man who suggested that the Moon hadbeen formed by a ic impact, and his ideas teo be sidered iing, evenworthy, but a touch too exuberant for serious sideration. And so most Ameri academicsstuck to the belief that the tis had occupied their present positions forever and thattheir surface features could be attributed to something other than lateral motions.
Iingly, oil pany geologists had known for years that if you wao find oil youhad to allow for precisely the sort of surfaents that were implied by plate teics.
But oil geologists didn’t write academic papers; they just found oil.
There was oher major problem with Earth theories that no one had resolved, or evene close to resolving. That was the question of where all the sediments went. Every yearEarth’s rivers carried massive volumes of eroded material—500 million tons of calcium, forinstao the seas. If you multiplied the rate of deposition by the number of years it hadbeen going on, it produced a disturbing figure: there should be about twelve miles ofsediments on the o bottoms—or, put another way, the o bottoms should by now bewell above the o tops. Stists dealt with this paradox in the ha possible way.
They ig. But eventually there came a point when they could ig no longer.
In the Sed World War, a Prion Uy mineralogist named Harry Hess utin charge of an attack transport ship, the USS Cape Johnson. Aboard this vessel was a fanew depth sounder called a fathometer, which was desigo facilitate inshore maneuversduring beach landings, but Hess realized that it could equally well be used for stificpurposes and never switched it off, even when far out at sea, even in the heat of battle. Whathe found was entirely ued. If the o floors were a, as everyone assumed, theyshould be thickly blaed with sediments, like the mud otom of a river or lake. ButHess’s readings showed that the o floor offered anything but the gooey smoothness ofa silts. It was scored everywhere with yons, trenches, and crevasses and dotted withvolic seamounts that he called guyots after an earlier Prion geologist named ArnoldGuyot. All this uzzle, but Hess had a war to take part in, and put such thoughts to theback of his mind.
After the war, Hess returo Prion and the preoccupations of teag, but themysteries of the seafloor tio occupy a spa his thoughts. Meanwhile, throughoutthe 1950s oographers were uaking more and more sophisticated surveys of theo floors. In so doing, they found an even bigger surprise: the mightiest and mostextensive mountain range oh was—mostly—uer. It traced a tinuous pathalong the world’s seabeds, rather like the stitg on a baseball. If you began at Id, youcould follow it down the ter of the Atlantic O, around the bottom of Africa, and acrossthe Indian and Southern Os, below Australia; there it angled across the Pacific as ifmaking for Baja California before shooting up the west coast of the Uates to Alaska.
Occasionally its higher peaks poked above the water as an island or archipelago—the Azoresand aries ilantic, Hawaii in the Pacific, for insta mostly it was burieduhousands of fathoms of salty sea, unknown and unsuspected. When all its brancheswere added together, the work exteo 46,600 miles.
A very little of this had been known for some time. People laying o-floor cables in theeenth tury had realized that there was some kind of mountainous intrusion in the mid-Atlanti the way the cables ran, but the tinuous nature and overall scale of the was a stunning surprise. Moreover, it tained physical anomalies that couldn’t be explained.
Down the middle of t..mid-Atlantic ridge was a yon—a rift—up to a dozen miles widefor its entire 12,000-mile length. This seemed to suggest that the Earth litting apart atthe seams, like a nut bursting out of its shell. It was an absurd and unnerving notion, but theevidence couldn’t be denied.
Then in 1960 core samples showed that the o floor was quite young at the mid-Atlanticridge but grew progressively older as you moved away from it to the east or west. Harry Hesssidered the matter and realized that this could mean only ohing: new o crust wasbeing formed oher side of the tral rift, then being pushed away from it as new crustcame along behind. The Atlantic floor was effectively twe veyor belts, one carryingcrust toward North America, the other carrying crust toward Europe. The process becameknown as seafloor spreading.
When the crust reached the end of its jour the boundary with tis, it plungedbato the Earth in a process known as subdu. That explained where all the sedime. It was beiuro the bowels of the Earth. It also explained why o floorseverywhere were so paratively youthful. None had ever been found to be older than about175 million years, which uzzle because tial rocks were often billions of yearsold. Now Hess could see why. O rocks lasted only as long as it took them to travel toshore. It was a beautiful theory that explained a great deal. Hess elaborated his ideas in animportant paper, which was almost universally ignored. Sometimes the world just isn’t readyfood idea.
Meanwhile, two researchers, w indepely, were making some startling findingsby drawing on a curious fact of Earth history that had been discovered several decades earlier.
In 1906, a French physicist named Bernard Brunhes had found that the pla’s magic fieldreverses itself from time to time, and that the record of these reversals is permaly fixed iain rocks at the time of their birth. Specifically, tiny grains of irohin the rockspoint to wherever the magic poles happen to be at the time of their formation, then staypointing in that dire as the rocks cool and harden. In effect they “remember” where themagic poles were at the time of their creation. For years this was little more than acuriosity, but in the 1950s Patrick Blackett of the Uy of London and S. K. Run ofthe Uy of Newcastle studied the a magic patterns frozen in British rocks andwere startled, to say the very least, to find them indig that at some time in the distant pastBritain had spun on its axis and traveled some distao the north, as if it had somehowe loose from its ms. Moreover, they also discovered that if you placed a map ofEurope’s magic patterns alongside an Ameri one from the same period, they fit togetheras ly as two halves of a torer. It was uny.
Their findings were igoo.
It finally fell to two men from Cambridge Uy, a geophysicist named DrummondMatthews and a graduate student of his named Fred Vio draw all the strands together. In1963, using magic studies of the Atlantic O floor, they demonstrated clusively thatthe seafloors were spreading in precisely the manner Hess had suggested and that thetis were in motion too. An unlucky adian geologist named Lawrence Morley cameup with the same clusion at the same time, but couldn’t find ao publish his paper.
In what has bee a famous snub, the editor of the Journal of Geophysical Research toldhim: “Such speculations make iing talk at cocktail parties, but it is not the sort of thingthat ought to be published under serious stific aegis.” One geologist later described it as“probably the most signifit paper in the earth sces ever to be denied publication.”
At all events, mobile crust was an idea whose time had finally e. A symposium ofmany of the most important figures in the field was vened in London uhe auspices ofthe Royal Society in 1964, and suddenly, it seemed, everyone was a vert. The Earth, themeeting agreed, was a mosaic of interected segments whose various stately jostlingsated for much of the pla’s surface behavior.
The name “tial drift” was fairly swiftly discarded when it was realized that thewhole crust was in motion and not just the tis, but it took a while to settle on a namefor the individual segments. At first people called them “crustal blocks” or sometimes “pavingstones.” Not until late 1968, with the publication of an article by three Ameriseismologists in the Journal of Geophysical Research , did the segments receive the name bywhich they have since been known: plates. The same article called the new sce plateteics.
Old ideas die hard, and not everyone rushed to embrace the exg heory. Well intothe 1970s, one of the most popular and iial geological textbooks, The Earth by thevenerable Harold Jeffreys, strenuously insisted that plate teics hysicalimpossibility, just as it had in the first edition way ba 1924. It was equally dismissive ofve and seafloor spreading. And in Basin and Range, published in 1980, John McPheehat even then one Ameri geologist i still didn’t believe in plate teics.
Today we know that Earth’s surface is made up of eight to twelve big plates (depending onhow you define big) and twenty or so smaller ones, and they all move in different diresand at different speeds. Some plates are large and paratively inactive, others small buteic. They bear only an ial relationship to the landmasses that sit upoheNorth Ameri plate, for instance, is much larger than the ti with which it isassociated. It roughly traces the outline of the ti’s western coast (which is why thatarea is so seismically active, because of the bump and crush of the plate boundary), butighe eastern seaboard altogether and instead extends halfway across the Atlantic to themid-o ridge. Id is split down the middle, which makes it teically half Amerid half European. New Zealand, meanwhile, is part of the immense Indian O plate eventhough it is nowhere he Indian O. And so it goes for most plates.
The es between modern landmasses and those of the past were found to beinfinitely more plex than anyone had imagined. Kazakhstan, it turns out, was oached to Norway and New England. One er of Staten Island, but only a er, isEuropean. So is part of Newfoundland. Pick up a pebble from a Massachusetts beach, and its kin will now be in Africa. The Scottish Highlands and much of Sdinavia aresubstantially Ameri. Some of the Shacklete of Antarctica, it is thought, may oncehave beloo the Appalas of the eastern U.S. Rocks, in shet around.
The stant turmoil keeps the plates from fusing into a single immobile plate. Assumingthings tinue much as at present, the Atlantic O will expand until eventually it is muchbigger than the Pacific. Much of California will float off and bee a kind of Madagascar ofthe Pacific. Africa will push northward into Europe, squeezing the Mediterranean out ofexistend thrusting up a of mountains of Himalayan majesty running from Paris toCalcutta. Australia will ize the islands to its north and ect by some isthmianumbilicus to Asia. These are future outes, but not future events. The events are happeningnow. As we sit here, tis are adrift, like leaves on a pond. Thanks to Global PositioningSystems we see that Europe and North America are parting at about the speed a fingernailgrhly two yards in a human lifetime. If you were prepared to wait long enough,you could ride from Los Angeles all the to San Francisco. It is only the brevity oflifetimes that keeps us from appreciating the ges. Look at a globe and what you areseeing really is a snapshot of the tis as they have been for just oh of 1 pertof the Earth’s history.
Earth is alone among the rocky plas in havionics, and why this should be is a bitof a mystery. It is not simply a matter of size or density—Venus is nearly a twin of Earth inthese respects a has onic activity. It is thought—though it is really nothing morethan a thought—that teics is an important part of the pla’s anic well-being. As thephysicist and writer James Trefil has put it, “It would be hard to believe that the tinuousmovement of teic plates has no effe the development of life oh.” He suggeststhat the challenges induced by teics—ges in climate, for instance—were animportant spur to the development of intelligehers believe the driftings of thetis may have produced at least some of the Earth’s various extin events. InNovember of 2002, Tony Di of Cambridge Uy in England produced a report,published in the journal Sce, strongly suggesting that there may well be a relationshipbetween the history of rocks and the history of life. What Di established was that thechemical position of the world’s os has altered abruptly and vigorously throughoutthe past half billion years and that these ges often correlate with importas inbiological history—the huge outburst of tiny anisms that created the chalk cliffs ofEngland’s south coast, the sudden fashion for shells among marine anisms during theCambrian period, and so on. No one say what causes the os’ chemistry to ge sodramatically from time to time, but the opening and shutting of o ridges would be anobvious possible culprit.
At all events, plate teiot only explaihe surface dynamics of the Earth—how ana Hipparion got from Frao Florida, for example—but also many of its internalas. Earthquakes, the formation of island s, the carbon cycle, the locations ofmountains, the ing of ice ages, the ins of life itself—there was hardly a matter thatwasn’t directly influenced by this remarkable heeologists, as McPhee has noted,found themselves in the giddying position that “the whole earth suddenly made sense.”
But only up to a point. The distribution of tis in former times is much less lyresolved than most people outside geophysics think. Although textbooks give fident-looking representations of a landmasses with names like Laurasia, Gondwana, Rodinia,and Pahese are sometimes based on clusions that don’t altogether hold up. AsGeaylord Simpson observes in Fossils and the History of Life, species of plants andanimals from the a world have a habit of appearing invely where they shouldn’tand failing to be where they ought.
The outline of Gondwana, a once-mighty ti eg Australia, Afritarctica, and South America, was bas.９９ｌｉb.
6,000 miles—in ic termsthe equivalent of a bullet passing through one’s sleeve without toug the arm. Two yearslater, another, somewhat larger asteroid missed us by just 90,000 miles—the closest pass yetrecorded. It, too, was not seen until it had passed and would have arrived without warning.
Acc to Timothy Ferris, writing in the New Yorker, suear misses probably happentwo or three times a week and go unnoticed.
An object a hundred yards across couldn’t be picked up by ah-based telescope untilit was within just a few days of us, and that is only if a telescope happeo be trained on it,which is unlikely because even now the number of people searg for such objects ismodest. The arresting analogy that is always made is that the number of people in the worldwho are actively searg for asteroids is fewer thaaff of a typical Mald’srestaurant. (It is actually somewhat higher now. But not much.)While Gene Shoemaker was trying to get people galvanized about the potential dangers ofthe inner solar system, another development—wholly ued on the face of it—was quietlyunfolding in Italy with the work of a young geologist from the Lamont Doherty Laboratory atbia Uy. In the early 1970s, Walter Alvarez was doing fieldwork in a elydefile known as the Bottae Ge, he Umbrian hill town of Gubbio, when he grewcurious about a thin band of reddish clay that divided two a layers of limestone—onefrom the Cretaceous period, the other from the Tertiary. This is a point known to geology asthe KT boundary,1and it marks the time, sixty-five million years ago, when the dinosaurs androughly half the world’s other species of animals abruptly vanish from the fossil record.
Alvarez wondered what it was about a thin lamina of clay, barely a quarter of an inch thick,that could at for such a dramatient ih’s history.
At the time the ventional wisdom about the dinosaur extin was the same as it hadbeen in Charles Lyell’s day a tury earlier—hat the dinosaurs had died out overmillions of years. But the thinness of the clay layer clearly suggested that in Umbria, if1It is KT rather than CT because C had already been appropriated for Cambrian. Depending on which sourceyou credit, the K es either from the Greek Kreta erman Kreide. Both vely mean “chalk,” whichis also what Cretaeans.
nowhere else, something rather more abrupt had happened. Unfortunately in the 1970s s existed for determining how long such a deposit might have taken to accumulate.
In the normal course of things, Alvarez almost certainly would have had to leave theproblem at that, but luckily he had an impeccable e to someoside hisdiscipline who could help—his father, Luis. Luis Alvarez was an emi nuclear physicist;he had won the Nobel Prize for physics the previous decade. He had always been mildlysful of his son’s attat to rocks, but this problem intrigued him. It occurred to himthat the answer might lie in dust from space.
Every year the Earth accumulates some thirty thousaris of “icspherules”—space dust in plainer language—which would be quite a lot if you swept it intoone pile, but is infinitesimal when spread across the globe. Scattered through this thin dustingare exotic elements not normally much found oh. Among these is the element iridium,which is a thousand times more abundant in space than in the Earth’s crust (because, it isthought, most of the iridium oh sank to the core when the pla was young).
Alvarez khat a colleague of his at the Lawrence Berkeley Laboratory in California,Frank Asaro, had developed a teique for measuring very precisely the chemiposition of clays using a process called ron activation analysis. This involvedb samples with rons in a small nuclear reactor and carefully ting thegamma rays that were emitted; it was extremely finicky work. Previously Asaro had used theteique to analyze pieces of pottery, but Alvarez reasohat if they measured the amountof one of the exotic elements in his son’s soil samples and pared that with its annual rateof deposition, they would know how long it had taken the samples to form. On an Octoberafternoon in 1977, Luis and Walter Alvarez dropped in on Asaro and asked him if he wouldrun the necessary tests for them.
It was really quite a presumptuous request. They were asking Asaro to devote months tomaking the most painstaking measurements of geological samples merely to firm whatseemed entirely self-evident to begin with—that the thin layer of clay had been formed asquickly as its thinness suggested. Certainly no one expected his survey to yield any dramaticbreakthroughs.
“Well, they were very charming, very persuasive,” Asaro recalled in an interview in 2002.
“And it seemed an iing challenge, so I agreed to try. Unfortunately, I had a lot of otherwork on, so it was eight months before I could get to it.” He sulted his notes from theperiod. “On June 21, 1978, at 1:45 p.m., we put a sample iector. It ran for 224minutes and we could see we were getting iis, so we stopped it and had alook.”
The results were so ued, in fact, that the three stists at first thought they had tobe wrong. The amount of iridium in the Alvarez sample was more than three huimesnormal levels—far beyond anything they might have predicted. Over the following monthsAsaro and his colleague Helen Michel worked up to thirty hours at a stretch (“Once youstarted you couldn’t stop,” Asaro explained) analyzing samples, always with the same results.
Tests on other samples—from Denmark, Spain, Franew Zealand, Antarctica—showedthat the iridium deposit was worldwide and greatly elevated everywhere, sometimes by asmuch as five huimes normal levels. Clearly something big and abrupt, and probablycataclysmic, had produced this arresting spike.
After much thought, the Alvarezes cluded that the most plausible explanation—plausible to them, at any rate—was that the Earth had been struck by an asteroid or et.
The idea that the Earth might be subjected to devastating impacts from time to time was notquite as new as it is now sometimes presented. As far back as 1942, a NorthwesternUy astrophysicist named Ralph B. Baldwin had suggested such a possibility in anarticle in Popular Astronomy magazine. (He published the article there because no academicpublisher repared to run it.) And at least two well-known stists, the astronomerErnst ?pik and the chemist and Nobel laureate Harold Urey, had also voiced support for thenotion at various times. Even among paleontologists it was not unknown. In 1956 a professorat on State Uy, M. W. de Laubenfels, writing in the Journal of Paleontology, hadactually anticipated the Alvarez theory by suggesting that the dinosaurs may have bee adeath blow by an impact from space, and in 1970 the president of the AmeriPaleontological Society, Dewey J. McLaren, proposed at the group’s annual ferehepossibility that araterrestrial impact may have been the cause of an earlier event knownas the Frasniain.
As if to underline just how un-he idea had bee by this time, in 1979 aHollywood studio actually produced a movie called Meteor (“It’s five miles wide . . . It’sing at 30,000 m.p.h.—and there’s no place to hide!”) starring Henry Fonda, NatalieWood, Karl Malden, and a very large rock.
So when, in the first week of 1980, at a meeting of the Ameri Association for theAdva of Sce, the Alvarezes annouheir belief that the dinosaur extinhad not taken place over millions of years as part of some slow inexorable process, butsuddenly in a single explosive event, it shouldn’t have e as a shock.
But it did. It was received everywhere, but particularly in the paleontological unity,as an eous heresy.
“Well, you have to remember,” Asaro recalls, “that we were amateurs in this field. Walterwas a geologist specializing in paleomagism, Luis hysicist and I was a nuclearchemist. And now here we were telling paleontologists that we had solved a problem that hadeluded them for over a tury. It’s not terribly surprising that they didn’t embrace itimmediately.” As Luis Alvarez joked: “We were caught practig geology without alise.”
But there was also something much deeper and more fually abhorrent in the impacttheory. The belief that terrestrial processes were gradual had beeal in natural historysihe time of Lyell. By the 1980s, catastrophism had been out of fashion for so long that ithad bee literally unthinkable. For most geologists the idea of a devastating impact was, asEugene Shoemaker noted, “against their stific religion.”
Nor did it help that Luis Alvarez enly ptuous of paleontologists and theirtributions to stifiowledge. “They’re really not very good stists. They’re morelike stamp collectors,” he wrote in the New York Times in an article that stings yet.
Oppos of the Alvarez theory produced any number of alternative explanations for theiridium deposits—for instahat they were geed by prolonged volic eruptions inIndia called the De Traps—and above all insisted that there was no proof that thedinosaurs disappeared abruptly from the fossil record at the iridium boundary. One of themost vigorous oppos was Charles Officer of Dartmouth College. He insisted that theiridium had been deposited by volic a even while g in a neer interviewthat he had no actual evidence of it. As late as 1988 more than half of all Ameripaleontologists tacted in a survey tio believe that the extin of the dinosaurswas in no way related to an asteroid or etary impact.
The ohing that would most obviously support the Alvarezes’ theory was the ohingthey didn’t have—an impact site. Enter Eugene Shoemaker. Shoemaker had an Iowae—his daughter-in-law taught at the Uy of Iowa—and he was familiar withthe Manson crater from his own studies. Thanks to him, all eyes now turo Iowa.
Geology is a profession that varies from place to place. In Iowa, a state that is flat andstratigraphically uful, it tends to be paratively serehere are no Alpine peaks rinding glaciers, no great deposits of oil or preetals, not a hint of a pyroclastic flow.
If you are a geologist employed by the state of Iowa, a big part of the work you do is toevaluate Manure Ma Plans, which all the state’s “animal fi operators”—hog farmers to the rest of us—are required to file periodically. There are fifteen million hogsin Iowa, so a lot of mao manage. I’m not mog this at all—it’s vital and enlightenedwork; it keeps Iowa’s water —but with the best will in the world it’s ly dodginglava bombs on Mount Pinatubo or scrabbling over crevasses on the Greenland ice sheet insearch of a life-bearing quartzes. So we may well imagihe flutter of excitement thatswept through the Ioartment of Natural Resources when in the mid-1980s the world’sgeological attention focused on Manson and its crater.
Tre Hall in Iowa City is a turn-of-the-tury pile of red brick that houses theUy of Iowa’s Earth Sces department and— in a kind of garret—thegeologists of the Ioartment of Natural Resources. No one now remember quitewhen, still less why, the state geologists were placed in an academic facility, but you get theimpression that the space was ceded grudgingly, for the offices are cramped and low-ceilinged and not very accessible. When being shown the way, you half expect to be taken outonto a roof ledge and helped in through a window.
Ray Anderson and Brian Witzke spend their w lives up here amid disordered heapsof papers, journals, furled charts, ay spe stones. (Geologists are a lossfor paperweights.) It’s the kind of space where if you want to find anything—ara chair, acoffee cup, a ringing telephone—you have to move stacks of dots around.
“Suddenly we were at the ter of things,” Anderson told me, gleaming at the memory ofit, when I met him and Witzke in their offices on a dismal, rainy m in June. “It was awonderful time.”
I asked them about Gene Shoemaker, a man who seems to have been universally revered.
“He was just a great guy,” Witzke replied without hesitation. “If it hadn’t been for him, thewhole thing would never have gotten off the ground. Even with his support, it took two yearsto get it up and running. Drilling’s an expensive business—about thirty-five dollars a footback then, more now, and we o go down three thousa.”
“Sometimes more than that,” Anderson added.
“Sometimes more than that,” Witzke agreed. “And at several locations. So you’re talking alot of money. Certainly more than our budget would allow.”
So a collaboration was formed between the Iowa Geological Survey and the U.S.
Geological Survey.
“At least we thought it was a collaboration,” said Anderson, produg a small painedsmile.
“It was a real learning curve for us,” Witzke went on. “There was actually quite a lot of badsce going on throughout the period—people rushing in with results that didn’t alwaysstand up to scrutiny.” One of those moments came at the annual meeting of the AmeriGeophysical Union in 1985, when Glen and C. L. Pillmore of the U.S. GeologicalSurvey annouhat the Manson crater was of the right age to have been involved with thedinosaurs’ extin. The declaration attracted a good deal of press attention but wasunfortunately premature. A more careful examination of the data revealed that Manson wasnot only too small, but also nine million years too early.
The first Anderson or Witzke learned of this setback to their careers was when they arrivedat a feren South Dakota and found people ing up to them with sympathetic looksand saying: “We hear you lost your crater.” It was the first they khat Izett and the S stists had just announced refined figures revealing that Manson couldn’t after allhave beein crater.
“It retty stunning,” recalls Anderson. “I mean, we had this thing that was reallyimportant and then suddenly we didn’t have it anymore. But even worse was the realizationthat the people we thought we’d been collaborating with hadn’t bothered to share with us theirnew findings.”
“Why not?”
He shrugged. “Who knows? Anyway, it retty good insight into how unattractivesce get when you’re playing at a certain level.”
The search moved elsewhere. By 1990 one of the searchers, Alan Hildebrand ofthe Uy of Arizona, met a reporter from the Houston icle who happeo knowabout a large, unexplained ring formation, 120 miles wide and 30 miles deep, under Mexico’sYu Peninsula at Chicxulub, he city reso, about 600 miles due south of NewOrleans. The formation had been found by Pemex, the Mexi oil pany, in 1952—theyear, tally, that Gene Shoemaker first visited Meteor Crater in Arizona—but thepany’s geologists had cluded that it was voli lih the thinking of the day.
Hildebrand traveled to the site and decided fairly swiftly that they had their crater. By early1991 it had beeablished to nearly everyone’s satisfa that Chicxulub was the impactsite.
Still, many people didn’t quite grasp what an impact could do. As Stephen Jay Gouldrecalled in one of his essays: “I remember harb some strong initial doubts about theefficacy of su event . . . [W]hy should an objely six miles across wreak such havo a pla with a diameter of eight thousand miles?”
vely a natural test of the theory arose when the Shoemakers and Levy discoveredet Shoemaker-Levy 9, which they soon realized was headed for Jupiter. For the first time,humans would be able to witness a ic collision—and witness it very well thanks to thenew Hubble space telescope. Most astronomers, acc to Curtis Peebles, expected little,particularly as the et was not a coherent sphere but a string of twenty-one fragments. “Mysense,” wrote one, “is that Jupiter will swallow these ets up without so much as a burp.”
One week before the impaature ran an article, “The Big Fizzle Is ing,” predigthat the impact would stitute nothing more than a meteor shower.
The impacts began on July 16, 1994, went on for a week and were bigger by far thanah the possible exception of Gene Shoemaker—expected. One fragment, knownas Nucleus G, struck with the force of about six milliooy-five times morethan all the nuclear onry ienucleus G was only about the size of a smallmountain, but it created wounds in the Jovian surface the size of Earth. It was the final blowfor critics of the Alvarez theory.
Luis Alvarez never knew of the discovery of the Chicxulub crater or of the Shoemaker-Levy et, as he died in 1988. Shoemaker also died early. Ohird anniversary of theShoemaker-Levy impact, he and his wife were in the Australian outback, where they wentevery year to searpact sites. On a dirt tra the Tanami Desert—normally ohe emptiest places oh—they came over a> slight rise just as another vehicle roag. Shoemaker was killed instantly, his wife injured. Part of his ashes were sent tothe Moon aboard the Lunar Prospector spacecraft. The rest were scattered aroueorCrater.
Anderson and Witzke no longer had the crater that killed the dinosaurs, “but we still hadthe largest and most perfectly preserved impact crater in the mainland Uates,”
Anderson said. (A little verbal dexterity is required to keep Manson’s superlative status. Othercraters are larger—notably, Chesapeake Bay, which was reized as an impact site in1994—but they are either offshore or deformed.) “Chicxulub is buried uwo to threekilometers of limestone and mostly offshore, which makes it difficult to study,” Anderso on, “while Manson is really quite accessible. It’s because it is buried that it is actuallyparatively pristine.”
I asked them how much warning we would receive if a similar hunk of rock was ingtoward us today.
“Oh, probably none,” said Anderson breezily. “It wouldn’t be visible to the naked eye untilit warmed up, and that wouldn’t happen until it hit the atmosphere, which would be about onesed before it hit the Earth. You’re talking about something moving many tens of timesfaster than the fastest bullet. Unless it had been seen by someoh a telescope, and that’sby no means a certainty, it would take us pletely by surprise.”
How hard an impactor hits depends on a lot of variables—angle of entry, velocity andtrajectory, whether the collision is head-on or from the side, and the mass ay of theimpag object, among much else—none of which we know so many millions of yearsafter the fact. But what stists do—and Anderson and Witzke have done—is measurethe impact site and calculate the amount of energy released. From that they work outplausible sarios of what it must have been like—or, more chillingly, would be like if ithappened now.
An asteroid or et traveling at ic velocities would ehe Earth’s atmosphere atsuch a speed that the air beh it couldn’t get out of the way and would be pressed, as ina bicycle pump. As anyone who has used such a pump knows, pressed air grows swiftlyhot, and the temperature below it would rise to some 60,000 Kelvin, or ten times the surfacetemperature of the Sun. In this instant of its arrival in our atmosphere, everything ieor’s path—people, houses, factories, cars—would kle and vanish like cellophane in aflame.
One sed after entering the atmosphere, the meteorite would slam into the Earth’ssurface, where the people of Manson had a moment before been going about their business.
The meteorite itself would vaporize instantly, but the blast would blow out a thousand cubieters of rock, earth, and superheated gases. Every living thing within 150 miles thathadn’t been killed by the heat of entry would now be killed by the blast. Radiating outward atalmost the speed of light would be the initial shock wave, sweeping everything before it.
For those outside the zone of immediate devastation, the first inkling of catastrophe wouldbe a flash of blinding light—the brightest ever seen by human eyes—followed an instant to aminute or two later by an apocalyptic sight of unimaginable grandeur: a roiling wall ofdarkness reag high into the heavens, filling aire field of view and traveling atthousands of miles an hour. Its approach would be eerily silent si would be moving farbeyond the speed of sound. Anyone in a tall building in Omaha or Des Moines, say, whoced to look in the right dire would see a bewildering veil of turmoil followed byinstantaneous oblivion.
Within minutes, over aretg from Deo Detroit and enpassing what hadonce been Chicago, St. Louis, Kansas City, the Twin Cities—the whole of the Midwest, inshort—nearly every standing thing would be flattened or on fire, and nearly every living thingwould be dead. People up to a thousand miles away would be knocked off their feet and slicedor clobbered by a blizzard of flying projectiles. Beyond a thousand miles the devastation fromthe blast would gradually diminish.
But that’s just the initial shockwave. No one do more than guess what the associateddamage would be, other than that it would be brisk and global. The impact would almostcertainly set off a of devastatihquakes. Voloes across the globe would beginto rumble and spew. Tsunamis would rise up and head devastatingly for distant shores. Withinan hour, a cloud of blaess would cover the pla, and burning rod other debriswould be pelting down everywhere, setting much of the pla ablaze. It has beeimatedthat at least a billion and a half people would be dead by the end of the first day. The massivedisturbao the ionosphere would knock out unications systems everywhere, sosurvivors would have no idea what was happening elsewhere or where to turn. It would hardlymatter. As one entator has put it, fleeing would meaing a slow death over aquie. The death toll would be very little affected by any plausible relocation effort, sih’s ability to support life would be universally diminished.”
The amount of soot and floating ash from the impad following fires would blot out thesuainly for months, possibly for years, disrupting growing cycles. In 2001 researchers atthe California Institute of Teology analyzed helium isotopes from sediments left from thelater KT impad cluded that it affected Earth’s climate for about ten thousand years.
This was actually used as evideo support the notion that the extin of dinosaurs wasswift and emphatid so it was in geological terms. We only guess how well, orwhether, humanity would cope with su event.
And in all likelihood, remember, this would e without warning, out of a clear sky.
But let’s assume we did see the objeing. What would we do? Everyone assumes wewould send up a nuclear warhead and blast it to smithereens. The idea has some problems,however. First, as John S. Lewis notes, our missiles are not designed for space work. Theyhaven’t the oomph to escape Earth’s gravity and, even if they did, there are no meisms toguide them across tens of millions of miles of space. Still less could we send up a shipload ofspace cowboys to do the job for us, as in the movie Armageddon; we no longer possess arocket powerful enough to send humans even as far as the Moon. The last rocket that could,Saturn 5, was retired years ago and has never been replaced. Nor could we quickly build anew one because, amazingly, the plans for Saturn launchers were destroyed as part of aNASA houseing exercise.
Even if we did manage somehow to get a warhead to the asteroid and blasted it to pieces,the ces are that we would simply turn it into a string of rocks that would slam into us oer the other in the manner of et Shoemaker-Levy on Jupiter—but with the differe now the rocks would be intensely radioactive. Tom Gehrels, an asteroid hu theUy of Arizona, thinks that even a year’s warning would probably be insuffit totake appropriate a. The greater likelihood, however, is that we wouldn’t see any object—even a et—until it was about six months away, which would be much too late.
Shoemaker-Levy 9 had been orbiting Jupiter in a fairly spianner since 1929, but ittook over half a tury before aiced.
Iingly, because these things are so difficult to co.mpute and must incorporate such asignifit margin of error, even if we knew an object was heading our ouldn’tknow until nearly the end—the last couple of weeks anyway—whether collision was certain.
For most of the time of the object’s approach we would exist in a kind of e of uainty.
It would certainly be the most iing few months in the history of the world. And imagihe party if it passed safely.
“So how often does something like the Manson impact happen?” I asked Anderson andWitzke before leaving.
“Oh, about once every million years on average,” said Witzke.
“And remember,” added Anderson, “this was a relatively mi. Do you know howmains were associated with the Manson impact?”
“No idea,” I replied.
“None,” he said, with a strange air of satisfa. “Not one.”
Of course, Witzke and Anderson added hastily and more or less in unison, there wouldhave been terrible devastation auch of the Earth, as just described, and pleteannihilation for hundreds of miles around ground zero. But life is hardy, and when the smokecleared there were enough lucky survivors from every species that none permalyperished.
The good news, it appears, is that it takes an awful lot to extinguish a species. The badnews is that the good news ever be ted on. Worse still, it isn’t actually necessary tolook to space for petrifying danger. As we are about to see, Earth provide plenty of dangerof its own.
14 THE FIRE BELOW
IN THE SUMMER of 1971, a young geologist named Mike Voorhies was scouting around onsome grassy farmland iern Nebraska, not far from the little town of Orchard, where hehad grown up. Passing through a steep-sided gully, he spotted a curious glint in the brushabove and clambered up to have a look. What he had seen was the perfectly preserved skull ofa young rhinoceros, which had been washed out by ret heavy rains.
A few yards beyond, it turned out, was one of the most extraordinary fossil beds everdiscovered in North America, a dried-up water hole that had served as a mass grave for scoresof animals—rhinoceroses, zebra-like horses, saber-toothed deer, camels, turtles. All had diedfrom some mysterious cataclysm just uwelve million years ago iime known togeology as the Mioe. In those days Nebraska stood on a vast, hot plain very like theSerei of Africa today. The animals had been found buried under volic ash up to te deep. The puzzle of it was that there were not, and never had been, any voloes inNebraska.
Today, the site of Voorhies’s discovery is called Ashfall Fossil Beds State Park, and it has astylish new visitors’ ter and museum, with thoughtful displays on the geology of Nebraskaand the history of the fossil beds. The ter incorporates a lab with a glass wall throughwhich visitors watch paleontologists ing bones. W alone in the lab on them I passed through was a cheerfully grizzled-looking fellow in a blue work shirt whnized as Mike Voorhies from a BBC television dotary in which he featured.
They don’t get a huge number of visitors to Ashfall Fossil Beds State Park—it’s slightly inthe middle of nowhere—and Voorhies seemed pleased to show me around. He took me to thespot atop a twenty-foot ravine where he had made his find.
“It was a dumb place to look for bones,” he said happily. “But I wasn’t looking for bones. Iwas thinking of making a geological map of eastern Nebraska at the time, and really just kindof poking around. If I hadn’t gone up this ravine or the rains hadn’t just washed out that skull,I’d have walked on by and this would never have been found.” He indicated a roofedenclosure nearby, which had bee the main excavation site. Some two hundred animalshad been found lying together in a jumble.
I asked him in what way it was a dumb place to hunt for bones. “Well, if you’re looking forbones, you really need exposed rock. That’s why most paleontology is done in hot, dry places.
It’s not that there are more bohere. It’s just that you have some ce of spotting them.
In a setting like this”—he made a sweepiure across the vast and unvarying prairie—“you wouldn’t know where to begin. There could be really magnifit stuff out there, butthere’s no surface clues to show you where to start looking.”
At first they thought the animals were buried alive, and Voorhies stated as mu aNational Geographic article in 1981. “The article called the site a ‘Pompeii of prehistoriimals,’ ” he told me, “which was unfortunate because just afterward we realized that theanimals hadn’t died suddenly at all. They were all suffering from something calledhypertrophic pulmonary osteodystrophy, which is what you would get if you were breathing alot of abrasive ash—and they must have beehing a lot of it because the ash was feetthick for hundreds of miles.” He picked up a k of grayish, claylike dirt and crumbled itinto my hand. It owdery but slightly gritty. “Nasty stuff to have to breathe,” he went on,“because it’s very fi also quite sharp. So anyway they came here to this watering hole,presumably seeking relief, and died in some misery. The ash would have ruined everything. Itwould have buried all the grass and coated every leaf and turhe water into an undrinkablegray sludge. It couldn’t have been very agreeable at all.”
The BBentary had suggested that the existence of so much ash in Nebraska rise. In faebraska’s huge ash deposits had been known about for a long time. Foralmost a tury they had been mio make household ing powders like et andAjax. But curiously no one had ever thought to wonder where all the ash came from.
“I’m a little embarrassed to tell you,” Voorhies said, smiling briefly, “that the first I thoughtabout it was when aor at the National Geographic asked me the source of all the ash andI had to fess that I didn’t know. Nobody knew.”
Voorhies sent samples to colleagues all over the western Uates asking if there wasanything about it that they reized. Several months later a geologist named BillBonni from the Idaho Geological Survey got in toud told him that the ash matcheda volic deposit from a place called Bruneau-Jarbidge in southwest Idaho. The event thatkilled the plains animals of Nebraska was a volic explosion on a scale previouslyunimagined—but big enough to leave an ash layer te deep almost a thousand miles awayiern Nebraska. It turned out that uhe western Uates there was a hugecauldron of magma, a colossal volic hot spot, which erupted cataclysmically every600,000 years or so. The last such eruption was just over 600,000 years ago. The hot spot isstill there. These days we call it Yellowston?９9lｉｂ?ional Park.
We know amazingly little about what happeh our feet. It is fairly remarkable tothink that Ford has been building cars and baseball has been playing World Series for lohan we have known that the Earth has a core. And of course the idea that the tis moveabout on the surface like lily pads has been on wisdom for much less than a geion.
“Strange as it may seem,” wrote Richard Feynman, “we uand the distribution of matterierior of the Sun far better than we uand the interior of the Earth.”
The distance from the surface of Earth to the ter is 3,959 miles, which isn’t so very far.
It has been calculated that if you sunk a well to the ter and dropped a brito it, it wouldtake only forty-five minutes for it to hit the bottom (though at that point it would beweightless since all the Earth’s gravity would be above and around it rather thah it).
Our own attempts to pee toward the middle have been modest indeed. One or two SouthAfri gold mines reach to a depth of two miles, but most mines oh go no more thanabout a quarter of a mile beh the surface. If the pla were an apple, we wouldn’t yethave broken through the skin. Indeed, we haven’t even e close.
Until slightly under a tury ago, what the best-informed stifids knew aboutEarth’s interior was not much more than what a iner knew—namely, that you could digdown through soil for a distand then you’d hit rod that was about it. Then in 1906,an Irish geologist named R. D. Oldham, while examining some seismograph readings from ahquake in Guatemala, noticed that certain shock waves had peed to a point deepwithin the Earth and then bounced off at an angle, as if they had entered some kind ofbarrier. From this he deduced that the Earth has a core. Three years later a Croatianseismologist named Andrija Mohorovi?i′c was studying graphs from ahquake in Zagrebwheiced a similar odd defle, but at a shallower level. He had discovered theboundary between the crust and the layer immediately below, the mahis zone has beenknown ever since as the Mohorovi?i′c distinuity, or Moho for short.
We were beginning to get a vague idea of the Earth’s layered interior—though it really wasonly vague. Not until 1936 did a Danish stist named Inge Lehmann, studyingseismographs of earthquakes in New Zealand, discover that there were two cores—an innerohat we now believe to be solid and an outer ohe ohat Oldham had detected) thatis thought to be liquid and the seat of magism.
At just about the time that Lehmann was refining our basiderstanding of the Earth’sinterior by studying the seismic waves of earthquakes, two geologists at Calte Californiawere devising a way to make parisoween ohquake and the . They wereCharles Richter and Beno Gutenberg, though for reasons that have nothing to do with fairhe scale became known almost at once as Richter’s alone. (It has nothing to do with Richtereither. A modest fellow, he never referred to the scale by his own name, but always called it“the Magnitude Scale.”)The Richter scale has always been widely misuood by noists, though perhapsa little less so now than in its early days when visitors to Richter’s office often asked to seehis celebrated scale, thinking it was some kind of mae. The scale is of course more ahan an object, an arbitrary measure of the Earth’s tremblings based on surfacemeasurements. It rises expoially, so that a 7.3 quake is fifty times more powerful than a6.3 earthquake and 2,500 times more powerful than a 5.3 earthquake.
At least theoretically, there is no upper limit for ahquake—nor, e to that, a lowerlimit. The scale is a simple measure of force, but says nothing about damage. A magnitude 7quake happening deep in the mantle—say, four hundred miles down—might cause no surfacedamage at all, while a signifitly smaller one happening just four miles uhe surfacecould wreak widespread devastation. Much, too, depends oure of the subsoil, thequake’s duration, the frequend severity of aftershocks, and the physical setting of theaffected area. All this means that the most fearsome quakes are not necessarily the mostforceful, though force obviously ts for a lot.
The largest earthquake sihe scale’s iion was (depending on which source youcredit) either oered on Prince William Sound in Alaska in March 1964, whichmeasured 9.2 on the Richter scale, or one in the Pacific O off the coast of Chile in 1960,which was initially logged at 8.6 magnitude but later revised upward by some authorities(including the Uates Geological Survey) to a truly grand-scale 9.5. As you will gatherfrom this, measurihquakes is not always a sce, particularly wheninterpreting readings from remote locations. At all events, both quakes were whopping. The1960 quake not only caused widespread damage across coastal South America, but also set offa giant tsunami that rolled six thousand miles across the Pacifid slapped away much ofdowntown Hilo, Hawaii, destroying five hundred buildings and killing sixty people. Similarwave surges claimed yet more victims as far away as Japan and the Philippines.
For pure, focused, devastation, however, probably the most intehquake in recordedhistory was ohat strud essentially shook to pieces—Lisbon, Pal, on All SaintsDay (November 1), 1755. Just before ten in the m, the city was hit by a suddensideways lurow estimated at magnitude 9.0 and shaken ferociously for seven full minutes.
The vulsive force was so great that the water rushed out of the city’s harbor aurnedin a wave fifty feet high, adding to the destru. When at last the motion ceased, survivorsenjoyed just three minutes of calm before a sed shock came, only slightly less severe thanthe first. A third and final shock followed two hours later. At the end of it all, sixty thousandpeople were dead and virtually every building for miles reduced to rubble. The San Franciscoearthquake of 1906, for parison, measured aimated 7.8 on the Richter scale andlasted less than thirty seds.
Earthquakes are fairly on. Every day on average somewhere in the world there aretwo of magnitude 2.reater—that’s enough to give anyone nearby a pretty good jolt.
Although they tend to cluster iain plaotably around the rim of the Pacific—they occur almost anywhere. In the Uates, only Florida, eastern Texas, and the upperMidwest seem—so far—to be almost entirely immune. New England has had two quakes ofmagnitude 6.reater in the last two hundred years. In April 2002, the region experienceda 5.1 magnitude shaking in a quake near Lake Champlain on the New York–Vermont border,causiensive local damage and (I attest) knog pictures from walls and childrenfrom beds as far away as Neshire.
The most on types of earthquakes are those where two plates meet, as in Californiaalong the San Andreas Fault. As the plates push against each other, pressures build up untilone or the ives way. In general, the lohe interval between quakes, the greater thepent-up pressure and thus the greater the scope for a really big jolt. This is a particular worryfor Tokyo, which Bill McGuire, a hazards specialist at Uy College London, describesas “the city waiting to die” (not a motto you will find on many tourism leaflets). Tokyo standson the boundary of three teic plates in a try already well known for its seismistability. In 1995, as you will remember, the city of Kobe, three hundred miles to the west,was struck by a magnitude 7.2 quake, which killed 6,394 people. The damage was estimatedat $99 billion. But that was as nothing—well, as paratively little—pared with whatmay await Tokyo.
Tokyo has already suffered one of the most devastatihquakes in modern times. Oember 1, 1923, just before noon, the city was hit by what is known as the Great Kantoquake—a more thaimes more powerful than Kobe’s earthquake. Two huhousand people were killed. Sihat time, Tokyo has been eerily quiet, so the straih the surface has been building fhty years. Eventually it is bound to snap. In 1923,Tokyo had a population of about three million. Today it is approag thirty million. Nobodycares to guess hoeople might die, but the potential eic cost has been put ashigh as $7 trillion.
Even more unnerving, because they are less well uood and capable of anywhere at any time, are the rarer type of shakings known as intraplate quakes. Thesehappen away from plate boundaries, which makes them wholly uable. And becausethey e from a much greater depth, they tend tate over much wider areas. Themost notorious such quakes ever to hit the Uates were a series of three in NewMadrid, Missouri, in the winter of 1811–12. The advearted just after midnight onDecember 16 when people were awakened first by the noise of panig farm animals (therestiveness of animals before quakes is not an old wives’ tale, but is in fact well established,though not at all uood) and then by an almighty rupturing noise from deep withih. Emerging from their houses, locals found the land rolling in waves up to three feet highand opening up in fissures several feet deep. A strong smell of sulfur filled the air. Theshaking lasted for four minutes with the usual devastating effects to property. Among thewitnesses was the artist John James Audubon, who happeo be in the area. The quakeradiated outward with such force that it knocked down eys in ati four hundredmiles away and, acc to at least one at, “wrecked boats i Coast harbors and .
. . even collapsed scaffoldied around the Capitol Building in Washington, D.C.” OnJanuary 23 and February 4 further quakes of similar magnitude followed. New Madrid hasbeen silent ever si not surprisingly, since such episodes have never been known tohappen in the same place twice. As far as we know, they are as random as lightning. The one could be under Chicago or Paris or Kinshasa. No one even begin to guess. And whatcauses these massive intraplate rupturings? Something deep within the Earth. More than thatwe don’t know.
By the 1960s stists had grown suffitly frustrated by how little they uood ofthe Earth’s interior that they decided to try to do something about it. Specifically, they got theidea to drill through the o floor (the tial crust was too thick) to the Mohodistinuity and to extract a.９9lｉb.
als. That means that all modern humans arose from a very small population base,which would explain our lack of geic diversity. At all events, there is some evideosuggest that for the wenty thousand years the total number of people oh was nevermore than a few thousand at any time. That is, needless to say, a long time to recover from asingle volic blast.
All this was hypothetically iing until 1973, when an odd occurrence made itsuddenly momentous: water in Yellowstone Lake, in the heart of the park, began to ruhe banks at the lake’s southern end, flooding a meadow, while at the opposite end of the lakethe water mysteriously flowed away. Geologists did a hasty survey and discovered that a largearea of the park had developed an ominous bulge. This was lifting up one end of the lake andcausing the water to run out at the other, as would happen if you lifted one side of a child’swading pool. By 1984, the whole tral region of the park—several dozen square miles—was more than three feet higher than it had been in 1924, when the park was last formallysurveyed. Then in 1985, the whole of the tral part of the park subsided by eight inches. Itnow seems to be swelling again.
The geologists realized that only ohing could cause this—a restless magma chamber.
Yellowstone wasn’t the site of an a supervolo; it was the site of an active o wasalso at about this time that they were able to work out that the cycle of Yellowstoions averaged one massive blow every 600,000 years. The last one, iingly enough,was 630,000 years ago. Yellowsto appears, is due.
“It may not feel like it, but you’re standing on the largest active volo in the world,” PaulDoss, Yellowstoional Park geologist, told me soon after climbing off an enormousHarley-Davidson motorcycle and shaking hands whe at the park headquarters atMammoth Hot Springs early on a lovely m in June. A native of Indiana, Doss is anamiable, soft-spokeremely thoughtful man who looks nothing like a National ParkService employee. He has a graying beard and hair tied ba a long ponytail. A smallsapphire stud graces one ear. A slight paunch strains against his crisp Park Serviiform.
He looks more like a blues musi than a gover employee. In fact, he is a bluesmusi (harmonica). But he sure knows and loves geology. “And I’ve got the best plathe world to do it,” he says as we set off in a bouncy, battered four-wheel-drive vehicle in thegeneral dire of Old Faithful. He has agreed to let me apany him for a day as he goesabout doing whatever it is a park geologist does. The first assigoday is to give anintroductory talk to a new crop of tuides.
Yellowstone, I hardly need point out, is sensationally beautiful, with plump, statelymountains, bison-specked meadows, tumbling streams, a sky-blue lake, wildlife beyondting. “It really doesn’t get aer than this if you’re a geologist,” Doss says. “You’vegot rocks up at Beartooth Gap that are nearly three billion years old—three-quarters of theway back to Earth’s beginning—and then you’ve got mineral springs here”—he points at thesulfurous hot springs from which Mammoth takes its title—“where you see rocks as theyare being born. And iween there’s everything you could possibly imagine. I’ve neverbeen any place where geology is more evident—or prettier.”
“So you like it?” I say.
“Oh, no, I love it,” he answers with profound siy. “I mean I really love it here. Thewinters are tough and the pay’s not too hot, but when it’s good, it’s just—”
He interrupted himself to point out a distant gap in a range of mountains to the west, whichhad just e into view over a rise. The mountains, he told me, were known as the Gallatins.
“That gap is sixty or maybe seventy miles across. For a long time nobody could uandwhy that gap was there, and then Bob Christiansen realized that it had to be because themountains were just blown away. When you’ve got sixty miles of mountains just obliterated,you know you’re dealing with something pretty potent. It took Christiansen six years to figureit all out.”
I asked him what caused Yellowstoo blow when it did.
“Don’t know. Nobody knows. Voloes are strahings. We really don’t ua all. Vesuvius, in Italy, was active for three hundred years until aion in 1944and then it just stopped. It’s been silent ever since. Some volologists think that it isrecharging in a big way, which is a little w because two million people live on oraround it. But nobody knows.”
“And how much warning would you get if Yellowstone was going to go?”
He shrugged. “Nobody was around the last time it blew, so nobody knows what thewarning signs are. Probably you would have swarms of earthquakes and some surface upliftand possibly some ges iterns of behavior of the geysers and steam vents, butnobody really knows.”
“So it could just blow without warning?”
He houghtfully. The trouble, he explained, is that nearly all the things that wouldstitute warning signs already exist in some measure at Yellowstone. “Earthquakes aregenerally a precursor of volic eruptions, but the park already has lots of earthquakes—1,260 of them last year. Most of them are too small to be felt, but they are earthquakesheless.”
A ge itern of geyser eruptions might also be taken as a clue, he said, but thesetoo vary uably. Ohe most famous geyser in the park was Excelsieyser. Itused to erupt regularly and spectacularly to heights of three hundred feet, but in 1888 it juststopped. Then in 1985 it erupted again, though only to a height of eighty feet. SteamboatGeyser is the biggest geyser in the world when it blows, shooting water four hundred feet intothe air, but the intervals between its eruptions have ranged from as little as four days to almostfifty years. “If it blew today and agai week, that wouldn’t tell us anything at all aboutwhat it might do the following week or the week after or twenty years from now,” Doss says.
“The whole park is so volatile that it’s essentially impossible to draw clusions from almostanything that happens.”
Evacuating Yellowstone would never be easy. The park gets some three million visitors ayear, mostly ihree peak months of summer. The park’s roads are paratively few andthey are kept iionally narrow, partly to slow traffic, partly to preserve an air ofpicturesqueness, and partly because of topographical straints. At the height of summer, it easily take half a day to cross the park and hours to get anywhere within it. “Wheneverpeople see animals, they just stop, wherever they are,” Doss says. “We get bear jams. We getbison jams. We get wolf jams.”
Iumn of 2000, representatives from the U.S. Geological Survey and National ParkService, along with some academics, met and formed something called the YellowstoneVolic Observatory. Four such bodies were ience already—in Hawaii, California,Alaska, and Washington—but oddly none in the largest volie in the world. The YVOis not actually a thing, but more an idea—an agreement to coordinate efforts at studying andanalyzing the park’s diverse geology. One of their first tasks, Doss told me, was to draw up ahquake and volo hazards plan”—a plan of a in the event of a crisis.
“There isn’t one already?” I said.
“No. Afraid not. But there will be soon.”
“Isn’t that just a little tardy?”
He smiled. “Well, let’s just say that it’s not any too soon.”
O is in place, the idea is that three people—Christiansen in Menlo Park, California,Professor Robert B. Smith at the Uy of Utah, and Doss in the park—would assess thedegree of danger of any potential cataclysm and advise the park superinte. Thesuperinte would take the decisioher to evacuate the park. As for surroundingareas, there are no plans. If Yellowstone were going to blow in a really big way, you would beon your own once you left the park gates.
Of course it may be tens of thousands of years before that day es. Doss thinks such aday may not e at all. “Just because there attern in the past doesn’t mean that it stillholds true,” he says. “There is some evideo suggest that the pattern may be a series ofcatastrophic explosions, then a long period of quiet. We may be in that now. The evidenow is that most of the magma chamber is cooling and crystallizing. It is releasing itsvolatiles; you o trap volatiles for an explosive eruption.”
In the meahere are plenty of other dangers in and around Yellowstone, as was madedevastatingly evident on the night of August 17, 1959, at a place called Hebgen Lake justoutside the park. At twenty mio midnight on that date, Hebgen Lake suffered acatastrophic quake. It was magnitude 7.5, not vast as earthquakes go, but so abrupt andwreng that it collapsed aire mountai was the height of the summer season,though fortunately not so many people went to Yellowstone in those days as now. Eightymillion tons of rock, moving at more than one hundred miles an hour, just fell off themountain, traveling with such ford momentum that the leading edge of the landslide ranfour hundred feet up a mountain oher side of the valley. Along its path lay part of theRock Creek Campground. Twe campers were killed, een of them buried toodeep ever to be found again. The devastation was swift but heartbreakingly fickle. Threebrothers, sleeping ient, were spared. Their parents, sleeping in aent besidethem, were swept away and never seen again.
“A big earthquake—and I mean big—will happen sometime,” Doss told me. “You t on that. This is a big fault zone for earthquakes.”
Despite the Hebgen Lake quake and the other known risks, Yellowstone didn’t getperma seismometers until the 1970s.
If you needed a way to appreciate the grandeur and inexorable nature of geologic processes,you could do worse than to sider the Tetons, the sumptuously jagged rahat stands justto the south of Yellowstoional Park. Nine million years ago, the Tetons did.
The land around Ja Hole was just a high grassy plain. But then a forty-mile-long faultopened within the Earth, and sihen, about once every nine hundred years, the Tetonsexperience a really big earthquake, enough to jerk them another six feet higher. It is theserepeated jerks over eons that have raised them to their present majestic heights of seventhousa.
That nine hundred years is an average—and a somewhat misleading one. Acc toRobert B. Smith and Lee J. Siegel in Windows into the Earth , a geological history of theregion, the last major Teton quake was somewhere between about five and seven thousandyears ago. The Tetons, in short, are about the most overdue earthquake zone on the pla.
Hydrothermal explosions are also a signifit risk. They happen anytime, pretty muywhere, and without any predictability. “You know, by design we funnel visitors intothermal basins,” Doss told me after we had watched Old Faithful blow. “It’s what they eto see. Did you know there are meysers and hot springs at Yellowstohan in all therest of the world bined?”
“I didn’t know that.”
He nodded. “Ten thousand of them, and nobody knows when a new vent might open.” Wedrove to a place called Duck Lake, a body of water a couple of hundred yards across. “It lookspletely innocuous,” he said. “It’s just a big pond. But this big hole didn’t used to be here.
At some time in the last fifteen thousand years this blew in a really big way. You’d have hadseveral tens of millions of tons of earth and rod superheated water blowing out athypersonic speeds. You imagine what it would be like if this happened under, say, theparking lot at Old Faithful or one of the visitors’ ters.” He made an unhappy face.
“Would there be any warning?”
“Probably not. The last signifit explosion in the park was at a place called Pork >hopGeyser in 1989. That left a crater about five meters across—not huge by any means, but bigenough if you happeo be standing there at the time. Fortunately, nobody was around sonobody was hurt, but that happened without warning. In the very a past there have beenexplosions that have made holes a mile across. And nobody tell you where or when thatmight happen again. You just have to hope that you’re not standing there when it does.”
Big rockfalls are also a dahere was a big o Gardiner yon in 1999, but againfortunately no one was hurt. Late iernoon, Doss and I stopped at a place where therewas a rock poised above a busy park road. Cracks were clearly visible. “It could goat any time,” Doss said thoughtfully.
“You’re kidding,” I said. There wasn’t a moment when there weren’t tassih it, all filled with, in the most literal sense, happy campers.
“Oh, it’s not likely,” he added. “I’m just saying it could. Equally it could stay like that fordecades. There’s just no telling. People have to accept that there is risk in ing here. That’sall there is to it.”
As we walked back to his vehicle to head bamoth Hot Springs, Doss added: “Butthe thing is, most of the time bad things don’t happen. Rocks don’t fall. Earthquakes don’toccur. New vents don’t suddenly open up. For all the instability, it’s mostly remarkably andamazingly tranquil.”
“Like Earth itself,” I remarked.
“Precisely,” he agreed.
The risks at Yellowstone apply to park employees as much as to visitors. Doss got ahorrifise of that in his first week on the job five years earlier. Late one night, three youngsummer employees engaged in an illicit activity known as “hot-potting”—swimming orbasking in ools. Though the park, for obvious reasons, doesn’t publicize it, not all thepools in Yellowstone are dangerously hot. Some are extremely agreeable to lie in, and it wasthe habit of some of the summer employees to have a dip late at night even though it wasagainst the rules to do so. Foolishly the threesome had failed to take a flashlight, which wasextremely dangerous because much of the soil around the ools is crusty and thin andone easily fall through into a scaldi below. In any case, as they made their wayback to their dorm, they came across a stream that they had had to leap over earlier. Theybacked up a few paces, linked arms and, on the t of three, took a running jump. In fact, itwasn’t the stream at all. It was a boiling pool. In the dark they had lost their bearings. he three survived.
I thought about this the m as I made a brief call, on my way out of the park, at aplace called Emerald Pool, in the Upper Geyser Basin. Doss hadn’t had time to take me therethe day before, but I９9ｌｉb? thought I ought at least to have a look at it, for Emerald Pool is a historicsite.
In 1965, a husband-and-wife team of biologists homas and Louise Brock, while ona summer study trip, had done a crazy thing. They had scooped up some of the yellowy-brown scum that rimmed the pool and exami for life. To their, aually the widerworld’s, deep surprise, it was full of living microbes. They had found the world’s firstextremophiles—anisms that could live in water that had previously been assumed to bemuch too hot or acid or choked with sulfur to bear life. Emerald Pool, remarkably, was allthese things, yet at least two types of living things, Sulpholobus acidocaldarius andThermophilus aquaticus as they became known, found it genial. It had always beensupposed that nothing could survive above temperatures of 50°C (122°F), but here wereanisms basking in rank, acidic waters nearly twice that hot.
For almost twenty years, one of the Brocks’ two new bacteria, Thermophilus aquaticus,remained a laboratory curiosity until a stist in California named Kary B. Mullis realizedthat heat-resistant enzymes within it could be used to create a bit of chemical wizardry knownas a polymerase rea, which allows stists to gee lots of DNA from verysmall amounts—as little as a single molecule in ideal ditions. It’s a kind of geicphotocopying, and it became the basis for all subsequeic sce, from academicstudies to police forensic work. It won Mullis the Nobel Prize iry in 1993.
Meanwhile, stists were finding even hardier microbes, now knoerthermophiles, which demand temperatures of 80°C (176°F) or more. The warmestanism found so far, acc to Frances Ashcroft in Life at the Extremes, is Pyrolobusfumarii, which dwells in the walls of o vents where the temperature reach 113°C(235.4°F). The upper limit for life is thought to be about 120°C (248°F), though no oually knows. At all events, the Brocks’ findings pletely ged our perception of theliving world. As NASA stist Jay Bergstralh has put it: “Wherever we go oh—eveninto what’s seemed like the most hostile possible enviros for life—as long as there isliquid water and some source of chemical energy we find life.”
Life, it turns out, is infinitely more clever and adaptable than anyone had ever supposed.
This is a very good thing, for as we are about to see, we live in a world that doesn’t altogetherseem to want us here.
PART V LIFE ITSELFThe more I examihe universeand study the details of its architecture,the more evidence I find that theuniverse in some sense must haveknoere ing.
-Freeman Dyson
16 LONELY PLANET
IT ISN’T EASY being an anism. In the whole universe, as far as we yet know, there isonly one place, an inspicuous outpost of the Milky Way called Earth, that will sustain you,and even it be pretty grudging.
From the bottom of the deepest o trench to the top of the highest mountain, the zo covers nearly the whole of known life, is only something over a dozen miles—not muchwhe against the roominess of the os at large.
For humans it is even worse because en to belong to the portion of living thingsthat took the rash but venturesome decision 400 million years ago to crawl out of the seas andbee land based and oxygehing. In sequeno less than 99.5 pert of theworld’s habitable space by volume, acc to oimate, is fually—in practicalterms pletely—off-limits to us.
It isn’t simply that we ’t breathe in water, but that we couldn’t bear the pressures.
Because water is about 1,300 times heavier than air, pressures rise swiftly as you desd—by the equivalent of omosphere for every teers (thirty-three feet) of depth. On land,if you rose to the top of a five-hundred-foot eminence—Cologhedral or the WashingtonMo, say—the ge in pressure would be so slight as to be indisible. At the samedepth uer, however, your veins would collapse and your lungs would press to theapproximate dimensions of a Coke . Amazingly, people do voluntarily dive to such depths,without breathing apparatus, for the fun of it in a sport known as free diving. Apparently theexperience of having your internal ans rudely deformed is thought exhilarating (though notpresumably as exhilarating as having them return to their former dimensions uponresurfag). To reach such depths, however, divers must be dragged down, and quite briskly,by weights. Without assistahe deepest anyone has gone and lived to talk about itafterward was an Italian named Umberto Pelizzari, who in 1992 dove to a depth of 236 feet,lingered for a nanosed, and then shot back to the surface. In terrestrial terms, 236 feet isjust slightly over the length of one New York City block. So even in our most exuberantstunts we hardly claim to be masters of the abyss.
anisms do of course mao deal with the pressures at depth, though quite howsome of them do so is a mystery. The deepest point in the o is the Mariana Tren thePacific. There, some seven miles down, the pressures rise to over sixteen thousand pounds persquare inch. We have managed once, briefly, to send humans to that depth in a sturdy divingvessel, yet it is home to ies of amphipods, a type of crusta similar to shrimp buttransparent, which survive without any prote at all. Most os are of course muchshallower, but even at the average o depth of two and a half miles the pressure isequivalent to being squashed beh a stack of fourteen loaded t trucks.
Nearly everyone, including the authors of some popular books on oography, assumesthat the human body would crumple uhe immense pressures of the deep o. In fact,this appears not to be the case. Because we are made largely of water ourselves, and water is“virtually inpressible,” in the words of Frances Ashcroft of Oxford Uy, “the bodyremains at the same pressure as the surrounding water, and is not crushed at depth.” It is thegases inside your body, particularly in the lungs, that cause the trouble. These do press,though at oint the pression bees fatal is not known. Until quite retly it wasthought that anyone diving to one hundred meters or so would die painfully as his or her lungsimploded or chest wall collapsed, but the free divers have repeatedly proved otherwise. Itappears, acc to Ashcroft, that “humans may be more like whales and dolphins than hadbeen expected.”
Plenty else g, however. In the days of diving suits—the sort that wereected to the surface by long hoses—divers sometimes experienced a dreadedphenomenon known as “the squeeze.” This occurred when the surface pumps failed, leadingto a catastrophic loss of pressure in the suit. The air would leave the suit with such viole the hapless diver would be, all too literally, sucked up into the helmet and hosepipe.
When hauled to the surface, “all that is left in the suit are his bones and ss of flesh,”
the biologist J. B. S. Haldane wrote in 1947, adding for the be of doubters, “This hashappened.”
(Ially, the inal divi, designed in 1823 by an Englishman namedCharles Deane, was intended not for diving but for fire-fighting. It was called a “smokehelmet,” but being made of metal it was hot and cumbersome and, as Deane soon discovered,firefighters had no particular eagero enter burning structures in any form of attire, butmost especially not in something that heated up like a kettle and made them clumsy into thebargain. In an attempt to save his iment, Dearied it uer and found it was idealfor salvage work.)The real terror of the deep, however, is the bends—not so much because they areunpleasant, though of course they are, as because they are so much more likely. The air webreathe is 80 pert nitrogen. Put the human body under pressure, and that nitrogen istransformed into tiny bubbles that migrate into the blood and tissues. If the pressure isged too rapidly—as with a too-quick ast by a diver—the bubbles trapped within thebody will begin to fizz ily the manner of a freshly opened bottle of champagne,clogging tiny blood vessels, depriving cells of oxygen, and causing pain so excruciating thatsufferers are proo bend double in agony—hehe bends.”
The bends have been an occupational hazard for sponge and pearl divers siimeimmemorial but didn’t attract much attention in the Western world until the eeury, and then it was among people who didn’t get wet at all (or at least not very wet andnot generally much above the ankles). They were caisson workers. Caissons were encloseddry chambers built on riverbeds to facilitate the stru e piers. They were filledwith pressed air, and oftehe workers emerged after aended period uhis artificial pressure they experienced mild symptoms like tingling or itchyskin. But an uable few felt more insistent pain in the joints and occasionally collapsedin agony, sometimes o get up again.
It was all most puzzling. Sometimes workers would go to bed feeling fine, but wake upparalyzed. Sometimes they wouldn’t wake up at all. Ashcroft relates a story ing thedirectors of a unnel uhe Thames who held a celebratory ba as the tunnelneared pletion. To their sternation their champagne failed to fizz when uncorked inthe pressed air of the tunnel. However, when at length they emerged into the fresh air of aLondon evening, the bubbles sprang instantly to fizziness, memorably enlivening thedigestive process.
Apart from avoiding high-pressure enviros altogether, only twies are reliablysuccessful against the bends. The first is to suffer only a very short exposure to the ges inpressure. That is why the free divers I mentioned earlier desd to depths of five hundredfeet without ill effect. They don’t stay under long enough for the nitrogen in their system todissolve into their tissues. The other solution is to asd by careful stages. This allows thelittle bubbles of nitrogen to dissipate harmlessly.
A great deal of what we know about surviving at extremes is owed to the extraordinaryfather-and-son team of John Scott and J. B. S. Haldane. Even by the demanding standards ofBritish intellectuals, the Haldanes were outstandingly etric. The senior Haldane was bornin 1860 to an aristocratic Scottish family (his brother was Vist Haldane) but spent mostof his career in parative modesty as a professor of physiology at Oxford. He wasfamously absent-minded. Oer his wife had sent him upstairs to ge for a dinnerparty he failed to return and was discovered asleep in bed in his pajamas. When roused,Haldane explaihat he had found himself disrobing and assumed it was bedtime. His ideaof a vacation was to travel to wall to study hookworm in miners. Aldous Huxley, the grandson of T. H. Huxley, who lived with the Haldanes for a time, parodied him, atouch mercilessly, as the stist Edward Tantamount in the novel Point ter Point .
Haldane’s gift to diving was to work out the rest intervals necessary to manage an astfrom the depths without getting the bends, but his is ranged across the whole ofphysiology, from studying altitude siess in climbers to the problems of heatstroke iregions. He had a particular i in the effects of toxic gases on the human body. Touand more exactly how onoxide leaks killed miners, he methodically poisonedhimself, carefully taking and measuring his own blood samples the while. He quit only whenhe was on the verge of losing all muscle trol and his blood saturation level had reached 56pert—a level, as Trevor Norton notes in his eaining history of diving, Stars Behe Sea, only fraally removed from nearly certaihality.
Haldane’s son Jack, known to posterity as J.B.S., was a remarkable prodigy who took a in his father’s work almost from infancy. At the age of three he was overhearddemanding peevishly of his father, “But is it oxyhaemoglobin or carboxyhaemoglobin?”
Throughout his youth, the young Haldane helped his father with experiments. By the time hewas a teehe two ofteed gases and gas masks together, taking turns to see howlong it took them to pass out.
Though J. B. S. Haldane ook a degree in sce (he studied classics at Oxford), hebecame a brilliant stist in his ht, mostly in Cambridge. The biologist PeterMedawar, who spent his life aroual Olympians, called him “the cleverest man I everknew.” Huxley likewise parodied the younger Haldane in his novel Antic Hay, but also usedhis ideas oiipulation of humans as the basis for the plot of Brave New World.
Among many other achievements, Haldane played a tral role in marrying Darrinciples of evolution to the geic work or Meo produce what is known togeicists as the Modern Synthesis.
Perhaps uniquely among human beings, the younger Haldane found World War I “a veryenjoyable experience” and freely admitted that he “ehe opportunity of killing people.”
He was himself wouwice. After the war he became a successful popularizer of sd wrote twenty-three books (as well as over four hundred stific papers). His books arestill thhly readable and instructive, though not always easy to find. He also became ahusiastic Marxist. It has been suggested, not altogether ically, that this was out of apurely trarian instinct, and that if he had been born in the Soviet Union he would havebeen a passionate monarchist. At all events, most of his articles first appeared in theunist Daily Worker.
Whereas his father’s principal is ed miners and poisoning, the youngerHaldane became obsessed with saving submariners and divers from the unpleasantsequences of their work. With Admiralty funding he acquired a depression chamberthat he called the “pressure pot.” This was a metal der into which three people at a timecould be sealed and subjected to tests of various types, all painful and nearly all dangerous.
Volunteers might be required to sit ier while breathing “aberrant atmosphere” orsubjected to rapid ges of pressurization. In one experiment, Haldane simulated adangerously hasty ast to see what would happen. What happened was that the dentalfillings in his teeth exploded. “Almost every experiment,” Norton writes, “ended withsomeone having a seizure, bleeding, or vomiting.” The chamber was virtually soundproof, sothe only way for octs to signal unhappiness or distress was to tap insistently on thechamber wall or to hold up o a small window.
On another occasion, while poisoning himself with elevated levels of oxygen, Haldane hada fit so severe that he crushed several vertebrae. Collapsed lungs were a routine hazard.
Perforated eardrums were quite on, but, as Haldane reassuringly noted in one of hisessays, “the drum generally heals up; and if a hole remains in it, although one is somewhatdeaf, one blow tobaoke out of the ear iion, which is a socialaplishment.”
What was extraordinary about this was not that Haldane was willing to subject himself tosuch risk and disfort in the pursuit of sce, but that he had no trouble talkingcolleagues and loved ones into climbing into the chamber, too. Sent on a simulated dest,his wife once had a fit that lasted thirteen minutes. When at last she stopped boung acrossthe floor, she was helped to her feet a home to cook dinner. Haldane happily employedwhoever happeo be around, including on one memorable occasion a former primeminister of Spain, Juan Negrín. Dr. Negrín plained afterward of minor tingling and “acurious velvety sensation on the lips” but otherwise seems to have escaped unharmed. He mayhave sidered himself very lucky. A similar experiment with oxygen deprivatioHaldahout feeling in his buttocks and lower spine for six years.
Among Haldane’s many specific preoccupations was nitrogen intoxication. For reasons thatare still poorly uood, beh depths of about a hundred feet nitrogen bees apowerful intoxit. Us influence divers had been known to offer their air hoses topassing fish or decide to try to have a smoke break. It also produced wild mood swings. Iest, Haldaed, the subject “alternated between depression aion, at onemoment begging to be depressed because he felt ‘bloody awful’ and the minutelaughing and attempting to interfere with his colleague’s dexterity test.” In order to measurethe rate of deterioration in the subject, a stist had to go into the chamber with thevoluo duct simple mathematical tests. But after a few minutes, as Haldaerrecalled, “the tester was usually as intoxicated as the testee, and often fot to press thespindle of his stopwatch, or to take proper notes.” The cause of the inebriation is even now amystery. It is thought that it may be the same thing that causes alcohol intoxication, but as noone knows for certain what causes that we are he wiser. At all events, without thegreatest care, it is easy to get in trouble once you leave the surface world.
Which brings us back (well, nearly) to our earlier observation that Earth is not the easiestplace to be an anism, even if it is the only place. Of the small portion of the pla’ssurface that is dry enough to stand on, a surprisingly large amount is too hot or cold or dry orsteep or lofty to be of much use to us. Partly, it must be ceded, this is our fault. In terms ofadaptability, humans are pretty amazingly useless. Like most animals, we don’t much likereally hot places, but because we sweat so freely and easily stroke, we are especiallyvulnerable. In the worst circumstances—on foot without water in a hot desert—most peoplewill grow delirious and keel over, possibly o rise again, in no more than six or sevenhours. We are no less helpless in the face of cold. Like all mammals, humans are good atgei but—because we are so nearly hairless—not good at keeping it. Even in quitemild weather half the calories you burn go to keep your body warm. Of course, we ter these frailties to a large extent by employing clothing and shelter, but even so theportions of Earth on which repared or able to live are modest indeed: just 12 pertof the total land area, and only 4 pert of the whole surface if you include the seas.
Yet when you sider ditions elsewhere in the known universe, the wonder is not thatwe use so little of our pla but that we have mao find a plahat we use even abit of. You have only to look at our own solar system—or, e to that, Earth at certainperiods in its own history—to appreciate that most places are much harsher and much lessameo life than our mild, blue watery globe.
So far space stists have discovered about seventy plas outside the solar system, outof the ten billion trillion or so that are thought to be out there, so humans hardly claim tospeak with authority oter, but it appears that if you wish to have a pla suitable forlife, you have to be just awfully lucky, and the more advahe life, the luckier you have tobe. Various observers have identified about two dozen particularly helpful breaks we havehad oh, but this is a flying survey so we’ll distill them down to the principal four. Theyare:
Excellent location.We are, to an almost uny degree, the right distance from the right sortof star, ohat is big enough to radiate lots of energy, but not so big as to burn itself outswiftly. It is a curiosity of physics that the larger a star the more rapidly it burns. Had our suen times as massive, it would have exhausted itself after ten million years instead of tenbillion and we wouldn’t be here now. We are also fortuo orbit where we do. Too muearer and everything oh would have boiled away. Much farther away and everythingwould have frozen.
In 1978, an astrophysicist named Michael Hart made some calculations and cluded thatEarth would have been uninhabitable had it been just 1 pert farther from or 5 pertcloser to the Sun. That’s not much, and in fact it wasn’t enough. The figures have since beenrefined and made a little menerous—5 pert nearer and 15 pert farther are thoughtto be more accurate assessments for our zone of habitability—but that is still a narrow belt.
1To appreciate just how narrow, you have only to look at Venus. Venus is only twenty-fivemillion miles closer to the Sun than we are. The Sun’s warmth reaches it just two minutesbefore it touches us. In size and position, Venus is very like Earth, but the smalldifferen orbital distance made all the differeo how it turned out. It appears thatduring the early years of the solar system Venus was only slightly warmer thah andprobably had os. But those few degrees of extra warmth meant that Venus could not holdon to its surface water, with disastrous sequences for its climate. As its water evaporated,the hydrogen atoms escaped into space, and the oxygen atoms bined with carbon to forma demosphere of the greenhouse gas CO2. Venus became stifling. Although people ofmy age will recall a time when astronomers hoped that Venus might harbor life beh itspadded clouds, possibly even a kind of tropical verdure, we now know that it is much toofier enviro for any kind of life that we reasonably ceive of. Its surfacetemperature is a roasting 470 degrees tigrade (roughly 900 degrees Fahre), which ishot enough to melt lead, and the atmospheric pressure at the surface is imes that ofEarth, or more than any human body could withstand. We lack the teology to make suitsor even spaceships that would allow us to visit. Our knowledge of Venus’s surface is based ondistant radar imagery and some startled squawks from an unmanned Soviet probe that wasdropped hopefully into the clouds in 1972 and funed for barely an hour beforepermaly shutting down.
So that’s what happens when you move two light minutes closer to the Sun. Travel fartherout and the problem bees not heat but cold, as Mars frigidly attests. It, too, was once amuch more genial place, but couldn’t retain a usable atmosphere and turned into a frozenwaste.
But just being the right distance from the Sun ot be the whole story, for otherwise theMoon would be forested and fair, which patently it is not. For that you o have:
The right kind of pla.I don’t imagine even many geophysicists, when asked to ttheir blessings, would include living on a pla with a molten interior, but it’s a pretty nearcertainty that without all that magma swirling arouh us we wouldn’t be here now.
Apart from much else, our lively interior created the outgassing that helped to build anatmosphere and provided us with the magic field that shields us from ic radiation. Italso gave us plate teics, which tinually renews and rumples the surface. If Earth wereperfectly smooth, it would be covered everywhere with water to a depth of four kilometers.
There might be life in that lonesome o, but there certainly wouldn’t be baseball.
In addition to having a beneficial interior, we also have the right elements in the correctproportions. In the most literal way, we are made of the right stuff. This is so crucial to ourwell-being that we are going to discuss it more fully in a minute, but first we o siderthe two remaining factors, beginning with another ohat is often overlooked:
1The discovery of extremophiles in the boiling mudpots of Yellowstone and similar anisms found elsewheremade stists realize that actually life of a type could range much farther than that-even, perhaps, beh theicy skin of Pluto. What we are talking about here are the ditions that would produce reasonably plexsurface creatures.
We’re a twin pla.Not many of us normally think of the Moon as a panion pla,but that is in effect what it is. Most moons are tiny iion to their master plaheMartian satellites of Phobos and Deimos, for instance, are only about ten kilometers indiameter. Our Moon, however, is more than a quarter the diameter of the Earth, .９9ｌｉｂ.ich makesours the only pla in the solar system with a sizeable moon in parison to itself (exceptPluto, which doesn’t really t because Pluto is itself so small), and what a differehatmakes to us.
Without the Moon’s steadying influehe Earth would wobble like a dying top, withgoodness knows what sequences for climate aher. The Moon’s steady gravitationalinfluence keeps the Earth spinning at the right speed and ao provide the sort of stabilitynecessary for the long and successful development of life. This won’t go on forever. TheMoon is slipping from rasp at a rate of about 1.5 inches a year. In awo billionyears it will have receded so far that it won’t keep us steady and we will have to e up withsome other solution, but in the meantime you should think of it as much more than just apleasaure in the night sky.
For a long time藏书网, astronomers assumed that the Moon ah either formed together orthat the Earth captured the Moon as it drifted by. We now believe, as you will recall from anearlier chapter, that about 4.5 billion years ago a Mars-sized object slammed ih,blowing out enough material to create the Moon from the debris. This was obviously a verygood thing for us—but especially so as it happened such a long time ago. If it had happened in1896 or last Wednesday clearly we wouldn’t be nearly so pleased about it. Which brings us toour fourth and in many ways most crucial sideration:
Timing.The universe is an amazingly fickle aful place, and our existehin itis a wonder. If a long and unimaginably plex sequence of events stretg back 4.6billion years or so hadn’t played out in a particular ma particular times—if, to take justone obvious instahe dinosaurs hadn’t been wiped out by a meteor when they were—youmight well be six inches long, with whiskers and a tail, and reading this in a burrow.
We don’t really know for sure because we have nothing else to pare our oweo, but it seems evident that if you wish to end up as a moderately advahinking society,you o be at the right end of a very long of outes involving reasonable periodsof stability interspersed with just the right amount of stress and challenge (ice ages appear tobe especially helpful in this regard) and marked by a total absence of real cataclysm. As weshall see in the pages that remain to us, we are very lucky to find ourselves in that position.
And on that note, let us now turn briefly to the elements that made us.
There are wo naturally elements oh, plus a further twenty or so thathave beeed in labs, but some of these we immediately put to one side—as, in fact,chemists themselves tend to do. Not a few of our earthly chemicals are surprisingly littleknown. Astatine, for instance, is practically unstudied. It has a name and a pla theperiodic table ( door to Marie Curie’s polonium), but almost nothing else. The problemisn’t stifidifference, but rarity. There just isn’t much astati there. The mostelusive element of all, however, appears to be francium, which is so rare that it is thought thatour entire pla may tain, at any given moment, fewer thay francium atoms.
Altogether only about thirty of the naturally elements are widespread oh, andbarely half a dozen are of tral importao life.
As you might expect, oxygen is our most abundant element, ating for just under 50pert of the Earth’s crust, but after that the relative abundances are often surprising. Whowould guess, for instahat sili is the seost o oh or thattitanium is tenth? Abundance has little to do with their familiarity or utility to us. Many of themore obscure elements are actually more on thater-knowhere is morecerium oh than copper, more neodymium and lanthanum than cobalt or nitrogen. Tinbarely makes it into the top fifty, eclipsed by such relative obscurities as praseodymium,samarium, gadolinium, and dysprosium.
Abundance also has little to do with ease of dete. Aluminum is the fourth mosto oh, ating for nearly a tenth of everything that’s underh yourfeet, but its existence wasn’t even suspected until it was discovered in the eenth turyby Humphry Davy, and for a long time after that it was treated as rare and precious. gressnearly put a shiny lining of aluminum foil atop the Washington Moo show what aclassy and prosperous nation we had bee, and the French imperial family in the sameperiod discarded the state silver dinner servid replaced it with an aluminum ohefashion was cutting edge even if the knives weren’t.
Nor does abundanecessarily relate to importance. Carbon is only the fifteenth mosto, ating for a very modest 0.048 pert of Earth’s crust, but we wouldbe lost without it. What sets the carbon atom apart is that it is shamelessly promiscuous. It isthe party animal of the atomic world, latg on to many other atoms (including itself) andholding tight, f molecular ga lines of hearty robusthe very trick of naturenecessary to build proteins and DNA. As Paul Davies has written: “If it wasn’t for carbon, lifeas we know it would be impossible. Probably any sort of life would be impossible.” Yetcarbon is not all that plentiful even in humans, who so vitally depend on it. Of every 200atoms in your body, 126 are hydrogen, 51 are oxygen, and just 19 are carbon.
2Other elements are critiot for creating life but for sustaining it. We need iron tomanufacture hemoglobin, and without it we would die. Cobalt is necessary for the creation ofvitamin B12. Potassium and a very little sodium are literally good for your nerves.
Molybdenum, manganese, and vanadium help to keep your enzymes purring. Zinc—bless it—oxidizes alcohol.
We have evolved to utilize or tolerate these things—we could hardly be here otherwise—but even then we live within narres of acceptance. Selenium is vital to all of us, buttake in just a little too mud it will be the last thing you ever do. The degree to whichanisms require or tolerate certais is a relic of their evolution. Sheep and cattlenow graze side by side, but actually have very different mineral requirements. Modern cattleneed quite a lot of copper because they evolved in parts of Europe and Africa where copperwas abundant. Sheep, oher hand, evolved in copper-poor areas of Asia Minor. As arule, and not surprisingly, our tolerance for elements is directly proportioo their2Of the remaining four, three are nitrogen and the remaining atom is divided among all the other elements.
abundan the Earth’s crust. We have evolved to expect, and in some cases actually he tiny amounts of rare elements that accumulate in the flesh or fiber that we eat. But step upthe doses, in some cases by only a tiny amount, and we >99lｉb?n soon cross a threshold. Much ofthis is only imperfectly uood. No one knows, for example, whether a tiny amount ofarsenic is necessary for our well-being or not. Some authorities say it is; some not. All that iscertain is that too much of it will kill you.
The properties of the elements beore curious still when they are bined.
Oxygen and hydrogen, for instance, are two of the most bustion-friendly elements around,but put them together and they make inbustible water.
3Odder still in bination aresodium, one of the most unstable of all elements, and chlorine, one of the most toxic. Drop asmall lump of pure sodium into ordinary water and it will explode with enough force to kill.
Chlorine is even more notoriously hazardous. Though useful in small trations forkilling micranisms (it’s chlorine you smell in bleach), in larger volumes it is lethal.
Chlorine was the element of choiany of the poison gases of the First World War. And,as many a sore-eyed swimmer will attest, even in exceedingly dilute form the human bodydoesn’t appreciate it. Yet put these two nasty elements together and what do you get? Sodiumchloride—on table salt.
By and large, if a doesn’t naturally find its way into our systems—if it isn’tsoluble in water, say—we tend to be i of it. Lead poisons us because we were neverexposed to it until we began to fashion it into food vessels and pipes for plumbing. (Notially, lead’s symbol is Pb, for the Latin plumbum, the source word for our modernplumbing.) The Romans also flavored their wih lead, which may be part of the reasonthey are not the force they used to be. As we have seen elsewhere, our own performahlead (not to mention mercury, cadmium, and all the other industrial pollutants with which weroutinely dose ourselves) does not leave us a great deal of room for smirking. Whesdon’t ocaturally oh, we have evolved no tolerance for them, and so they tend to beextremely toxic to us, as with plutonium. Our tolerance for plutonium is zero: there is no levelat which it is not going to make you want to lie down.
I have brought you a long way to make a small point: a big part of the reason that Earthseems so miraculously aodating is that we evolved to suit its ditions. What wemarvel at is not that it is suitable to life but that it is suitable to our life—and hardlysurprising, really. It may be that many of the things that make it so splendid to us—well-proportioned Sun, doting Moon, sociable ore magma than you shake a stick at,and all the rest—seem splendid simply because they are what we were born to t on. Noone altogether say.
Other worlds may harbor beings thankful for their silvery lakes of mercury and driftingclouds of ammonia. They may be delighted that their pla doesn’t shake them silly with itsgrinding plates or spew messy gobs of lava over the landscape, but rather exists in aperma onic tranquility. Any visitors to Earth from afar would almost certainly, atthe very least, be bemused to find us living in an atmosphere posed of nitrogen, a gassulkily disined to react with anything, and oxygen, which is so partial to bustion thatwe must place fire stations throughout our cities to protect ourselves from its livelier effects.
But even if our visitors were oxygehing bipeds with shopping malls and a fondness for3Oxygen itself is not bustible; it merely facilitates the bus tion of other things. This is just as well, for ifoxygen were bustible, each time you lit a match all the air around you would bur into flame. Hydrogen gas,oher hand, is extremely bustible, as the dirigible Hindenburg demonstrated on May 6, 193 inLakehurst, New Jersey, when its hydrogen fuel burst explosive) into flame, killing thirty-six people.
aovies, it is uhat they would fih ideal. We couldn’t even give themlunch because all our foods tain traanganese, selenium, zind other elementalparticles at least some of which would be poisonous to them. To them Earth might not seem awondrously genial place at all.
The physicist Richard Feynmao make a joke about a posteriori clusions, as theyare called. “You know, the most amazing thing happeo me tonight,” he would say. “Isaw a car with the lise plate ARW 357. you imagine? Of all the millions of liseplates iate, what was the ce that I would see that particular oonight?
Amazing!” His point, of course, was that it is easy to make any banal situatioraordinary if you treat it as fateful.
So it is possible that the events and ditions that led to the rise of life oh are notquite as extraordinary as we like to think. Still, they were extraordinary enough, and ohingis certain: they will have to do until we find some better.
17 INTO THE TROPOSPHERE
THANK GOODNESS FOR the atmosphere. It keeps us warm. Without it, Earth would be alifeless ball of ice with an average temperature of minus 60 degrees Fahre. In additiomosphere absorbs or deflects ining swarms of ic rays, charged particles,ultraviolet rays, and the like. Altogether, the gaseous padding of the atmosphere is equivalentto a fifteen-foot thiess of protective crete, and without it these invisible visitors fromspace would slice through us like tiny daggers. Even raindrops would pound us senseless if itweren’t for the atmosphere’s slowing drag.
The most striking thing about our atmosphere is that there isn’t very much of it. It extendsupward for about 120 miles, which might seem reasonably bounteous when viewed fromground level, but if you shrank the Earth to the size of a standard desktop globe it would onlybe about the thiess of a couple of coats of varnish.
For stifiveniehe atmosphere is divided into four unequal layers: troposphere,stratosphere, mesosphere, and ionosphere (now often called the thermosphere). Thetroposphere is the part that’s dear to us. It alone tains enough warmth and oxygen to allowus to fun, though even it swiftly bees ungenial to life as you climb up through it.
From ground level to its highest point, the troposphere (or “turning sphere”) is about ten milesthick at the equator and no more than six or seven miles high iemperate latitudes wheremost of us live. Eighty pert of the atmosphere’s mass, virtually all the water, and thusvirtually all the weather are tained within this thin and wispy layer. There really isn’tmuch between you and oblivion.
Beyond the troposphere is the stratosphere. When you see the top of a storm cloudflattening out into the classivil shape, you are looking at the boundary betweeroposphere and stratosphere. This invisible ceiling is known as the tropopause and wasdiscovered in 1902 by a Fren in a balloon, Léon-Philippe Teisserenc de Bort. Pause inthis sense doesn’t mean to stop momentarily but to cease altogether; it’s from the same Greekroot as menopause. Even at its greatest extent, the tropopause is not very distant. A fastelevator of the sort used in modern skyscrapers could get you there in about twenty mihough you would be well advised not to make the trip. Such a rapid ast withoutpressurization would, at the very least, result in severe cerebral and pulmonary edemas, adangerous excess of fluids in the body’s tissues. When the doors ope the viewingplatform, anyone inside would almost certainly be dead or dying. Even a more measuredast would be apanied by a great deal of disfort. The temperature six miles up be -70 degrees Fahre, and you would need, or at least very much appreciate,supplementary oxygen.
After you have left the troposphere the temperature soon warms up again, to about 40degrees Fahre, thanks to the absorptive effects of ozone (something else de Bortdiscovered on his daring 1902 ast). It then pluo as low as -130 degrees Fahre inthe mesosphere before skyrocketing to 2,700 degrees Fahre or more ily very erratic thermosphere, where temperatures vary by a thousand degrees from dayto night—though it must be said that “temperature” at such a height bees a somewhatnotional cept. Temperature is really just a measure of the activity of molecules. At sealevel, air molecules are so thick that one molecule move only the ti distance—aboutthree-millionths of an inch, to be precise—before banging into another. Because trillions ofmolecules are stantly colliding, a lot of heat gets exged. But at the height of thethermosphere, at fifty miles or more, the air is so thin that any two molecules will be milesapart and hardly ever e in tact. So although each molecule is very warm, there are fewiioween them and thus little heat transferehis is good news for satellitesand spaceships because if the exge of heat were more effit any man-made objectorbiting at that level would burst into flame.
Even so, spaceships have to take care ier atmosphere, particularly ourn trips toEarth, as the space shuttle bia demonstrated all tically in February 2003.
Although the atmosphere is very thin, if a craft es in at too steep an angle—more thanabout 6 degrees—or too swiftly it strike enough molecules to gee drag of anexceedingly bustible nature. versely, if an ining vehicle hit the thermosphere attoo shallow an a could well bounce bato space, like a pebble skipped across water.
But you veo the edge of the atmosphere to be reminded of what hopelesslyground-hugging beings we are. As anyone who has spent time in a lofty city will know, youdon’t have to rise too many thousands of feet from sea level before your body begins toprotest. Even experienced mountaineers, with the bes of fitness, training, and bottledoxygen, quickly bee vulnerable at height to fusion, nausea, exhaustion, frostbite,hypothermia, migraine, loss of appetite, and a great many other stumbling dysfuns. In ahundred emphatic ways the human body reminds its owhat it wasn’t desigo operateso far above sea level.
“Even uhe most favorable circumstances,” the climber Peter Habeler has written ofditions atop Everest, “every step at that altitude demands a colossal effort of will. Youmust force yourself to make every movement, reach for every handhold. You are perpetuallythreatened by a leaden, deadly fatigue.” Iher Side of Everest, the British mountaineerand filmmaker Matt Dison records how Howard Somervell, on a 1924 British expeditionup Everest, “found himself choking to death after a piece of ied flesh came loose andblocked his windpipe.” With a supreme effort Somervell mao cough up theobstru. It turned out to be “the entire mucus lining of his larynx.”
Bodily distress is notorious above 25,000 feet—the area known to climbers as the DeathZo many people bee severely debilitated, even dangerously ill, at heights of nomore than 15,000 feet or so. Susceptibility has little to do with fitness. Grannies sometimescaper about in lofty situations while their fitter offspring are reduced to helpless, groaningheaps until veyed to lower altitudes.
The absolute limit of human tolerance for tinuous living appears to be about 5,500meters, or 18,000 feet, but even people ditioo living at altitude could not tolerate suchheights for long. Frances Ashcroft, in Life at the Extremes, hat there are Andean sulfurmi 5,800 meters, but that the miners prefer to desd 460 meters each evening andclimb back up the following day, rather than live tinuously at that elevation. People whohabitually live at altitude have oftehousands of years developing disproportionatelylarge chests and lungs, increasing their density of oxygen-bearing red blood cells by almost athird, though there are limits to how much thiing with red cells the blood supply stand. Moreover, above 5,500 meters even the most well-adapted women ot provide agrowius with enough oxygen t it to its full term.
In the 1780s when people began to make experimental balloon asts in Europe,something that surprised them was how chilly it got as they rose. The temperature drops about3 degrees Fahre with every thousa you climb. Logic would seem to indicate thatthe closer you get to a source of heat, the warmer you would feel. Part of the explanation isthat you are not really getting he Sun in any meaningful sehe Sun is hreemillion miles away. To move a couple of thousa closer to it is like taking oepcloser to a bushfire in Australia when you are standing in Ohio, and expeg to smell smoke.
The answer again takes us back to the question of the density of molecules imosphere.
Sunlight energizes atoms. It increases the rate at which they jiggle and jounce, and in theirenliveate they crash into one another, releasi. When you feel the sun warm onyour ba a summer’s day, it’s really excited atoms you feel. The higher you climb, thefewer molecules there are, and so the fewer collisioween them.
Air is deceptive stuff. Even at sea level, we tend to think of the air as beihereal and allbut weightless. In fact, it has plenty of bulk, and that bulk oftes itself. As a marinestist named Wyville Thomson wrote more than a tury ago: “We sometimes find whe up in the m, by a rise of an in the barometer, that nearly half a ton has beely piled upon us during the night, but we experieno invenience, rather a feeling ofexhilaration and buoyancy, si requires a little less exertion to move our bodies in thedenser medium.” The reason you don’t feel crushed uhat extra half ton of pressure is thesame reason your body would not be crushed deep beh t藏书网he sea: it is made mostly ofinpressible fluids, which push back, equalizing the pressures within and without.
But get air in motion, as with a hurrie or even a stiff breeze, and you will quickly beremihat it has very siderable mass. Altogether there are about 5,200 million milliontons of air around us—25 million tons for every square mile of the pla—a notinsequential volume. When you get millions of tons of atmosphere rushing past at thirty orforty miles an hour, it’s hardly a surprise that limbs snap and roof tiles go flying. As AnthonySmith notes, a typical weather front may sist of 750 million tons of cold air pinh a billion tons of warmer air. Hardly a wohat the result is at timesmeteically exg.
Certainly there is no she of energy in the world above our heads. Ohuorm, ithas been calculated, tain an amount of energy equivalent to four days’ use ofelectricity for the whole Uates. In the right ditions, storm clouds rise to heightsof six to ten miles and tain updrafts and downdrafts of one hundred miles an hour. Theseare often side by side, which is why pilots don’t want to fly through them. In all, the internalturmoil particles within the cloud pick up electrical charges. For reasons irelyuood the lighter particles tend to bee positively charged and to be wafted by aircurrents to the top of the cloud. The heavier particles li the base, accumulatiivecharges. These ively charged particles have a powerful urge to rush to the positivelycharged Earth, and good luck to anything that gets in their way. A bolt of lightning travels at270,000 miles an hour and heat the air around it to a decidedly crisp 50,000 degreesFahre, several times hotter than the surface of the sun. At any one moment 1,800thuorms are in progress around the globe—some 40,000 a day. Day and night across thepla every sed about a hundred lightning bolts hit the ground. The sky is a lively place.
Much of our knowledge of what goes on up there is surprisingly ret. Jet streams, usuallylocated about 30,000 to 35,000 feet up, bowl along at up to 180 miles an hour and vastlyinfluence weather systems over whole tis, yet their existence wasn’t suspected untilpilots began to fly into them during the Sed World War. Even now a great deal ofatmospheric phenomena is barely uood. A form of wave motion popularly known asclear-air turbulence occasionally enlivens airplane flights. About twenty suts a yearare serious enough to need rep. They are not associated with cloud structures oranything else that be detected visually or by radar. They are just pockets of startlingturbulen the middle of tranquil skies. In a typical i, a plane en route fromSingapore to Sydney was flying over tral Australia in calm ditions when it suddehree hundred feet—enough to fling unsecured people against the ceiling. Twelve peoplewere injured, one seriously. No one knows what causes such disruptive cells.. of air.
The process that moves air around imosphere is the same process that drives theinternal engine of the pla, namely veoist, warm air from the equatorial regionsrises until it hits the barrier of the tropopause and spreads out. As it travels away from theequator and cools, it sinks. When it hits bottom, some of the sinking air looks for an area oflow pressure to fill and heads back for the equator, pleting the circuit.
At the equator the ve process is generally stable and the weather predictably fair,but in temperate zohe patterns are far more seasonal, localized, and random, whichresults in an endless battle between systems of high-pressure air and low. Low-pressuresystems are created by rising air, which veys water molecules into the sky, f cloudsaually rain. Warm air hold more moisture than cool air, which is why tropical andsummer storms tend to be the heaviest. Thus low areas tend to be associated with clouds andrain, and highs generally spell sunshine and fair weather. When two such systems meet, itoften bees ma in the clouds. For instaratus clouds—those unlovable,featureless sprawls that give us our overcast skies—happen when moisture-bearing updraftslack the oomph to break through a level of more stable air above, and instead spread out, likesmoke hitting a ceiling. Indeed, if you watch a smoker sometime, you get a very goodidea of how things work by watg how smoke rises from a cigarette in a still room. Atfirst, it goes straight up (this is called a laminar flow, if you o impress anyone), and thenit spreads out in a diffused, wavy layer. The greatest superputer in the world, takingmeasurements in the most carefully trolled enviro, ot tell you what forms theseripplings will take, so you imagihe difficulties that froeists whery to predict such motions in a spinning, windy, large-scale world.
What we do know is that because heat from the Sun is unevenly distributed, differences inair pressure arise on the pla. Air ’t abide this, so it rushes around trying to equalizethings everywhere. Wind is simply the air’s way to keep things in balance. Airalways flows from areas of high pressure to areas of low pressure (as you would expect; thinkof anything with air under pressure—a balloon or an air tank—and think how insistently thatpressured air wants to get someplace else), and the greater the discrepan pressures thefaster the wind blows.
Ially, wind speeds, like most things that accumulate, grow expoially, so a windblowing at two hundred miles an hour is not simply ten times strohan a wind blowing attwenty miles an hour, but a huimes stronger—and hehat much more destructive.
Introduce several million tons of air to this accelerator effed the result be exceedinglyeic. A tropical hurrie release iy-four hours as muergy as a rich,medium-sized nation like Britain or France uses in a year.
The impulse of the atmosphere to seek equilibrium was first suspected by EdmondHalley—the man who was everywhere—and elaborated upon in the eighteenth tury by hisfellow Briton Gee Hadley, who saw that rising and falling ns of air teoproduce “cells” (known ever since as “Hadley cells”). Though a lawyer by profession, Hadleyhad a keen i in the weather (he was, after all, English) and also suggested a liween his cells, the Earth’s spin, and the apparent defles of air that give us our tradewinds. However, it was an engineering professor at the école Polyteique in Paris,Gustave-Gaspard de Coriolis, who worked out the details of these iions in 1835, andthus we call it the Coriolis effect. (Coriolis’s other distin at the school was to introducewatercoolers, which are still known there as Corios, apparently.) The Earth revolves at a brisk1,041 miles an hour at the equator, though as you move toward the poles the rate slopes offsiderably, to about 600 miles an hour in London or Paris, for instahe reason for thisis self-evident when you think about it. If you are on the equator the spinnih has tocarry you quite a distance—about 40,000 kilometers—to get you back to the same spot. If youstand beside the North Pole, however, you may ravel only a few feet to plete arevolutio in both cases it takes twenty-four hours to get you back to where you began.
Therefore, it follows that the closer you get to the equator the faster you must be spinning.
The Coriolis effect explains why anything moving through the air in a straight lierallyto the Earth’s spin will, given enough distance, seem to curve to the right in the northernhemisphere and to the left in the southern as the Earth revolves beh it. The standard wayto envision this is to imagine yourself at the ter of a large carousel and tossing a ball tosomeone positioned on the edge. By the time the ball gets to the perimeter, the target personhas moved on and the ball passes behind him. From his perspective, it looks as if it has curvedaway from him. That is the Coriolis effect, and it is what gives weather systems their curl andsends hurries spinning off like tops. The Coriolis effect is also why naval guns firingartillery shells have to adjust to left ht; a shell fired fifteen miles would otherwisedeviate by about a hundred yards and plop harmlessly into the sea.
sidering the practical and psychological importance of the weather to nearly everyo’s surprising that metey didn’t really get going as a stil shortly before theturn of the eenth tury (though the term metey itself had been around since1626, when it was ed by a T. Granger in a book of logic).
Part of the problem was that successful metey requires the precise measurement oftemperatures, and thermometers for a long time proved more difficult to make than you mightexpect. An accurate reading was depe oing a very even bore in a glass tube, andthat wasn’t easy to do. The first person to crack the problem was Daniel Gabriel Fahre, aDutch maker of instruments, who produced an accurate thermometer in 1717. However, forreasons unknown he calibrated the instrument in a way that put freezing at 32 degrees andboiling at 212 degrees. From the outset this numeric etricity bothered some people, and in1742 Anders Celsius, a Swedish astronomer, came up with a peting scale. In proof of theproposition that iors seldom get matters entirely right, Celsius made boiling point zeroand freezing point 100 on his scale, but that was soon reversed.
The person most frequently identified as the father of moderey was an Englishpharmacist named Luke Howard, who came to promi the beginning of the eeury. Howard is chiefly remembered now fiving cloud types their names in 1803.
Although he was an active and respected member of the Linnaean Society and employedLinnaean principles in his new scheme, Howard chose the rather more obscure AskesianSociety as the forum to announce his new system of classification. (The Askesian Society,you may just recall from an earlier chapter, was the body whose members were unusuallydevoted to the pleasures of nitrous oxide, so we only hope they treated Howard’spresentation with the sober attention it deserved. It is a point on which Howard scholars arecuriously silent.)Howard divided clouds introups: stratus for the layered clouds, cumulus for thefluffy ohe word means “heaped” in Latin), and cirrus (meaning “curled”) for the high,thihery formations that generally presage colder weather. To these he subsequentlyadded a fourth term, nimbus (from the Latin for “cloud”), for a rain cloud. The beauty ofHoward’s system was that the basipos could be freely rebio describe everyshape and size of passing cloud—stratocumulus, cirrostratus, cumulogestus, and so on. Itwas an immediate hit, and not just in England. The poet Johann vohe in Germany wasso taken with the system that he dedicated four poems to Howard.
Howard’s system has been much added to over the years, so much so that the encyclopedicif little read Iional Cloud Atlas runs to two volumes, but iingly virtually all thepost-Howard cloud types—mammatus, pileus, nebulosis, spissatus, floccus, and mediocris area sampling—have never caught on with aside metey and not terribly muchthere, I’m told. Ially, the first, much thinion of that atlas, produced in 1896,divided clouds into ten basic types, of which the plumpest and most cushiony-looking wasnumber nine, cumulonimbus.
1That seems to have been the source of the expression “to be oncloud nine.”
For all the heft and fury of the occasional anvil-headed storm cloud, the average cloud isactually a benign and surprisingly insubstantial thing. A fluffy summer cumulus severalhundred yards to a side may tain no more thay-five or thirty gallons of water—“about enough to fill a bathtub,” as James Trefil has noted. You get some sense of theimmaterial quality of clouds by strolling through fog—which is, after all, nothing more than acloud that lacks the will to fly. To quote Trefil again: “If you walk 100 yards through a typicalfog, you will e into tact with only about half a cubich of water—not enough togive you a det drink.” In sequence, clouds are not great reservoirs of water. Only about0.035 pert of the Earth’s fresh water is floating around above us at any moment.
Depending on where it falls, the prognosis for a water molecule varies widely. If it lands iile soil it will be soaked up by plants or reevaporated directly within hours or days. If itfinds its way down to the groundwater, however, it may not see sunlight again for manyyears—thousands if it gets really deep. When you look at a lake, you are looking at acolle of molecules that have been there on average for about a decade. In the o theresideime is thought to be more like a hundred years. Altogether about 60 pert of1If you have ever been struck by how beautifully crisp and well defihe edges of cumulus clouds tend to be,while other clouds are more blurry, the explanation is that in a cumulus cloud there is a pronounced boundarybetween the moist interior of the cloud and the dry air beyond it. Any water molecule that strays beyond the edgeof the cloud is immediately zapped by the dry air beyond, allowing the cloud to keep its fine edge. Much highercirrus clouds are posed of ice, and the zoween the edge of the cloud and the air beyond is not soclearly delied, which is why they tend to be blurry at the edges.
water molecules in a rainfall are returo the atmosphere within a day or two. Onceevaporated, they spend no more than a week or so—Drury says twelve days—in the skybefore falling again as rain.
Evaporation is a swift process, as you easily gauge by the fate of a puddle on asummer’s day. Even something as large as the Mediterranean would dry out in a thousandyears if it were not tinually replenished. Su event occurred a little under six millionyears ago and provoked what is known to sce as the Messinian Salinity Crisis. pened was that tial movement closed the Strait of Gibraltar. As the Mediterraneandried, its evaporated tents fell as freshwater rain into other seas, mildly diluting theirsaltiness—indeed, making them just dilute enough to freeze over larger areas than normal.
The enlarged area of ice bounced back more of the Sun’s heat and pushed Earth into an iceage. So at least the theoes.
What is certainly true, as far as we tell, is that a little ge in the Earth’s dynami have repercussions beyond our imagining. Su event, as we shall see a little furtheron, may even have created us.
Os are the real powerhouse of the pla’s surface behavior. Indeed, meteistsincreasingly treat os and atmosphere as a single system, which is why we must give thema little of our attention here. Water is marvelous at holding and transp heat. Every day,the Gulf Stream carries an amount of heat to Europe equivalent to the world’s output of coalfor ten years, which is why Britain and Ireland have such mild winters pared with adaand Russia.
But water also warms slowly, which is why lakes and swimming pools are cold even oest days. For that reasoends to be a lag in the official, astronomical start of aseason and the actual feeling that that season has started. S may officially start ihern hemisphere in March, but it doesn’t feel like it in most places until April at the veryearliest.
The os are not one uniform mass of water. Their differences in temperature, salinity,depth, density, and so on have huge effects on how they move heat around, whi turs climate. The Atlantic, for instance, is saltier than the Pacifid a good thing too. Thesaltier water is the de is, and deer sinks. Without its extra burden of salt, theAtlantic currents would proceed up to the Arctic, warming the North Pole but deprivingEurope of all that kindly warmth. The mai of heat transfer oh is what is knownas thermohaline circulation, which inates in slow, deep currents far below the surface—aprocess first detected by the stist-adventurer t von Rumford in 1797.
2What happensis that surface waters, as they get to the viity of Europe, grow dense and sink to greatdepths and begin a slow trip back to the southern hemisphere. When they reatarctica,they are caught up iarctic Circumpolar Current, where they are driven onward intothe Pacific. The process is very slow—it take 1,500 years for water to travel from the2The term means a number of things to different people, it appears. In November 2002, Carl WunsITpublished a report in Sce, "What Is the Thermohaline Circulation?," in which he hat the expressionhas been used in leading journals to signify at least seven different phenomena (circulation at the abyssal level,circulation driven by differences iy or buoyancy, "meridional overturning circulation of mass," and soon)-though all have to do with o circulations and the transfer of heat, the cautiously vague and embragsense in which I have employed it here.
North Atlantic to the mid-Pacific—but the volumes of heat and water they move are verysiderable, and the influen the climate is enormous.
(As for the question of how anyone could possibly figure out how long it takes a drop ofwater to get from one o to ahe answer is that stists measure poundsier like chlorofluorocarbons and work out how long it has been sihey were lastin the air. By paring a lot of measurements from differehs and locations they reasonably chart the water’s movement.)Thermohaline circulation not only moves heat around, but also helps to stir up nutrients asthe currents rise and fall, making greater volumes of the o habitable for fish and othermarine creatures. Unfortunately, it appears the circulation may also be very sensitive toge. Acc to puter simulations, even a modest dilution of the o’s salttent—from increased melting of the Greenland ice sheet, for instance—could disrupt thecycle disastrously.
The seas do oher great favor for us. They soak up tremendous volumes of carbon andprovide a means for it to be safely locked away. One of the oddities of our solar system is thatthe Sun burns about 25 pert more brightly now thahe solar system was young.
This should have resulted in a much warmer Earth. Indeed, as the English geologist AubreyManning has put it, “This colossal ge should have had an absolutely catastrophic effe the Earth a appears that our world has hardly been affected.”
So what keeps the world stable and cool?
Life does. Trillions upon trillions of tiny marine anisms that most of us have neverheard of—foraminiferans and coccoliths and calcareous algae—capture atmospheric carbon,in the form of carbon dioxide, when it falls as rain and use it (in bination with otherthings) to make their tiny shells. By log the carbon up in their shells, they keep it frombeing reevaporated into the atmosphere, where it would build up dangerously as a greenhousegas. Eventually all the tiny foraminiferans and coccoliths and so on die and fall to the bottomof the sea, where they are pressed into limesto is remarkable, when you behold araordinary natural feature like the White Cliffs of Dover in England, to reflect that it ismade up of nothing but tiny deceased marine anisms, but even more remarkable when yourealize how much carbon they cumulatively sequester. A six-inch cube of Dover chalk willtain well over a thousand liters of pressed carbon dioxide that would otherwise bedoing us no good at all. Altogether there is about twenty thousand times as much carbonlocked away in the Earth’s rocks as imosphere. Eventually much of that limestone willend up feeding voloes, and the carbon will return to the atmosphere and fall to the Earth inrain, which is why the whole is called the long-term carbon cycle. The process takes a verylong time—about half a million years for a typical carbon atom—but in the absence of anyother disturba works remarkably well at keeping the climate stable.
Unfortunately, human beings have a careless predile for disrupting this cycle byputting lots of extra carbon into the atmosphere whether the foraminiferans are ready for it ornot. Since 1850, it has beeimated, we have lofted about a hundred billion tons of extracarbon into the air, a total that increases by about seven billion tons each year. Overall, that’snot actually all that muature—mostly through the belgs of voloes and the decayof plants—sends about 200 billion tons of carbon dioxide into the atmosphere each year,nearly thirty times as much as we do with our cars and factories. But you have only to look atthe haze that hangs over our cities to see what a difference our tribution makes.
We know from samples of very old ice that the “natural” level of carbon dioxide imosphere—that is, before we started inflating it with industrial activity—is about 280 partsper million. By 1958, when people in lab coats started to pay attention to it, it had risen to 315parts per million. Today it is over 360 parts per million and rising by roughly one-quarter of 1pert a year. By the end of the twenty-first tury it is forecast to rise to about 560 partsper million.
So far, the Earth’s os and forests (which also pack away a lot of carbon) have mao save us from ourselves, but as Peter Cox of the British Meteical Office puts it:
“There is a critical threshold where the natural biosphere stops buffering us from the effects ofour emissions and actually starts to amplify them.” The fear is that there would be a runawayincrease in the Earth’s warming. Uo adapt, many trees and other plants would die,releasing their stores of carbon and adding to the problem. Such cycles have occasionallyhappened in the distant past even without a human tribution. The good news is that eveure is quite wonderful. It is almost certain that eventually the carbon cycle wouldreassert itself aurn the Earth to a situation of stability and happiness. The last time thishappened, it took a mere sixty thousand years.
18 THE BOUNDING MAIN
IMAGIRYING TO live in a world dominated by dihydrogen oxide, a pound that hasno taste or smell and is so variable in its properties that it is generally benign but at othertimes swiftly lethal. Depending on its state, it scald you or freeze you. In the presence ofcertain anic molecules it form carbonic acids so nasty that they strip the leavesfrom trees ahe faces off statuary. In bulk, when agitated, it strike with a fury thatno human edifice could withstand. Even for those who have learo live with it, it is anoften murderous substance. We call it water.
Water is everywhere. A potato is 80 pert water, a cow 74 pert, a bacterium 75pert. A tomato, at 95 pert, is little but water. Even humans are 65 pert water,making us more liquid than solid by a margin of almost two to one. Water is strauff. It isformless and transparent, a we long to be beside it. It has no taste a we love thetaste of it. We will travel great distances and pay small fortuo see it in sunshine. Ahough we know it is dangerous and drowns tens of thousands of people every year, we’t wait to froli it.
Because water is so ubiquitous we tend to overlook what araordinary substa is.
Almost nothing about it be used to make reliable predis about the properties of otherliquids and vice versa. If you knew nothing of water and based your assumptions on thebehavior of pounds most chemically akin to it—hydrogen selenide or hydrogen sulphidenotably—you would expect it to boil at minus 135 degrees Fahre and to be a gas at roomtemperature.
Most liquids when chilled tract by about 10 pert. Water does too, but only down to apoint. O is within whispering distance of freezing, it begins—perversely, beguilingly,extremely improbably—to expand. By the time it is solid, it is almost a tenth morevoluminous than it was before. Because it expands, ice floats on water—“an utterly bizarreproperty,” acc to John Gribbin. If it lacked this splendid waywardness, ice would sink,and lakes and os would freeze from the bottom up. Without surface ice to hold heat ier’s warmth would radiate away, leaving it even chillier and creati more ice.
Soohe os would freeze and almost certainly stay that way for a very long time,probably forever—hardly the ditions to nurture life. Thankfully for us, water seemsunaware of the rules of chemistry or laws of physics.
Everyone knows that water’s chemical formula is H2O, which means that it sists of onelargish oxygen atom with two smaller hydrogen atoms attached to it. The hydrogen atomsg fiercely to their oxygen host, but also make casual bonds with other water molecules.
The nature of a water molecule means that it engages in a kind of dah other watermolecules, briefly pairing and then moving on, like the ever-ging partners in a quadrille,to use Robert Kunzig’s nice phrase. A glass of water may not appear terribly lively, but everymolecule in it is ging partners billions of times a sed. That’s why water moleculesstick together to form bodies like puddles and lakes, but not so tightly that they ’t be easilyseparated as when, for instance, you dive into a pool of them. At any given moment only 15pert of them are actually toug.
In one sehe bond is very strong—it is why water molecules flow uphill whensiphoned and why water droplets on a car hood show such a singular determination to beadwith their partners. It is also why water has surface tension. The molecules at the surface areattracted more powerfully to the like molecules beh and beside them than to the airmolecules above. This creates a sort of membrarong enough to support is andskipping stones. It is what gives the sting to a belly flop.
I hardly need point out that we would be lost without it. Deprived of water, the human bodyrapidly falls apart. Within days, the lips vanish “as if amputated, the gums bla, the hers to half its length, and the skin so tracts around the eyes as to prevent blinking.”
Water is so vital to us that it is easy to overlook that all but the smallest fra of the wateroh is poisonous to us—deadly poisonous—because of the salts within it.
We need salt to live, but only in very small amounts, aer tains way more—about seventy times more—salt than we safely metabolize. A typical liter of seawater willtain only about 2.5 teaspoons of on salt—the kind we sprinkle on food—but muchlarger amounts of other elements, pounds, and other dissolved solids, which arecollectively known as salts. The proportions of these salts and minerals in our tissues isunily similar to seawater—we sweat and cry seawater, as Margulis and Sagan have putit—but curiously we ot tolerate them as an input. Take a lot of salt into your body andyour metabolism very quickly goes into crisis. From every cell, water molecules rush off likeso many volunteer firemen to try to dilute and carry off the sudden intake of salt. This leavesthe cells dangerously short of the water they o carry out their normal funs. Theybee, in a word, dehydrated. Ireme situations, dehydration will lead to seizures,unsciousness, and brain damage. Meanwhile, the overworked blood cells carry the salt tothe kidneys, which eventually bee overwhelmed and shut down. Without funingkidneys you die. That is why we don’t drier.
There are 320 million cubic miles of water oh and that is all we’re ever going to get.
The system is closed: practically speaking, nothing be added or subtracted. The water youdrink has been around doing its job sihe Earth was young. By 3.8 billion years ago, theos had (at least more or less) achieved their present volumes.
The water realm is known as the hydrosphere and it is overwhelmingly oiiy-seven pert of all the water oh is in the seas, the greater part of it in the Pacific, whichcovers half the pla and is bigger than all the landmasses put together. Altogether thePacific holds just over half of all the o water (51.6 pert to be precise); the Atlantic has23.6 pert and the Indian O 21.2 pert, leaving just 3.6 pert to be ated forby all the other seas. The average depth of the o is 2.4 miles, with the Pacifi averageabout a thousa deeper thalantid Indian Os. Altogether 60 pert ofthe pla’s surface is o more than a mile deep. As Philip Ball notes, we would better callour pla h but Water.
Of the 3 pert of Earth’s water that is fresh, most exists as ice sheets. Only the tiamount—0.036 pert—is found in lakes, rivers, and reservoirs, and an even smaller part—just 0.001 pert—exists in clouds or as vapor. Nearly 90 pert of the pla’s ice is inAntarctica, and most of the rest is in Greenland. Go to the South Pole and you will bestanding on nearly two miles of ice, at the North Pole just fiftee of it. Antarctica alonehas six million cubic miles of iough to raise the os by a height of two hundred feetif it all melted. But if all the water imosphere fell as rain, evenly everywhere, theos would deepen by only an inch.
Sea level, ially, is an almost entirely notional cept. Seas are not level at all.
Tides, winds, the Coriolis force, and other effects alter water levels siderably from oo another and within os as well. The Pacific is about a foot and a half higher alongits western edge—a sequence of the trifugal force created by the Earth’s spin. Just aswhen you pull on a tub of water the water tends to flow toward the other end, as if relut toe with you, so the eastward spin of Earth piles water up against the o’s westernmargins.
sidering the age-old importance of the seas to us, it is striking how long it took theworld to take a stifiterest in them. Until well into the eenth tury most of whatwas known about the os was based on what washed ashore or came up in fishis,and nearly all that was written was based more oe and supposition than on physicalevidence. In the 1830s, the British naturalist Edward Forbes surveyed o beds throughoutthe Atlantid Mediterranean and declared that there was no life at all in the seas below2,000 feet. It seemed a reasonable assumption. There was no light at that depth, so no plantlife, and the pressures of water at such depths were known to be extreme. So it came assomething of a surprise when, in 1860, one of the first transatlantic telegraph cables washauled up for repairs from more than two miles down, and it was found to be thicklyencrusted with corals, clams, and other livius.
The first really anized iigation of the seas didn’t e until 1872, when a jointexpeditioween the British Museum, the Royal Society, and the British gover setforth from Portsmouth on a former warship called HMS Challenger. For three and a halfyears they sailed the world, sampling waters, ing fish, and hauling a dredge throughsediments. It was evidently dreary work. Out of a plement of 240 stists and crew, onein four jumped ship a more died or went mad—“driven to distra by the mind-numbing routine of years ing” in the words of the historian Samantha Weinberg. Butthey sailed across almost 70,000 nautical miles of sea, collected over 4,700 new species ofmarine anisms, gathered enough information to create a fifty-volume report (which tookeen years to put together), and gave the world the name of a new stific discipline:
oography. They also discovered, by means of depth measurements, that there appeared tobe submerged mountains in the mid-Atlantic, prompting some excited observers to speculatethat they had found the lost ti of Atlantis.
Because the institutional world mostly ighe seas, it fell to devoted—and veryoccasional—amateurs to tell us what was down there. Modern deep-water exploration beginswith Charles William Beebe and Otis Barton in 1930. Although they were equal partners, themore colorful Beebe has always received far more written attention. Born in 1877 into a well-to-do family in New York City, Beebe studied zoology at bia Uy, then took ajob as a birdkeeper at the New York Zoological Society. Tiring of that, he decided to adoptthe life of an adventurer and for the quarter tury traveled extehrough Asiaand South America with a succession of attractive female assistants whose jobs wereiively described as “historian and teicist” or “assistant in fish problems.” Hesupported these endeavors with a succession of popular books with titles like Edge of theJungle and Jungle Days, though he also produced some respectable books on wildlife andornithology.
In the mid-1920s, on a trip to the Galápagos Islands, he discovered “the delights ofdangling,” as he described deep-sea diving. Soon afterward he teamed up with Barton, whocame from an evehier family, had also attended bia, and also longed foradventure. Although Beebe nearly always gets the credit, it was in fact Barton who desighe first bathysphere (from the Greek word for “deep”) and fuhe $12,000 cost of itsstru. It was a tiny and necessarily robust chamber, made of cast iron 1.5 ihid with two small portholes taining quartz blocks three ihick. It held two men, butonly if they were prepared to bee extremely well acquainted. Even by the standards of theage, the teology was unsophisticated. The sphere had no maneuverability—it simply hungon the end of a long cable—and only the most primitive breathing system: to ralize theirown carbon dioxide they set out open s of soda lime, and to absorb moisture they opened asmall tub of calcium chloride, over which they sometimes waved palm fronds to encechemical reas.
But the nameless little bathysphere did the job it was inteo do. On the first dive, inJune 1930 in the Bahamas, Barton and Beebe set a world record by desding to 600 feet. By1934, they had pushed the record to 3,028 feet, where it would stay until after the war. Bartonwas fident the device was safe to a depth of 4,500 feet, though the strain on every bolt andrivet was audibly evident with each fathom they desded. At ah, it was brave andrisky work. At 3,000 feet, their little porthole was subjected to een tons of pressure persquare inch. Death at such a depth would have been instantaneous, as Beebe never failed toobserve in his many books, articles, and radio broadcasts. Their main , however, wasthat the shipboard winch, straining to hold on to a metal ball and two tons of steel cable,would snap ahe two men plunging to the seafloor. In su event, nothing couldhave saved them.
The ohing their dests didn’t produce was a great deal of worthwhile sce.
Although they entered many creatures that had not been seen before, the limits ofvisibility and the fact that her of the intrepid aquanauts was a trained oographer meantthey often weren’t able to describe their findings in the kind of detail that real stistscraved. The sphere didn’t carry aernal light, merely a 250-watt bulb they could hold upto the window, but the water below five hundred feet ractically imperable anyway,and they were peering into it through three inches of quartz, so anything they hoped to viewwould have to be nearly as ied in them as they were in it. About all they could report, insequence, was that there were a lot of strahings down there. On one dive in 1934,Beebe was startled to spy a giant serpent “more thay feet long and very wide.” Itpassed too swiftly to be more than a shadow. Whatever it was, nothing like it has been seenby anyone since. Because of such vagueheir reports were generally ignored byacademics.
After their record-breaking dest of 1934, Beebe lost i in diving and moved on toother adventures, but Barton persevered. To his credit, Beebe always told anyone who askedthat Barton was the real brains behind the enterprise, but Barton seemed uo step fromthe shadows. He, too, wrote thrilling ats of their uer adventures and even starredin a Hollywood movie called Titans of the Deep, featuring a bathysphere and maingand largely fialized enters with aggressive giant squid and the like. He eveised Camel cigarettes (“They don’t give me jittery nerves”). In 1948 he increased thedepth record by 50 pert, with a dive to 4,500 feet in the Pacific O near California, butthe world seemed determio overlook him. One neer reviewer of Titans of the Deepactually thought the star of the film was Beebe. Nowadays, Barton is lucky to get a mention.
At all events, he was about to be prehensively eclipsed by a father-and-son team fromSwitzerland, Auguste and Jacques Piccard, who were designing a ype of probe called abathyscaphe (meaning “deep boat”). Christerieste, after the Italian city in which it wasbuilt, the new device maneuvered indepely, though it did little more than just go up anddown. On one of its first dives, in early 1954, it desded to below 13,287 feet, nearly threetimes Barton’s record-breaking dive of six years earlier. But deep-sea dives required a greatdeal of costly support, and the Piccards were gradually going broke.
In 1958, they did a deal with the U.S. Navy, which gave the Navy ownership but left themin trol. Now flush with funds, the Piccards rebuilt the vessel, giving it walls five ihid shrinking the windows to just two inches in diameter—little more than peepholes.
But it was now strong enough to withstand truly enormous pressures, and in January 1960Jacques Piccard and Lieutenant Don Walsh of the U.S. Navy sank slowly to the bottom of theo’s deepest yon, the Mariana Trench, some 250 miles off Guam in the western Pacifid discovered, not ially, by Harry Hess with his fathometer). It took just under fourhours to fall 35,820 feet, or almost seven miles. Although the pressure at that depth wasnearly 17,000 pounds per square inch, they noticed with surprise that they disturbed a bottom-dwelling flatfish just as they touched down. They had no facilities for taking photographs, sothere is no visual record of the event.
After just twenty mi the world’s deepest point, they returo the surface. It wasthe only occasion on which human beings have gone so deep.
Forty years later, the question that naturally occurs is: Why has no one gone back siobegin with, further dives were vigorously opposed by Vice Admiral Hyman G. Rickover, aman who had a lively temperament, forceful views, and, most pertily, trol of thedepartmental checkbook. He thought uer exploration a waste of resources and poi that the Navy was not a researstitute. The nation, moreover, was about to beefully preoccupied with space travel and the quest to send a man to the Moon, which madedeep sea iigations seem unimportant and rather old-fashioned. But the decisivesideration was that the Trieste dest didn’t actually achieve much. As a Navy officialexplained years later: “We didn’t learn a hell of a lot from it, other than that we could do it.
Why do it again?” It was, in short, a long way to go to find a flatfish, and expeoo.
Repeating the exercise today, it has beeimated, would cost at least $100 million.
When uer researchers realized that the Navy had no iion of pursuing apromised exploratiram, there ained outcry. Partly to placate its critics, theNavy provided funding for a more advanced submersible, to be operated by the Woods HoleOographistitution of Massachusetts. Called Alvin, in somewhat tracted honor ofthe oographer Allyn C. Vi would be a fully maneuverable minisubmarihough itwouldn’t go anywhere near as deep as the Trieste. There was just one problem: the designerscouldn’t find anyone willing to build it. Acc to William J. Broad in The UniverseBelow: “No big pany like General Dynamics, which made submarines for the Navy,wao take on a project disparaged by both the Bureau of Ships and Admiral Rickover, thegods of naval patronage.” Eventually, not to say improbably, Alvin was structed byGeneral Mills, the food pany, at a factory where it made the maes to producebreakfast cereals.
As for what else was down there, people really had very little idea. Well into the 1950s, thebest maps available .to oographers were overwhelmingly based on a little detail fromscattered surveys going back to 1929 grafted onto, essentially an o of guesswork. TheNavy had excellent charts with which to guide submarihrough yons and aroundguyots, but it didn’t wish suformation to fall into Soviet hands, so it kept its knowledgeclassified. Academics therefore had to make do with sketchy and antiquated surveys or relyon hopeful surmise. Even today our knowledge of the o floors remains remarkably lowresolution. If you look at the Moon with a standard backyard telescope you will seesubstantial craters—Fracastorious, Blanus, Zach, Planck, and many others familiar to anylunar stist—that would be unknown if they were on our own o floors. We have bettermaps of Mars than we do of our own seabeds.
At the surface level, iigative teiques have also been a trifle ad ho 1994, thirty-four thousand ice hockey gloves were swept overboard from a Korean cargo ship during astorm in the Pacific. The gloves washed up all over, from Vancouver to Vietnam, helpingoographers to trace currents more accurately than they ever had before.
Today Alvin is nearly forty years old, but it still remains America’s premier research vessel.
There are still no submersibles that go anywhere he depth of the Mariana Trend only five, including Alvin, that reach the depths of the “abyssal plain”—the deepo floor—that covers more than half the pla’s surface. A typical submersible costsabout $25,000 a day to operate, so they are hardly dropped into the water on a whim, still lessput to sea in the hope that they will randomly stumble on something of i. It’s rather asif our firsthand experience of the surface world were based on the work of five guys explon garden tractors after dark. Acc to Robert Kunzig, humans may have scrutinized“perhaps a millionth or a billionth of the sea’s darkness. Maybe less. Maybe much less.”
But oographers are nothing if not industrious, and they have made several importantdiscoveries with their limited resources—including, in 1977, one of the most important andstartling biological discoveries of the tweh tury. In that year Alvin found teemingies of large anisms living on and around deep-sea vents off the Galápagos Islands—tube worms over te long, clams a foot wide, shrimps and mussels in profusiling spaghetti worms. They all owed their existeo vast ies of bacteria thatwere deriving their energy and sustenance from hydrogen sulfides—pounds profoundlytoxic to surface creatures—that were p steadily from the vents. It was a worldindepe of sunlight, oxygen, or anything else normally associated with life. This was aliving system based not on photosynthesis but on chemosynthesis, an arrahatbiologists would have dismissed as preposterous had anyone been imaginative enough tosuggest it.
Huge amounts of heat and energy flow from these vents. Two dozen of them together willproduce as muergy as a large power station, and the range of temperatures around themis enormous. The temperature at the point of outflow be as much as 760 degreesFahre, while a few feet away the water may be only two or three degrees above freezing.
A type of worm called an alvinellid was found living right on the margins, with the watertemperature 140 degrees warmer at its head than at its tail. Before this it had been thought thatno plex anisms could survive in water warmer than about 130 degrees, and here wasohat was surviving warmer temperatures than that areme cold to boot. Thediscovery transformed our uanding of the requirements for life.
It also answered one of the great puzzles of oography—something that many of usdidn’t realize uzzle—namely, why the os don’t grow saltier with time. At the riskof stating the obvious, there is a lot of salt in the sea—enough to bury every bit of land on theplao a depth of about five hundred feet. Millions of gallons of fresh water evaporate fromthe o daily, leaving all their salts behind, so logically the seas ought to grow more saltywith> the passing years, but they don’t. Something takes an amount of salt out of the waterequivalent to the amount being put in. For the loime, no one could figure out whatcould be responsible for this.
Alvin’s discovery of the deep-sea vents provided the answer. Geophysicists realized that thevents were ag much like the filters in a fish tank. As water is taken down into the crust,salts are stripped from it, aually water is blown out again through the eystacks. The process is not swift—it take up to ten million years to an o—but itis marvelously effit as long as you are not in a hurry.
Perhaps nothing speaks more clearly of our psychological remoteness from the odepths than that the main expressed goal for oographers during Iional GeophysicalYear of 1957–58 was to study “the use of o depths for the dumping of radioactivewastes.” This wasn’t a secret assig, you uand, but a proud public boast. In fact,though it wasn’t much publicized, by 1957–58 the dumping of radioactive wastes had alreadybeen going on, with a certain appalling vigor, for over a decade. Since 1946, the Uateshad been ferrying fifty-five-gallon drums of radioactive gunk out to the Farallon Islands,some thirty miles off the California coast near San Francisco, where it simply threw themoverboard.
It was all quite extraordinarily sloppy. Most of the drums were exactly the sort you seerusting behind gas stations or standing outside factories, with no protective linings of anytype. When they failed to sink, which was usually, Navy gunners riddled them with bullets tolet water in (and, of course, plutonium, uranium, and strontium out). Before it was halted inthe 1990s, the Uates had dumped many hundreds of thousands of drums into aboutfifty o sites—almost fifty thousand of them in the Farallons alone. But the U.S. was by nomeans alone. Among the other enthusiastic dumpers were Russia, a, Japan, New Zealand,and nearly all the nations of Europe.
And what effect might all this have had on life beh the seas? Well, little, we hope, butwe actually have no idea. We are astoundingly, sumptuously, radiantly ignorant of lifebeh the seas. Even the most substantial o creatures are often remarkably little knownto us—including the most mighty of them all, the great blue whale, a creature of suchleviathan proportions that (to quote David Attenbh) its “tongue weighs as much as anelephant, its heart is the size of a car and some of its blood vessels are so wide that you couldswim down them.” It is the most gargantua that Earth has yet produced, bigger eventhan the most cumbrous dinosaurs. Yet the lives of blue whales are largely a mystery to us.
Much of the time we have no idea where they are—where they go to breed, for instance, orwhat routes they follow to get there. What little we know of them es almost entirely fromeavesdropping on their songs, but even these are a mystery. Blue whales will sometimes breakoff a song, then pick it up again at the same spot six months later. Sometimes they strike upwith a new song, whiber have heard before but which each already knows.
How they do this is not remotely uood. And these are animals that must routinely eto the surface to breathe.
For animals that need never surface, obscurity be even more tantalizing. sider thefabled giant squid. Though nothing on the scale of the blue whale, it is a decidedly substantialanimal, with eyes the size of soccer balls and trailiacles that reach lengths of sixtyfeet. It weighs nearly a ton and is Earth’s largest iebrate. If you dumped one in a normalhousehold swimming pool, there wouldn’t be mu for anything else. Yet no stist—no person as far as we know—has ever seen a giant squid alive. Zoologists have devotedcareers t to capture, or just glimpse, living giant squid and have always failed. Theyare known mostly from being washed up on beaches—particularly, for unknown reasons, thebeaches of the South Island of New Zealand. They must exist in large numbers because theyform a tral part of the sperm whale’s diet, and sperm whales take a lot of feeding.
1Acc to oimate, there could be as many as thirty million species of animalsliving in the sea, most still undiscovered. The first hint of how abundant life is in the deepseas didn’t e until as retly as the 1960s with the iion of the epibenthic sled, adredging device that captures anisms not just on ahe seafloor but also buried inthe sediments beh. In a single one-hour trawl along the tial shelf, at a depth of justunder a mile, Woods Hole oographers Howard Sandler and Robert Hessler ed over25,000 creatures—worms, starfish, sea cucumbers, and the like—representing 365 species.
Even at a depth of three miles, they found some 3,700 creatures representing almost 200species anism. But the dredge could only capture things that were too slow or stupid toget out of the way. Ie 1960s a marine biologist named John Isaacs got the idea tolower a camera with bait attached to it, and found still more, in particular dense swarms ofwrithing hagfish, a primitive eel-like creature, as well as darting shoals of grenadier fish.
Where a good food source is suddenly available—for instance, when a whale dies and sinks tothe bottom—as many as 390 species of marine creature have been found dining off it.
Iingly, many of these creatures were found to have e from vents up to a thousandmiles distant. These included such types as mussels and clams, which are hardly known asgreat travelers. It is now thought that the larvae of certain anisms may drift through thewater until, by some unknown chemical means, they detect that they have arrived at a foodopportunity and fall onto it.
So why, if the seas are so vast, do we so easily overtax them? Well, to begin with, theworld’s seas are not uniformly bounteous. Altogether less than a tenth of the o issidered naturally productive. Most aquatic species like to be in shallow waters where thereis warmth and light and an abundance anic matter to prime the food . Coral reefs,for instance, stitute well under 1 pert of the o’s space but are home to about 25pert of its fish.
Elsewhere, the os aren’t nearly so rich. Take Australia. With over 20,000 miles ofcoastline and almost nine million square miles of territorial waters, it has more sea lapping itsshores than any other try, yet, as Tim Flannery notes, it doesn’t even make it into the topfifty among fishing nations. Indeed, Australia is a large importer of seafood. This isbecause much of Australia’s waters are, like much of Australia itself, essentially desert. (Anotable exception is the Great Barrier Reef off Queensland, which is sumptuously fed.)Because the soil is poor, it produces little in the way of nutrient-rich runoff.
Even where life thrives, it is ofteremely sensitive to disturbance. In the 1970s, fishermenfrom Australia and, to a lesser extent, New Zealand discovered shoals of a little-known fishliving at a depth of about half a mile on their tial shelves. They were known as e1The iible parts of giant squid, in particular their beaks, accumulate in sperm whales stomachs into thesubstanown as ambergris, which is used as a fixative in perfumes. The ime you spray on el No. 5(assuming you do), you may wish to reflect that you are dousing yourself in distillate of unseen sea monster.
roughy, they were delicious, and they existed in huge numbers. In no time at all, fishing fleetswere hauling in forty thousaris hy a year. Then marine biologists madesome alarming discoveries. Roughy are extremely long lived and slow maturing. Some maybe 150 years old; any roughy you have eaten may well have been born when Victoria wasQueen. Roughy have adopted this exceedingly unhurried lifestyle because the waters they livein are so resource-poor. In such waters, some fish spawn just on a lifetime. Clearly theseare populations that ot stand a great deal of disturbance. Unfortunately, by the time thiswas realized the stocks had been severely depleted. Even with careful ma it will bedecades before the populations recover, if they ever do.
Elsewhere, however, the misuse of the os has been more wanton than ient.
Many fishermen “fin” sharks—that is, slice their fins off, then dump them bato the waterto die. In 1998, shark fins sold in the Far East for over $250 a pound. A bowl of shark finsoup retailed in Tokyo for $100. The World Wildlife Fuimated in 1994 that the numberof sharks killed each year was between 40 million and 70 million.
As of 1995, some 37,000 industrial-sized fishing ships, plus about a million smaller boats,were betweeaking twice as many fish from the sea as they had just twenty-five yearsearlier. Trawlers are sometimes now as big as cruise ships and haul behind them s bigenough to hold a dozen jumbo jets. Some even use spotter plao locate shoals of fish fromthe air.
It is estimated that about a quarter of every fishi hauled up tains “by-catch”—fishthat ’t be landed because they are too small or of the wrong type or caught in the wrongseason. As one observer told the Eist: “We’re still in the Dark Ages. We just drop a down and see what es up.” Perhaps as much as twenty-two millioris of suwanted fish are dumped ba the sea each year, mostly in the form of corpses. For everypound of shrimp harvested, about four pounds of fish and other marine creatures aredestroyed.
Large areas of the North Sea floor are dragged by beam trawlers as many as seventimes a year, a degree of disturbahat no ecosystem withstand. At least two-thirds ofspecies in the North Sea, by maimates, are being overfished. Across the Atlantic thingsare er. Halibut once abounded in suumbers off New England that individual boatscould land twenty thousand pounds of it in a day. Now halibut is all but extinct off thenortheast coast of North America.
Nothing, however, pares with the fate of cod. Ie fifteenth tury, the explorerJohn Cabot found cod in incredible numbers on the eastern banks of North America—shallowareas of water popular with bottom-feeding fish like cod. Some of these banks were vast.
Gees Banks off Massachusetts is bigger thaate it abuts. The Grand Banks offNewfoundland is bigger still and for turies was always deh cod. They were thoughtto be inexhaustible. Of course they were anything but.
By 1960, the number of spawning cod in the north Atlantic had fallen to aimated 1.6millioris. By 1990 this had sunk to 22,000 metris. In ercial terms, thecod were extinct. “Fishermen,” wrote Mark Kurlansky in his fasating history, Cod, “hadcaught them all.” The ay have lost the western Atlantic forever. In 1992, cod fishingwas stopped altogether on the Grand Banks, but as of last autumn, acc to a report inNature, stocks had not staged a eback. Kurlansky hat the fish of fish fillets and fishsticks was inally cod, but then was replaced by haddock, then by redfish, and lately byPacific pollock. These days, he notes drily, “fish” is “whatever is left.”
Much the same be said of many other seafoods. In the New England fisheries offRhode Island, it was once routio haul in lobsters weighing twenty pounds. Sometimes theyreached thirty pounds. Left ued, lobsters live for decades—as much as seventyyears, it is thought—and they op growing. Nowadays few lobsters weigh more thantwo pounds on capture. “Biologists,” acc to the New York Times, “estimate that 90pert of lobsters are caught within a year after they reach the legal minimum size at aboutage six.” Despite deing catches, New England fishermen tio receive state andfederal tax iives that ence them—in some cases all but pel them—to acquirebigger boats and to harvest the seas more intensively. Today fishermen of Massachusetts arereduced to fishing the hideous hagfish, for which there is a slight market in the Far East, buteven their numbers are now falling.
We are remarkably ignorant of the dynamics that rule life in the sea. While marine life ispoorer than it ought to be ihat have been overfished, in some naturally impoverishedwaters there is far more life than there ought to be. The 藏书网southern os around Antarcticaproduly about 3 pert of the world’s phytoplankton—far too little, it would seem, tosupport a plex ecosystem, a does. Crab-eater seals are not a species of animal thatmost of us have heard of, but they may actually be the seost numerous large species ofanimal oh, after humans. As many as fifteen million of them may live on the pack icearound Antarctica. There are also perhaps two million Weddel seals, at least half a millionemperor penguins, and maybe as many as four million Adélie penguins. The food isthus hopelessly top heavy, but somehow it works. Remarkably no one knows how.
All this is a very roundabout way of making the point that we know very little about Earth’sbiggest system. But then, as we shall see in the pages remaining to us, once you start talkingabout life, there is a great deal we don’t know, not least how it got going in the first place.
19 THE RISE OF LIFE
IN 1953, STANLEY Miller, a graduate student at the Uy of Chicago, took twoflasks—one taining a little water to represent a primeval o, the other holding amixture of methane, ammonia, and hydrogen sulphide gases to represeh’s earlyatmosph９9liｂ?ere—ected them with rubber tubes, and introduced some electrical sparks as astand-in fhtning. After a few days, the water in the flasks had turned green and yellow iy broth of amino acids, fatty acids, sugars, and anipounds. “If Goddidn’t do it this way,” observed Miller’s delighted supervisor, the Nobel laureate HaroldUrey, “He missed a good bet.”
Press reports of the time made it sound as if about all that was needed now was forsomebody to give the whole a good shake and life would crawl out. As time has shown, itwasn’t nearly so simple. Despite half a tury of further study, we are no osynthesizing life today than we were in 1953 and much further away from thinking we .
Stists are now pretty certain that the early atmosphere was nothing like as primed fordevelopment as Miller and Urey’s gaseous stew, but rather was a much less reactive blend ofnitrogen and carbon dioxide. Repeating Miller’s experiments with these more challenginginputs has so far produced only one fairly primitive amino acid. At all events, creating aminoacids is not really the problem. The problem is proteins.
Proteins are what you get when you string amino acids together, and we need a lot of them.
No one really knows, but there may be as many as a million types of protein in the humanbody, and eae is a little miracle. By all the laws of probability proteins should.
To make a protein you o assemble amino acids (which I am obliged by long tradition torefer to here as “the building blocks of life”) in a particular order, in much the same way thatyou assemble letters in a particular order to spell a word. The problem is that words in theamino acid alphabet are often exceedingly long. To spell collagen, the name of a ontype of protein, you e eight letters in the right order. But to make collagen, youe 1,055 amino acids in precisely the right sequence. But—and here’s anobvious but crucial point—you don’t make it. It makes itself, spontaneously, withoutdire, and this is where the unlikelihoods e in.
The ces of a 1,055-sequence molecule like collagen spontaneously self-assembling are,frankly, nil. It just isn’t going to happen. To grasp what a long shot its existence is, visualize astandard Las Vegas slot mae but broadened greatly—to about y feet, to be precise—to aodate 1,055 spinning wheels instead of the usual three or four, and with twentysymbols on each wheel (one for eaon amino acid).
1How long would you have topull the handle before all 1,055 symbols came up in the right order? Effectively forever. Evenif you reduced the number of spinning wheels to two hundred, which is actually a moretypiumber of amino acids for a protein, the odds against all two hundred ing up in a1There are actually twenty-two naturally amino acids known oh, and more may await discovery,but only twenty of them are necessary to produce us and most other living things. The twenty-sed, calledpyrrolysine, was discovered in 2002 by researchers at Ohio State Uy and is found only in a siype ofarchaean (a basi of life that we will discuss a little further on.. iory) called Methanosara barkeri.
prescribed sequence are 1 in 10260(that is a 1 followed by 260 zeroes). That in itself is a largerhan all the atoms in the universe.
Proteins, in short, are plex entities. Hemoglobin is only 146 amino acids long, a runt byprotein standards, yet even it offers 10190possible amino acid binations, which is why ittook the Cambridge Uy chemist Max Perutz twenty-three years—a career, more orless—to u. For random events to produce even a single protein would seem astunning improbability—like a whirlwind spinning through a junkyard and leaving behind afully assembled jumbo jet, in the colorful simile of the astronomer Fred Hoyle.
Yet we are talking about several huhousand types of protein, perhaps a million, eaique and each, as far as we know, vital to the maintenance of a sound and happy you. Andit goes on from there. A protein to be of use must not only assemble amino acids in the rightsequence, but then must engage in a kind of chemical ami and fold itself into a veryspecific shape. Even having achieved this structural plexity, a protein is no good to you ifit ’t reproduce itself, and proteins ’t. For this you need DNA. DNA is a whiz atreplig—it make a copy of itself in seds—but do virtually nothing else. So wehave a paradoxical situation. Proteins ’t exist without DNA, and DNA has no purposewithout proteins. Are we to assume then that they arose simultaneously with the purpose ofsupp each other? If so: wow.
And there is more still. DNA, proteins, and the other pos of life couldn’t prosperwithout some sort of membrao tain them. No atom or molecule has ever achieved lifeindepely. Pluy atom from your body, and it is no more alive than is a grain of sand.
It is only when they e together within the nurturing refuge of a cell that these diversematerials take part in the amazing dahat we call life. Without the cell, they arenothing more than iing chemicals. But without the chemicals, the cell has no purpose.
As the physicist Paul Davies puts it, “If everything needs everything else, how did theunity of molecules ever arise in the first place?” It is rather as if all the ingredients inyour kit somehow got together and baked themselves into a cake—but a cake that oreover divide when necessary to produce more cakes. It is little wohat we call it themiracle of life. It is also little wohat we have barely begun to uand it.
So what ats for all this wondrous plexity? Well, one possibility is that perhaps itisn’t quite—not quite—so wondrous as at first it seems. Take those amazingly improbableproteins. The wonder we see in their assembly es in assuming that they arrived on these fully formed. But what if the protein s didn’t assemble all at once? What if, in thegreat slot mae of creation, some of the wheels could be held, as a gambler might hold anumber of promising cherries? What if, in other words, proteins didn’t suddenly burst intobeing, but evolved .
Imagine if you took all the pos that make up a human being—carbon, hydrogen,oxygen, and so on—and put them in a tainer with some water, gave it a vigorous stir, andout stepped a pleted person. That would be amazing. Well, that’s essentially what Hoyleand others (including many ardent creationists) argue when they suggest that proteinsspontaneously formed all at ohey didn’t—they ’t have. As Richard Dawkins arguesin The Blind Watchmaker, there must have been some kind of cumulative sele processthat allowed amino acids to assemble in ks. Perhaps two or three amino acids linked upfor some simple purpose and then after a time bumped into some other similar small clusterand in so doing “discovered” some additional improvement.
Chemical reas of the sort associated with life are actually something of aonplace. It may be beyond us to cook them up in a lab, à la Stanley Miller and HaroldUrey, but the universe does it readily enough. Lots of molecules in nature get together to formlong s called polymers. Sugars stantly assemble to form starches. Crystals do anumber of lifelike things—replicate, respond to enviroal stimuli, take on a patternedplexity. They’ve never achieved life itself, of course, but they demonstrate repeatedly thatplexity is a natural, spontaneous, entirely onplace event. There may or may not be agreat deal of life in the universe at large, but there is no she of ordered self-assembly, ihing from the transfixing symmetry of snowflakes to the ely rings of Saturn.
So powerful is this natural impulse to assemble that many stists now believe that lifemay be more iable thahink—that it is, in the words of the Belgian biochemist andNobel laureate Christian de Duve, “an obligatory maion of matter, bound to arisewherever ditions are appropriate.” De Duve thought it likely that such ditions would beentered perhaps a million times in every galaxy.
Certainly there is nothing terribly exoti the chemicals that animate us. If you wished tocreate another living object, whether a goldfish or a head of lettuce or a human being, youwould need really only four principal elements, carbon, hydrogen, oxygen, and nitrogen, plussmall amounts of a few others, principally sulfur, phosphorus, calcium, and iron. Put thesetogether in three dozen or so binations to form some sugars, acids, and other basipounds and you build anything that lives. As Dawkins notes: “There is nothingspecial about the substances from which living things are made. Living things are collesof molecules, like everything else.”
The bottom line is that life is amazing and gratifying, perhaps even miraculous, but hardlyimpossible—as we repeatedly attest with our own modest existeo be sure, many of thedetails of life’s beginnings remaiy imponderable. Every sario you have ever reading the ditions necessary for life involves water—from the “warm little pond”
where Darwin supposed life began to the bubbling sea vents that are now the most populardidates for life’s beginnings—but all this overlooks the fact that to turn monomers intopolymers (which is to say, to begin to create proteins) involves what is known to biology as“dehydration linkages.” As one leading biology text puts it, with perhaps just a tiny hint ofdisfort, “Researchers agree that such reas would not have beeicallyfavorable in the primitive sea, or indeed in any aqueous medium, because of the mass alaw.” It is a little like putting sugar in a glass of water and having it bee a cube. Itshouldn’t happen, but somehow in nature it does. The actual chemistry of all this is a littleare for our purposes here, but it is enough to know that if you make monomers wet theydon’t turn into polymers—except wheing life oh. How and why it happens thenand not otherwise is one of biology’s great unanswered questions.
One of the biggest surprises in the earth sces i decades was the discovery ofjust how early ih’s history life arose. Well into the 1950s, it was thought that life wasless than 600 million years old. By the 1970s, a few adventurous souls felt that maybe it wentback 2.5 billion years. But the present date of 3.85 billion years is stunningly early. Earth’ssurface didn’t bee solid until about 3.9 billion years ago.
“We only infer from this rapidity that it is not ‘difficult’ for life of bacterial grade toevolve on plas with appropriate ditions,” Stephen Jay Gould observed in the New YorkTimes in 1996. Or as he put it elsewhere, it is hard to avoid the clusion that “life, arising assoon as it could, was chemically destio be.”
Life emerged so swiftly, in fact, that some authorities think it must have had help—perhapsa good deal of help. The idea that earthly life might have arrived from space has a surprisinglylong and even occasionally distinguished history. The great Lord Kelvin himself raised thepossibility as long ago as 1871 at a meeting of the British Association for the Adva ofSce when he suggested that “the germs of life might have been brought to the earth bysome meteorite.” But it remained little more than a friion until one Sunday iember 1969 when tens of thousands of Australians were startled by a series of sonis and the sight of a fireball streaking from east to west across the sky. The fireball madea strange crag sound as it passed a behind a smell that some likeo methylatedspirits and others described as just awful.
The fireball exploded above Murchison, a town of six hundred people in the GoulburnValley north of Melbourne, and came raining down in ks, some weighing up to twelvepounds. Fortunately, no one was hurt. The meteorite was of a rare type known as acarbonaceous drite, and the townspeople helpfully collected and brought in some twohundred pounds of it. The timing could hardly have beeer. Less than two months earlier,the Apollo 11 astronauts had returo Earth with a bag full of lunar rocks, so labsthroughout the world were geared up—indeed clam—for rocks of extraterrestrial in.
The Mureteorite was found to be 4.5 billion years old, and it was studded withamino acids—seventy-four types in all, eight of which are involved in the formation of earthlyproteins. In late 2001, more than thirty years after it crashed, a team at the Ames Researter in California annouhat the Murchison rock also tained plex strings ofsugars called polyols, which had not been found off the Earth before.
A few other carbonaceous drites have strayed ih’s path sine that landedagish Lake in ada’s Yukon in January 2000 was seen over large parts of NorthAmerid they have likewise firmed that the universe is actually ri anipounds. Halley’s et, it is now thought, is about 25 pert anic molecules. Getenough of those crashing into a suitable place—Earth, for instand you have the basicelements you need for life.
There are two problems with notions of panspermia, as extraterrestrial theories are known.
The first is that it doesn’t answer any questions about how life arose, but merely movesresponsibility for it elsewhere. The other is that panspermia sometimes excites even the mostrespectable adherents to levels of speculation that be safely called imprudent. FrancisCrick, codiscoverer of the structure of DNA, and his colleague Leslie el have suggestedthat Earth was “deliberately seeded with life by intelligent aliens,” ahat Gribbin calls“at the very fringe of stific respectability”—or, put another way, a notion that would besidered wildly lunatic if not voiced by a Nobel laureate. Fred Hoyle and his colleaguedra Wickramasinghe further eroded enthusiasm for panspermia by suggesting that outerspace brought us not only life but also many diseases such as flu and bubonic plague, ideasthat were easily disproved by biochemists. Hoyle—and it seems necessary to i areminder here that he was one of the great stifids of the tweh tury—alsoonce suggested, as mentioned earlier, that our noses evolved with the nostrils underh as away of keeping ic pathogens from falling into them as they drifted down from space.
Whatever prompted life to begin, it happened just ohat is the most extraordinary fa biology, perhaps the most extraordinary fact we know. Everything that has ever lived, plantor animal, dates its beginnings from the same primordial twitch. At some point in anunimaginably distant past some little bag of chemicals fidgeted to life. It absorbed somenutrients, gently pulsed, had a brief existehis much may have happened before, perhapsmany times. But this aral packet did something additional araordinary: it cleaveditself and produced an heir. A tiny bundle of geic material passed from one liviy toanother, and has opped moving si was the moment of creation for us all.
Biologists sometimes call it the Big Birth.
“Wherever you go in the world, whatever animal, plant, bug, or blob you look at, if it isalive, it will use the same diary and know the same code. All life is one,” says MattRidley. We are all the result of a single geic trick handed down from geion togeion nearly four billion years, to su extent that you take a fragment of humaistru, patch it into a faulty yeast cell, and the yeast cell will put it to work as if itwere its own. In a very real se is its own.
The dawn of life—or something very like it—sits on a shelf in the office of a friendlyisotope geochemist named Victoria Be in the Earth Sces building of the AustralianNational Uy in berra. An Ameri, Ms. Be came to the ANU fromCalifornia on a two-year tra 1989 and has been there ever since. When I visited her, inlate 2001, she handed me a modestly hefty hunk of roposed of thin alternating stripesof white quartz and a gray-green material called opyroxehe rock came from AkiliaIsland in Greenland, where unusually a rocks were found in 1997. The rocks are 3.85billion years old and represent the oldest marine sediments ever found.
“We ’t be certain that what you are holding once tained living anisms becauseyou’d have to pulverize it to find out,” Beold me. “But it es from the same depositwhere the oldest life was excavated, so it probably had life in it.” Nor would you find actualfossilized microbes, however carefully you searched. Any simple anisms, alas, would havebeen baked away by the processes that turned o mud to stone. Instead what we would seeif we ched up the rod exami microscopically would be the chemical residuesthat the anisms left behind—carbon isotopes and a type of phosphate called apatite, whichtogether provide strong evidehat the roce tained ies of living things. “We only guess what the anism might have looked like,” Be said. “It robablyabout as basic as life get—but it was life heless. It lived. It propagated.”
Aually it led to us.
If you are into very old rocks, at indubitably is, the ANU has long been a primeplace to be. This is largely thanks to the iy of a man named Bill pston, who isnow retired but in the 1970s built the world’s first Sensitive High Resolution Ion MicroProbe—or SHRIMP, as it is more affeately known from its initial letters. This is amae that measures the decay rate of uranium in tiny minerals called zirs. Zirsappear in most rocks apart from basalts and are extremely durable, surviving every naturalprocess but subduost of the Earth’s crust has been slipped bato the oven at somepoint, but just occasionally—iern Australia and Greenland, for example—geologistshave found outcrops of rocks that have remained always at the surface. pston’s maeallowed such rocks to be date藏书网d with unparalleled precision. The prototype SHRIMP was builtand maed in the Earth Sce department’s own workshops, and looked like somethingthat had been built from spare parts on a budget, but it worked great. On its first formal test, in1982, it dated the oldest thing ever found—a 4.3-billion-year-old rock from WesternAustralia.
“It caused quite a stir at the time,” Beold me, “to find something so important soquickly with braeology.”
She took me down the hall to see the current model, SHRIMP II. It was a big heavy pieceof stainless-steel apparatus, perhaps twelve feet long and five feet high, and as solidly built asa deep-sea probe. At a sole in front of it, keeping an eye on ever-ging strings offigures on a s, was a man named Bob from terbury Uy in New Zealand. Hehad been there since 4 A.M., he told me. SHRIMP II runs twenty-four hours a day; there’s thatmany rocks to date. It was just after 9A.M. and Bob had the mae till noon. Ask a pair ofgeochemists how something like this works, and they will start talking about isotopidances and ionization levels with ahusiasm that is more endearing than fathomable.
The upshot of it, however, was that the mae, by b a sample of rock withstreams of charged atoms, is able to detect subtle differences in the amounts of lead anduranium in the zir samples, by which means the age of rocks be accurately adduced.
Bob told me that it takes about seventeen mio read one zir and it is necessary toread dozens from each roake the data reliable. In practice, the process seemed toinvolve about the same level of scattered activity, and about as much stimulation, as a trip to alaundromat. Bob seemed very happy, however; but then people from New Zealand verygenerally do.
The Earth Sces pound was an odd bination of things—part offices, part labs,part mae shed. “We used to build everything here,” Be said. “We even had our ownglassblower, but he’s retired. But we still have two full-time rock crushers.” She caught mylook of mild surprise. “We get through a lot of rocks. And they have to be very carefullyprepared. You have to make sure there is no ination from previous samples—no dustor anything. It’s quite a meticulous process.” She showed me the rock-crushing maes,which were indeed pristihough the rock crushers had apparently gone for coffee. Besidethe maes were large boxes taining rocks of all shapes and sizes. They do indeed getthrough a lot of rocks at the ANU.
Ba Be’s office after our tour, I noticed hanging on her wall a piving anartist’s colorfully imaginative interpretation of Earth as it might have looked 3.5 billion yearsago, just when life was getting going, in the a period known to earth sce as theArchaean. The poster showed an alien landscape of huge, very active voloes, and asteamy, copper-colored sea beh a harsh red sky. Stromatolites, a kind of bacterial rock,filled the shallows in the fround. It didn’t look like a very promising place to create andnurture life. I asked her if the painting was accurate.
“Well, one school of thought says it was actually cool then because the sun was muchweaker.” (I later learhat biologists, when they are feeling jocose, refer to this as the“ese restaurant problem”—because we had a dim sun.) “Without an atmosphereultraviolet rays from the sun, even from a weak sun, would have teo break apart anyincipient bonds made by molecules. A right there”—she tapped the stromatolites—“youhave anisms almost at the surface. It’s a puzzle.”
“So we don’t know what the world was like back then?”
“Mmmm,” she agreed thoughtfully.
“Either way it doesn’t seem very ducive to life.”
She nodded amiably. “But there must have been something that suited life. Otherwise wewouldn’t be here.”
It certainly wouldn’t have suited us. If you were to step from a time mae into thata Archaean world, you would very swiftly scamper baside, for there was no moreoxygen to breathe oh back then than there is on Mars today. It was also full of noxiousvapors from hydrochlorid sulfuric acids powerful enough to eat through clothing andblister skin. Nor would it have provided the and glowing vistas depicted in the poster inVictoria Be’s office. The chemical stew that was the atmosphere then would haveallowed little sunlight to reach the Earth’s surface. What little you could see would beillumined only briefly by bright and frequent lightning flashes. In short, it was Earth, but ah we wouldn’t reize as our own.
Anniversaries were few and far between in the Archaean world. For two billion yearsbacterial anisms were the only forms of life. They lived, they reproduced, they swarmed,but they didn’t shoarticular ination to move on to another, more challenging levelof existe some point in the first billion years of life, obacteria, or blue-green algae,learo tap into a freely available resource—the hydrogen that exists iacularabundan water. They absorbed water molecules, supped on the hydrogen, and releasedthe oxygen as waste, and in so doing ied photosynthesis. As Margulis and Sagan note,photosynthesis is “undoubtedly the most important siaboliovation in the historyof life on the pla”—and it was ied not by plants but by bacteria.
As obacteria proliferated the world began to fill with O2to the sternation of thanisms that found it poisonous—whi those days was all of them. In an anaerobic (or anon-oxygen-using) world, oxygen is extremely poisonous. Our white cells actually useoxygen to kill invading bacteria. That oxygen is fually toxic often es as a surpriseto those of us who find it so vivial to our well-being, but that is only because we haveevolved to exploit it. To other things it is a terror. It is what turns butter rancid and makes ironrust. Even we tolerate it only up to a point. The oxygen level in our cells is only about atenth the level found imosphere.
The new oxygen-using anisms had two advantages. Oxygen was a more effit way toproduergy, and it vanquished petitanisms. Some retreated into the oozy,anaerobic world of bogs and lake bottoms. Others did likewise but then later (much later)migrated to the digestive tracts of beings like you and me. Quite a number of these primevalentities are alive inside your bht now, helping to digest your food, but abh evei hint of O2. Untold numbers of others failed to adapt and died.
The obacteria were a runaway success. At first, the extra oxygen they produced didn’taccumulate imosphere, but bined with iron to form ferric oxides, which sank to thebottom of primitive seas. For millions of years, the world literally rusted—a phenomenonvividly recorded in the banded iron deposits that provide so much of the world’s irooday. For many tens of millions of years not a great deal more than this happened. If youwent back to that early Proterozoic world you wouldn’t find many signs of promise forEarth’s future life. Perhaps here and there iered pools you’d enter a film of livingscum or a coating of glossy greens and browns on shoreline rocks, but otherwise life remainedinvisible.
But about 3.5 billion years ago something more emphatic became apparent. Wherever theseas were shallow, visible structures began to appear. As they went through their chemicalroutihe obacteria became very slightly tacky, and that taess trappedmicroparticles of dust and sand, which became bound together to form slightly weird but solidstructures—the stromatolites that were featured in the shallows of the poster on VictoriaBe’s office wall. Stromatolites came in various shapes and sizes. Sometimes they lookedlike enormous cauliflowers, sometimes like fluffy mattresses (stromatolite es from theGreek for “mattress”), sometimes they came in the form of ns, rising tens of metersabove the surface of the water—sometimes as high as a hundred meters. In all theirmaions, they were a kind of living rock, and they represehe world’s firstcooperative venture, with some varieties of primitive anism living just at the surfadothers living just underh, each taking advantage of ditions created by the other. Theworld had its first ecosystem.
For many years, stists knew about stromatolites from fossil formations, but in 1961they got a real surprise with the discovery of a unity of living stromatolites at SharkBay on the remote northwest coast of Australia. This was most ued—so ued,in fact, that it was some years before stists realized quite what they had found. Today,however, Shark Bay is a tourist attra—or at least as much of a tourist attra as a pladreds of miles from anywhere mud dozens of miles from anywhere at all ever be.
Boardwalks have been built out into the bay so that visitors stroll over the water to get agood look at the stromatolites, quietly respiring just beh the surface. They are lusterlessand gray and look, as I recorded in an earlier book, like very large cow-pats. But it is acuriously giddying moment to find yourself staring at living remnants of Earth as it was 3.5billion years ago. As Richard Fortey has put it: “This is truly time traveling, and if the worldwere attuo its real wohis sight would be as well-known as the pyramids of Giza.”
Although you’d never guess it, these dull rocks swarm with life, with aimated (well,obviously estimated) three billion individual anisms on every square yard of rock.
Sometimes when you look carefully you see tiny strings of bubbles rising to the surface asthey give up their oxygen. In two billion years such tiions raised the level of oxygeh’s atmosphere to 20 pert, preparing the way for the , more plex chapter inlife’s history.
It has been suggested that the obacteria at Shark Bay are perhaps the slowest-evolvinganisms oh, aainly now they are among the rarest. Having prepared the way formore plex life forms, they were then grazed out of existenearly everywhere by thevery anisms whose existehey had made possible. (They exist at Shark Bay becausethe waters are too saline for the creatures that would normally feast on them.)One reason life took so long to grow plex was that the world had to wait until thesimpler anisms had oxygehe atmosphere suffitly. “Animals could not summonup the energy to work,” as Fortey has put it. It took about two billion years, roughly 40pert of Earth’s history, for oxygen levels to reach more or less modern levels oftration imosphere. But ohe stage was set, and apparently quite suddenly, airely ype of cell arose—oh a nucleus and other little bodies collectively calledanelles (from a Greek word meaning “little tools”). The process is thought to have startedwhen some blundering or adventuresome bacterium either invaded or was captured by someother bacterium and it turned out that this suited them both. The captive bacterium became, itis thought, a mitodrion. This mitodrial invasion (or endosymbiotic event, asbiologists like to term it) made plex life possible. (In plants a similar invasion producedchloroplasts, whiable plants to photosynthesize.)Mitodria manipulate oxygen in a way that liberates energy from foodstuffs. Withoutthis niftily facilitating trick, life oh today would be nothing more than a sludge ofsimple microbes. Mitodria are very tiny—you could pack a billion into the spaceoccupied by a grain of sand—but also very hungry. Almost every nutriment you absoesto feeding them.
We couldn’t live for two minutes without them, yet even after a billion years mitodriabehave as if they think things might not work out between us. They maintain their own DNA.
They reproduce at a different time from their host cell. They look like bacteria, divide likebacteria, and sometimes respond to antibioti the way bacteria do. In short, they keep theirbags packed. They don’t evehe same geiguage as the cell in which they live.
It is like having a stranger in your house, but one who has been there for a billion years.
The ype of cell is known as a eukaryote (meaning “truly ed”), as trastedwith the old type, which is known as a prokaryote (“preed”), and it seems to havearrived suddenly in the fossil record. The oldest eukaryotes yet known, called Grypania, werediscovered in iron sediments in Michigan in 1992. Such fossils have been found just once, andthen no more are known for 500 million years.
pared with the new eukaryotes the old prokaryotes were little more than “bags ofchemicals,” in the words of the geologist Stephen Drury. Eukaryotes were bigger—eventuallyas much as ten thousand times bigger—than their simpler cousins, and carried as much as athousand times more DNA. Gradually a system evolved in which life was dominated by twotypes of form—anisms that expel oxygen (like plants) and those that take it in (you andme).
Single-celled eukaryotes were once called protozoa (“pre-animals”), but that term isincreasingly disdaioday the on term for them is protists . pared with thebacteria that had gone before, these new protists were wonders of design and sophistication.
The simple amoeba, just one cell big and without any ambitions but to exist, tains 400million bits of geiformation in its DNA—enough, as Carl Sagan o fill eightybooks of five hundred pages.
Eventually the eukaryotes learned an even more singular trick. It took a long time—abillion years or so—but it was a good one when they mastered it. They learether into plex multicellular beings. Thanks to this innovation, big, plicated,visible entities like us were possible. Plah was ready to move on to its ambitiousphase.
But before we get too excited about that, it is worth remembering that the world, as we areabout to see, still belongs to the very small.
20 SMALL WORLD
IT’S PROBABLY NOT a good idea to take too personal an i in your microbes. LouisPasteur, the great French chemist and bacteriologist, became so preoccupied with them that hetook to peering critically at every dish placed before him with a magnifying glass, a habit thatpresumably did not win him ma invitations to dinner.
In fact, there is no point in trying to hide from your bacteria, for they are on and around youalways, in numbers you ’t ceive. If you are in good health and averagely diligent abouthygiene, you will have a herd of about orillion bacteria grazing on your fleshy plains—about a huhousand of them on every square timeter of skin. They are there to dineoff the ten billion or so flakes of skin you shed every day, plus all the tasty oils and fortifyingminerals that seep out from every pore and fissure. You are for them the ultimate food court,with the venience of warmth and stant mobility thrown in. By way of thanks, they giveyou B.O.
And those are just the bacteria that inhabit your skin. There are trillions more tucked awayin yut and nasal passages, ging to your hair and eyelashes, swimming over thesurface of your eyes, drilling through the enamel of your teeth. Yestive system alone ishost to more than a hurillion microbes, of at least four huypes. Some deal withsugars, some with starches, some attack other bacteria. A surprising number, like theubiquitous iinal spirochetes, have able fun at all. They just seem to like tobe with you. Every human body sists of about 10 quadrillion cells, but about 100quadrillion bacterial cells. They are, in short, a big part of us. From the bacteria’s point ofview, of course, we are a rather small part of them.
Because we humans are big and clever enough to produd utilize antibiotiddisiants, it is easy to vince ourselves that we have banished bacteria to the fringes ofexistence. Don’t you believe it. Bacteria may not build cities or have iing social lives,but they will be here when the Sun explodes. This is their pla, and we are on it onlybecause they allow us to be.
Bacteria, never fet, got along for billions of years without us. We couldn’t survive a daywithout them. They process our wastes and make them usable again; without their diligentmung nothing would rot. They purify our water and keep our soils productive. Bacteriasynthesize vitamins in ut, vert the things we eat into useful sugars andpolysaccharides, and go to war on alien microbes that slip down ullet.
We depend totally on bacteria to pluitrogen from the air and vert it into usefulides and amino acids for us. It is a prodigious and gratifyi. As Margulis andSagan o do the same thing industrially (as when makiilizers) manufacturers mustheat the source materials to 500 degrees tigrade and squeeze them to three huimesnormal pressures. Bacteria do it all the time without fuss, and thank goodness, for neranism could survive without the nitrogen they pass on. Above all, microbes tioprovide us with the air we breathe and to keep the atmosphere stable. Microbes, including themodern versions of obacteria, supply the greater part of the pla’s breathable oxygen.
Algae and other tiny anisms bubbling away in the sea blow out about 150 billion kilos ofthe stuff every year.
And they are amazingly prolific. The more frantic among them yield a new geionihan ten minutes; Clostridium perfringens, the disagreeable little anism that causesgangrene, reprodu nine minutes. At such a rate, a single bacterium could theoreticallyproduce more offspring in two days than there are protons in the universe. “Given aesupply of nutrbbr>.９９ｌiｂ.ients, a single bacterial cell gee 280,000 billion individuals in a singleday,” acc to the Belgian biochemist and Nobel laureate Christian de Duve. In the sameperiod, a human cell just about manage a single division.
About once every million divisions, they produce a mutant. Usually this is bad luck for themutant—ge is always risky for an anism—but just occasionally the new bacterium isendowed with some actal advantage, such as the ability to elude or shrug off an attack ofantibiotics. With this ability to evolve rapidly goes another, even scarier advantage. Bacteriashare information. Any bacterium take pieces of geic g from any other.
Essentially, as Margulis and Sagan put it, all bacteria swim in a single gene pool. Anyadaptive ge that occurs in one area of the bacterial universe spread to any other. It’srather as if a human could go to an io get the necessary geic g to sprout wingsor walk on ceilings. It means that from a geic point of view bacteria have bee a singlesuperanism—tiny, dispersed, but invincible.
They will live and thrive on almost anything you spill, dribble, or shake loose. Just givethem a little moisture—as when you run a damp cloth over a ter—and they will bloom asif created from nothing. They will eat wood, the glue in aper, the metals in hardenedpaint. Stists in Australia found microbes known as Thiobacillus cretivorans that livedin—indeed, could not live without—trations of sulfuric acid strong enough to dissolvemetal. A species called Micrococcus radiophilus was found living happily in the waste tanksof nuclear react itself on plutonium and whatever else was there. Some bacteriabreak down chemical materials from which, as far as we tell, they gain no be at all.
They have been found living in boiling mud pots and lakes of caustic soda, deep insiderocks, at the bottom of the sea, in hidden pools of icy water in the McMurdo Dry Valleys ofAntarctica, and seven miles down in the Pacific O where pressures are more than athousand times greater than at the surface, or equivalent to being squashed beh fiftyjumbo jets. Some of them seem to be practically iructible. Deinococcus radiodurans is,acc to theEist , “almost immuo radioactivity.” Blast its DNA with radiation,and the pieces immediately reform “like the scuttling limbs of an undead creature from ahorror movie.”
Perhaps the most extraordinary survival yet found was that of a Streptococcus bacteriumthat was recovered from the sealed lens of a camera that had stood on the Moon for two years.
In short, there are few enviros in which bacteria aren’t prepared to live. “They arefinding now that when they push probes into o vents so hot that the probes actually startto melt, there are bacteria even there,” Victoria Beold me.
In the 1920s two stists at the Uy of Chicago, Edson Bastin and Frank Greer,annouhat they had isolated from oil wells strains of bacteria that had been living atdepths of two thousa. The notion was dismissed as fually preposterous—therewas nothing to live on at two thousa—and for fifty years it was assumed that theirsamples had been inated with surface microbes. We now know that there are a lot ofmicrobes living deep within the Earth, many of which have nothing at all to do with theanic world. They eat rocks or, rather, the stuff that’s in rocks—iron, sulfur, manganese,and so on. And they breathe odd things too—iron, , cobalt, even uranium. Suchprocesses may be instrumental in trating gold, copper, and other preetals, andpossibly deposits of oil and natural gas. It has even been suggested that their tireless nibblingscreated the Earth’s crust.
Some stists now think that there could be as much as 100 trillion tons of bacteria livih our feet in what are known as subsurface lithoautotrophic microbial ecosystems—SLiME for short. Thomas Gold of ell has estimated that if you took all the bacteria out ofthe Earth’s interior and dumped it on the surface, it would cover the plao a depth of fivefeet. If the estimates are correct, there could be more life uhe Earth than on top of it.
At depth microbes shrink in size and bee extremely sluggish. The liveliest of them maydivide no more than once a tury, some no more than perhaps on five hundred years.
As the Eist has put it: “The key to long life, it seems, is not to do too much.” Whenthings are really tough, bacteria are prepared to shut down all systems and wait for bettertimes. In 1997 stists successfully activated some anthrax spores that had lain dormant fhty years in a museum display in Trondheim, Norway. Other micranisms have leaptback to life after being released from a 118-year-old eat and a 166-year-old bottle ofbeer. In 1996, stists at the Russian Academy of Sce claimed to have revived bacteriafrozen in Siberian permafrost for three million years. But the record claim for durability so faris one made by Russell Vreeland and colleagues at West Chester Uy in Pennsylvaniain 2000, when they annouhat they had resuscitated 250-million-year-old bacteria calledBacillus permians that had been trapped in salt deposits two thousa underground inCarlsbad, New Mexico. If so, this microbe is older than the tis.
The report met with some uandable dubiousness. Many biochemists maintaihatover such a span the microbe’s pos would have bee uselessly degraded uhebacterium roused itself from time to time. However, if the bacterium did stir occasionallythere was no plausible internal source of energy that could have lasted so long. The moredoubtful stists suggested that the sample may have been inated, if not during itsretrieval then perhaps while still buried. In 2001, a team from Tel Aviv Uy argued thatB. permians were almost identical to a strain of modern bacteria, Bacillus marismortui, foundin the Dead Sea. Only two of its geic sequences differed, and then only slightly.
“Are we to believe,” the Israeli researchers wrote, “that in 250 million years B. permianshas accumulated the same amount of geic differehat could be achieved in just 3–7days in the laboratory?” In reply, Vreeland suggested that “bacteria evolve faster in the labthan they do in the wild.”
Maybe.
It is a remarkable fact that well into the space age, most school textbooks divided the worldof the living into just two categories—plant and animal. Micranisms hardly featured.
Amoebas and similar single-celled anisms were treated as proto-animals and algae asproto-plants. Bacteria were usually lumped in with plants, too, even though everyone khey didn’t belong there. As far back as the late eenth tury the German naturalistErnst Haeckel had suggested that bacteria deserved to be placed in a separate kingdom, whichhe called Monera, but the idea didn’t begin to catong biologists until the 1960s andthen only among some of them. (I hat my trusty Ameri Heritage desk diaryfrom 1969 doesn’t reize the term.)Many anisms in the visible world were also poorly served by the traditional division.
Fungi, the group that includes mushrooms, molds, mildews, yeasts, and puffballs, were nearlyalways treated as botanical objects, though in fact almost nothing about them—how theyreprodud respire, how they build themselves—matches anything in the plant world.
Structurally they have more in on with animals in that they build their cells from chitin,a material that gives them their distinctive texture. The same substance is used to make theshells of is and the claws of mammals, though it isn’t nearly so tasty in a stag beetle as ina Portobello mushroom. Above all, unlike all plants, fungi don’t photosynthesize, so theyhave no chlorophyll and thus are not green. Ihey grow directly on their food source,which be almost anything. Fungi will eat the sulfur off a crete wall or the degmatter between your toes—two things no plant will do. Almost the only plantlike quality theyhave is that they root.
Even less fortably susceptible to categorization was the peculiar group anismsformally called myxomycetes but more only known as slime molds. The name no doubthas much to do with their obscurity. An appellation that sounded a little more dynamic—“ambulant self-activating protoplasm,” say—and less like the stuff you find when you reachdeep into a clogged drain would almost certainly have earhese extraordinary entities amore immediate share of the attention they deserve, for slime molds are, make no mistake,among the most iing anisms in nature. When times are good, they exist as one-celled individuals, much like amoebas. But when ditions grow tough, they crawl to atral gathering plad bee, almost miraculously, a slug. The slug is not a thing ofbeauty and it doesn’t go terribly far—usually just from the bottom of a pile of leaf litter to thetop, where it is in a slightly more exposed position—but for millions of years this may wellhave been the niftiest tri the universe.
And it doesn’t stop there. Having hauled itself up to a more favorable locale, the slimemold transforms itself yet again, taking on the form of a plant. By some curious orderlyprocess the cells refigure, like the members of a tiny marg band, to make a stalk atopof whis a bulb known as a fruiting body. Ihe fruiting body are millions ofspores that, at the appropriate moment, are released to the wind to blow away and beesingle-celled anisms that start the process again.
For years slime molds were claimed as protozoa by zoologists and as fungi by mycologists,though most people could see they didn’t really belong anywhere. Wheic testingarrived, people in lab coats were surprised to find that slime molds were so distinctive andpeculiar that they weren’t directly related to anything else in nature, and sometimes o each other.
In 1969, in an attempt t some order to the growing inadequacies of classification, anecologist from ell Uy named R. H. Whittaker unveiled in the journalSce aproposal to divide life into five principal branches—kingdoms, as they are known—calledAnimalia, Plantae, Fungi, Protista, and Monera. Protista, was a modification of an earlierterm, Protoctista, which had been suggested a tury earlier by a Scottish biologist namedJohn Hogg, and was meant to describe any anisms that were her plant nor animal.
Though Whittaker’s new scheme was a great improvement, Protista remained ill defined.
Some taxonomists reserved it for large unicellular anisms—the eukaryotes—but otherstreated it as the kind of odd sock drawer of biology, putting into it anything that didn’t fitanywhere else. It included (depending on which text you sulted) slime molds, amoebas,and even seaweed, among much else. By one calculation it tained as many as 200,000different species anism all told. That’s a lot of odd socks.
Ironically, just as Whittaker’s five-kingdom classification was beginning to find its wayinto textbooks, a retiring academic at the Uy of Illinois was groping his way toward adiscovery that would challenge everything. His name was Carl Woese (rhymes with rose), andsihe mid-1960s—or about as early as it ossible to do so—he had been quietlystudyiic sequences in bacteria. In the early days, this was an exceedingly painstakingprocess. Work on a single bacterium could easily e a year. At that time, acc toWoese, only about 500 species of bacteria were known, which is fewer than the number ofspecies you have in your mouth. Today the number is about ten times that, though that is stillfar short of the 26,900 species of algae, 70,000 of fungi, and 30,800 of amoebas aedanisms whose biographies fill the annals of biology.
It isn’t simple indifferehat keeps the total low. Bacteria be exasperatingly difficultto isolate and study. Only about 1 pert will grow in culture. sidering how wildlyadaptable they are in nature, it is an odd fact that the one place they seem not to wish to live isa petri dish. Plop them on a bed of agar and pamper them as you will, and most will just liethere, deing every i to bloom. Any bacterium that thrives in a lab is bydefinition exceptional, ahese were, almost exclusively, the anisms studied bymicrobiologists. It was, said Woese, “like learning about animals from visiting zoos.”
Genes, however, allowed Woese to approach micranisms from anle. As heworked, Woese realized that there were more fual divisions in the microbial worldthan anyone suspected. A lot of little anisms that looked like bacteria and behaved likebacteria were actually something else altogether—something that had branched off frombacteria a long time ago. Woese called these anisms archaebacteria, later shorteoarchaea.
It has be said that the attributes that distinguish archaea from bacteria are not the sort thatwould qui the pulse of any but a biologist. They are mostly differences in their lipids andan absence of something called peptidogly. But in practice they make a world ofdifference. Archaeans are more different from bacteria than you and I are from a crab orspider. Singlehandedly Woese had discovered an unsuspected division of life, so fualthat it stood above the level of kingdom at the apogee of the Universal Tree of Life, as it israther reverentially known.
In 1976, he startled the world—or at least the little bit of it that aying attention—byredrawing the tree of life to incorporate not five main divisions, but twenty-three. These hegrouped uhree new principal categories—Bacteria, Archaea, and Eukarya (sometimesspelled Eucarya)—which he called domains.
Woese’s new divisions did not take the biological world by storm. Some dismissed them asmuch too heavily weighted toward the microbial. Many just ighem. Woese, accto Frances Ashcroft, “felt bitterly disappointed.” But slowly his new scheme began to catong microbiologists. Botanists and zoologists were much slower to admire its virtues.
It’s not hard to see why. On Woese’s model, the worlds of botany and zoology are relegatedto a few twigs oermost branch of the Eukaryan limb. Everything else belongs tounicellular beings.
“These folks were brought up to classify in terms of gross morphological similarities anddifferences,” Woese told an interviewer in 1996. “The idea of doing so in terms of molecularsequence is a bit hard for many of them to swallow.” In short, if they couldn’t see a differeh their owhey didn’t like it. And so they persisted with the traditional five-kingdom division—an arrahat Woese called “not very useful” in his mildermoments and “positively misleading” much of the rest of the time. “Biology, like physicsbefore it,” Woese wrote, “has moved to a level where the objects of i and theiriions often ot be perceived through direct observation.”
In 1998 the great and a Harvard zoologist Ernst Mayr (who then was in his y-fourth year and at the time of my writing is nearing one hundred and still going strong) stirredthe pot further by declaring that there should be just two prime divisions of life—“empires”
he called them. In a paper published in the Proceedings of the National Academy of Sces,Mayr said that Woese’s findings were iing but ultimately misguided, noting that“Woese was not trained as a biologist and quite naturally does not have aensivefamiliarity with the principles of classification,” which is perhaps as close as oinguished stist e to saying of ahat he doesn’t know what he is talkingabout.
The specifiayr’s criticisms are too teical to need extensive airiheyinvolve issues of meiotic sexuality, Hennigian cladification, and troversial interpretationsof the genome of Methanobacterium thermoautrophicum, among rather a lot else—butessentially he argues that Woese’s arra unbalahe tree of life. The bacterialrealm, Mayr notes, sists of no more than a few thousand species while the archaean has amere 175 named spes, with perhaps a few thousand more to be found—“but hardlymore than that.” By trast, the eukaryotic realm—that is, the plicated anisms withed cells, like us—numbers already in the millions. For the sake of “the principle ofbalance,” Mayr argues for bining the simple bacterial anisms in a siegory,Prokaryota, while plag the more plex and “highly evolved” remainder in the empireEukaryota, which would stand alongside as an equal. Put another way, he argues for keepingthings much as they were before. This divisioween simple cells and plex cells “iswhere the great break is in the living world.”
The distin between halophilic archaeans ahanosara or between flavobacteriaand gram-positive bacteria clearly will never be a matter of moment for most of us, but it isworth remembering that each is as different from its neighbors as animals are from plants. IfWoese’s new arraeaches us anything it is that life really is various and that most ofthat variety is small, unicellular, and unfamiliar. It is a natural human impulse to think ofevolution as a long of improvements, of a never-ending advaoward largeness andplexity—in a word, toward us. We flatter ourselves. Most of the real diversity inevolution has been small-scale. We large things are just flukes—an iing side branch. Ofthe twenty-three main divisions of life, only three—plants, animals, and fungi—are largeenough to be seen by the human eye, and even they tain species that are microscopic.
Indeed, acc to Woese, if you totaled up all the biomass of the pla—every livingthing, plants included—microbes would at for at least 80 pert of all there is, perhapsmore. The world belongs to the very small—and it has for a very long time.
So why, you are bound to ask at some point in your life, do microbes so often want to hurtus? ossible satisfa could there be to a microbe in having us grow feverish orchilled, or disfigured with sores, or above all expire? A dead host, after all, is hardly going toprovide long-term hospitality.
To begin with, it is worth remembering that most micranisms are ral or evenbeneficial to human well-being. The most rampantly iious anism oh, abacterium called Wolbachia, doesn’t hurt humans at all—or, e to that, any othervertebrates—but if you are a shrimp or worm or fruit fly, it make you wish you had neverbeen born. Altogether, only about one microbe in a thousand is a pathogen for humans,acc to National Geographic —though, knowing what some of them do, we couldbe fiven for thinking that that is quite enough. Even if mostly benign, microbes are still thehree killer in the Western world, and even many less lethal ones of course make usdeeply rue their existence.
Making a host unwell has certain bes for the microbe. The symptoms of an illnessofteo spread the disease. Vomiting, sneezing, and diarrhea are excellehods ofgetting out of one host and into position for ahe most effective strategy of all is toenlist the help of a mobile third party. Iious anisms love mosquitoes because themosquito’s sting delivers them directly to a bloodstream where they get straight to workbefore the victim’s defense meisms figure out what’s hit them. This is why so manygrade-A diseases—malaria, yellow fever, dengue fever, encephalitis, and a hundred or soother less celebrated but often rapaaladies—begin with a mosquito bite. It is afortunate fluke for us that HIV, the AIDS agent, isn’t among them—at least not yet. Any HIVthe mosquito sucks up on its travels is dissolved by the mosquito’s owabolism. Whenthe day es that the virus mutates its way around this, we may be irouble.
It is a mistake, however, to sider the matter too carefully from the position of logicbecause micranisms clearly are not calculatiies. They don’t care what they do toyou any more than you care what distress you cause when you slaughter them by the millionswith a soapy shower or a swipe of deodorant. The only time your tinuing well-being is ofsequeo a pathogen is when it kills you too well. If they eliminate you before they move on, then they may well die out themselves. This in faetimes happens. History,Jared Diamond notes, is full of diseases that “once caused terrifying epidemid thendisappeared as mysteriously as they had e.” He cites the robust but mercifully traEnglish sweating siess, which raged from 1485 to 1552, killing tens of thousands as itwent, before burning itself out. Too much efficy is not a good thing for any iianism.
A great deal of siess arises not because of what the anism has doo you but whatyour body is trying to do to the anism. In its quest to rid the body of pathogens, theimmune system sometimes destroys cells or damages critical tissues, so often when you areunwell what you are feeling is not the pathogens but your own immune responses. Anyway,getting sick is a sensible respoo iion. Sick people retire to their beds and thus areless of a threat to the wider unity. Resting also frees more of the body’s resources toattend to the iion.
Because there are so many things out there with the potential to hurt you, your body holdslots of different varieties of defensive white cells—some ten million types in all, eachdesigo identify aroy a particular sort of invader. It would be impossibly ineffitto maintain ten million separate standing armies, so each variety of white cell keeps only afew scouts on active duty. When an iious agent—what’s known as an antigen—invades,relevant scouts identify the attacker and put out a call for reinforts of the right type.
While your body is manufacturing these forces, you are likely to feel wretched. The o ofrecovery begins wheroops finally swing into a.
White cells are merciless and will hunt down and kill every last pathogen they find. Toavoid extin, attackers have evolved two elemental strategies. Either they strike quicklyand move on to a new host, as with on iious illnesses like flu, or they disguisethemselves so that the white cells fail to spot them, as with HIV, the virus responsible forAIDS, which sit harmlessly and unnoticed in the nuclei of cells for years before springinginto a.
One of the odder aspects of iion is that microbes that normally do no harm at allsometimes get into the wrong parts of the body and “go kind of crazy,” in the words of Dr.
Bryan Marsh, an iious diseases specialist at Dartmouth–Hitedical ter inLebanon, Nehire. “It happens all the time with car acts when people sufferinternal injuries. Microbes that are normally benign i get into other parts of thebody—the bloodstream, for instand cause terrible havoc.”
The scariest, most out-of-trol bacterial disorder of the moment is a disease calledizing fasciitis in which bacteria essentially eat the victim from the i, devinternal tissue and leaving behind a pulpy, noxious residue. Patients often e in withparatively mild plaints—a skin rash and fever typically—but then dramaticallydeteriorate. When they are opened up it is often found that they are simply being ed.
The only treatment is what is known as “radical excisional surgery”—cutting out every bit ofied area. Seventy pert of victims die; many of the rest are left terribly disfigured. Thesource of the iion is a mundane family of bacteria called Group A Streptococcus, whially do no more than cause strep throat. Very occasionally, for reasons unknown, someof these bacteria get through the lining of the throat and into the body proper, where theywreak the most devastating havoc. They are pletely resistant to antibiotics. About athousand cases a year occur in the Uates, and no one say that it won’t get worse.
Precisely the same thing happens with meningitis. At least 10 pert of young adults, andperhaps 30 pert of teenagers, carry the deadly meningococcal bacterium, but it lives quiteharmlessly ihroat. Just occasionally—in about one young person in a huhousand—it gets into the bloodstream and makes them very ill indeed. In the worst cases,death e in twelve hours. That’s shogly quick. “You have a person who’s inperfect health at breakfast and dead by evening,” says Marsh.
We would have much more success with bacteria if we weren’t so profligate with our beston against them: antibiotics. Remarkably, by oimate some 70 pert of theantibiotics used in the developed world are given to farm animals, often routinely in stockfeed, simply to promote growth or as a precaution against iion. Such applications givebacteria every opportunity to evolve a resistao them. It is an opportunity that they haveenthusiastically seized.
In 1952, penicillin was fully effective against all strains of staphylococcus bacteria, to su extent that by the early 1960s the U.S. surgeon general, William Stewart, felt fidentenough to declare: “The time has e to close the book on iious diseases. We havebasically wiped out iion in the Uates.” Even as he spoke, however, some 90pert of those strains were in the process of developing immunity to penicillin. Soohese rains, called Methicilliant Staphylococcus Aureus, began to show up inhospitals. Only oype of antibiotic, vany, remained effective against it, but in 1997a hospital in Tokyo reported the appearance of a strain that could resist even that. Withinmonths it had spread to six other Japanese hospitals. All over, the microbes are beginning towin the war again: in U.S. hospitals alone, some fourteen thousand people a year die fromiions they pick up there. As James Surowiecki has noted, given a choice betweendeveloping antibiotics that people will take every day for two weeks or antidepressants thatpeople will take every day forever, drug panies not surprisingly opt for the latter.
Although a few antibiotics have been toughened up a bit, the pharmaceutical industry hasn’tgiven us airely new antibiotice the 1970s.
Our carelessness is all the more alarming sihe discovery that many other ailments maybe bacterial in in. The process of discovery began in 1983 when Barry Marshall, a doctorih, Western Australia, found that many stomach cers and most stomach ulcers arecaused by a bacterium called Helicobacter pylori. Even though his findings were easily tested,the notion was so radical that more than a decade would pass before they were generallyaccepted. America’s National Institutes of Health, for instance, didn’t officially endorse theidea until 1994. “Hundreds, even thousands of people must have died from ulcers whowouldn’t have,” Marshall told a reporter from Forbes in 1999.
Sihen further research has shown that there is or may well be a bacterial po inall kinds of other disorders—heart disease, asthma, arthritis, multiple sclerosis, several typesof mental disorders, many cers, even, it has been suggested (inSo less), obesity.
The day may not be far off when we desperately require an effective antibiotid haven’tgot oo call on.
It may e as a slight fort to know that bacteria themselves get sick. They aresometimes ied by bacteriophages (or simply phages), a type of virus. A virus is a strangeand unlovely entity—“a piece of nucleic acid surrounded by bad news” in the memorablephrase of the Nobel laureate Peter Medawar. Smaller and simpler than bacteria, viruses aren’tthemselves alive. In isolation they are i and harmless. But introduce them into a suitablehost and they burst into busyness—into life. About five thousand types of virus are known,aweehey afflict us with many hundreds of diseases, ranging from the flu andon cold to those that are most invidious to human well-being: smallpox, rabies, yellowfever, ebola, polio, and the human immunodeficy virus, the source of AIDS.
Viruses prosper by hijag the geic material of a living cell and using it to producemore virus. They reprodu a fanatical mahen burst out in searore cells toinvade. Not being living anisms themselves, they afford to be very simple. Many,including HIV, have ten genes or fewer, whereas even the simplest bacteria require severalthousand. They are also very tiny, muall to be seen with a ventional microscope.
It wasn’t until 1943 and the iion of the eleicroscope that sce got its first lookat them. But they do immense damage. Smallpox iweh tury alone killed aimated 300 million people.
They also have an unnerving capacity to burst upon the world in some new and startlingform and then to vanish again as quickly as they came. In 1916, in one such case, people inEurope and America began to e down with a strange sleeping siess, which becameknown as encephalitis lethargica. Victims would go to sleep and not wake up. They could beroused without great difficulty to take foo to the lavatory, and would answer questionssensibly—they knew who and where they were—though their manner was always apathetic.
However, the moment they were permitted to rest, they would sink at once batodeepest slumber and remain in that state for as long as they were left. Some went on in thismanner for months before dying. A very few survived and regained sciousness but nottheir former liveliness. They existed in a state of profound apathy, “like extinct voloes,” inthe words of one doctor. In ten years the disease killed some five million people and thely went away. It didn’t get much lasting attention because in the meantime an even worseepidemideed, the worst in history—swept across the world.
It is sometimes called the Great Swine Flu epidemid sometimes the Great Spanish Fluepidemic, but iher case it was ferocious. World War I killed twenty-one million people infour years; swine flu did the same in its first four months. Almost 80 pert of Americasualties in the First World War came not from enemy fire, but from flu. In some units themortality rate was as high as 80 pert.
Swine flu arose as a normal, hal flu in the spring of 1918, but somehow over thefollowing months—no one knows how or where—it mutated into something more severe. Afifth of victims suffered only mild symptoms, but the rest became gravely ill and often died.
Some succumbed within hours; others held on for a few days.
In the Uates, the first deaths were recorded among sailors in Boston in late August1918, but the epidemic quickly spread to all parts of the try. Schools closed, publitertais were shut down, people everywhere wore masks. It did little good. Betweeumn of 1918 and spring of the following year, 548,452 people died of the flu inAmerica. The toll in Britain was 220,000, with similar numbers dead in Frand Germany.
No one knows the global toll, as records ihird World were often poor, but it was han 20 million and probably more like 50 million. Some estimates have put the globaltotal as high as 100 million.
In an attempt to devise a vae, medical authorities ducted tests on volunteers at amilitary prison on Deer Island in Boston Harbor. The prisoners were promised pardons if theysurvived a battery of tests. These tests were rigorous to say the least. First the subjects wereied with ied lung tissue taken from the dead and then sprayed in the eyes, nose, andmouth with iious aerosols. If they still failed to succumb, they had their throats swabbedwith discharges taken from the sid dying. If all else failed, they were required to sitopen-mouthed while a gravely ill victim was helped to cough into their faces.
Out of—somewhat amazingly—three hundred men who volunteered, the doctors chosesixty-two for the tests. None tracted the flu—not ohe only person who did grow illwas the ward doctor, who swiftly died. The probable explanation for this is that the epidemichad passed through the prison a few weeks earlier and the volunteers, all of whom hadsurvived that visitation, had a natural immunity.
Much about the 1918 flu is uood poorly or not at all. One mystery is how it eruptedsuddenly, all over, in places separated by os, mountain ranges, and other earthlyimpediments. A virus survive for no more than a few hours outside a host body, so howcould it appear in Madrid, Bombay, and Philadelphia all in the same week?
The probable answer is that it was incubated and spread by people who had only slightsymptoms or all. Even in normal outbreaks, about 10 pert of people have the flubut are unaware of it because they experieno ill effects. And because they remain incirculatioend to be the great spreaders of the disease.
That would at for the 1918 outbreak’s widespread distribution, but it still doesn’texplain how it mao lay low for several months before erupting so explosively at moreor less the same time all over. Even more mysterious is that it rimarily devastating topeople in the prime of life. Flu normally is hardest on infants and the elderly, but in the 1918outbreak deaths were overwhelmingly among people iwenties and thirties. Olderpeople may have beed from resistance gained from an earlier exposure to the same strain,but why the very young were similarly spared is unknown. The greatest mystery of all is whythe 1918 flu was so ferociously deadly when most flus are not. We still have no idea.
From time to time certain strains of virus return. A disagreeable Russian virus known asH1N1 caused severe outbreaks over wide areas in 1933, then again in the 1950s, a againin the 1970s. Where it went in the meantime each time is uain. One suggestion is thatviruses hide out unnoticed in populations of wild animals before trying their hand at a newgeion of humans. No one rule out the possibility that the Great Swine Flu epidemicmight once again rear its head.
And if it doesn’t, others well might. New and frightening viruses crop up all the time.
Ebola, Lassa, and Marburg fevers all have teo flare up and die down again, but no one say that they aren’t quietly mutating away somewhere, or simply awaiting the rightopportunity to burst forth in a catastrophiner. It is noarent that AIDS has beenamong us much lohan anyone inally suspected. Researchers at the MaerRoyal Infirmary in England discovered that a sailor who had died of mysterious, uablecauses in 1959 in fact had AIDS. But for whatever reasons the disease remained generallyquiest for awenty years.
The miracle is that other such diseases haven’t gone rampant. Lassa fever, which wasn’tfirst detected until 1969, i Africa, is extremely virulent and little uood. In 1969, adoctor at a Yale Uy lab in New Haven, ecticut, who was studying Lassa fevercame down with it. He survived, but, more alarmingly, a tei in a nearby lab, with nodirect exposure, also tracted the disease and died.
Happily the outbreak stopped there, but we ’t t on such good fortune always. Ourlifestyles invite epidemics. Air travel makes it possible to spread iious agents across thepla with amazing ease. An ebola virus could begin the day in, say, Benin, and finish it inNew York or Hamburg or Nairobi, or all three. It means also that medical authoritiesincreasingly o be acquainted with pretty much every malady that exists everywhere, butof course they are not. In 1990, a Nigerian living in Chicago was exposed to Lassa fever on avisit to his homeland, but didn’t develop symptoms until he had returo the Uates.
He died in a Chicago hospital without diagnosis and without aaking any specialprecautions iing him, unaware that he had one of the most lethal and iious diseaseson the pla. Miraculously, no one else was ied. We may not be so luext time.
And on that s ’s time to return to the world of the visibly living.
21 LIFE GOES ON
IT ISN’T EASY to bee a fossil. The fate of nearly all living anisms—over 99.9pert of them—is to post down to nothingness. When your spark is gone, everymolecule you own will be nibbled off you or sluiced away to be put to use in some othersystem. That’s just the way it is. Even if you make it into the small pool anisms, the lessthan 0.1 pert, that don’t get devoured, the ces of being fossilized are very small.
In order to bee a fossil, several things must happen. First, you must die in the rightplace. Only about 15 pert of rocks preserve fossils, so it’s no good keeling over on afuture site of granite. In practical terms the deceased must bee buried in sediment, whereit leave an impression, like a leaf i mud, or depose without exposure to oxygeting the molecules in its bones and hard parts (and very occasionally softer parts) to bereplaced by dissolved minerals, creating a petrified copy of the inal. Then as thesediments in which the fossil lies are carelessly pressed and folded and pushed about byEarth’s processes, the fossil must somehow maintain aifiable shape. Finally, but aboveall, after tens of millions or perhaps hundreds of millions of years hidden away, it must befound and reized as something worth keeping.
Only about one bone in a billion, it is thought, ever bees fossilized. If that is so, itmeans that the plete fossil legacy of all the Ameris alive today—that’s 270 millionpeople with 206 bones each—will only be about fifty bones, one quarter of a pleteskeleton. That’s not to say of course that any of these bones will actually be found. Bearing inmind that they be buried anywhere within an area of slightly over 3.6 million squaremiles, little of which will ever be turned over, much less examined, it would be something ofa miracle if they were. Fossils are in every sense vanishingly rare. Most of what has lived oh has left behind no record at all. It has beeimated that less than one species ihousand has made it into the fossil record. That in itself is a stunningly infinitesimalproportion. However, if you accept the oimate that the Earth has produced 30billion species of creature in its time and Richard Leakey and Roger Lewin’s statement (inThe Sixth Extin ) that there are 250,000 species of creature in the fossil record, thatreduces the proportion to just one in 120,000. Either way, what we possess is the merestsampling of all the life that Earth has spawned.
Moreover, the record we do have is hopelessly skewed. Most land animals, of course, don’tdie in sediments. They drop in the open and are eaten or left to rot or weather down tonothing. The fossil record sequently is almost absurdly biased in favor of marine creatures.
About 95 pert of all the fossils we possess are of animals that once lived under water,mostly in shallow seas.
I mention all this to explain why on a gray day in February I went to the Natural HistoryMuseum in London to meet a cheerful, vaguely rumpled, very likeable paleontologist namedRichard Fortey.
Fortey knows an awful lot about an awful lot. He is the author of a wry, splendid bookcalled Life: An Unauthorised Biography, which covers the whole pageant of animate creation.
But his first love is a type of marine creature called trilobites that oeemed in Ordoviseas but haveed for a long time except in fossilized form. All shared a basic body planof three parts, or lobes—head, tail, thorax—from whies the name. Fortey found hisfirst when he was a boy clambering over rocks at St. David’s Bay in Wales. He was hookedfor life.
He took me to a gallery of tall metal cupboards. Each cupboard was filled with shallowdrawers, and each drawer was filled with stony trilobites—twenty thousand spes in all.
“It seems like a big number,” he agreed, “but you have to remember that millions uponmillions of trilobites lived for millions upon millions of years in a seas, so twentythousand isn’t a huge number. And most of these are only partial spes. Finding aplete trilobite fossil is still a big moment for a paleontologist.”
Trilobites first appeared—fully formed, seemingly from nowhere—about 540 million yearsago, he start of the great outburst of plex life popularly known as the Cambrianexplosion, and then vanished, along with a great deal else, in the great and still mysteriousPermiain 300,000 or so turies later. As with all extinct creatures, there is anatural temptation tard them as failures, but in fact they were among the most successfulanimals ever to live. Their reign ran for 300 million years—twice the span of dinosaurs,which were themselves one of history’s great survivors. Humans, Fortey points out, havesurvived so far for one-half of 1 pert as long.
With so much time at their disposal, the trilobites proliferated prodigiously. Most remainedsmall, about the size of moderles, but some grew to be as big as platters. Altogetherthey formed at least five thousand genera and sixty thousand species—though more turn upall the time. Fortey had retly been at a feren South America where he roached by an academi a small provincial uy in Argentina. “She had a boxthat was full of iing things—trilobites that had never been seen before in SouthAmerica, or indeed anywhere, and a great deal else. She had no research facilities to studythem and no funds to look for more. Huge parts of the world are still unexplored.”
“In terms of trilobites?”
“No, in terms of everything.”
Throughout the eenth tury, trilobites were almost the only known forms of earlyplex life, and for that reason were assiduously collected and studied. The big mysteryabout them was their sudden appearance. Even now, as Fortey says, it be startling to go tothe right formation of rocks and to work your ward through the eons finding no visiblelife at all, and then suddenly “a whole Profallotaspis or Elenellus as big as a crab will popinto your waiting hands.” These were creatures with limbs, gills, nervous systems, probingantennae, “a brain of sorts,” in Fortey’s words, and the stra eyes ever seen. Made ofcalcite rods, the same stuff that forms limestohey stituted the earliest visual systemsknown. More than this, the earliest trilobites didn’t sist of just ouresome speciesbut dozens, and didn’t appear in one or two locations but all over. Many thinking people inthe eenth tury saw this as proof of God’s handiwork aation of Darwin’sevolutionary ideals. If evolution proceeded slowly, they asked, then how did he at forthis sudden appearance of plex, fully formed creatures? The fact is, he couldn’t.
And so matters seemed destio remain forever until one day in 1909, three months shyof the fiftieth anniversary of the publication of Darwin’s On the in of Species , when apaleontologist named Charles Doolittle Walade araordinary find in the adianRockies.
Walcott was born in 1850 and grew up near Utiew York, in a family of modest means,which became more modest still with the suddeh of his father when Walcott was aninfant. As a boy Walcott discovered that he had a knack for finding fossils, particularlytrilobites, and built up a colle of suffit distin that it was bought by LouisAgassiz for his museum at Harvard for a small fortune—about $70,000 in today’s money.
Although he had barely a high school education and was self taught in the sces, Walcottbecame a leading authority on trilobites and was the first person to establish that trilobiteswere arthropods, the group that includes modern is and crustas.
In 1879 he took a job as a field researcher with the newly formed Uates GeologicalSurvey and served with such distin that within fifteen years he had risen to be its head. In1907 he ointed secretary of the Smithsonian Institution, where he remained until hisdeath in 1927. Despite his administrative obligations, he tio do fieldwork and towrite prolifically. “His books fill a library shelf,” acc to Fortey. Not ially, hewas also a founding director of the National Advisory ittee for Aeronautics, whicheventually became the National Aeronautid Space Agency, or NASA, and thus rightly be sidered the grandfather of the space age.
But what he is remembered for now is an astute but lucky find in British bia, highabove the little town of Field, ie summer of 1909. The ary version of the storyis that Walcott, apanied by his wife, was riding on horseba a mountain trail behe spot called the Burgess Ridge when his wife’s horse slipped on loose stones. Dismountingto assist her, Walcott discovered that the horse had turned a slab of shale that tained fossilcrustas of an especially a and unusual type. Snow was falling—winter es earlyto the adian Rockies—so they didn’t linger, but the year at the first opportunityWalcott returo the spot. Trag the presumed route of the rocks’ slide, he climbed 750feet to he mountain’s summit. There, 8,000 feet above sea level, he found a shaleoutcrop, about the length of a city block, taining an unrivaled array of fossils from soohe moment when plex life burst forth in dazzling profusion—the famous Cambrianexplosion. Walcott had found, in effect, the holy grail of paleontology. The outcrop becameknown as the Burgess Shale, and for a long time it provided “our sole vista upon the iionof modern life in all its fullness,” as the late Stephen Jay Gould recorded in his popular bookWonderful Life .
Gould, ever scrupulous, discovered from reading Walcott’s diaries that the story of theBurgess Shale’s discovery appears to have been somewhat embroidered—Walakes ion of a slipping horse or falling snow—but there is no disputing that it was araordinary find.
It is almost impossible for us whose time oh is limited to a breezy few decades toappreciate how remote in time from us the Cambrian outburst was. If you could fly backwardsinto the past at the rate of one year per sed, it would take you about half an hour to reachthe time of Christ, and a little over three weeks to get back to the beginnings of human life.
But it would take you twenty years to reach the dawn of the Cambrian period. It was, in otherwords, aremely long time ago, and the world was a very different place.
For ohing, 500-million-plus years ago when the Burgess Shale was formed it wasn’t atthe top of a mountain but at the foot of one. Specifically it was a shallow o basin at thebottom of a steep cliff. The seas of that time teemed with life, but normally the animals left norecord because they were soft-bodied and decayed upon dying. But at Burgess the cliffcollapsed, and the creatures below, entombed in a mudslide, were pressed like flowers in abook, their features preserved in wondrous detail.
In annual summer trips from 1910 to 1925 (by which time he was seventy-five years old),Walcott excavated tens of thousands of spes (Gould says 80,000; the normallyunimpeachable fact checkers of National Geraphic say 60,000), which he brought back toWashington for further study. In both sheer numbers and diversity the colle aralleled. Some of the Burgess fossils had shells; many others did not. Some were sighted,others blind. The variety was enormous, sisting of 140 species by one t. “The BurgessShale included a range of disparity in anatomical designs never again equaled, and notmatched today by all the creatures in the world’s os,” Gould wrote.
Unfortunately, acc to Gould, Walcott failed to dis the significe of what hehad found. “Snatg defeat from the jaws of victory,” Gould wrote in another work, EightLittle Piggies, “Walcott then proceeded to misinterpret these magnifit fossils in the deepestpossible way.” He placed them into mroups, making them aral to today’s worms,jellyfish, and other creatures, and thus failed to appreciate their distiness. “Under suinterpretation,” Gould sighed, “life began in primordial simplicity and moved inexorably,predictably onward to more aer.”
Walcott died in 1927 and the Burgess fossils were largely fotten. For nearly half atury they stayed shut away in drawers in the Ameri Museum of Natural History inWashington, seldom sulted and never questiohen in 1973 a graduate student fromCambridge Uy named Simon way Morris paid a visit to the colle. He wasastonished by what he found. The fossils were far more varied and magnifit than Walcotthad indicated in his writings. In taxonomy the category that describes the basic body plans ofall anisms is the phylum, and here, way Morris cluded, were drawer after drawer ofsuatomical singularities—all amazingly and unatably unreized by the manwho had found them.
With his supervisor, Harry Whittington, and fellow graduate student Derek Briggs, wayMorris spent the several years making a systematic revision of the entire colle, andking out oing monograph after another as discovery piled upon discovery. Manyof the creatures employed body plans that were not simply unlike anything seen before orsince, but were bizarrely different. One, Opabinia, had five eyes and a nozzle-like snout withclaws on the end. Another, a disc-shaped being called Peytoia, looked almost ically like apineapple slice. A third had evidently tottered about on rows of stilt-like legs, and was so oddthat they Halluia. There was so mureized y in the collethat at one point upon opening a new drawer way Morris famously was heard to mutter,“Oh fuot another phylum.”
The English team’s revisions showed that the Cambrian had been a time of unparalleledinnovation and experimentation in body designs. For almost four billion years life haddawdled along without aable ambitions in the dire of plexity, and thensuddenly, in the space of just five or ten million years, it had created all the basic bodydesigns still ioday. Name a creature, from a ode worm to Cameron Diaz, and theyall use architecture first created in the Cambrian party.
What was most surprising, however, was that there were so many body designs that hadfailed to make the cut, so to speak, a no desdants. Altogether, acc to Gould, atleast fifteen and perhaps as many as twenty of the Burgess animals beloo nnizedphylum. (The number soon grew in some popular ats to as many as one hundred—farmore than the Cambridge stists ever actually claimed.) “The history of life,” wrote Gould,“is a story of massive removal followed by differentiation within a few surviving stocks, notthe ventional tale of steadily increasing excellence, plexity, and diversity.”
Evolutionary success, it appeared, was a lottery.
One creature thatdid mao slip through, a small wormlike being called Pikaiagras, was found to have a primitive spinal n, making it the earliest known aorof all later vertebrates, including us.Pikaia were by no means abundant among the Burgessfossils, so goodness knows how close they may have e to extin. Gould, in a famousquotation, leaves no doubt that he sees our lineal success as a fortunate fluke: “Wind back thetape of life to the early days of the Burgess Shale; let it play again from aical startingpoint, and the ce bees vanishingly small that anything like human intelligence wouldgrace the replay.”
Gould’s book ublished in 1989 to general critical acclaim and was a great ercialsuccess. What wasn’t generally known was that many stists didn’t agree with Gould’sclusions at all, and that it was all soon to get very ugly. In the text of the Cambrian,“explosion” would soon have more to do with modern tempers than a physiologicalfacts.
In fact, we now know, plex anisms existed at least a hundred million years beforethe Cambrian. We should have known a whole lot sooner. Nearly forty years after Walade his discovery in ada, oher side of the pla in Australia, a young geologistnamed Reginald Sprigg found something even older and in its way just as remarkable.
In 1946 Sprigg was a young assistant gover geologist for the state of South Australiawhen he was sent to make a survey of abandoned mines in the Edia Hills of the FlindersRange, an expanse of baking outbae three hundred miles north of Adelaide. The ideawas to see if there were any old mihat might be profitably reworked usieologies, so he wasn’t studying surface rocks at all, still less fossils. But one day whileeating his lunch, Sprigg idly overturned a hunk of sandstone and was surprised—to put itmildly—to see that the rock’s surface was covered in delicate fossils, rather like theimpressions leaves make in mud. These rocks predated the Cambrian explosion. He waslooking at the dawn of visible life.
Sprigg submitted a paper to Nature , but it was turned down. He read it instead at the annual meeting of the Australian and New Zealand Association for the Adva ofSce, but it failed to find favor with the association’s head, who said the Ediaimprints were merely “fortuitous inanic marking.９９lｉｂ.s”—patterns made by wind or rain ortides, but not living beings. His hopes not yet entirely crushed, Sprigg traveled to London aed his findings to the 1948 Iional Geological gress, but failed to exciteeither i or belief. Finally, for want of a better outlet, he published his findings iransas of the Royal Society of South Australia. Then he quit his gover job andtook up oil exploration.
Nine years later, in 1957, a schoolboy named John Mason, while walking throughwood Forest in the English Midlands, found a rock with a strange fossil in it, similar toa modern sea pen aly like some of the spes Sprigg had found arying totell everyone about ever sihe schoolboy tur in to a paleontologist at the Uyof Leicester, who identified it at once as Precambrian. Young Mason got his picture in thepapers and was treated as a precocious hero; he still is in many books. The spe wasnamed in his honor Chamia masoni.
Today some of Sprigg’s inal Edia spes, along with many of the other fifteenhundred spes that have been found throughout the Flinders Range sihat time, be seen in a glass case in an upstairs room of the stout and lovely South Australian Museumin Adelaide, but they don’t attract a great deal of attention. The delicately etched patterns arerather faint and not terribly arresting to the untrained eye. They are mostly small and disc-shaped, with occasional, vague trailing ribbons. Fortey has described them as “soft-bodiedoddities.”
There is still very little agreement about what these things were or how they lived. Theyhad, as far as be told, no mouth or anus with which to take in and discharge digestivematerials, and no internal ans with which to process them along the way. “In life,” Forteysays, “most of them probably simply lay upon the surface of the sandy sediment, like soft,structureless and inanimate flatfish.” At their liveliest, they were no more plex thanjellyfish. All the Edia creatures were diploblastic, meaning they were built from twolayers of tissue. With the exception of jellyfish, all animals today are triploblastic.
Some experts think they weren’t animals at all, but more like plants or fungi. Thedistins between plant and animal are not always clear even now. The modern spongespends its life fixed to a single spot and has no eyes or brain or beati, a is ananimal. “When we go back to the Precambrian the differences between plants and animalswere probably even less clear,” says Fortey. “There isn’t any rule that says you have to bedemonstrably one or the other.”
Nor is it agreed that the Edia anisms are in any way aral to anything alivetoday (except possibly some jellyfish). Many authorities see them as a kind of failedexperiment, a stab at plexity that didn’t take, possibly because the sluggish Ediaanisms were devoured or outpeted by the lither and more sophisticated animals of theCambrian period.
“There is nothing closely similar alive today,” Fortey has written. “They are difficult tointerpret as any kind of aors of what was to follow.”
The feeling was that ultimately they weren’t terribly important to the development of lifeoh. Many authorities believe that there was a mass extermination at the Precambrian–Cambrian boundary and that all the Edia creatures (except the uain jellyfish) failedto move on to the phase. The real business of plex life, in other words, started withthe Cambrian explosion. That’s how Gould saw it in any case.
As for the revisions of the Burgess Shale fossils, almost at once people began to questioerpretations and, in particular, Gould’s interpretation of the interpretations. “From thefirst there were a number of stists who doubted the at that Steve Gould hadpresented, however much they admired the manner of its delivery,” Fortey wrote in Life. Thatis putting it mildly.
“If only Stephen Gould could think as clearly as he writes!” barked the Oxford academicRichard Dawkins in the opening line of a review (in the London Sunday Telegraph) ofWonderful Life. Dawkins aowledged that the book was “unputdownable” and a “literarytour-de-force,” but accused Gould of engaging in a “grandiloquent and near-disingenuous”
misrepresentation of the facts by suggesting that the Burgess revisions had stuhepaleontological unity. “The view that he is attag—that evolution marchesinexorably toward a pinnacle such as man—has not been believed for 50 years,” Dawkinsfumed.
Ahat was exactly the clusion to which many general reviewers were drawn.
One, writing in the New York Times Book Review, cheerfully suggested that as a result ofGould’s book stists “have been throwing out some preceptions that they had notexamined feions. They are, relutly or enthusiastically, accepting the idea thathumans are as mu act of nature as a product of orderly development.”
But the real heat directed at Gould arose from the belief that many of his clusions weresimply mistaken or carelessly inflated. Writing in the journal Evolution, Dawkins attackedGould’s assertions that “evolution in the Cambrian was a different kind of process fromtoday” and expressed exasperation at Gould’s repeated suggestions that “the Cambrian eriod of evolutionary ‘experiment,’ evolutionary ‘trial and error,’ evolutionary ‘false starts.’ .
. . It was the fertile time when all the great ‘fual body plans’ were ied.
Nowadays, evolution just tinkers with old body plans. Ba the Cambrian, new phyla andnew classes arose. Nowadays we only get new species!”
Noting how often this idea—that there are no new body plans—is picked up, Dawkins says:
“It is as though a gardener looked at an oak tree and remarked, wly: ‘Isn’t it stra no major new boughs have appeared on this tree for many years? These days, all the newgroears to be at the twig level.’ ”
“It was a straime,” Fortey says now, “especially when you reflected that this was allabout something that happened five hundred million years ago, but feelings really did runquite high. I joked in one of my books that I felt as if I ought to put a safety helmet on beforewriting about the Cambrian period, but it did actually feel a bit like that.”
Stra of all was the response of one of the heroes of Wonderful Life, Simon wayMorris, who startled many in the paleontological unity by rounding abruptly on Gouldin a book of his own, The Crucible of Creation. The book treated Gould “with pt, evenloathing,” in Fortey’s words. “I have never entered such spleen in a book by aprofessional,” Fortey wrote later. “The casual reader of The Crucible of Creation, unaware ofthe history, would never gather that the author’s views had once been close to (if not actuallyshared with) Gould’s.”
When I asked Fortey about it, he said: “Well, it was very strange, quite shog really,because Gould’s portrayal of him had been so flattering. I could only assume that Simon wasembarrassed. You know, sce ges but books are perma, and I suppose he regrettedbeing so irremediably associated with views that he no longer altogether held. There was allthat stuff about ‘oh fuck, another phylum’ and I expect he regretted being famous for that.”
What happened was that the early Cambrian fossils began to undergo a period of criticalreappraisal. Fortey and Derek Briggs—one of the other principals in Gould’s book—used amethod known as cladistipare the various Burgess fossils. In simple terms, cladistisists anizing anisms on the basis of shared features. Fortey gives as an examplethe idea of paring a shrew and an elephant. If you sidered the elephant’s large size andstriking trunk you might clude that it could have little in on with a tiny, sniffingshrew. But if you pared both of them with a lizard, you would see that the elephant andshrew were in fact built to much the same plan. In essence, what Fortey is saying is thatGould saw elephants and shrews where they saw mammals. The Burgess creatures, theybelieved, weren’t as strange and various as they appeared at first sight. “They were often ner than trilobites,” Fortey says now. “It is just that we have had a tury or so to getused to trilobites. Familiarity, you know, breeds familiarity.”
This wasn’t, I should note, because of sloppiness or iion. Interpreting the forms aionships of a animals on the basis of often distorted and fragmentary evidence isclearly a tricky business. Edward O. Wilson has hat if you took selected species ofmodern is and presehem as Burgess-style fossils nobody would ever guess that theywere all from the same phylum, so different are their body plans. Also instrumental in helpingrevisiohe discoveries of two further early Cambrian sites, one in Greenland and onein a, plus more scattered finds, which between them yielded many additional and ofteer spes.
The upshot is that the Burgess fossils were found to be not so different after all.
Halluia, it turned out, had been restructed upside down. Its stilt-like legs wereactually spikes along its back. Peytoia, the weird creature that looked like a pineapple slice,was found to be not a distinct creature but merely part of a larger animal called Anomalocaris.
Many of the Burgess spes have now been assigo living phyla—just where Walcottput them in the first place. Halluia and some others are thought to be related toOnychophora, a group of caterpillar-like animals. Others have been reclassified as precursorsof the modern annelids. In fact, says Fortey, “there are relatively few Cambrian designs thatare wholly novel. More ofteurn out to be just iing elaborations of well-established designs.” As he wrote in his book Life: “None was as strange as a present daybarnacle, nor as grotesque as a queee.”
So the Burgess Shale spes weren’t so spectacular after all. This made them, as Forteyhas written, “no less iing, or odd, just more explicable.” Their weird body plans werejust a kind of youthful exuberahe evolutionary equivalent, as it were, of spiked hair andtouds. Eventually the forms settled into a staid and stable middle age.
But that still left the enduring question of where all these animals had e from—howthey had suddenly appeared from out of nowhere.
Alas, it turns out the Cambrian explosion may not have been quite so explosive as all that.
The Cambrian animals, it is now thought, were probably there all along, but were just toosmall to see. Once again it was trilobites that provided the clue—in particular that seeminglymystifying appearance of different types of trilobite in widely scattered locations around theglobe, all at more or less the same time.
On the face of it, the sudden appearance of lots of fully formed but varied creatures wouldseem to enhahe miraculousness of the Cambrian outburst, but in fact it did the opposite.
It is ohing to have one well-formed creature like a trilobite burst forth in isolation—thatreally is a wonder—but to have many of them, all distinct but clearly related, turning upsimultaneously in the fossil record in places as far apart as a and New York clearlysuggests that we are missing a big part of their history. There could be ner evide they simply had to have a forebear—some grandfather species that started the line in amuch earlier past.
And the reason we haven’t found these earlier species, it is now thought, is that they weretoo tiny to be preserved. Says Fortey: “It isn’t necessary to be big to be a perfectlyfuning, plex anism. The sea swarms with tiny arthropods today that have left nofossil record.” He cites the little copepod, whiumbers irillions in modern seas andclusters in shoals large enough to turn vast areas of the o black, a our totalknowledge of its ary is a single spe found in the body of an a fossilized fish.
“The Cambrian explosion, if that’s the word for it, probably was more an increase in sizethan a sudden appearance of new body types,” Fortey says. “And it could have happened quiteswiftly, so in that sense I suppose it was an explosion.” The idea is that just as mammalsbided their time for a hundred million years until the dinosaurs cleared off and then seeminglyburst forth in profusion all over the pla, so too perhaps the arthropods and other triploblastswaited in semimicroscopiity for the dominant Edia anisms to have theirday. Says Fortey: “We know that mammals increased in size quite dramatically after thedinosaurs went—though when I say quite abruptly I of course mean it in a geological sense.
We’re still talking millions of years.”
Ially, Reginald Sprigg did eventually get a measure of overdue credit. One of themain early genera, Spriggina, was named in his honor, as were several species, and the wholebecame known as the Edia fauna after the hills through which he had searched. By thistime, however, Sprigg’s fossil-hunting days were long over. After leaving geology he foundeda successful oil pany aually retired to ae in his beloved Flinders Range,where he created a wildlife reserve. He died in 1994 a rich man.
22 GOOD-BYE TO ALL THAT
WHEN YOU SIDER it from a human perspective, and clearly it would be difficult forus to do otherwise, life is an odd thing. It couldn’t wait to get going, but then, having gottengoing, it seemed in very little hurry to move on.
sider the li. Lis are just about the hardiest visible anisms oh, butamong the least ambitious. They will groily enough in a sunny churchyard, but theyparticularly thrive in enviros where no anism would go—on blowymountaintops and arctic wastes, wherever there is little but rod rain and cold, and almostno petition. In areas of Antarctica where virtually nothing else will grow, you findvast expanses of li—four huypes of them—adheriedly to every wind-whipped rock.
For a long time, people couldn’t uand how they did it. Because lis grew on barerock without evident nourishment or the produ of seeds, many people—educatedpeople—believed they were stones caught in the process of being plants. “Spontaneously,inanic stone bees living plant!” rejoiced one observer, a Dr. Homschuch, in 1819.
Closer iion showed that lis were more iing than magical. They are in facta partnership between fungi and algae. The fungi excrete acids that dissolve the surface of therock, freeing minerals that the algae vert into food suffit to sustain both. It is not avery exg arra, but it is a spicuously successful ohe world has more thay thousand species of lis.
Like most things that thrive in harsh enviros, lis are slow-growing. It may take ali more than half a tury to attain the dimensions of a shirt button. Those the size ofdinner plates, writes David Attenbh, are therefore “likely to be hundreds if notthousands of years old.” It would be hard to imagine a less fulfilliehey simplyexist,” Attenbh adds, “testifying to the moving fact that life even at its simplest leveloccurs, apparently, just for its own sake.”
It is easy to overlook this thought that life just is. As humans we are ined to feel that lifemust have a point. lans and aspirations and desires. We want to take stantadvantage of all the intoxig existence we’ve been endowed with. But what’s life to ali? Yet its impulse to exist, to be, is every bit as strong as ours—arguably even stronger.
If I were told that I had to spend decades being a furry growth on a ro the woods, Ibelieve I would lose the will to go on. Lis don’t. Like virtually all living things, they willsuffer any hardship, endure any insult, for a moment’s additioence. Life, in short, justwants to be. But—and here’s an iing point—for the most part it doesn’t want to bemuch.
This is perhaps a little odd because life has had plenty of time to develop ambitions. If youimagihe 4,500-billion-odd years of Earth’s history pressed into a normal earthly day,then life begins very early, about 4A.M., with the rise of the first simple, single-celledanisms, but then advano further for the sixteen hours. Not until almost 8:30 inthe evening, with the day five-sixths over, has Earth anything to show the universe but arestless skin of microbes. Then, finally, the first sea plants appear, followed twenty mier by the first jellyfish and the enigmatic Edia fauna first seen by Reginald Sprigg inAustralia. At 9:04P.M. trilobites swim onto the se, followed more or less immediately bythe shapely creatures of the Burgess Shale. Just before 10P.M. plants begin to pop up on theland. Soon after, with less than two hours left in the day, the first land creatures follow.
Thanks to ten minutes or so of balmy weather, by 10:24 the Earth is covered in the greatcarboniferous forests whose residues give us all our coal, and the first winged is areevident. Dinosaurs plod onto the se just before 11P.M. and hold sway for about three-quarters of an hour. At twenty-one mio midnight they vanish and the age of mammalsbegins. Humans emerge one minute aeen seds before midnight. The whole of ourrecorded history, on this scale, would be no more than a few seds, a single human lifetimebarely an instant. Throughout this greatly speeded-up day tis slide about and bangtogether at a clip that seems positively reckless. Mountains rise a away, o basinse and go, ice sheets advand withdraw. And throughout the whole, about three timesevery minute, somewhere on the plahere is a flashbulb pop of light marking the impaanson-sized meteor or one even larger. It’s a wohat anything at all survive insuch a pummeled and uled enviro. In faot many things do for long.
Perhaps an even more effective way of grasping our extreme reess as a part of this4.5-billion-year-old picture is to stretch your arms to their fulbbr>?lest extent and imagihatwidth as the entire history of the Earth. On this scale, acc to John McPhee in Basin andRahe distance from the fiips of one hand to the wrist of the other is Precambrian.
All of plex life is in one hand, “and in a siroke with a medium-grained nail file youcould eradicate human history.”
Fortunately, that moment hasn’t happened, but the ces are good that it will. I don’twish to interject a note of gloom just at this point, but the fact is that there is oherextremely perti quality about life oh: it goes extinct. Quite regularly. For all thetrouble they take to assemble and preserve themselves, species crumple and die remarkablyroutinely. And the more plex they get, the more quickly they appear to go extinct. Whichis perhaps one reason why so much of life isn’t terribly ambitious.
So anytime life does something bold it is quite a, and few occasions were moreeventful than when life moved on to the stage in our narrative and came out of the sea.
Land was a formidable enviro: hot, dry, bathed in interaviolet radiation,lag the buoyancy that makes movement in water paratively effortless. To live onland, creatures had to undergo wholesale revisions of their anatomies. Hold a fish at eadand it sags in the middle, its bae too weak to support it. To survive out of water, mariures o e up with new load-bearing internal architecture—not the sort ofadjustment that happens ht. Above all and most obviously, any land creature wouldhave to develop a way to take its oxygen directly from the air rather than filter it from water.
These were not trivial challeo overe. Oher hand, there owerfuliive to leave the water: it was getting dangerous down there. The slow fusion of thetis into a single landmass, Pangaea, meant there was much, much less coastlihanformerly and thus much less coastal habitat. So petition was fierce. There was also anomnivorous and uliype of predator on the se, one so perfectly designed forattack that it has scarcely ged in all the long eons sis emergehe shark. Neverwould there be a more propitious time to find an alternative enviroo water.
Plants began the process of land ization about 450 million years ago, apanied ofy by tiny mites and anisms that they o break down and recycle deadanic matter on their behalf. Larger animals took a little loo emerge, but by about 400million years ago they were venturing out of the water, too. Popular illustrations haveenced us to envision the first venturesome land dwellers as a kind of ambitious fish—something like the modern mudskipper, which hop from puddle to puddle duringdroughts—or even as a fully formed amphibian. In fact, the first visible mobile residents ondry land were probably much more like modern wood lice, sometimes also knoillbugsor sow bugs. These are the little bugs (crustas, in fact) that are only thrown intofusion when you upturn a rock .
For those that learo breathe oxygen from the air, times were good. Oxygen levels inthe Devonian and Carboniferous periods, when terrestrial life first bloomed, were as high as35 pert (as opposed to nearer 20 pert now). This allowed animals to grow remarkablylarge remarkably quickly.
And how, you may reasonably wonder, stists know what oxygen levels were likehundreds of millions of years ago? The answer lies in a slightly obscure but ingenious fieldknown as isotope geochemistry. The long-ago seas of the Carboniferous and Devonianswarmed with tiny plankton that ed themselves iiny protective shells. Then, asnow, the planktoed their shells by drawing oxygen from the atmosphere and biningit with other elements (carbon especially) to form durable pounds such as calciumcarbo’s the same chemical trick that goes on in (and is discussed elsewhere iionto) the long-term carbon cycle—a process that doesn’t make for terribly exg narrative butis vital for creating a livable pla.
Eventually in this process all the tiny anisms die and drift to the bottom of the sea,where they are slowly pressed into limestone. Among the tiny atomic structures theplankton take to the grave with them are two very stable isotopes—oxygen-16 and oxygen-18.
(If you have fotten what an isotope is, it doesn’t matter, though for the record it’s an atomwith an abnormal number of rons.) This is where the geochemists e in, for theisotopes accumulate at different rates depending on how much oxygen or carbon dioxide is imosphere at the time of their creation. By paring these a ratios, thegeochemists ingly read ditions in the a world—oxygen levels, air and otemperatures, the extent and timing of ice ages, and much else. By bining their isotopefindings with other fossil residues—pollen levels and so on—stists , with siderablefidence, re-create entire landscapes that no human eye ever saw.
The principal reason oxygen levels were able to build up so robustly throughout the periodof early terrestrial life was that much of the world’s landscape was dominated by giant treeferns and vast ss, which by their boggy nature disrupted the normal carbon recygprocess. Instead of pletely rotting down, falling fronds and other dead vegetative matteraccumulated in rich, wet sediments, which were eventually squeezed into the vast coal bedsthat sustain much eic activity even now.
The heady levels of oxygen clearly enced outsized growth. The oldest indication of asurfaimal yet found is a track left 350 million years ago by a millipede-like creature on aro Scotland. It was over three feet long. Before the era was out some millipedes wouldreach lengths more than double that.
With such creatures on the prowl, it is perhaps not surprising that is in the periodevolved a trick that could keep them safely out of tongue shot: they learo fly. Some tookto this new means of lootion with suy facility that they haven’t ged theirteiques in all the time sihen, as now, dragonflies could cruise at up to thirty-fivemiles an hour, instantly stop, hover, fly backwards, and lift far more proportiohan anyhuman flying mae. “The U.S. Air Force,” one entator has written, “has put them inwind tuo see how they do it, and despaired.” They, too, ged on the rich air. InCarboniferous forests dragonflies grew as big as ravens. Trees and etation likewiseattained outsized proportions. Horsetails and tree ferns grew to heights of fifty feet, clubmosses to a hundred and thirty.
The first terrestrial vertebrates—which is to say, the first land animals from which wewould derive—are something of a mystery. This is partly because of a she of relevantfossils, but partly also because of an idiosyncratic Swede named Erik Jarvik whose oddinterpretations aive manner held back progress on this question for almost half atury. Jarvik art of a team of Sdinavian scholars who went to Greenland in the1930s and 1940s looking for fossil fish. In particular they sought lobe-finned fish of the typethat presumably were aral to us and all other walking creatures, known as tetrapods.
Most animals are tetrapods, and all livirapods have ohing in on: four limbsthat end in a maximum of five fingers or toes. Dinosaurs, whales, birds, humans, even fish—all are tetrapods, which clearly suggests they e from a single on aor. The clueto this aor, it was assumed, would be found in the Devonian era, from about 400 millionyears ago. Before that time nothing walked on land. After that time lots of things did. Luckilythe team found just such a creature, a three-foot-long animal called an Ichthyostega. Theanalysis of the fossil fell to Jarvik, who began his study in 1948 a at it for the forty-eight years. Unfortunately, Jarvik refused to let audy his tetrapod. The world’spaleontologists had to be tent with two sketchy interim papers in which Jarvik hatthe creature had five fingers in each of four limbs, firming its aral importance.
Jarvik died in 1998. After his death, other paleontologists eagerly examihe speand found that Jarvik had severely misted the fingers and toes—there were actually eighton each limb—and failed to observe that the fish could not possibly have walked. Thestructure of the fin was such that it would have collapsed us ow. Needless tosay, this did not do a great deal to advance our uanding of the first land animals. Todaythree early tetrapods are known and none has five digits. In short, we don’t know quite wherewe came from.
But e we did, though reag our present state of eminence has not of course alwaysbeen straightforward. Since life on land began, it has sisted of fadynasties, as theyare sometimes called. The first sisted of primitive, plodding but sometimes fairly heftyamphibians ailes. The best-known animal of this age was the Dimetrodon, a sail-backed creature that is only fused with dinosaurs (including, I note, in a picturecaption in the Carl Sagan book et). The Dimetrodon was in fact a synapsid. So, onceupon a time, were we. Synapsids were one of the four main divisions of early reptilian life,the others being anapsids, euryapsids, and diapsids. The names simply refer to the number andlocation of small holes to be found in the sides of their owners’ skulls. Synapsids had one holein their lower temples; diapsids had two; euryapsids had a single hole higher up.
Over time, each of these principal groupings split into further subdivisions, of whieprospered and some faltered. Anapsids gave rise to the turtles, which for a time, perhaps atouch improbably, appeared poised to predominate as the pla’s most advanced and deadlyspecies, before an evolutionary lurch let them settle for durability rather than domihesynapsids divided into four streams, only one of which survived beyond the Permian.
Happily, that was the stream we beloo, and it evolved into a family of protomammalsknown as therapsids. These formed Megadynasty 2.
Unfortunately for the therapsids, their cousins the diapsids were also productively evolving,in their case into dinosaurs (among other things), which gradually proved too much for thetherapsids. Uo pete head to head with these aggressive new creatures, thetherapsids by and large vanished from the record. A very few, however, evolved into small,furry, burrowing beings that bided their time for a very long while as little mammals. Thebiggest of them grew ner than a house cat, and most were no bigger than mice.
Eventually, this would prove their salvation, but they would have to wait nearly 150 millionyears fadynasty 3, the Age of Dinosaurs, to e to an abrupt end and make room fadynasty 4 and our own Age of Mammals.
Each of these massive transformations, as well as many smaller ones between and since,was depe on that paradoxically important motor ress: extin. It is a curiousfact that oh species death is, in the most literal sense, a way of life. No one knows howmany species anisms have existed since life began. Thirty billion is a only citedfigure, but the number has been put as high as 4,000 billion. Whatever the actual total, 99.99pert of all species that have ever lived are no longer with us. “To a first approximation,” asDavid Raup of the Uy of Chicago likes to say, “all species are extinct.” For plexanisms, the average lifespan of a species is only about four million years—roughly aboutwhere we are now.
Extin is always bad news for the victims, of course, but it appears to be a good thingfor a dynamic pla. “The alternative to extin is stagnation,” says Ian Tattersall of theAmeri Museum of Natural History, “and stagnation is seldom a good thing in any realm.”
(I should perhaps hat we are speaking here of extin as a natural, long-term process.
Extin brought about by human carelessness is another matter altogether.)Crises ih’s history are invariably associated with dramatic leaps afterward. The fall ofthe Edia fauna was followed by the creative outburst of the Cambrian period. TheOrdovi extin of 440 million years ago cleared the os of a lot of immobile filterfeeders and, somehow, created ditions that favored darting fish and giant aquatic reptiles.
These in turn were in an ideal position to send ists onto dry land when another blowoutie Devonian period gave life another sound shaking. And so it has go scatteredintervals through history. If most of these events hadn’t happened just as they did, just whenthey did, we almost certainly wouldn’t be here now.
Earth has seen five major extin episodes in its time—the Ordovi, Devonian,Permian, Triassid Cretaceous, in that order—and many smaller ohe Ordovi(440 million years ago) and Devonian (365 million) each wiped out about 80 to 85 pert ofspecies. The Triassic (210 million years ago) and Cretaceous (65 million years) each wipedout 70 to 75 pert of species. But the real whopper was the Permiain of about 245million years ago, which raised the curtain on the long age of the dinosaurs. In the Permian, atleast 95 pert of animals known from the fossil record check out, o return. Evenabout a third of i species went—the only occasion on which they were lost en masse. It isas close as we have ever e to total obliteration.
“It was, truly, a mass extin, a age of a magnitude that had roubled the Earthbefore,” says Richard Fortey. The Permia articularly devastating to sea creatures.
Trilobites vanished altogether. Clams and sea urs nearly went. Virtually all other marineanisms were staggered. Altogether, on land and ier, it is thought that Earth lost 52pert of its families—that’s the level above genus and below order on the grand scale of life(the subject of the chapter)—and perhaps as many as 96 pert of all its species. Itwould be a long time—as much as eighty million years by one reing—before speciestotals recovered.
Two points o be kept in mind. First, these are all just informed guesses. Estimates forthe number of animal species alive at the end of the Permian range from as low as 45,000 toas high as 240,000. If you don’t know how many species were alive, you hardly specifywith vi the proportion that perished. Moreover, we are talking about the death ofspecies, not individuals. For individuals the death toll could be much higher—in many cases,practically total. The species that survived to the phase of life’s lottery almost certainlyowe their existeo a few scarred and limping survivors.
Iween the big kill-offs, there have also been many smaller, less well-knowinepisodes—the Hemphillian, Frasnian, Famennian, Rancholabrean, and a dozen or so others—which were not so devastating to total species numbers, but often critically hit certainpopulations. Grazing animals, including horses, were nearly wiped out in the Hemphillia about five million years ago. Horses deed to a single species, which appears sosporadically in the fossil record as to suggest that for a time it teetered on the brink ofoblivion. Imagine a human history without horses, without grazing animals.
In nearly every case, for both big extins and more modest ones, we have bewilderinglylittle idea of what the cause was. Even after stripping out the more crackpot notions there arestill more theories for what caused the extin events than there have bees. At leasttwo dozen potential culprits have beeified as causes or prime tributlobalwarming, global cooling, ging sea levels, oxygeion of the seas (a ditionknown as anoxia), epidemics, giant leaks of methane gas from the seafloor, meteor and etimpacts, runaway hurries of a type known as hyperes, huge volic upwellings,catastrophic solar flares.
This last is a particularly intriguing possibility. Nobody knows how big solar flares getbecause we have only been watg them sihe beginning of the space age, but the Sun isa mighty engine and its storms are ensurately enormous. A typical solar flare—something we wouldn’t even noti Earth—will release the energy equivalent of a billionhydrogen bombs and fling into space a hundred billion tons or so of murderous high-energyparticles. The magosphere and atmosphere between them normally swat these batospace or steer them safely toward the poles (where they produce the Earth’s ely auroras),but it is thought that an unusually big blast, say a huimes the typical flare, couldoverwhelm our ethereal defehe light show would be a glorious one, but it would almostcertainly kill a very high proportion of all that basked in its glow. Moreover, and ratherchillingly, acc to Bruce Tsurutani of the NASA Jet Propulsion Laboratory, “it wouldleave no tra history.”
What all this leaves us with, as one researcher has put it, is “tons of jecture and verylittle evidence.” Cooling seems to be associated with at least three of the big extinevents—the Ordovi, Devonian, and Permian—but beyond that little is agreed, includiher a particular episode happened swiftly or slowly. Stists ’t agree, for instance,whether the late Devoniain—the event that was followed by vertebrates movingonto the land—happened over millions of years or thousands of years or in one lively day.
One of the reasons it is so hard to produce ving explanations for extins is that itis so very hard to exterminate life on a grand scale. As we have seen from the Manson impact,you receive a ferocious blow and still stage a full, if presumably somewhat wobbly,recovery. So why, out of all the thousands of impacts Earth has endured, was the KT event sosingularly devastating? Well, first itositively enormous. It struck with the force of 100millioons. Su outburst is not easily imagined, but as James Lawrence Powell haspointed out, if you exploded one Hiroshima-sized bomb for every person alive oh todayyou would still be about a billion bombs short of the size of the KT impact. But even thatalone may not have been enough to wipe out 70 pert of Earth’s life, dinosaurs included.
The KT meteor had the additional advantage—advantage if you are a mammal, that is—that it landed in a shallow sea just teers deep, probably at just the right a a timewhen oxygen levels were 10 pert higher than at present and so the world was morebustible. Above all the floor of the sea where it landed was made of rock ri sulfur.
The result was an impact that turned an area of seafloor the size of Belgium into aerosols ofsulfuric acid. For months afterward, the Earth was subjected to rains acid enough to burn skin.
In a sense, an eveer question than that of what wiped out 70 pert of the speciesthat were existing at the time is how did the remaining 30 pert survive? Why was the eventso irremediably devastating to every single dinosaur that existed, while other reptiles, likesnakes and crocodiles, passed through unimpeded? So far as we tell no species of toad,, salamander, or other amphibia extin North America. “Why should thesedelicate creatures have emerged unscathed from su unparalleled disaster?” asks TimFlannery in his fasating prehistory of America, Eternal Frontier.
In the seas it was much the same story. All the ammonites vanished, but their cousins thenautiloids, who lived similar lifestyles, swam on. Among plankton, some species werepractically wiped out—92 pert of foraminiferans, for instance—while anisms likediatoms, desigo a similar plan and living alongside, were paratively unscathed.
These are difficult insistencies. As Richard Fortey observes: “Somehow it does notseem satisfying just to call them ‘lucky ones’ and leave it at that.” If, as seems entirely likely,the event was followed by months of dark and choking smoke, then many of the isurvivors bee difficult to at for. “Some is, like beetles,” Fortey notes, “couldlive on wood or other things lying around. But what about those like bees that navigate bysunlight and need pollen? Explaining their survival isn’t so easy.”
Above all, there are the corals. Corals require algae to survive and algae require sunlight,and both together require steady minimum temperatures. Much publicity has been given i few years to corals dying from ges iemperature of only a degree or so. If theyare that vulnerable to small ges, how did they survive the long impact winter?
There are also many hard-to-explain regional variatioins seem to have been farless severe in the southern hemisphere than the northern. New Zealand in particular appears tohave e through largely unscathed even though it had almost no burrowing creatures. Evenits vegetation was overwhelmingly spared, ahe scale of flagration elsewheresuggests that devastation was global. In short, there is just a great deal we don’t know.
Some animals absolutely prospered—including, a little surprisingly, the turtles once again.
As Flannery he period immediately after the dinosaur extin could well be knownas the Age of Turtles. Sixteen species survived in North Amerid three more came ience soon after.
Clearly it helped to be at home in water. The KT impact wiped out almost 90 pert ofland-based species but only 10 pert of those living in fresh water. Water obviously offeredprote against heat and flame, but also presumably provided more sustenan the leanperiod that followed. All the land-based animals that survived had a habit of retreating to asafer enviro during times of danger—into water or undergrouher of whichwould have provided siderable shelter against the ravages without. Animals thatsged for a living would also have enjoyed an advantage. Lizards were, and are, largelyimpervious to the bacteria in rotting carcasses. Indeed, often they are positively drawn to it,and for a long while there were clearly a lot of putrid carcasses about.
It is often wrongly stated that only small animals survived the KT event. In fact, among thesurvivors were crocodiles, which were not just large but three times larger than they are today.
But on the whole, it is true, most of the survivors were small and furtive. Indeed, with theworld dark and hostile, it erfect time to be small, warm-blooded, noal, flexible i, and cautious by nature—the very qualities that distinguished our mammalian forebears.
Had our evolution been more advanced, we would probably have been wiped out. Instead,mammals found themselves in a world to which they were as well suited as anything alive.
However, it wasn’t as if mammals swarmed forward to fill every niche. “Evolution mayabhor a vacuum,” wrote the paleobiologist Steven M. Stanley, “but it often takes a long timeto fill it.” For perhaps as many as ten million years mammals remained cautiously small. Inthe early Tertiary, if you were the size of a bobcat you could be king.
But ohey got going, mammals expanded prodigiously—sometimes to an almostpreposterous degree. For a time, there were guinea pigs the size of rhinos and rhinos the sizeof a two-story house. Wherever there was a va the predatory , mammals rose(often literally) to fill it. Early members of the ra family migrated to South America,discovered a vacy, and evolved into creatures the size and ferocity of bears. Birds, too,prospered disproportionately. For millions of years, a gigantic, flightless, ivorous birdcalled Titanis ossibly the most fero>ous creature in North America. Certainly it was themost daunting bird that ever lived. It stood te high, weighed ht hundred pounds,and had a beak that could tear the head off pretty muything that irked it. Its familysurvived in formidable fashion for fifty million years, yet until a skeleton was discovered inFlorida in 1963, we had no idea that it had ever existed.
Which brings us to another reason for our uainty about extins: the paltriness ofthe fossil record. We have touched already on the unlikelihood of a of bones beingfossilized, but the record is actually worse than you might think. sider dinosaurs.
Museums give the impression that we have a global abundance of dinosaur fossils. In fact,overwhelmingly museum displays are artificial. The giant Diplodocus that domiheentrance hall of the Natural History Museum in London and has delighted and infeions of visitors is made of plaster—built in 1903 in Pittsburgh and preseo themuseum by Andrew egie. The entrance hall of the Ameri Museum of Natural Historyin New York is dominated by an even graableau: a skeleton of a large Barosaurusdefending her baby from attack by a darting and toothy Allosaurus. It is a wonderfullyimpressive display—the Barosaurus rises perhaps thirty feet toward the high ceiling—but alsoentirely fake. Every one of the several hundred bones in the display is a cast. Visit almost anylarge natural history museum in the world—in Paris, Vienna, Frankfurt, Buenos Aires,Mexico City—and what will greet you are antique models, not a bones.
The fact is, we don’t really know a great deal about the dinosaurs. For the whole of the Ageof Dinosaurs, fewer than a thousand species have beeified (almost half of them knownfrom a single spe), which is about a quarter of the number of mammal species alivenow. Dinosaurs, bear in mind, ruled the Earth fhly three times as long as mammalshave, so either dinosaurs were remarkably unproductive of species or we have barelyscratched the surface (to use an irresistibly apt cliché).
For millions of years through the Age of Dinosaurs not a single fossil has yet been found.
Even for the period of the late Cretaceous—the most studied prehistoric period there is,thanks to our long i in dinosaurs and their extin—some three quarters of allspecies that lived may yet be undiscovered. Animals bulkier than the Diplodooreforbidding than tyrannosaurus may have roamed the Earth ihousands, and we maynever know it. Until very retly everything known about the dinosaurs of this period camefrom only about three hundred spes representing just sixteen species. The stiness ofthe record led to the widespread belief that dinosaurs were on their way out already whe impact occurred.
Ie 1980s a paleontologist from the Milwaukee Public Museum, Peter Sheehan,decided to du experiment. Using two hundred volunteers, he made a painstakingsus of a well-defined, but also well-picked-over, area of the famous Hell Creek formationin Montana. Siftiiculously, the volunteers collected every last tooth aebra andchip of bone—everything that had been overlooked by previous diggers. The work took threeyears. When fihey found that they had more than tripled the global total of dinosaurfossils from the late Cretaceous. The survey established that dinosaurs remained numerht up to the time of the KT impact. “There is no reason to believe that the dinosaurs weredying out gradually during the last three million years of the Cretaceous,” Sheehaed.
We are so used to the notion of our owability as life’s dominant species that it ishard to grasp that we are here only because of timely extraterrestrial bangs and other randomflukes. The ohing we have in on with all other living things is that for nearly fourbillion years our aors have mao slip through a series of closing doors every timewe hem to. Stephen Jay Gould expressed it suctly in a well-known line: “Humansare here today because our particular line never fractured—never o any of the billionpoints that could have erased us from history.”
We started this chapter with three points: Life wants to be; life doesn’t always want to bemuch; life from time to time goes extinct. To this we may add a fourth: Life goes on. Andoften, as we shall see, it goes on in ways that are decidedly amazing.
23 THE RICHNESS OF BEING
HERE AND THERE iural History Museum in London, built into recesses along theu corridors or standiween glass cases of minerals and ostrich eggs and a turyor so of other productive clutter, are secret doors—at least secret in the sehat there isnothing about them to attract the visitor’s notice. Occasionally you might see someohthe distracted manner and iingly willful hair that mark the scholar emerge from ohe doors and hasten down a corridor, probably to disappear through another door a littlefurther on, but this is a relatively rare event. For the most part the doors stay shut, giving nohint that beyond them exists another—a parallel—Natural History Museum as vast as, and inmany ways more wonderful than, the ohe publiows and adores.
The Natural History Museum tains some seventy million objects from every realm oflife and every er of the pla, with another huhousand or so added to thecolle each year, but it is really only behind the ses that you get a sense of what atreasure house this is. In cupboards and ets and long rooms full of close-packed shelvesare kept tens of thousands of pickled animals in bottles, millions of is pio squaresof card, drawers of shiny mollusks, bones of dinosaurs, skulls of early humans, endlessfolders of ly pressed plants. It is a little like wandering through Darwin’s brain. The spiritroom alone holds fifteen miles of shelving taining jar upon jar of animals preserved ihylated spirit.
Back here are spes collected by Joseph Banks in Australia, Alexander von Humboldtin Amazonia, Darwin on the Beagle voyage, and much else that is either very rare orhistorically important or both. Many people would love to get their hands ohings. Afew actually have. In 1954 the museum acquired an outstanding ornithological colle fromthe estate of a devoted collector named Richard Meizhagen, author of Birds of Arabia,among other scholarly works. Meizhagen had been a faithful attendee of the museum foryears, ing almost daily to take notes for the produ of his books and monographs.
When the crates arrived, the curators excitedly jimmied them open to see what they had bee and were surprised, to put it mildly, to discover that a very large number of spesbore the museum’s own labels. Mr. Meizhagen, it turned out, had been helping himself totheir colles for years. It also explained his habit of wearing a large overcoat even duringwarm weather.
A few years later a charming ular in the mollusks department—“quite a distinguishedgentleman,” I was told—was caught iing valued seashells into the hollow legs of hisZimmer frame.
“I don’t suppose there’s anything ihat somebody somewhere doesn’t covet,”
Richard Fortey said with a thoughtful air as he gave me a tour of the beguiling world that isthe behind-the-ses part of the museum. We wahrough a fusion of departmentswhere people sat at large tables doing i, iigative things with arthropods and palmfronds and boxes of yellowed bones. Everywhere there was an air of unhurried thhness,of people being engaged in a gigantideavor that could never be pleted and mustn’t berushed. In 1967, I had read, the museum issued its report on the John Murray Expedition, anIndian O survey, forty-four years after the expedition had cluded. This is a worldwhere things move at their own pace, including a tiny lift Fortey and I shared with a scholarlylooking elderly man with whom Fortey chatted genially and familiarly as we proceededupwards at about the rate that sediments are laid down.
When the maed, Fortey said to me: “That was a very nice chap named Normanwho’s spent forty-two years studying one species of plant, St. John’s wort. He retired in 1989,but he still es in every week.”
“How do you spend forty-two years on one species of plant?” I asked.
“It’s remarkable, isn’t it?” Fortey agreed. He thought for a moment. “He’s very thhapparently.” The lift door opeo reveal a bricked-over opening. Fortey lookedfounded. “That’s very strange,” he said. “That used to be Botany back there.” He puncheda button for another floor, and we found our way at length to Botany by means of backstaircases and discreet trespass through yet more departments where iigators toiledlovingly over once-living objects. And so it was that I was introduced to Len Ellis and thequiet world of bryophytes—mosses to the rest of us.
When Emersoically hat mosses favor the north sides of trees (“The moss uponthe forest bark, ole-star when the night was dark”) he really meant lis, for in theeenth tury mosses and lis weren’t distinguished. True mosses aren’t actuallyfussy about where they grow, so they are no good as natural passes. In fact, mosses aren’tactually much good for anything. “Perhaps no great group of plants has so few uses,ercial or eic, as the mosses,” wrote Henry S. ard, perhaps just a touch sadly,in How to Know the Mosses and Liverworts, published in 1956 and still to be found on manylibrary shelves as almost the only attempt to popularize the subject.
They are, however, prolific. Even with lis removed, bryophytes is a busy realm, withover ten thousand species tained within some seven hundred genera. The plump andstately Moss Flora of Britain and Ireland by A. J. E. Smith runs to seven hundred pages, andBritain and Ireland are by no means outstandingly mossy places. “The tropics are where youfind the variety,” Len Ellis told me. A quiet, spare man, he has been at the Natural HistoryMuseum for twenty-seven years and curator of the department since 1990. “You go outinto a place like the rain forests of Malaysia and find new varieties with relative ease. I didthat myself not long ago. I looked down and there ecies that had never beenrecorded.”
“So we don’t know how many species are still to be discovered?”
“Oh, no. No idea.”
You might not think there would be that many people in the world prepared to devotelifetimes to the study of something so inescapably low key, but in fact moss people number inthe hundreds and they feel very strongly about their subject. “Oh, yes,” Ellis told me, “themeetings get very lively at times.”
I asked him for an example of troversy.
“Well, here’s one inflicted on us by one of your trymen,” he said, smiling lightly, andopened a hefty reference work taining illustrations of mosses whose most notablecharacteristic to the uninstructed eye was their uny similarity oo another. “That,” hesaid, tapping a moss, “used to be one genus, Drepanocladus. Now it’s been reanized intothree: Drepanocladus, Wamstorfia, and Hamatacoulis.”
“And did that lead to blows?” I asked perhaps a touch hopefully.
“Well, it made se made perfect sense. But it meant a lot of re of collesand it put all the books out of date for a time, so there was a bit of, you know, grumbling.”
Mosses offer mysteries as well, he told me. One famous case—famous to moss peopleanyway—involved a retiring type called Hyophila stanfordensis, which was discovered on thecampus of Stanford Uy in California and later also found growing beside a path inwall, on the southwest tip of England, but has never been entered anywhere iween. How it came to exist in two suected locations is anybody’s guess. “It9９liｂ?’snow known as Hennediella stanfordensis,” Ellis said. “Another revision.”
We houghtfully.
When a new moss is found it must be pared with all other mosses to make sure that ithasn’t been recorded already. Then a formal description must be written and illustrationsprepared and the result published in a respectable journal. The whole process seldom takesless than six months. The tweh tury was not a great age for moss taxonomy. Much ofthe tury’s work was devoted to untangling the fusions and duplicatio behind bythe eenth tury.
That was the golden age of moss colleg. (You may recall that Charles Lyell’s fatherwas a great moss man.) Oly named Englishman, Gee Hunt, hunted British mosses soassiduously that he probably tributed to the extin of several species. But it is thanksto such efforts that Len Ellis’s colle is one of the world’s most prehensive. All780,000 of his spes are pressed inte folded sheets of heavy paper, some very oldand covered with spidery Victorian script. Some, for all we knew, might have been in thehand of Robert Brown, the great Victorian botanist, unveiler of Brownian motion and thenucleus of cells, who founded and ran the museum’s botament for its first thirty-oneyears until his death in 1858. All the spes are kept in lustrous old mahogany ets sostrikingly fihat I remarked upon them.
“Oh, those were Sir Joseph Banks’s, from his house in Soho Square,” Ellis said casually, asif identifying a ret purchase from Ikea. “He had them built to hold his spes from theEndeavour voyage.” He regarded the ets thoughtfully, as if for the first time in a longwhile. “I don’t knoe ended up with them in bryology,” he added.
This was an amazing disclosure. Joseph Banks was England’s greatest botanist, and theEndeavour voyage—that is the one on which Captain Cook charted the 1769 transit of Venusand claimed Australia for the , among rather a lot else—was the greatest botanicalexpedition in history. Banks paid ￡10,000, about $1 million in today’s mohimself and a party of hers—a naturalist, a secretary, three artists, and four servants—ohree-year adventure around the world. Goodness knows what the bluff Captain ade of such a velvety and pampered assemblage, but he seems to have liked Banks wellenough and could not but admire his talents in botany—a feeling shared by posterity.
Never before or since has a botanical party enjoyed greater triumphs. Partly it was becausethe voyage took in so many new or little-known places—Tierra del Fuego, Tahiti, NewZealand, Australia, New Guinea—but mostly it was because Banks was su astute andiive collector. Even when uo go ashore at Rio de Janeiro because of a quarantine,he sifted through a bale of fodder sent for the ship’s livestod made new discoveries.
Nothing, it seems, escaped his notice. Altogether he brought back thirty thousand plantspes, including fourteen hundred not seen before—enough to increase by about aquarter the number of known plants in the world.
But Banks’s grand cache was only part of the total haul in what was an almost absurdlyacquisitive age. Plant colleg in the eighteenth tury became a kind of iionalmania. Glory ah alike awaited those who could find new species, and botanists andadventurers went to the most incredible lengths to satisfy the world’s craving for horticulturaly. Thomas Nuttall, the man who he wisteria after Caspar Wistar, came toAmerica as an uneducated printer but discovered a passion for plants and walked halfwayacross the try and back again, colleg hundreds of growing things never seen before.
John Fraser, for whom is he Fraser fir, spent years in the wilderness colleg onbehalf of Catherihe Great and emerged at length to find that Russia had a new czar whothought he was mad and refused to honor his tract. Fraser took everything to Chelsea,where he opened a nursery and made a handsome living selling rhododendrons, azaleas,magnolias, Virginia creepers, asters, and other ial exotica to a delighted English gentry.
Huge sums could be made with the right finds. John Lyon, an amateur botanist, spent twohard and dangerous years colleg spes, but cleared almost $200,000 in today’smoney for his efforts. Many, however, just did it for the love of botany. Nuttall gave most ofwhat he found to the Liverpool Botanic Gardeually he became director of Harvard’sBotanic Garden and author of the encyclopediera of North Ameri Plants (which henot only wrote but alsely typeset).
And that was just plants. There was also all the fauna of the new worlds—kangaroos, kiwis,ras, bobcats, mosquitoes, and other curious forms beyond imagining. The volume of lifeoh was seemingly infinite, as Jonathan Swift noted in some famous lines:
So, naturalists observe, a fleaHath smaller fleas that on him prey;And these have smaller still to bite ’em;And so proceed ad infinitum.
All this new information o be filed, ordered, and pared with what was known.
The world was desperate for a workable system of classification. Fortuhere was a manin Sweden who stood ready to provide it.
His name was Carl Linné (later ged, with permission, to the more aristocratiLinné), but he is remembered now by the Latinized form Carolus Linnaeus. He was born in1707 in the village of R?shult in southern Sweden, the son of a poor but ambitious Lutherancurate, and was such a sluggish student that his exasperated father apprenticed him (or, bysome ats, nearly apprenticed him) to a cobbler. Appalled at the prospect of spending alifetime banging tacks into leather, young Linné begged for another ce, which wasgranted, and he hereafter wavered from academic distin. He studied medie inSweden and Holland, though his passion became the natural world. In the early 1730s, still inhis twenties, he began to produce catalogues of the world’s plant and animal species, using asystem of his own devising, and gradually his fame grew.
Rarely has a man been more fortable with his owness. He spent much of hisleisure time penning long and flattering portraits of himself, declaring that there had never“been a greater botanist or zoologist,” and that his system of classification was “the greatestachievement in the realm of sce.” Modestly he suggested that his gravestone should bearthe inscription Princeps Botani, “Prince of Botanists.” It was never wise to question hisgenerous self-assessments. Those who did so were apt to find they had weeds named afterthem.
Linnaeus’s other striking quality was an abiding—at times, one might say, a feverish—preoccupation with sex. He articularly struck by the similarity betweeain bivalvesand the female pudenda. To the parts of one species of clam he gave the names vulva, labia,pubes, anus, and hymen. He grouped plants by the nature of their reproductive ans andehem with an arrestingly anthropomorphic amorousness. His descriptions of flowersand their behavior are full of refereo “promiscuous intercourse,” “barren es,”
and “the bridal bed.” In spring, he wrote i-quoted passage:
Love es even to the plants. Males and females . . . hold their nuptials . . .
showing by their sexual ans which are males, which females. The flowers’
leaves serve as a bridal bed, which the Creator has so gloriously arranged, adorh suoble bed curtains, and perfumed with so many soft sts that thebridegroom with his bride might there celebrate their nuptials with so much thegreater solemnity. When the bed has thus been made ready, then is the time for thebridegroom to embrace his beloved bride and surrender himself to her.
He named one genus of plants Clitoria. Not surprisingly, many people thought him strange.
But his system of classification was irresistible. Before Linnaeus, plants were given hat were expansively descriptive. The on ground cherry was called Physalis amnoramosissime ramis angulosis glabris foliis deis. Linnaeus lopped it back to Physalisangulata, whiame it still uses. The plant world was equally disordered by insistenciesof naming. A botanist could not be sure ifRosa sylvestris alba cum rubore, folio glabro wasthe same plant that others called Rosa sylvestris inodora seu a. Linnaeus solved thepuzzlement by calling it simply Rosa a. To make these excisions useful and agreeable toall required much more than simply being decisive. It required an instinct—a genius, in fact—for spotting the salient qualities of a species.
The Linnaean system is so well established that we hardly imagine an alternative, butbefore Linnaeus, systems of classification were often highly whimsical. Animals might becategorized by whether they were wild or domesticated, terrestrial or aquatic, large or small,eveher they were thought handsome and noble or of no sequence. Buffedhis animals by their utility to man. Anatomical siderations barely came into it. Linnaeusmade it his life’s work to rectify this deficy by classifying all that was alive acc toits physical attributes. Taxonomy—which is to say the sce of classification—has neverlooked back.
It all took time, of course. The first edition of his great Systema Naturae in 1735 was justfourteen pages long. But it grew and grew until by the twelfth edition—the last that Linnaeuswould live to see—it exteo three volumes and 2,300 pages. In the end he named orrecorded some 13,000 species of plant and animal. Other works were more prehensive—John Ray’s three-volume Histeneralis Plantarum in England, pleted a geionearlier, covered no fewer than 18,625 species of plants alo what Linnaeus had that noone else could touch were sistency, order, simplicity, and timeliness. Though his workdates from the 1730s, it didn’t bee widely known in England until the 1760s, just in timeto make Linnaeus a kind of father figure to British naturalists. Nowhere was his systemembraced with greater enthusiasm (which is why, for ohing, the Linnaean Society has itshome in London and not Sto).
Linnaeus was not flawless. He made room for mythical beasts and “monstrous humans”
whose descriptions he gullibly accepted from seamen and other imaginative travelers. Amongthese were a wild man, Homo ferus, who walked on all fours and had not yet mastered the artof speech, and Homo caudatus, “man with a tail.” But then it was, as we should not fet, analtogether more credulous age. Even the great Joseph Banks took a keen and believing iin a series of reported sightings of mermaids off the Scottish coast at the end of the eighteeury. For the most part, however, Linnaeus’s lapses were offset by sound and oftenbrilliant taxonomy. Among other aplishments, he saw that whales belonged with ice, and other on terrestrial animals in the order Quadrupedia (later ged toMammalia), whio one had done before.
In the beginning, Linnaeus intended only to give each plant a genus name and a number—volvulus 1, volvulus 2,and so on—but soon realized that that was unsatisfactory andhit on the binomial arrahat remains at the heart of the system to this day. Theiiinally was to use the binomial system for everything—rocks, minerals, diseases,winds, whatever existed in nature. Not everyone embraced the system warmly. Many weredisturbed by its tendency toward indelicacy, which was slightly ironic as before Liheon names of many plants and animals had beeily vulgar. The dandelion was longpopularly known as the “pissabed” because of its supposed diuretic properties, and othernames in everyday use included mare’s fart, naked ladies, twitch-ballock, hound’s piss, openarse, and bum-towel. One or two of these earthy appellations may unwittingly survive inEnglish yet. The “maidenhair” in maidenhair moss, for instance, does not refer to the hair onthe maiden’s head. At all events, it had long beehat the natural sces would beappreciably dignified by a dose of classical renaming, so there was a certain dismay indisc that the self-appointed Prince of Botany had sprinkled his texts with suchdesignations asClitoria, Fornicata, andVulva.
Over the years many of these were quietly dropped (though not all: the on slipperlimpet still answers on formal occasions to Crepidula fornicata) and many other refisintroduced as the needs of the natural sces grew more specialized. In particular the systemwas bolstered by the gradual introdu of additional hierarchies.Genus (pluralgenera) andspecies had been employed by naturalists for over a hundred years before Linnaeus, andorder, class, and family in their biological senses all came into use in the 1750s and 1760s.
But phylum wasn’t ed until 1876 (by the Germa Haeckel), and family and orderwere treated as intergeable until early iweh tury. For a time zoologists usedfamily where botanists placed order, to the occasional fusion of nearly everyone.
1Linnaeus had divided the animal world into six categories: mammals, reptiles, birds, fishes,is, and “vermes,” or worms, for everything that didn’t fit into the first five. From theoutset it was evident that putting lobsters and shrimp into the same category as worms wasunsatisfactory, and various new categories such as Mollusd Crustacea were created.
Unfortuhese new classifications were not uniformly applied from nation to nation. Inan attempt to reestablish order, the British in 1842 proclaimed a new set of rules called theStridian Code, but the French saw this as highhanded, and the Société Zoologiquetered with its own flig code. Meanwhile, the Ameri Ornithological Society, forobscure reasons, decided to use the 1758 edition of Systema Naturae as the basis for all itsnaming, rather than the 1766 edition used elsewhere, which meant that many Ameri birdsspent the eenth tury logged in different genera from their avian cousins in Europe.
Not until 1902, at an early meeting of the Iional gress of Zoology, did naturalistsbegin at last to shoirit of promise and adopt a universal code.
Taxonomy is described sometimes as a sd sometimes as an art, but really it’s abattleground. Even today there is more disorder in the system than most people realize. Takethe category of the phylum, the division that describes the basic body plans of all anisms.
A few phyla are generally well known, such as mollusks (the home of clams and snails),arthropods (is and crustas), and chordates (us and all other animals with a baeor protobae), though things then move swiftly in the dire of obscurity. Among thelatter we might list Gnathostomulida (marine worms), idaria (jellyfish, medusae,anemones, and corals), and the delicate Priapulida (or little “penis worms”). Familiar or not,these are elemental divisions. Yet there is surprisingly little agreement on hohylathere are ht to be. Most biologists fix the total at about thirty, but some opt for a numberin the low twenties, while Edward O. Wilson in The Diversity of Life puts the asurprisingly robust eighty- depends on where you decide to make your divisions—whether you are a “lumper” or a “splitter,” as they say in the biological world.
At the more workaday level of species, the possibilities for disagreements are eveer.
Whether a species of grass should be called Aegilops incurva, Aegilops incurvata, ilopsovata may not be a matter that would stir many nonbotanists to passion, but it be a sourceof very lively heat in the right quarters. The problem is that there are five thousand species ofgrass and many of them look awfully alike even to people who know grass. In sequene species have been found and least twenty times, and there are hardly any, itappears, that haven’t been indepely identified at least twice. The two-volume Manual ofthe Grasses of the Uates devotes two hundred closely typeset pages t out allthe synonymies, as the biological world refers to its ient but quite onduplications. And that is just for the grasses of a single try.
To deal with disagreements on the global stage, a body known as the IionalAssociation for Plant Taxonomy arbitrates oions of priority and duplication. At1To illustrate, humans are in the domain eucarya, in the kingdom animalia, in the phylum chordata, in thesubphylum vertebrata, in the class mammalia, in the order primates, in the family hominidae, in the genus homo,in the species sapiens. (The vention, Im informed, is to italicize genus and species names, but not those ofhigher divisions.) Some taxonomists employ further subdivisions: tribe, suborder, infraorder, parvorder, andmore.
intervals it hands down decrees, declaring that Zauseria californica (a on plant inrock gardens) is to be known heh as Epilobium um or that Aglaothamniontenuissimum may now be regarded as specific with Aglaothamnion byssoides, but notwithAglaothamnion pseudobyssoides. Normally these are small matters of tidying up thatattract little notice, but wheou beloved garden plants, as they sometimes do,shrieks of e iably follow. Ie 1980s the on chrysanthemum wasbanished (on apparently sound stific principles) from the genus of the same name andrelegated to the paratively drab and undesirable world of the genus Dendranthema.
Chrysanthemum breeders are a proud and numerous lot, and they protested to the real ifimprobable-sounding ittee oophyta. (There are also ittees forPteridophyta, Bryophyta, and Fungi, among others, all rep to aive called theRapporteur-Général; this is truly an institution to cherish.) Although the rules of nomenclatureare supposed to be rigidly applied, botanists are not indifferent to se, and in 1995 thedecision was reversed. Similar adjudications have saved petunias, euonymus, and a popularspecies of amaryllis from demotion, but not many species of geraniums, whie yearsago were transferred, amid howls, to the genus Pelargonium. The disputes are eaininglysurveyed in Charles Elliott’s The Potting-Shed Papers.
Disputes and res of much the same type be found in all the other realms of theliving, so keeping an overall tally is not nearly as straightforward a matter as you mightsuppose. In sequehe rather amazing fact is that we don’t have the fai idea—“noteven to the order of magnitude,” in the words of Edward O. Wilson—of the number ofthings that live on our pla. Estimates range from 3 million to 200 million. Moreextraordinary still, acc to a report in the Eist, as much as 97 pert of theworld’s plant and animal species may still await discovery.
Of the anisms that we do know about, more than 99 in 100 are only sketchilydescribed—“a stifiame, a handful of spes in a museum, and a few scraps ofdescription in stific journals” is how Wilson describes the state of our knowledge. In TheDiversity of Life, he estimated the number of known species of all types—plants, is,microbes, algae, everything—at 1.4 million, but added that that was just a guess. Otherauthorities have put the number of known species slightly higher, at around 1.5 million to 1.8million, but there is ral registry of these things, so o cheumbers. In short,the remarkable position we find ourselves in is that we don’t actually know what we actuallyknow.
In principle you ought to be able to go to experts in each area of specialization, ask howmany species there are in their fields, then add the totals. Many people have in fact done so.
The problem is that seldom do any two e up with matg figures. Some sources put thenumber of known types of fungi at 70,000, others at 100,000—nearly half as many again. You find fident assertions that the number of described earthworm species is 4,000 andequally fident assertions that the figure is 12,000. For is, the numbers run from750,000 to 950,000 species. These are, you uand, supposedly the known number ofspecies. For plants, the only accepted numbers range from 248,000 to 265,000. Thatmay not seem too vast a discrepancy, but it’s more thay times the number of flplants in the whole of North America.
Putting things in order is not the easiest of tasks. In the early 1960s, Groves of theAustralian National Uy began a systematic survey of the 250-plus known species ofprimate. Ofte turned out that the same species had been described more than onetimes several times—without any of the discoverers realizing that they were dealing withan animal that was already known to sce. It took Groves four decades to untangleeverything, and that was with a paratively small group of easily distinguished, generallynontroversial creatures. Goodness knows what the results would be if aempted asimilar exercise with the pla’s estimated 20,000 types of lis, 50,000 species ofmollusk, or 400,000-plus beetles.
What is certain is that there is a great deal of life out there, though the actual quantities arenecessarily estimates based orapolations—sometimes exceedingly exparapolations. In a well-known exercise in the 1980s, Terry Erwin of the SmithsonianInstitution saturated a stand of een rain forest trees in Panama with an iicide fog,then collected everything that fell into his s from the opy. Among his haul (actuallyhauls, since he repeated the experiment seasonally to make sure he caught migrant species)were 1,200 types of beetle. Based on the distribution of beetles elsewhere, the number ofother tree species in the forest, the number of forests in the world, the number of other iypes, and so on up a long of variables, he estimated a figure of 30 million species ofis for the entire pla—a figure he later said was too servative. Others using thesame or similar data have e up with figures of 13 million, 80 million, or 100 millioypes, underlining the clusion that however carefully arrived at, such figuresiably owe at least as much to supposition as to sce.
Acc to the Wall Street Journal, the world has “about 10,000 active taxonomists”—not a great number when you sider how much there is to be recorded. But, the Journaladds, because of the cost (about $2,000 per species) and paperwork, only about fifteenthousand new species of all types are logged per year.
“It’s not a biodiversity crisis, it’s a taxonomist crisis!” barks Koen Maes, Belgian-bornhead of iebrates at the Kenyan National Museum in Nairobi, whom I met briefly on avisit to the try iumn of 2002. There were no specialized taxonomists in thewhole of Africa, he told me. “There was one in the Ivory Coast, but I think he has retired,” hesaid. It takes eight to ten years to train a taxonomist, but none are ing along in Africa.
“They are the real fossils,” Maes added. He himself was to be let go at the end of the year, hesaid. After seven years in Kenya, his tract was not being renewed. “No funds,” Maesexplained.
Writing in the journal Nature last year, the British biologist G. H. Godfray hat thereis a ic “lack of prestige and resources” for taxonomists everywhere. In sequence,“many species are being described poorly in isolated publications, with no attempt to relate aaxon2to existing species and classifications.” Moreover, much of taxonomists’ time istaken up not with describing new species but simply with s out old ones. Many,acc to Godfray, “spend most of their career trying to interpret the work of eenth-tury systematicists: destrug their often ie published descriptions orsc the world’s museums for type material that is often in very poor dition.” Godfrayparticularly stresses the absence of attention being paid to the systematizing possibilities ofthe I. The fact is that taxonomy by and large is still quaintly wedded to paper.
2The formal word for a zoological category, such as phylum enus. The plural is taxa.
In an attempt to haul things into the me, in 2001 Kevin Kelly, cofounder of Wiredmagazine, launched aerprise called the All Species Foundation with the aim of findingevery living anism and rec it on a database. The cost of su exercise has beeimated at anywhere from $2 billion to as much as $50 billion. As of the spring of 2002, thefoundation had just $1.2 million in funds and four full-time employees. If, as the numberssuggest, erhaps 100 million species of is yet to find, and if our rates ofdiscovery ti the present pace, we should have a definitive total for is in a littleover fifteen thousand years. The rest of the animal kingdom may take a little longer.
So why do we know as little as we do? There are nearly as many reasons as there areanimals left to t, but here are a few of the principal causes:
Most living things are small and easily overlooked.In practical terms, this is not always abad thing. You might not slumber quite so tentedly if you were aware that your mattress ishome to perhaps two million microscopic mites, whie out in the wee hours to sup onyour sebaceous oils a on all those lovely, chy flakes of skin that you shed as youdoze and toss. Your pillow alone may be home to forty thousand of them. (To them your headis just one large oily bon-bon.) And don’t think a pillowcase will make a differeosomething on the scale of bed mites, the weave of the tightest human fabric looks like ship’srigging. Indeed, if your pillow is six years old—which is apparently about the average age fora pillow—it has beeimated that oh of its weight will be made up of “sloughedskin, living mites, dead mites and mite dung,” to quote the man who did the measuring, Dr.
John Maunder of the British Medical Entomology ter. (But at least they areyour mites.
Think of what you snuggle up with each time you climb into a motel bed.)3These mites havebeen with us siime immemorial, but they weren’t discovered until 1965.
If creatures as intimately associated with us as bed mites escaped our notitil the age ofcolor television, it’s hardly surprising that most of the rest of the small-scale world is barelyknown to us. Go out into a woods—any woods at all—bend down and scoop up a handful ofsoil, and you will be holding up to 10 billion bacteria, most of them unknown to sce. Yoursample will also tain perhaps a million plump yeasts, some 200,000 hairy little fungiknown as molds, perhaps 10,000 protozoans (of which the most familiar is the amoeba), andassorted rotifers, flatworms, roundworms, and other microscopic creatures known collectivelyas cryptozoa. A large portion of these will also be unknown.
The most prehensive handbook of micranisms, Bergey’s Manual of SystematicBacteriology, lists about 4,000 types of bacteria. In the 1980s, a pair of Nian stists,Jostein Goks?yr and Vigdis Torsvik, collected a gram of random soil from a beech forest heir lab in? Bergen and carefully analyzed its bacterial tent. They found that this singlesmall sample tained between 4,000 and 5,000 separate bacterial species, more than in thewhole of Bergey’s Manual. They then traveled to a coastal location a few miles away,scooped up anram of earth, and found that it tained 4,000 to 5,000 other species. AsEdward O. Wilson observes: “If over 9,000 microbial types exist in two pinches of substratefrom two localities in Norway, how many more await discovery in other, radically differenthabitats?” Well, acc to oimate, it could be as high as 400 million.
3We are actually getting worse at some matters of hygiene. Dr. Maunder believes that the move toward low-temperature washing mae detergents has enced bugs to proliferate. As he puts it: "If you wash lousyclothing at low temperatures, all you get is er lice."We don’t look in the right places. In The Diversity of Life, Wilson describes how oanist spent a few days tramping around teares of jungle in Borneo and discovered athousand new species of fl plant—more than are found in the whole of NorthAmerica. The plants weren’t hard to find. It’s just that no one had looked there before. KoenMaes of the Kenyan National Museum told me that he went to one cloud forest, asmountaintop forests are known in Kenya, and in a half hour “of not particularly dedicatedlooking” found four new species of millipedes, three representing new genera, and one newspecies of tree. “Big tree,” he added, and shaped his arms as if about to dah a verylarge partner. Cloud forests are found oops of plateaus and have sometimes beenisolated for millions of years. “They provide the ideal climate for biology and they havehardly been studied,” he said.
Overall, tropical rain forests cover only about 6 pert of Earth’s surface, but harbor morethan half of its animal life and about two-thirds of its fl plants, and most of this liferemains unknown to us because too few researchers spend time in them. Not ially,much of this could be quite valuable. At least 99 pert of fl plants have never beeed for their medial properties. Because they ’t flee from predators, plants have hadto trive chemical defenses, and so are particularly enriched in intriguing pounds. Evennow nearly a quarter of all prescribed medies are derived from just forty plants, withanother 16 pert ing from animals or microbes, so there is a serious risk with everyhectare of forest felled of losing medically vital possibilities. Using a method calledbinatorial chemistry, chemists gee forty thousand pounds at a time in labs,but these products are random and not unonly useless, whereas any natural moleculewill have already passed what the Eist calls “the ultimate sing programme: overthree and a half billion years of evolution.”
Looking for the unknown isn’t simply a matter of traveling to remote or distant places,however. In his book Life: An Unauthorised Biography, Richard Fortey notes how onea bacterium was found on the wall of a try pub “where men had urinated feions”—a discovery that would seem to involve rare amounts of lud devotion andpossibly some other quality not specified.
There aren’t enough specialists.The stock of things to be found, examined, and recordedvery much outruns the supply of stists available to do it. Take the hardy and little-knanisms known as bdelloid rotifers. These are microscopiimals that survive almostanything. When ditions are tough, they curl up into a pact shape, switch off theirmetabolism, and wait for better times. In this state, you drop them into boiling water orfreeze them almost to absolute zero—that is the level where even atoms give up—and, whenthis torment has finished and they are returo a more pleasing enviro, they willuncurl and move on as if nothing has happened. So far, about 500 species have beeified(though other sources say 360), but nobody has any idea, eveely, how many there maybe altogether. For years almost all that was known about them was thanks to the work of adevoted amateur, a London clerical worker named David Bryce who studied them in his sparetime. They be found all over the world, but you could have all the bdelloid rotifer expertsin the world to dinner and not have to borrow plates from the neighbors.
Even something as important and ubiquitous as fungi—and fungi are both—attraparatively little notice. Fungi are everywhere and e in many forms—as mushrooms,molds, mildews, yeasts, and puffballs, to a sampling—and they exist in volumesthat most of us little suspect. Gather together all the fungi found in a typical aeadowand you would have 2,500 pounds of the stuff. These are not marginal anisms. Withoutfungi there would be no potato blights, Dutch elm disease, jock itch, or athlete’s foot, but alsono yogurts or beers or cheeses. Altogether about 70,000 species of fungi have beeified,but it is thought the number could be as high as 1.8 million. A lot of mycologists work inindustry, making cheeses and yogurts and the like, so it is hard to say how many are activelyinvolved in research, but we safely take it that there are more species of fungi to be foundthan there are people to find them.
The world is a really big place.We have been gulled by the ease of air travel and otherforms of unication into thinking that the world is not all that big, but at ground level,where researchers must work, it is actually enormous—enormous enough to be full ofsurprises. The okapi, the liviive of the giraffe, is now known to exist insubstantial numbers in the rain forests of Zaire—the total population is estimated at perhapsthirty thousas existence wasn’t even suspected until the tweh tury. The largeflightless New Zealand bird called the takahe had been presumed extinct for two hundredyears before being found living in a rugged area of the try’s South Island. In 1995 a teamof Frend British stists in Tibet, who were lost in a snowstorm in a remote valley,came across a breed of horse, called the Riwoche, that had previously been known only fromprehistoric cave drawings. The valley’s inhabitants were astoo learn that the horse wassidered a rarity in the wider world.
Some people think even greater surprises may await us. “A leading British ethno-biologist,” wrote the Eist in 1995, “thinks a megatherium, a sort of giant ground slothwhich may stand as high as a giraffe . . . may lurk in the fastnesses of the Amazon basin.”
Perhaps signifitly, the ethnobiologist wasn’t named; perhaps even more signifitly,nothing more has been heard of him or his giant sloth. No one, however, categorically saythat no such thing is there until every jungly glade has been iigated, and we are a longway from achieving that.
But even if we groomed thousands of fieldworkers and dispatched them to the farthesters of the world, it would not be effort enough, for wherever life be, it is. Life’sextraordinary fedity is amazing, even gratifying, but also problematic. To survey it all, youwould have to turn over every rock, sift through the litter on every forest floor, sieveunimaginable quantities of sand and dirt, climb into every forest opy, and devise muchmore effit ways to examihe seas. Even then you would overlook whole ecosystems. Inthe 1980s, spelunkers entered a deep cave in Romania that had been sealed off from theoutside world for a long but unknown period and found thirty-three species of is andother small creatures—spiders, tipedes, lice—all blind, colorless, ao sce.
They were living off the microbes in the surface scum of pools, whi turn were feeding onhydrogen sulfide from hot springs.
Our instinct may be to see the impossibility of trag everything down as frustrating,dispiriting, perhaps even appalling, but it just as well be viewed as almost unbearablyexg. We live on a plahat has a more or less infinite capacity to surprise. Whatreasoning person could possibly want it any other way?
What is nearly always most arresting in any ramble through the scattered disciplines ofmodern sce is realizing hoeople have been willing to devote lifetimes to themost sumptuously esoteries of inquiry. In one of his essays, Stephen Jay Gould notes howa hero of his named Henry Edward Crampto fifty years, from 1906 to his death in1956, quietly studying a genus of land snails in Polynesia called Partula. Over and over, yearafter year, Crampton measured to the ti degree—to eight decimal places—the whorls andard gentle curves of numberless Partula, piling the results into fastidiously detailedtables. A single line of text in a Crampton table could represent weeks of measurement andcalculation.
Only slightly less devoted, aainly more ued, was Alfred C. Kinsey, whobecame famous for his studies of human sexuality in the 1940s and 1950s. But before hismind became filled with sex, so to speak, Kinsey was aomologist, and a dogged ohat. In one expedition lasting two years, he hiked 2,500 miles to assemble a colle of300,000 s. How many stings he collected along the way is not, alas, recorded.
Something that had been puzzling me was the question of how you assured a ofsuccession in these are fields. Clearly there ot be many institutions in the world thatrequire or are prepared to support specialists in barnacles or Pacifiails. As we parted at theNatural History Museum in London, I asked Richard Fortey how ssures that whenone persohere’s someone ready to take his place.
He chuckled rather heartily at my é. “I’m afraid it’s not as if we have substitutessitting on the benewhere waiting to be called in to play. When a specialist retires or,even more unfortunately, dies, that bring a stop to things in that field, sometimes for avery long while.”
“And I suppose that’s why you value someone who spends forty-two years studying asingle species of plant, even if it doesn’t produything terribly new?”
“Precisely,” he said, “precisely.” And he really seemed to mean it.
24 CELLS
IT STARTS WITH a single cell. The first cell splits to bee two and the two bee fourand so on. After just forty-seven doublings, you have ten thousand trillion(10,000,000,000,000,000) cells in your body and are ready t forth as a human being.
1And every one of those cells knows exactly what to do to preserve and nurture you from themoment of ception to your last breath.
You have s from your cells. They know far more about you than you do. Eaecarries a copy of the plete geic code—the instruanual for your body—so itknows not only how to do its job but every other job in the body. Never in your life will youhave to remind a cell to keep an eye on its adenosiriphosphate levels or to find a place forthe extra squirt of folic acid that’s just uedly turned up. It will do that for you, andmillions more things besides.
Every cell in nature is a thing of wonder. Even the simplest are far beyond the limits ofhuman iy. To build the most basic yeast cell, for example, you would have tominiaturize about the same number of pos as are found in a Boeing 777 jetliner andfit them into a sphere just five mis across; then somehow you would have to persuade thatsphere to reproduce.
But yeast cells are as nothing pared with human cells, which are not just more variedand plicated, but vastly more fasating because of their plex iions.
Your cells are a try of ten thousand trillion citizens, each devoted in some intensivelyspecific way to your overall well-being. There isn’t a thing they don’t do for you. They letyou feel pleasure and form thoughts. They enable you to stand and stretd caper. Whenyou eat, they extract the nutrients, distribute the energy, and carry off the wastes—all thosethings you learned about in junih school biology—but they also remember to make youhungry in the first plad reward you with a feeling of well-being afterward so that youwon’t fet to eat again. They keep your hair growing, your ears waxed, your brain quietlypurring. They manage every er of your being. They will jump to your defehe instantyou are threatehey will uatingly die for you—billions of them do so daily. Andnot on all your years have you thanked even one of them. So let us take a moment now tard them with the wonder and appreciation they deserve.
We uand a little of how cells do the things they do—how they lay down fat ormanufacture insulin age in many of the other aecessary to maintain a plicatedentity like yourself—but only a little. You have at least 200,000 different types of protein1Actually, quite a lot of cells are lost in the process of development, so the number you emerge with is reallyjust a guess. Depending on which source you sult the number vary by several orders of magnitude. Thefigure of ten thousand trillion (or quadrillion) is from Margulis and Sagan, 1986.
lab away inside you, and so far we uand what no more than about 2 pert ofthem do. (Others put the figure at more like 50 pert; it depends, apparently, on what youmean by “uand.”)Surprises at the cellular level turn up all the time. In nature, nitric oxide is a formidabletoxin and a on po of air pollution. So stists were naturally a little surprisedwhen, in the mid-1980s, they found it being produced in a curiously devoted manner inhuman cells. Its purpose was at first a mystery, but then stists began to find it all over theplace—trolling the flow of blood and the energy levels of cells, attag cers andother pathogens, regulating the sense of smell, even assisting in penile eres. It alsoexplained why nitroglye, the well-known explosive, soothes the heart pain known asangina. (It is verted into nitric oxide in the bloodstream, relaxing the muscle linings ofvessels, allowing blood to flow more freely.) In barely the space of a decade this one gassysubstance went from extraneous toxin to ubiquitous elixir.
You possess “some few hundred” different types of cell, acc to the Belgianbiochemist Christian de Duve, and they vary enormously in size and shape, from nerve cellswhose filaments stretch to several feet to tiny, disc-shaped red blood cells to the rod-shaped photocells that help to give us vision. They also e in a sumptuously wide range ofsizes—nowhere more strikingly than at the moment of ception, when a single beatingsperm fronts an egg eighty-five thousand times bigger than it (which rather puts the notionof male quest into perspective). On average, however, a human cell is about twentymis wide—that is about two huhs of a millimeter—which is too small to be seenbut roomy enough to hold thousands of plicated structures like mitodria, and millionsupon millions of molecules. In the most literal way, cells also vary in liveliness. Your skincells are all dead. It’s a somewhat galling notion to reflect that every inch of your surface isdeceased. If you are an average-sized adult you are lugging around about five pounds of deadskin, of which several billion tiny fragments are sloughed off each day. Run a finger along adusty shelf and you are drawing a pattern very largely in old skin.
Most living cells seldom last more than a month or so, but there are some notableexceptions. Liver cells survive for years, though the pos within them may berenewed every few days. Brain cells last as long as you do. You are issued a hundred billionor so at birth, and that is all you are ever going to get. It has beeimated that you lose fivehundred of them an hour, so if you have any serious thinking to do there really isn’t a momentto waste. The good news is that the individual pos of your brain cells are stantlyrenewed so that, as with the liver cells, no part of them is actually likely to be more than abouta month old. Indeed, it has been suggested that there isn’t a si of any of us—not somuch as a stray molecule—that art of us nine years ago. It may not feel like it, but at thecellular level we are all youngsters.
The first person to describe a cell was Robert Hooke, whom we last enteredsquabbling with Isaaewton over credit for the iion of the inverse square law. Hookeachieved many things in his sixty-eight years—he was both an aplished theoreti anda dab hand at making ingenious and useful instruments—but nothing he did brought himgreater admiration than his popular book Microphagia: or Some Physiological Descriptions ofMiniature Bodies Made by Magnifying Glasses, produced in 1665. It revealed to an entedpublic a universe of the very small that was far more diverse, crowded, and finely structuredthan anyone had ever e close to imagining.
Among the microscopic features first identified by Hooke were little chambers in plantsthat he called “cells” because they reminded him of monks’ cells. Hooke calculated that aone-inch square of cork would tain 1,259,712,000 of these tiny chambers—the firstappearance of such a very large number anywhere in sce. Microscopes by this time hadbeen around feion or so, but what set Hooke’s apart were their teicalsupremacy. They achieved magnifications of thirty times, making them the last word ieenth-tury optical teology.
So it came as something of a shock when just a decade later Hooke and the other membersof London’s Royal Society began to receive drawings as from an uered linendraper in Holland employing magnifications of up to 275 times. The draper’s name wasAntoni van Leeuwehough he had little formal education and no background insce, he erceptive and dedicated observer and a teical genius.
To this day it is not known how he got such magnifit magnifications from simplehandheld devices, which were little more than modest wooden dowels with a tiny bubble ofglass embedded in them, far more like magnifying glasses than what most of us think of asmicroscopes, but really not much like either. Leeuwenhoek made a new instrument for everyexperiment he performed and was extremely secretive about his teiques, though he didsometimes offer tips to the British on how they might improve their resolutions.
2Over a period of fifty years—beginning, remarkably enough, when he was already pastforty—he made almost two hundred reports to the Royal Society, all written in Low Dutch,the only tongue of which he was master. Leeuwenhoek offered no interpretations, but simplythe facts of what he had found, apanied by exquisite drawings. He ses on almosteverything that could be usefully examined—bread mold, a bee’s stinger, blood cells, teeth,hair, his own saliva, excrement, and semen (these last with fretful apologies for their unsavorynature)—nearly all of which had never been seen microscopically before.
After he reported finding “animalcules” in a sample of pepper water in 1676, the membersof the Royal Society spent a year with the best devices English teology could producesearg for the “little animals” before finally getting the magnificatiht. WhatLeeuwenhoek had found were protozoa. He calculated that there were 8,280,000 of these tinybeings in a single drop of water—more than the number of people in Holland. The worldteemed with life in ways and hat no one had previously suspected.
Inspired by Leeuwenhoek’s fantastidings, others began to peer into microscopes withsuch keehat they sometimes found things that weren’t in fact there. One respectedDutch observer, Nicolaus Hartsoecker, was vinced he saw “tiny preformed men” in spermcells. He called the little beings “homunculi” and for some time many people believed that allhumans—indeed, all creatures—were simply vastly inflated versions of tiny but pleteprecursor beings. Leeuwenhoek himself occasionally got carried away with his enthusiasms.
In one of his least successful experiments he tried to study the explosive properties ofgunpowder by a small blast at cle; he nearly blinded himself in the process.
2Leeuwenhoek was close friends with another Delft notable, the artist Jan Vermeer. In the mid-1660s, Vermeer,who previously had been a petent but not outstanding artist, suddenly developed the mastery of light andperspective for which he has been celebrated ever sihough it has never been proved, it has long beensuspected that he used a camera obscura, a device for projeg images onto a flat surface through a lens. Nosuch device was listed among Vermeers personal effects after his death, but it happens that the executor ofVermeers estate was her than Antoni van Leeuwehe most secretive lens-maker of his day.
In 1683 Leeuwenhoek discovered bacteria, but that was about as far as progress could getfor the tury and a half because of the limitations of microscope teology. Not until1831 would anyone first see the nucleus of a cell—it was found by the Scottish botanistRobert Brown, that frequent but always shadowy visitor to the history of sce. Brown, wholived from 1773 to 1858, called it nucleus from the Latin nucula, meaning little nut or kernel.
Not until 1839, however, did anyone realize that all living matter is cellular. It was TheodorSn, a German, who had this insight, and it was not only paratively late, as stifisights go, but not widely embraced at first. It wasn’t until the 1860s, and some landmarkwork by Louis Pasteur in Frahat it was shown clusively that life ot arisespontaneously but must e from preexisting cells. The belief became known as the “celltheory,” and it is the basis of all modern biology.
The cell has been pared to many things, from “a plex chemical refinery” (by thephysicist James Trefil) to “a vast, teemiropolis” (the biochemist Guy Brown). A cell isboth of those things aher. It is like a refinery in that it is devoted to chemical activityon a grand scale, and like a metropolis in that it is crowded and busy and filled withiions that seem fused and random but clearly have some system to them. But it is amuch more nightmarish place than any city or factory that you have ever seen. To begin withthere is no up or down ihe cell (gravity doesn’t meaningfully apply at the cellularscale), and not an atom’s width of space is uhere is activity every where and aceaseless thrum of electrical energy. You may not feel terribly electrical, but you are. Thefood we eat and the oxygen we breathe are bined in the cells iricity. The reasonwe don’t give each other massive shocks or scorch the sofa whe is that it is allhappening on a tiny scale: a mere 0.1 volts traveling distances measured in naers.
However, scale that up and it would translate as a jolt of twenty million volts per meter, aboutthe same as the charge carried by the main body of a thuorm.
Whatever their size or shape, nearly all your cells are built to fually the same plan:
they have an outer g or membrane, a nucleus wherein resides the necessary geiation to keep you going, and a busy space betweewo called the cytoplasm. Themembrane is not, as most of us imagi, a durable, rubbery g, something that youwould need a sharp pin to prick. Rather, it is made up of a type of fatty material known as alipid, which has the approximate sistency “of a light grade of mae oil,” to quoteSherwin B. Nuland. If that seems surprisingly insubstantial, bear in mind that at themicroscopic level things behave differently. To anything on a molecular scale water beesa kind of heavy-duty gel, and a lipid is like iron.
If you could visit a cell, you wouldn’t like it. Blown up to a scale at which atoms wereabout the size of peas, a cell itself would be a sphere roughly half a mile across, and supportedby a plex framework of girders called the cytoskeleton. Within it, millions upon millionsof objects—some the size of basketballs, others the size of cars—would whiz about likebullets. There wouldn’t be a place you could stand without being pummeled and rippedthousands of times every sed from every dire. Even for its full-time octs theinside of a cell is a hazardous place. Each strand of DNA is on average attacked or damagedonce every 8.4 seds—ten thousand times in a day—by chemicals and ents thatwhato or carelessly slice through it, and each of these wounds must be swiftly stitched upif the cell is not to perish.
The proteins are especially lively, spinning, pulsating, and flying into each other up to abillion times a sed. Ehemselves a type of protein, dash everywhere, perfup to a thousand tasks a sed. Like greatly speeded up worker ants, they busily build andrebuild molecules, hauling a piece off this one, adding a piece to that one. Some monitorpassing proteins and mark with a chemical those that are irreparably damaged or flawed. Onceso selected, the doomed proteins proceed to a structure called a proteasome, where they arestripped down and their pos used to build new proteins. Some types of proteifor less than half an hour; others survive for weeks. But all lead existehat areinceivably frenzied. As de Duve notes, “The molecular world must necessarily remaiirely beyond the powers of our imagination owing to the incredible speed with whichthings happen in it.”
But slow things down, to a speed at which the iions be observed, and thingsdon’t seem quite so unnerving. You see that a cell is just millions of objects—lysosomes,endosomes, ribosomes, ligands, peroxisomes, proteins of every size and shape—bumping intomillions of other objects and perf muasks: extrag energy from nutrients,assembling structures, getting rid of waste, warding off intruders, sending and receivingmessages, making repairs. Typically a cell will tain some 20,000 different types of protein,and of these about 2,000 types will each be represented by at least 50,000 molecules. “Thismeans,” says Nuland, “that even if we t only those molecules present in amounts of morethan 50,000 each, the total is still a very minimum of 100 million protein molecules in eachcell. Such a staggering figure gives some idea of the swarming immensity of biochemicalactivity within us.”
It is all an immensely demanding process. Your heart must pump 75 gallons of blood anhour, 1,800 gallons every day, 657,000 gallons in a year—that’s enough to fill four Olympic-sized swimming pools—to keep all those cells freshly oxygenated. (And that’s at rest. Duringexercise the rate increase as much as sixfold.) The oxygen is taken up by themitodria. These are the cells’ power stations, and there are about a thousand of them in atypical cell, though the number varies siderably depending on what a cell does and howmuergy it requires.
You may recall from an earlier chapter that the mitodria are thought to have inatedas captive bacteria and that they now live essentially as lodgers in our cells, preserving theirowistrus, dividing to their own timetable, speaking their own language. Youmay also recall that we are at the mercy of their goodwill. Here’s why. Virtually all the foodand oxygen you take into your body are delivered, after processing, to the mitodria,where they are verted into a molecule called adenosiriphosphate, or ATP.
You may not have heard of ATP, but it is what keeps you going. ATP molecules areessentially little battery packs that move through the cell providing energy for all the cell’sprocesses, and you get through a lot of it. At any given moment, a typical cell in your bodywill have about one billion ATP molecules in it, and in two minutes every one of them willhave been drained dry and another billion will have taken their place. Every day you produd use up a volume of ATP equivalent to about half your body weight. Feel the warmth ofyour skin. That’s your ATP at work.
When cells are no longer hey die with what only be called great dignity. Theytake down all the struts and buttresses that hold them together and quietly devour theirpo parts. The process is knooptosis rammed cell death. Every daybillions of your cells die for your be and billions of others up the mess. Cells also die violently—for instance, when ied—b..ut mostly they die because they are told to.
Indeed, if not told to live—if not given some kind of active instru from another cell—cells automatically kill themselves. Cells need a lot of reassurance.
When, as occasionally happens, a cell fails to expire in the prescribed manner, but ratherbegins to divide and proliferate wildly, we call the result cer. cer cells are really justfused cells. Cells make this mistake fairly regularly, but the body has elaboratemeisms for dealing with it. It is only very rarely that the process spirals out of trol. Onaverage, humans suffer oal malignancy for eaillion billion cell divisions.
cer is bad lu every possible sense of the term.
The wonder of cells is not that things occasionally g, but that they manageeverything so smoothly for decades at a stretch. They do so by stantly sending andmonit streams of messages—a cacophony of messages—from all around the body:
instrus, queries, corres, requests for assistance, updates, notices to divide or expire.
Most of these signals arrive by means of couriers called hormones, chemical entities such asinsulin, adrenalirogen, aosterohat vey information from remote outpostslike the thyroid and endoe glands. Still other messages arrive by telegraph from the brainor frional ters in a process called parae signaling. Finally, cells unicatedirectly with their neighbors to make sure their as are coordinated.
What is perhaps most remarkable is that it is all just random frantic a, a sequence ofendless enters directed by nothing more thaal rules of attra and repulsion.
There is clearly no thinking presence behind any of the as of the cells. It all just happens,smoothly aedly and so reliably that seldom are we even scious of it, yet somehowall this produot just order within the cell but a perfect harmht across the anism.
In ways that we have barely begun to uand, trillions upon trillions of reflexive chemicalreas add up to a mobile, thinking, deaking you—or, e to that, a rather lessreflective but still incredibly anized dule. Every living thing, never fet, is awonder of atomigineering.
Indeed, some anisms that we think of as primitive enjoy a level of cellular anizationthat makes our own look carelessly pedestrian. Disassemble the cells of a sponge (by passihrough a sieve, for instahen dump them into a solution, and they will find theirway back together and build themselves into a sponge again. You do this to them overand over, and they will doggedly reassemble because, like you and me and every other livingthing, they have one overwhelming impulse: to tio be.
And that’s because of a curious, determined, barely uood molecule that is itself notalive and for the most part doesn’t do anything at all. We call it DNA, and to begin touand its supreme importao sd to us we o go back 160 years or so toVictorian England and to the moment wheuralist Charles Darwin had what has beencalled “the single best idea that anyone has ever had”—and then, for reasons that take a littleexplaining, locked it away in a drawer for the fifteen years.
25 DARWIN’S SINGULAR NOTION
IE summer or early autumn of 1859, Whitwell Elwior of the respectedBritish journal the Quarterly Review, was sent an advance copy of a new book by thenaturalist Charles Darwin. Elwihe book with i and agreed that it had merit, butfeared that the subject matter was too narrow to attract a wide audience. He urged Darwin towrite a book about pigeons instead. “Everyone is ied in pigeons,” he observedhelpfully.
Elwin’s sage advice was ignored, and On the in of Species by Means of NaturalSele, or the Preservation of Favoured Races iruggle for Life ublished in lateNovember 1859, priced at fifteen shillings. The first edition of 1,250 copies sold out on thefirst day. It has never been out of print, and scarcely out of troversy, in all the time si bad going for a man whose principal other i was earthworms and who, but for asingle impetuous decision to sail around the world, would very probably have passed his lifeas an anonymous try parson known for, well, for an i ihworms.
Charles Robert Darwin was born on February 12, 1809,1in Shrewsbury, a sedate markettown in the west Midlands of England. His father rosperous and well-regardedphysi. His mother, who died when Charles was o, was the daughter of JosiahWedgwood, of pottery fame.
Darwin enjoyed every advantage of upbringing, but tinually pained his widowed fatherwith his lackluster academic performance. “You care for nothing but shooting, dogs, and rat-catg, and you will be a disgrace to yourself and all your family,” his father wrote in a li nearly always appears just about here in any review of Darwin’s early life. Although hisination was to natural history, for his father’s sake he tried to study medie at EdinburghUy but couldn’t bear the blood and suffering. The experience of witnessing aion on an un藏书网
derstandably distressed child—this was in the days before ahetics, ofcourse—left him permaly traumatized. He tried law instead, but found that insupportablydull and finally managed, more or less by default, to acquire a degree in divinity fromCambridge.
A life in a rural vicarage seemed to await him when from out of the blue there came a moretempting offer. Darwin was io sail on the naval survey ship HMS Beagle, essentiallyas dinner pany for the captain, Robert FitzRoy, whose rank precluded his socializing withaher than a gentleman. FitzRoy, who was very odd, chose Darwin in part because heliked the shape of Darwin’s nose. (It betokened depth of character, he believed.) Darwin wasnot FitzRoy’s first choice, but got the nod when FitzRoy’s preferred panion dropped out.
From a twenty-first-tury perspective the two men’s most striking joiure was their1An auspicious date in history: on the same day iucky, Abraham Lin was born.
extreme youthfulness. At the time of sailing, FitzRoy was only twenty-three, Darwin justtwenty-two.
FitzRoy’s formal assig was to chart coastal waters, but his hobby—passion really—was to seek out evidence for a literal, biblical interpretation of creation. That Darwin wastrained for the ministry was tral to FitzRoy’s decision to have him aboard. That Darwinsubsequently proved to be not only liberal of view but less than wholeheartedly devoted toChristian fuals became a source of lasting fri between them.
Darwin’s time aboard HMS Beagle, from 1831 to 1836, was obviously the formativeexperience of his life, but also one of the most trying. He and his captain shared a small ,which ’t have been easy as FitzRoy was subject to fits of fury followed by spells ofsimmeriment. He and Darwin stantly engaged in quarrels, some “b oninsanity,” as Darwin later recalled. O voyages teo beelancholyuakings at the best of times—the previous captain of the Beagle had put a bullet throughhis brain during a moment of lonely gloom—and FitzRoy came from a family well known fora depressive instinct. His uncle, Vist Castlereagh, had slit his throat the previous decadewhile serving as cellor of the Exchequer. (FitzRoy would himself it suicide by thesame method in 1865.) Even in his calmer moods, FitzRoy proved strangely unknowable.
Darwin was astouo learn upon the clusion of their voyage that almost at ozRoy married a young woman to whom he had long beehed. In five years inDarwin’s pany, he had not once hi an attat or eveioned her name.
In every other respect, however, the Beagle voyage was a triumph. Darwin experiencedadventure enough to last a lifetime and accumulated a hoard of spes suffit to makehis reputation and keep him occupied for years. He found a magnifit trove of giant afossils, including the fi Megatherium known to date; survived a lethal earthquake inChile; discovered a new species of dolphin (which he dutifully named Delphinus fitzroyi);ducted diligent and useful geological iigations throughout the Andes; and developeda new and much-admired theory for the formation of coral atolls, which suggested, nottally, that atolls could not form ihan a million years—the first hint of hislong-standing attat to the extreme antiquity of earthly processes. In 1836, aged twenty-seveurned home after being away for five years and two days. He never left Englandagain.
Ohing Darwin didn’t do on the voyage ropound the theory (or even a theory) ofevolution. For a start, evolution as a cept was already decades old by the 1830s. Darwin’sown grandfather, Erasmus, had paid tribute to evolutionary principles in a poem of inspiredmediocrity called “The Temple of Nature” years before Charles was even born. It wasn’t untilthe younger Darwin was ba England ahomas Malthus’s Essay on the Principleof Population (which proposed that increases in food supply could never keep up withpopulation growth for mathematical reasons) that the idea began to percolate through his mindthat life is a perpetual struggle and that natural sele was the means by whiespecies prospered while others failed. Specifically what Darwin saw was that all anismspeted for resources, and those that had some innate advantage would prosper and pass onthat advao their offspring. By such means would species tinuously improve.
It seems an awfully simple idea—it is an awfully simple idea—but it explained a great deal,and Darwin repared to devote his life to it. “How stupid of me not to have thought ofit!” T. H. Huxley cried upon reading On the in of Species. It is a view that has beenechoed ever since.
Iingly, Darwin didn’t use the phrase “survival of the fittest” in any of his work(though he did express his admiration for it). The expression was ed five years after thepublication of On the in of Species by Herbert Spencer in Principles of Biology in 1864.
Nor did he employ the word evolution in print until the sixth edition in (by which timeits use had bee too widespread to resist), preferring instead “dest with modification.”
Nor, above all, were his clusions in any way inspired by his notig, during his time inthe Galápagos Islands, an iing diversity in the beaks of fihe story asventionally told (or at least as frequently remembered by many of us) is that Darwin,while traveling from island to island, noticed that the finches’ beaks on each island weremarvelously adapted for exploiting local resources—that on one island beaks were sturdy andshort and good for crag nuts, while on the island beaks were perhaps long and thinand well suited for winkling food out of crevices—and it was this that set him to thinking thatperhaps the birds had not beeed this way, but had in a sense created themselves.
In fact, the birds had created themselves, but it wasn’t Darwin who noticed it. At the timeof the Beagle voyage, Darwin was fresh out of college and not yet an aplished naturalistand so failed to see that the Galápagos birds were all of a type. It was his friend theornithologist John Gould who realized that what Darwin had found was lots of finches withdifferent talents. Unfortunately, in his inexperience Darwin had not noted which birds camefrom which islands. (He had made a similar error with tortoises.) It took years to sort themuddles out.
Because of these hts, and the o sort through crates and crates of other Beaglespes, it wasn’t until 1842, six years after his return to England, that Darwin finallybegan to sketch out the rudiments of his heory. These he expanded into a 230-page“sketch” two years later. And then he did araordinary thing: he put his notes away andfor the decade and a half busied himself with other matters. He fathered ten childreed nearly eight years to writing an exhaustive opus on barnacles (“I hate a barnacle as noman ever did before,” he sighed, uandably, upon the work’s clusion), and fell preyte disorders that left him ically listless, faint, and “flurried,” as he put it. Thesymptoms nearly always included a terrible nausea and generally also incorporatedpalpitations, migraines, exhaustion, trembling, spots before the eyes, shortness of breath,“swimming of the head,” and, not surprisingly, depression.
The cause of the illness has never beeablished, but the most romantid perhapslikely of the many suggested possibilities is that he suffered from Chagas’s disease, alingering tropical malady that he could have acquired from the bite of a Benchuga bug inSouth America. A more prosaic explanation is that his dition syati eithercase, the misery was not. Often he could work for no more thay mi a stretetimes not that.
Much of the rest of his time was devoted to a series of increasingly desperate treatments—icy pluhs, dousings in vinegar, draping himself with “electric s” that subjectedhim to small jolts of current. He became something of a hermit, seldom leaving his home i, Down House. One of his first acts upon moving to the house was to erect a mirroroutside his study window so that he could identify, and if necessary avoid, callers.
Darwi his theory to himself because he well khe storm it would cause. In 1844,the year he locked his notes away, a book called Vestiges of the Natural History of Creationroused much of the thinking world to fury by suggesting that humans might have evolvedfrom lesser primates without the assistance of a divine creator. Anticipating the outcry, theauthor had taken careful steps to ceal his identity, which he kept a secret from even hisclosest friends for the forty years. Some wondered if Darwin himself might be the author.
Others suspected Prince Albert. In fact, the author was a successful and generally unassumingScottish publisher named Robert Chambers whose reluce to reveal himself had a practicaldimension as well as a personal one: his firm was a leading publisher of Bibles. Vestiges waswarmly blasted from pulpits throughout Britain and far beyond, but also attracted a good dealof more scholarly ire. The Edinburgh Review devoted nearly aire issue—eighty-fivepages—to pulling it to pieces. Even T. H. Huxley, a believer in evolution, attacked the bookwith some venom, unaware that the author was a friend.
2Darwin’s manuscript might have remained locked away till his death but for an alarmingblow that arrived from the Far East in the early summer of 1858 in the form of a packettaining a friendly letter from a young naturalist named Alfred Russel Wallad the draftof a paper, Oendency of Varieties to Depart Indefinitely from the inal Type,outlining a theory of natural sele that was unily similar to Darwin’s secret jottings.
Even some of the phrasing echoed Darwin’s own. “I never saw a more striking ce,”
Darwin reflected in dismay. “If Wallace had my manuscript sketch written out in 1842, hecould not have made a better short abstract.”
Wallace didn’t drop into Darwin’s life quite as uedly as is sometimes suggested.
The two were already corresponding, and Wallace had more than once generously sentDarwin spes that he thought might be of i. In the process of these exgesDarwin had discreetly warned Wallace that he regarded the subject of species creation as hisowory. “This summer will make the 20th year (!) since I opened my first note-book, onthe question of ho; in what way do species & varieties differ from each other,” he hadwritten to Wallae time earlier. “I am now preparing my work for publication,” headded, even though he wasn’t really.
In any case, Wallace failed to grasp what Darwin was trying to tell him, and of course hecould have no idea that his own theory was so nearly identical to ohat Darwin had beenevolving, as it were, for two decades.
Darwin laced in an agonizing quandary. If he rushed into print to preserve his priority,he would be taking advantage of an iip-off from a distant admirer. But if he steppedaside, as gentlemanly duct arguably required, he would lose credit for a theory that he hadindepely propounded. Wallace’s theory was, by Wallace’s own admission, the result of aflash of insight; Darwin’s was the product of years of careful, plodding, methodical thought. Itwas all crushingly unfair.
To pound his misery, Darwin’s you son, also named Charles, had tracted scarletfever and was critically ill. At the height of the crisis, on June 28, the child died. Despite thedistra of his son’s illness, Darwin found time to dash off letters to his friends CharlesLyell and Joseph Hooker, to step aside but noting that to do so would mean that allhis work, “whatever it may amount to, will be smashed.” Lyell and Hooker came up with thepromise solution of presenting a summary of Darwin’s and Wallace’s ideas together. Thevehey settled on was a meeting of the Linnaean Society, which at the time was strugglingto find its way bato fashion as a seat of stific eminence. On July 1, 1858, Darwin’s2Darwin was one of the few to guess correctly. He happeo be visiting Chambers one day when an advancecopy of the sixth edition of Vestiges was delivered. The keenness with which Chambers checked the revisionswas something of a giveaway, though it appears the two men did not discuss it.
and Wallace’s theory was unveiled to the world. Darwin himself was not present. On the dayof the meeting, he and his wife were burying their son.
The Darwin–resentation was one of seven that evening—one of the others was onthe flora of Angola—and if the thirty or so people in the audience had any idea that they werewitnessing the stific highlight of the tury, they showed no sign of it. No discussionfollowed. Nor did the event attract muotice elsewhere. Darwin cheerfully later hatonly one person, a Professor Haughton of Dubliiohe ters in print and hisclusion was “that all that was new in them was false, and what was true was old.”
Wallace, still in the dista, learned of these maneuverings long after the event, butwas remarkably equable and seemed pleased to have been included at all. He even referred tothe theory forever after as “Darwinism.” Much less ameo Darwin’s claim of prioritywas a Scottish gardener named Patrick Matthew who had, rather remarkably, also e upwith the principles of natural sele—in fact, in the very year that Darwin had set sail intheBeagle. Unfortunately, Mattheublished these views in a book called Naval Timberand Arboriculture, which had been missed not just by Darwin, but by the entire world.
Matthew kicked up in a lively manner, with a letter to Gardener’s icle, when he sawDarwin gaining credit everywhere for ahat really was his. Darologized withouthesitation, though he did note for the record: “I think that no one will feel surprised thather I, nor apparently any other naturalist, has heard of Mr. Matthew’s views, sideringhow briefly they are given, and they appeared in the Appendix to a work on Naval Timberand Arboriculture.”
Wallace tinued for another fifty years as a naturalist and thinker, occasionally a verygood one, but increasingly fell from stific favor by taking up dubious is such asspiritualism and the possibility of life existing elsewhere in the universe. So the theorybecame, essentially by default, Darwin’s alone.
Darwin never ceased being tormented by his ideas. He referred to himself as “the Devil’sChaplain” and said that revealing the theory felt “like fessing a murder.” Apart from allelse, he k deeply pained his beloved and pious wife. Even so, he set to work at onceexpanding his manuscript into a book-length work. Provisionally he called it An Abstract ofan Essay on the in of Species and Varieties through Natural Sele —a title so tepidaive that his publisher, John Murray, decided to issue just five hundred copies. Butonce presented with the manuscript, and a slightly more arresting title, Murray resideredand increased the initial print run to 1,250.
On the in of Species was an immediate ercial success, but rather less of a critie. Darwin’s theory presewo intractable difficulties. It needed far more time than LordKelvin was willing to cede, and it was scarcely supported by fossil evidence. Where,asked Darwin’s more thoughtful critics, were the transitional forms that his theory so clearlycalled for? If new species were tinuously evolving, then there ought to be lots ofintermediate forms scattered across the fossil record, but there were not.
3In fact, the record asit existed then (and for a long time afterward) showed no life at all right up to the moment ofthe famous Cambrian explosion.
3By ce, in 1861, at the height of the troversy, just such evideurned up when workers inBavaria found the bones of an a archaeopteryx, a creature halfway between a bird and a dinosaur. (It hadfeathers, but it also had teeth.) It was an impressive and helpful find, and its significe much debated, but asingle discovery could hardly be sidered clusive.
But now here was Darwin, without any evidence, insisting that the earlier seas must havehad abundant life and that we just hadn’t found it yet because, for whatever reason, it hadn’tbeen preserved. It simply could not be otherwise, Darwin maintained. “The case at presentmust remain inexplicable; and may be truly urged as a valid argument against the views hereeained,” he allowed most didly, but he refused to eain an alternative possibility.
By way of explanation he speculated—iively but incorrectly—that perhaps thePrecambrian seas had been too clear to lay down sediments and thus had preserved no fossils.
Even Darwin’s closest friends were troubled by the blitheness of some of his assertions.
Adam Sedgwick, who had taught Darwin at Cambridge and taken him on a geological tour ofWales in 1831, said the book gave him “more pain than pleasure.” Louis Agassiz dismissed itas poor jecture. Even Lyell cluded gloomily: “Darwioo far.”
T. H. Huxley disliked Darwin’s insisten huge amounts of geological time because hewas a saltationist, which is to say a believer in the idea that evolutionary ges happen notgradually but suddenly. Saltationists (the word es from the Latin for “leap”) couldn’taccept that plicated ans could ever emerge in slow stages. What good, after all, is oh of a wing or half an eye? Such ans, they thought, only made sense if they appeared ina fiate.
The belief was surprising in as radical a spirit as Huxley because it closely recalled a veryservative religious notion first put forward by the English theologian William Paley in1802 and known as argument from design. Paley tehat if you found a pocket wat the ground, even if you had never seen such a thing before, you would instantly perceivethat it had been made by an intelligey. So it was, he believed, with nature: itsplexity roof of its design. The notion owerful one in the eenth tury,and it gave Darwin trouble too. “The eye to this day gives me a cold shudder,” heaowledged in a letter to a friend. In the in he ceded that it “seems, I freely fess,absurd in the highest possible degree” that natural sele could produce su instrumentin gradual steps.
Even so, and to the unending exasperation of his supporters, Darwin not only insisted thatall ge was gradual, but in nearly every edition iepped up the amount of timehe supposed necessary to allow evolution tress, which pushed his ideas increasingly outof favor. “Eventually,” acc to the stist and historian Jeffrey Schwartz, “Darwin lostvirtually all the support that still remained among the ranks of fellow natural historians andgeologists.”
Ironically, sidering that Darwin called his book On the in of Species, the ohinghe couldn’t explain was how species inated. Darwin’s theory suggested a meism forhoecies might bee stronger or better or faster—in a word, fitter—but gave noindication of how it might throw up a new species. A Scottish engineer, Fleeming Jenkin,sidered the problem and noted an important flaw in Darwin’s argument. Darwin believedthat any beneficial trait that arose in one geion would be passed on to subsequentgeions, thus strengthening the species.
Jenkin pointed out that a favorable trait in one parent wouldn’t bee dominant insucceeding geions, but in fact would be diluted through blending. If you pour whiskeyinto a tumbler of water, you don’t make the whiskey stronger, you make it weaker. And if youpour that dilute solution into anlass of water, it bees weaker still. In the same way,any favorable trait introduced by one parent would be successively watered down bysubsequent matings until it ceased to be apparent at all. Thus Darwin’s theory was not a recipefor ge, but for stancy. Lucky flukes might arise from time to time, but they wouldsoon vanish uhe general impulse t everything back to a stable mediocrity. Ifnatural sele were to work, some alternative, unsidered meism was required.
Unknown to Darwin and everyone else, eight hundred miles away in a tranquil er ofMiddle Europe a retiring monk named Gregor Mendel was ing up with the solution.
Mendel was born in 1822 to a humble farming family in a backwater of the Austrianempire in what is now the Czech Republic. Schoolbooks once portrayed him as a simple butobservant provincial monk whose discoveries were largely serendipitous—the result ofnotig some iing traits of iance while p about with pea plants in themonastery’s kit garden. In fact, Mendel was a trained stist—he had studied physid mathematics at the Olmütz Philosophical Institute and the Uy of Vienna—and hebrought stific disciplio all he did. Moreover, the monastery at Brno where he livedfrom 1843 was known as a learned institution. It had a library of twenty thousand books and atradition of careful stifivestigation.
Before embarking on his experiments, Mendel spent two years preparing his trolspes, seven varieties of pea, to make sure they bred true. Then, helped by two full-timeassistants, he repeatedly bred and crossbred hybrids from thirty thousand pea plants. It wasdelicate work, requiring them to take the most exag pains to avoid actal cross-fertilization and to note every slight variation in the growth and appearance of seeds, pods,leaves, stems, and flowers. Mendel knew what he was doing.
He never used the we wasn’t ed until 1913, in an English medicaldiary—though he did ihe terms dominant and recessive. What he established wasthat every seed taiwo “factors” or “elemente,” as he called them—a dominant oneand a recessive one—and these factors, when bined, produced predictable patterns ofiance.
The results he verted into precise mathematical formulae. Altogether Mendel spe years on the experiments, then firmed his results with similar experiments onflowers, , and other plants. If anything, Mendel was too stifi his approach, forwhen he presented his findings at the February and March meetings of the Natural HistorySociety of Brno in 1865, the audience of about forty listened politely but was spicuouslyunmoved, even though the breeding of plants was a matter of great practical io manyof the members.
When Mendel’s report ublished, he eagerly sent a copy to the great Swiss botanistKarl-Wilhelm von N?geli, whose support was more or less vital for the theory’s prospects.
Unfortunately, N?geli failed to perceive the importance of what Mendel had found. Hesuggested that Mery breeding hawkweed. Mendel obediently did as N?geli suggested,but quickly realized that hawkweed had none of the requisite features for studyiability.
It was evident to him that N?geli had not read the paper closely, or possibly at all. Frustrated,Mendel retired from iigatiability and spent the rest of his life growingoutstandiables and studying bees, mice, and sunspots, among much else. Eventuallyhe was made abbot.
Mendel’s findings weren’t quite as widely ignored as is sometimes suggested. His studyreceived a glowiry in the Encyclopaedia Britannica —then a more leading record ofstific thought than now—and was cited repeatedly in an important paper by the GermanWilhelm Olbers Focke. Indeed, it was because Mendel’s ideas never entirely sank below thewaterline of stific thought that they were so easily recovered when the world was readyfor them.
Together, without realizing it, Darwin and Mendel laid the groundwork for all of lifesces iweh tury. Darwin saw that all living things are ected, thatultimately they “trace their ary to a single, on source,” while Mendel’s workprovided the meism to explain how that could happen. The two men could easily havehelped each other. Mendel owned a Germaion of the in of Species, which he isknown to have read, so he must have realized the applicability of his work to Darwin’s, yet heappears to have made no effort to get in touch. And Darwin for his part is known to havestudied Focke’s iial paper with its repeated refereo Mendel’s work, but didn’tect them to his own studies.
The ohing everyohinks featured in Darwin’s argument, that humans are desdedfrom apes, didn’t feature at all except as one passing allusion. Even so, it took no great leap ofimagination to see the implications for human development in Darwin’s theories, and itbecame an immediate talking point.
The showdown came on Saturday, June 30, 1860, at a meeting of the British Associationfor the Adva of S Oxford. Huxley had been urged to attend by RobertChambers, author of Vestiges of the Natural History of Creation, though he was still unawareof Chambers’s e to that tentious tome. Darwin, as ever, was absent. The meetingwas held at the Oxford Zoological Museum. More than a thousand people crowded into thechamber; hundreds more were turned aeople khat something big was going tohappen, though they had first to wait while a slumber-indug speaker named John WilliamDraper of New York Uy bravely slogged his way through two hours of introductoryremarks on “The Intellectual Development of Europe sidered with Refereo the Viewsof Mr. Darwin.”
Finally, the Bishop of Oxford, Samuel Wilberforce, rose to speak. Wilberforce had beenbriefed (or so it is generally assumed) by the ardent anti-Darwinian Richard Owen, who hadbeen a guest in his home the night before. As nearly always with events that end in uproar,ats vary widely on what exactly transpired. In the most popular version, Wilberforce,when properly in flow, turo Huxley with a dry smile and demanded of him whether heclaimed attat to the apes by way of his grandmother randfather. The remark wasdoubtless intended as a quip, but it came across as an icy challenge. Acc to his ownat, Huxley turo his neighbor and whispered, “The Lord hath delivered him into myhands,” then rose with a certain relish.
Others, however, recalled a Huxley trembling with fury and indignation. At all events,Huxley declared that he would rather claim kinship to ahan to someone who used hisemio propound uninformed twaddle in what was supposed to be a serious stifi. Such a riposte was a sdalous impertinence, as well as an insult to Wilberforce’soffice, and the proceedings instantly collapsed in tumult. A Lady Brewster fainted. RobertFitzRoy, Darwin’s panion on the Beagle twenty-five years before, wahrough thehall with a Bible held aloft, shouting, “The Book, the Book.” (He was at the fereopresent a paper on storms in his capacity as head of the newly created MeteicalDepartment.) Iingly, each side afterward claimed to have routed the other.
Darwin did eventually make his belief in our kinship with the apes explicit in The Desan in 1871. The clusion was a bold one sihing in the fossil record supportedsuch a notion. The only known early human remains of that time were the famous Neaalbones from Germany and a few uain fragments of jawbones, and many respectedauthorities refused to believe even in their antiquity. The Dest of Man was altogether amore troversial book, but by the time of its appearahe world had grown less excitableand its arguments caused much less of a stir.
For the most part, however, Darwin passed his twilight years with other projects, most ofwhich touched only taially oions of natural sele. He spent amazingly longperiods pig through bird droppings, scrutinizing the tents in an attempt to uandhow seeds spread between tis, and spent years more studying the behavior of worms.
One of his experiments was to play the piano to them, not to amuse them but to study theeffects on them of sound and vibration. He was the first to realize how vitally importantworms are to soil fertility. “It may be doubted whether there are many other animals whichhave played so important a part in the history of the world,” he wrote in his masterwork on thesubject, The Formation of Vegetable Mould Through the A of Worms (1881), which wasactually more popular thanOn the in of Species had ever been. Among his other bookswere On the Various trivances by Which British and Fn Orchids Are Fertilised byIs (1862), Expressions of the Emotions in Man and Animals (1872), which sold almost5,300 copies on its first day, The Effects of Cross and Self Fertilization in the VegetableKingdom (1876)—a subject that came improbably close to Mendel’s own work, withoutattaining anything like the same insights—and his last book, The Power of Movement inPlants. Finally, but not least, he devoted much effort to studying the sequences ofinbreeding—a matter of private io him. Having married his own cousin, Darwinglumly suspected that certain physical aal frailties among his children arose from alack of diversity in his family tree.
Darwin was often honored in his lifetime, but never for On the in of Species orDesan. When the Royal Society bestowed on him the prestigious Copley Medal it was for hisgeology, zoology, and botany, not evolutionary theories, and the Linnaean Society wassimilarly pleased to honor Darwin without embrag his radiotions. He was neverknighted, though he was buried iminster Abbey—o on. He died at Down inApril 1882. Mendel died two years later.
Darwin’s theory didn’t really gain widespread acceptail the 1930s and 1940s, withthe advance of a refiheory called, with a certain hauteur, the Modern Synthesis,bining Darwin’s ideas with those of Mendel and others. For Mendel, appreciation wasalso posthumous, though it came somewhat sooner. In 1900, three stists wseparately in Europe rediscovered Mendel’s work more or ..less simultaneously. It was onlybecause one of them, a Dut named Hugo de Vries, seemed set to claim Mendel’sinsights as his own that a rival made it noisily clear that the credit really lay with the fottenmonk.
The world was almost ready, but not quite, to begin to uand how we got here—howwe made each other. It is fairly amazing to reflect that at the beginning of the twehtury, and for some years beyond, the best stifids in the world couldn’t actuallytell you where babies came from.
And these, you may recall, were men who thought sce was nearly at an end.
26 THE STUFF OF LIFE
IF YOUR TWO parents hadn’t bonded just when they did—possibly to the sed, possiblyto the nanosed—you wouldn’t be here. And if their parents hadn’t bonded in a preciselytimely manner, you wouldn’t be here either. And if their parents hadn’t done likewise, andtheir parents before them, and so on, obviously and indefinitely, you wouldn’t be here.
Push backwards through time and these aral debts begin to add up. Go back just eightgeions to about the time that Charles Darwin and Abraham Lin were born, andalready there are over 250 people on whose timely couplings your existence depends.
tinue further, to the time of Shakespeare and the Mayflower Pilgrims, and you have nofewer than 16,384 aors early exgiic material in a way that would,eventually and miraculously, result in you.
At twenty geions ago, the number of people procreating on your behalf has risen to1,048,576. Five geions before that, and there are no fewer than 33,554,432 men andwomen on whose devoted couplings your existence depends. By thirty geions ago, yourtotal number of forebears—remember, these aren’t cousins and aunts and other ialrelatives, but only parents and parents of parents in a line leading iably to you—is overone billion (1,073,741,824, to be precise). If you go back sixty-feions, to the time ofthe Romans, the number of people on whose cooperative efforts your eventual existencedepends has risen to approximately 1,000,000,000,000,000,000, which is several thousandtimes the total number of people who have ever lived.
Clearly something has gone wrong with our math here. The answer, it may i you tolearn, is that your line is not pure. You couldn’t be here without a little i—actually quitea lot of i—albeit at a geically discreet remove. With so many millions of aors inyour background, there will have been many occasions when a relative from your mother’sside of the family procreated with some distant cousin from your father’s side of the ledger. Infact, if you are in a partnership now with someone from your own rad try, theces are excellent that you are at some level related. Indeed, if you look around you on abus or in a park or café or any crowded place, most of the people you see are very probablyrelatives. When someone boasts to you that he is desded from William the queror orthe Mayflower Pilgrims, you should a once: “Me, too!” In the most literal andfual sense we are all family.
We are also unily alike. pare yenes with any other human being’s and onaverage they will be about 99.9 pert the same. That is what makes us a species. The tinydifferences in that remaining 0.1 pert—“roughly one ide base ihousand,”
to quote the British geicist a Nobel laureate John Sulston—are what endow uswith our individuality. Much has been made i years of the unraveling of the humangenome. In fact, there is no such thing as “the” human genome. Every human genome isdifferent. Otherwise we would all be identical. It is the endless rebinations of enomes—eaearly identical, but not quite—that make us what we are, both as individualsand as a species.
But what exactly is this thing we call the genome? And what, e to that, are genes?
Well, start with a cell again. Ihe cell is a nucleus, and inside eaucleus are theosomes—forty-six little bundles of plexity, of which twenty-three e from yourmother and twenty-three from your father. With a very few exceptions, every cell in yourbody—99.999 pert of them, say—carries the same plement of osomes. (Theexceptions are red blood cells, some immune system cells, and egg and sperm cells, which forvarious anizational reasons don’t carry the full geic package.) osomes stitutethe plete set of instrus necessary to make and maintain you and are made of longstrands of the little wonder chemical called deoxyribonucleic acid or DNA—“the mostextraordinary molecule oh,” as it has been called.
Ds for just one reason—to create more DNA—and you have a lot of it inside you:
about six feet of it squeezed into almost every cell. Each length of DNA prises some 3.2billioers of g, enough to provide 103,480,000,000possible binations, “guaraobe unique against all ceivable odds,” in the words of Christian de Duve. That’s a lot ofpossibility—a one followed by more than three billion zeroes. “It would take more than fivethousand average-size books just to print that figure,” notes de Duve. Look at yourself in themirror and reflect upon the fact that you are beholdihousand trillion cells, and thatalmost every one of them holds two yards of densely pacted DNA, and you begin toappreciate just how much of this stuff you carry around with you. If all your DNA werewoven into a single firand, there would be enough of it to stretch from the Earth to theMoon and baot once or twice but again and again. Altogether, acc to onecalculation, you may have as much as twenty million kilometers of DNA bundled up insideyou.
Your body, in short, loves to make DNA and without it you couldn’t live. Yet DNA is notitself alive. No molecule is, but DNA is, as it were, especially unalive. It is “among the mostive, chemically i molecules in the living world,” in the words of the geicistRichard Lewontin. That is why it be recovered from patches of long-dried blood or semenin murder iigations and coaxed from the bones of a Neaals. It also explainswhy it took stists so long to work out how a substanystifyingly low key—so, in aword, lifeless—could be at the very heart of life itself.
As a knowy, DNA has been around lohan you might think. It was discoveredas far back as 1869 by Johann Friedrich Miescher, a Swiss stist w at the Uyof Tübingen in Germany. While delving microscopically through the pus in surgicalbandages, Miescher found a substance he didn’t reize and called it nu (because itresided in the nuclei of cells). At the time, Miescher did little more than s existence, butnu clearly remained on his mind, for twenty-three years later in a letter to his uncle heraised the possibility that such molecules could be the agents behind heredity. This was araordinary insight, but one so far in advance of the day’s stific requirements that itattracted no attention at all.
For most of the half tury the on assumption was that the material—nowcalled deoxyribonucleic acid, or DNA—had at most a subsidiary rol?e in matters of heredity. Itwas too simple. It had just four basipos, called ides, which was like havingan alphabet of just four letters. How could you possibly write the story of life with such arudimentary alphabet? (The answer is that you do it in much the way that you create plexmessages with the simple dots and dashes of Morse code—by bining them.) DNA didn’tdo anything at all, as far as anyone could tell. It just sat there in the nucleus, possibly bindingthe osome in some way or adding a splash of acidity on and or fulfilling someother trivial task that no one had yet thought of. The necessary plexity, it was thought,had to exist in proteins in the nucleus.
There were, however, two problems with dismissing DNA. First, there was so much of it:
two yards in nearly every nucleus, so clearly the cells esteemed it in some important way. Ontop of this, it kept turning up, like the suspe a murder mystery, in experiments. In twostudies in particular, one involving the Pneumonococcus bacterium and another involvingbacteriophages (viruses that i bacteria), Drayed an importahat could only beexplained if its role were more tral than prevailing thought allowed. The evidencesuggested that DNA was somehow involved in the making of proteins, a process vital to life,yet it was also clear that proteins were being made outside the nucleus, well away from theDNA that was supposedly direg their assembly.
No one could uand how DNA could possibly be getting messages to the proteins. Theanswer, we now know, was RNA, or ribonucleic acid, which acts as an interpreter betweewo. It is a notable oddity of biology that DNA and proteins don’t speak the samelanguage. For almost four billion years they have been the living world’s great double act, ahey ao mutually inpatible codes, as if one spoke Spanish and the other Hindi.
To unicate they need a mediator in the form of RNA. W with a kind of chemicalclerk called a ribosome, RNA translates information from a cell’s DNA into terms proteins uand and act upon.
However, by the early 1900s, where we resume our story, we were still a very long wayfrom uanding that, or indeed almost anything else to do with the fused business ofheredity.
Clearly there was a need for some inspired and clever experimentation, and happily the ageproduced a young person with the diligend aptitude to uake it. His name wasThomas Hunt Man, and in 1904, just four years after the timely rediscovery of Mendel’sexperiments with pea plants and still almost a decade befene would even bee a word,he began to do remarkably dedicated things with osomes.
osomes had been discovered by 1888 and were so called because theyreadily absorbed dye and thus were easy to see uhe microscope. By the turn of thetweh tury it was strongly suspected that they were involved in the passing on of traits,but no one knew how, or even really whether, they did this.
Man chose as his subject of study a tiny, delicate fly formally called Drosophilamelanogaster, but more only known as the fruit fly (or vinegar fly, banana fly, e fly). Drosophila is familiar to most of us as that frail, colorless ihat seems tohave a pulsive urge to drown in our drinks. As laboratory spes fruit flies had certainvery attractive advahey cost almost nothing to house and feed, could be bred by themillions in milk bottles, went from egg to productive parenthood in ten days or less, and hadjust four osomes, which kept things vely simple.
W out of a small lab (which became knowably as the Fly Room) inSchermerhorn Hall at bia Uy in New York, Man and his team embarked ona program of meticulous breeding and crossbreeding involving millions of flies (onebiographer says billions, though that is probably an exaggeration), each of which had to becaptured with tweezers and examined under a jeweler’s glass for any tiny variations iance. For six years they tried to produce mutations by any means they could think of—zapping the flies with radiation and X-rays, rearing them in bright light and darkness, bakingthem gently in ovens, spinning them crazily irifuges—but nothing worked. Man wason the brink of giving up when there occurred a sudden aable mutation—a fly thathad white eyes rather than the usual red ones. With this breakthrough, Man and hisassistants were able to gee useful deformities, allowing them to track a trait throughsuccessive geions. By such means they could work out the correlatioweenparticular characteristid individual osomes, eventually proving to more or lesseveryone’s satisfa that osomes were at the heart of iance.
The problem, however, remaihe level of biological intricacy: the enigmatiesand the DNA that posed them. These were much trickier to isolate and uand. Aslate as 1933, when Man was awarded a Nobel Prize for his work, many researchers stillweren’t vihat genes eveed. As Man the time, there was nosensus “as to what the genes are—whether they are real or purely fictitious.” It may seemsurprising that stists could struggle to accept the physical reality of something sofual to cellular activity, but as Wallace, King, and Sanders point out in Biology: TheSce of Life (that rarest thing: a readable college text), we are in much the same positiontoday with mental processes such as thought and memory. We know that we have them, ofcourse, but we don’t know what, if any, physical form they take. So it was for the loimewith gehe idea that you could plue from your body and take it away for study wasas absurd to many of Man’s peers as the idea that stists today might capture a straythought and exami under a microscope.
What was certainly true was that something associated with osomes was diregcell replication. Finally, in 1944, after fifteen years of effort, a team at the RockefellerInstitute in Manhattan, led by a brilliant but diffident adian named Oswald Avery,succeeded with an exceedingly tricky experiment in whi innocuous strain of bacteria ermaly iious by crossing it with alien DNA, proving that DNA was far morethan a passive molecule and almost certainly was the active agent in heredity. The Austrian-born biochemist Erwin Chargaff later suggested quite seriously that Avery’s discovery wasworth two Nobel Prizes.
Unfortunately, Avery posed by one of his own colleagues at the institute, a strong-willed and disagreeable proteihusiast named Alfred Mirsky, who did everything in hispower to discredit Avery’s work—including, it has been said, lobbying the authorities at theKarolinska Institute in Sto not to give Avery a Nobel Prize. Avery by this time wassixty-six years old and tired. Uo deal with the stress and troversy, he resigned hisposition and never went near a lab again. But other experiments elsewhere overwhelminglysupported his clusions, and soon the race was on to find t..９9ｌｉｂ?n as bases. The bases—theletters of the geic alphabet—sist of the four ides mentioned a page or two back:
adehiamine, guanine, and cytosine. Despite the importance of what they do, thesesubstances are not made of anythiic. Guanine, for instance, is the same stuff thatabounds in, and gives its o, guano.
The shape of a DNA molecule, as everyone knows, is rather like a spiral staircase ortwisted rope ladder: the famous double helix. The uprights of this structure are made of a typeof sugar called deoxyribose, and the whole of the helix is a nucleic acid—hehe name“deoxyribonucleic acid.” The rungs (or steps) are formed by two bases joining across thespace between, and they bine in only two ways: guanine is alaired withcytosine and thiamine always with adehe order in which these letters appear as youmove up or down the ladder stitutes the DNA code; logging it has been the job of theHuman Genome Project.
Now the particular brilliance of DNA lies in its manner of replication. When it is time toproduce a new DNA molecule, the two strands part down the middle, like the zipper on ajacket, and each half goes off to form a new partnership. Because eaucleotide along astrand pairs up with a specific other ide, each strand serves as a template for thecreation of a new matg strand. If you possessed just orand of your own DNA, youcould easily enough restruct the matg side by w out the necessary partnerships:
if the topm orand was made of guahen you would know that thetopm og strand must be cytosine. Work your way down the ladderthrough all the ide pairings, aually you would have the code for a newmolecule. That is just what happens in nature, except that nature does it really quickly—inonly a matter of seds, which is quite a feat.
Most of the time our DNA replicates with dutiful accuracy, but just occasionally—aboutoime in a million—a letter gets into the wrong place. This is known as a single idepolymorphism, or SNP, familiarly known to biochemists as a “Snip.” Generally these Snipsare buried in stretches of nong DNA and have able sequence for the body.
But occasionally they make a differehey might leave you predisposed to some disease,but equally they might fer some slight advantage—more protective pigmentation, forinstance, or increased produ of red blood cells for someone living at altitude. Over time,these slight modifications accumulate in both individuals and in populations, tributing tothe distinctiveness of both.
The balaween accurad errors in replication is a fine ooo many errors andthe anism ’t fun, but too few and it sacrifices adaptability. A similar balance mustexist between stability in an anism and innovation. An increase in red blood cells helpa persroup living at high elevations to move and breathe more easily because more redcells carry more oxygen. But additional red cells also thi the blood. Add too many,and “it’s like pumping oil,” in the words of Temple Uy anthropologist Charles Weitz.
That’s hard on the heart. Thus those desigo live at high altitude get increased breathingefficy, but pay for it with higher-risk hearts. By such means does Darwinian naturalsele look after us. It also helps to explain why we are all so similar. Evolution simplywon’t let you bee too different—not without being a new species anyway.
The 0.1 pert differeween yenes and mine is ated for by our Snips.
Now if you pared your DNA with a third person’s, there would also be 99.9 pertcorrespondence, but the Snips would, for the most part, be in different places. Add morepeople to the parison and you will get yet more Snips i more places. For every one ofyour 3.2 billion bases, somewhere on the plahere will be a person, roup of persons,with different g in that position. So not only is it wrong to refer to “the” human ge in a sense we don’t even have “a” human genome. We have six billion of them. We are all99.9 pert the same, but equally, in the words of the biochemist David Cox, “you could sayall humans share nothing, and that would be correct, too.”
But we have still to explain why so little of that DNA has any disible purpose. It startsto get a little unnerving, but it does really seem that the purpose of life is to perpetuate DNA.
The 97 pert of our DNA only called junk is largely made up of clumps of lettersthat, in Ridley’s words, “exist for the pure and simple reason that they are good at gettingthemselves duplicated.”
2Most of your DNA, in other words, is not devoted to you but toitself: you are a mae for reprodug it, not it for you. Life, you will recall, just wants tobe, and DNA is what makes it so.
Even when DNA includes instrus for making genes—when it codes for them, asstists put it—it is not necessarily with the smooth funing of the anism in mind.
One of the o genes we have is for a protein called reverse transcriptase, which hasno known beneficial fun in human beings at all. The ohing itdoes do is make itpossible for retroviruses, such as the AIDS virus, to slip unnoticed into the human system.
In other words, our bodies devote siderable energies to produg a protein that doesnothing that is beneficial and sometimes clobbers us. Our bodies have no choice but to do sobecause the genes order it. We are vessels for their whims. Altogether, almost half of humahe largest proportio found in any anism—don’t do anything at all, as far aswe tell, except reproduce themselves.
All anisms are in some sense slaves to their gehat’s why salmon and spiders andother types of creatures more or less beyond ting are prepared to die in the process ofmating. The desire to breed, to disperse one’s genes, is the most powerful impulse in nature.
As Sherwin B. Nuland has put it: “Empires fall, ids explode, great symphonies are written,and behind all of it is a single instinct that demands satisfa.” From an evolutionary pointof view, sex is really just a reward meism to ence us to pass on eic material.
Stists had only barely absorbed the surprisihat most of our DNA doesn’t doanything when even more ued findings began to turn up. First in Germany and then inSwitzerland researchers performed some rather bizarre experiments that produced curiouslyunbizarre outes. Ihey took the gehat trolled the development of a mouse’seye and ied it into the larva of a fruit fly. The thought was that it might produething iingly grotesque. In fact, the mouse-eye ge only made a viable eye inthe fruit fly, it made a fly’s eye. Here were two creatures that hadn’t shared a oor for 500 million years, yet could s geic material as if they were sisters.
The story was the same wherever researchers looked. They found that they could ihuman DNA into certain cells of flies, and the flies would accept it as if it were their own.
2Junk DNA does have a use. It is the portion employed in DNA fingerprinting. Its practicality for this purposewas discovered actally by Alec Jeffreys, a stist at the Uy of Leicester in England. In 1986Jeffreys was studying DNA sequences feic markers associated with heritable diseases when he roached by the polid asked if he could help ect a suspect to two murders. He realized his teiqueought to work perfectly for solving criminal cases-and so it proved. A young baker with the improbable name of Pitchfork was senteo two life terms in prison for the murders.
Over 60 pert of human genes, it turns out, are fually the same as those found infruit flies. At least 90 pert correlate at some level to those found in mice. (We even havethe same genes for making a tail, if only they would swit.) In field after field,researchers found that whatever anism they were w oher ode wormsor human beings—they were often studying essentially the same genes. Life, it appeared, wasdrawn up from a si of blueprints.
Further probings revealed the existence of a clutaster trol genes, each diregthe development of a se of the body, which were dubbed homeotic (from a Greek wordmeaning “similar”) or hox genes. Hox genes answered the long-bewildering question of howbillions of embryonic cells, all arising from a single fertilized egg and carrying identiA, know where to go and what to do—that this one should bee a liver cell, this oreteuron, this one a bubble of blood, this one part of the shimmer on a beating wing. Itis the hox gehat instruct them, and they do it for all anisms in much the same way.
Iingly, the amount of geic material and how it is anized doesn’t necessarily, oreven generally, reflect the level of sophistication of the creature that tains it. We haveforty-six osomes, but some ferns have more than six huhe lungfish, one of theleast evolved of all plex animals, has forty times as muA as we have. Even theo is meically splendorous than we are, by a factor of five.
Clearly it is not the number of genes you have, but what you do with them. This is a verygood thing because the number of genes in humans has taken a big hit lately. Until retly itwas thought that humans had at least 100,000 genes, possibly a good many more, but thatnumber was drastically reduced by the first results of the Human Genome Project, whichsuggested a figure more like 35,000 or 40,000 genes—about the same number as are found ingrass. That came as both a surprise and a disappoi.
It won’t have escaped your attention that genes have been only implicated in anynumber of human frailties. Exultant stists have at various times declared themselves tohave found the genes responsible for obesity, schizophrenia, homosexuality, criminality,violence, al, even shoplifting and homelessness. Perhaps the apogee (or nadir) of thisfaith in biodeterminism was a study published in the journal S 1980 tending thatwomen are geically inferior at mathematics. In fact, we now know, almost nothing aboutyou is so aodatingly simple.
This is clearly a pity in one important sense, for if you had individual gehat determi or propensity to diabetes or to baldness or any other distinguishing trait, then it wouldbe easy—paratively easy anyway—to isolate and tinker with them. Unfortunately, thirty-five thousand genes funing indepely is not nearly enough to produce the kind ofphysical plexity that makes a satisfactory human being. Genes clearly therefore mustcooperate. A few disorders—hemophilia, Parkinson’s disease, Huntington’s disease, andcystic fibrosis, for example—are caused by lone dysfunal genes, but as a rule disruptivegenes are weeded out by natural sele long before they bee permalytroublesome to a species or population. For the most part our fate and fort—and even oureye color—are determined not by individual genes but by plexes of genes w inalliahat’s why it is so hard to work out how it all fits together and on’t beprodug designer babies anytime soon.
In fact, the more we have learned i years the more plicated matters have teo bee. Even thinking, it turns out, affects the ways genes work. How fast a man’s beardgrows, for instance, is partly a fun of how much he thinks about sex (because thinkingabout sex produces a testosterone surge). In the early 1990s, stists made an even moreprofound discovery when they found they could knock out supposedly vital genes fromembryonic mice, and the mice were not only often borhy, but sometimes were actuallyfitter than their brothers and sisters who had not been tampered with. Wheain importantgenes were destroyed, it turned out, others were stepping in to fill the breach. This wasexcellent news for us as anisms, but not so good for our uanding of how cells worksi introduced ara layer of plexity to something that we had barely begun touand anyway.
It is largely because of these plig factors that crag the human genome becameseen almost at once as only a beginning. The genome, as Erider of MIT has put it, is likea parts list for the human body: it tells us what we are made of, but says nothing about hoork. What’s needed now is the operating manual—instrus for how to make it go.
We are not close to that poi.
So now the quest is to crack the human proteome—a cept so hat the termproteome didn’t eve a decade ago. The proteome is the library of information thatcreates proteins. “Unfortunately,” observed Stific Ameri in the spring of 2002, “theproteome is much more plicated than the genome.”
That’s putting it mildly. Proteins, you will remember, are the workhorses of all livingsystems; as many as a hundred million of them may be busy in any cell at any moment. That’sa lot of activity to try to figure out. Worse, proteins’ behavior and funs are based notsimply on their chemistry, as with genes, but also on their shapes. To fun, a protein mustnot only have the necessary chemical pos, properly assembled, but then must also befolded into aremely specific shape. “Folding” is the term that’s used, but it’s amisleading one as it suggests a geometrical tidihat doesn’t in fact apply. Proteins loopand coil and kle into shapes that are at oravagant and plex. They are more likefuriously mangled coat hahan folded towels.
Moreover, proteins are (if I may be permitted to use a handy archaism) the swingers of thebiological world. Depending on mood aabolic circumstahey will allowthemselves to be phosphorylated, glycosylated, acetylated, ubiquitinated, farneysylated,sulfated, and lio glycophosphatidylinositol anchors, among rather a lot else. Often ittakes relatively little to get them going, it appears. Drink a glass of wine, as StificAmeriotes, and you materially alter the number and types of proteins at large in yoursystem. This is a pleasaure for drinkers, but not nearly so helpful feicists who aretrying to uand what is going on.
It all begin to seem impossibly plicated, and in some ways itis impossiblyplicated. But there is an underlying simplicity in all this, too, owing to an equallyelemental underlying unity in the way life works. All the tiny, deft chemical processes thatanimate cells—the cooperative efforts of ides, the transcription of DNA into RNA—evolved just ond have stayed pretty well fixed ever since across the whole of nature. Asthe late French geicist Jacques Monod put it, only half i: “Anything that is true of E.
ust be true of elephants, except more so.”
Every living thing is an elaboration on a single inal plan. As humans we are mereis—each of us a musty archive of adjustments, adaptations, modifications, andprovidential tinkerings stretg back 3.8 billion years. Remarkably, we are even quiteclosely related to fruit aables. About half the chemical funs that take pla abanana are fually the same as the chemical funs that take pla you.
It ot be said too often: all life is ohat is, and I suspect will forever prove to be, themost profound true statement there is.
PART VITHE ROAD TO USDesded from the apes! My dear,let us hope that it is not true, but if it is,let us pray that it will not beegenerally known.
-Remark attributed to the wife ofthe Bishop of Worcester afterDarwin’s theory of evolution was Explaio her
27 ICE TIME
I had a dream, which was notall a dream.
The bright sun wasextinguish’d, and the starsDid wander . . .
—Byron, “Darkness”
IN 1815 on the island of Sumbawa in Indonesia, a handsome and long-quiest mountaiambora exploded spectacularly, killing a huhousand people with its blast andassociated tsunamis. It was the biggest volic explosion ihousand years—150 timesthe size of Mount St. Helens, equivalent to sixty thousand Hiroshima-sized atom bombs.
News didn’t travel terribly fast in those days. In London, The Times ran a small story—actually a letter from a mert—seven months after the event. But by this time Tambora’seffects were already bei. Thirty-six cubic miles of smoky ash, dust, and grit haddiffused through the atmosphere, obsg the Sun’s rays and causing the Earth to cool.
Sus were unusually but blearily colorful, an effect memorably captured by the artist J. M.
W. Turner, who could not have been happier, but mostly the world existed under anoppressive, dusky pall. It was this deathly dimhat inspired the Byron lines above.
Spring never came and summer never warmed: 1816 became known as the year withoutsummer. Crops everywhere failed to grow. In Ireland a famine and associated typhoidepidemic killed sixty-five thousand people. In New England, the year became popularlyknown as Eighteen Hundred and Froze to Death. M frosts tinued until June andalmost no planted seed would grow. Short of fodder, livestock died or had to be prematurelyslaughtered. In every way it was a dreadful year—almost certainly the worst for farmers iimes. Yet globally the temperature fell by only about 1.5 degrees Fahre. Earth’snatural thermostat, as stists would learn, is an exceedingly delicate instrument.
The eenth tury was already a chilly time. For two hundred years Europe and NorthAmeri particular had experienced a Little Ice Age, as it has bee known, whichpermitted all kinds of wintry events—frost fairs ohames, ice-skating races along Dutals—that are mostly impossible now. It eriod, in other words, when frigidity wasmu people’s minds. So erhaps excuse eenth-tury geologists for beingslow to realize that the world they lived in was in fact balmy pared with former epochs,and that much of the land around them had been shaped by crushing glaciers and cold thatwould wreck even a frost fair.
They khere was something odd about the past. The European landscape was litteredwith inexplicable anomalies—the bones of arctic reindeer in the warm south of France, hugerocks stranded in improbable places—and they often came up with iive but not terriblyplausible explanations. One Frenaturalist named de Luc, trying to explain how graniteboulders had e to rest high up on the limestone flanks of the Jura Mountains, suggestedthat perhaps they had been shot there by pressed air in caverns, like corks out of apopgun. The term for a displaced boulder is aic, but in the eenth tury theexpression seemed to apply more often to the theories than to the rocks.
The great British geologist Arthur Hallam has suggested that if James Hutton, the father ofgeology, had visited Switzerland, he would have seen at ohe significe of the carvedvalleys, the polished striations, the telltale strand lines where rocks had been dumped, and theother abundant clues that point to passing ice sheets. Unfortunately, Hutton was not a traveler.
But even with nothier at his disposal than sedhand ats, Huttoed out ofhand the idea that huge boulders had been carried three thousa up mountainsides byfloods—all the water in the world won’t make a boulder float, he pointed out—and becameone of the first tue for widespread glaciation. Unfortunately his ideas escaped notice, andfor another half tury most naturalists tio insist that the gouges on rocks could beattributed to passing carts or even the scrape of hobnailed boots.
Local peasants, uninated by stific orthodoxy, knew better, however. Thenaturalist Jean de Charpeold the story of how in 1834 he was walking along a trylah a Swiss woodcutter when they got to talking about the rocks along the roadside. Thewoodcutter matter-of-factly told him that the boulders had e from the Grimsel, a zone ofgranite some distance away. “When I asked him how he thought that these stones had reachedtheir location, he answered without hesitation: ‘The Grimsel glacier transported them on bothsides of the valley, because that glacier extended in the past as far as the town of Bern.’ ”
Charpentier was delighted. He had e to such a view himself, but when he raised thenotion at stific gatherings, it was dismissed. One of Charpentier’s closest friends wasanother Swiss naturalist, Louis Agassiz, who after some initial skepticism came to embrad eventually all but appropriate, the theory.
Agassiz had studied under Cuvier in Paris and now held the post of Professor of NaturalHistory at the College of Neuchatel in Switzerland. Another friend of Agassiz’s, a botanistnamed Karl Schimper, was actually the first to the term ice age (in German Eiszeit ), in1837, and to propose that there was good evideo show that ice had once lain heavilyacross not just the Swiss Alps, but over much of Europe, Asia, and North America. It was aradiotion. He lent Agassiz his hen came very much tret it as Agassizincreasingly got the credit for what Schimper felt, with some legitimacy, was his theory.
Charpentier likewise ended up a bitter enemy of his old friend. Alexander von Humboldt, yetanother friend, may have had Agassiz at least partly in mind when he observed that there arethree stages in stific discovery: first, people deny that it is true; then they deny that it isimportant; finally they credit the wrong person.
At all events, Agassiz made the field his own. In his quest to uand the dynamics ofglaciation, he went everywhere—deep into dangerous crevasses and up to the summits of thecraggiest Alpine peaks, often apparently unaware that he and his team were the first to climbthem. Nearly everywhere Agassiz entered an unyieldiao accept his theories.
Humboldt urged him to return to his area of real expertise, fossil fish, and give up this madobsession with ice, but Agassiz was a man possessed by an idea.
Agassiz’s theory found even less support in Britain, where most naturalists had never seena glacier and often couldn’t grasp the crushing forces that i bulk exerts. “Could scratchesand polish just be due to ice ?” asked Roderick Murchison in a mog to oing,evidently imagining the rocks as covered in a kind of light and glassy rime. To his dying day,he expressed the fra incredulity at those “ice-mad” geologists who believed that glacierscould at for so much. William Hopkins, a Cambridge professor and leading member ofthe Geological Society, endorsed this view, arguing that the notion that ice could transportboulders presented “such obvious meical absurdities” as to make it unworthy of thesociety’s attention.
Undaunted, Agassiz traveled tirelessly to promote his theory. In 1840 he read a paper to ameeting of the British Association for the Adva of S Glasgow at which heenly criticized by the great Charles Lyell. The followihe Geological Society ofEdinburgh passed a resolution g that there might be some general merit iheorybut that certainly none of it applied to Scotland.
Lyell did eventually e round. His moment of epiphany came when he realized that amoraine, or line of rocks, near his family estate in Scotland, which he had passed hundreds oftimes, could only be uood if one accepted that a glacier had dropped them there. Buthaving bee verted, Lyell then lost his nerve and backed off from public support of theIce Age idea. It was a frustrating time fassiz. His marriage was breaking up, Schimperwas hotly acg him of the theft of his ideas, Charpentier wouldn’t speak to him, and thegreatest living geologist offered support of only the most tepid and vacillating kind.
In 1846, Agassiz traveled to America to give a series of lectures and there at last found theesteem he craved. Harvard gave him a professorship and built him a first-rate museum, theMuseum of parative Zoology. Doubtless it helped that he had settled in New England,where the long winters enced a certain sympathy for the idea of interminable periods ofcold. It also helped that six years after his arrival the first stific expedition to Greenlaed that nearly the whole of that semiti was covered in an ice sheet just like thea one imagined in Agassiz’s theory. At long last, his ideas began to find a realfollowing. The oral defect of Agassiz’s theory was that his ice ages had no cause. Butassistance was about to e from an unlikely quarter.
In the 1860s, journals and other learned publications in Britain began to receive papers onhydrostatics, electricity, and other stific subjects from a James Croll of Anderson’sUy in Glasgow. One of the papers, on how variations ih’s orbit might haveprecipitated ice ages, ublished in the Philosophical Magazine in 1864 and wasreized at once as a work of the highest standard. So there was some surprise, and perhapsjust a toubarrassment, when it turned out that Croll was not an academic at theuy, but a janitor.
Born in 1821, Croll grew up poor, and his formal education lasted only to the age ofthirteen. He worked at a variety of jobs—as a carpenter, insurance salesman, keeper of atemperael—before taking a position as a janitor at Anderson’s (now the Uy ofStrathclyde) in Glasgow. By somehow indug his brother to do much of his work, he wasable to pass many quiet evenings in the uy library teag himself physics,meics, astronomy, hydrostatics, and the other fashionable sces of the day, andgradually began to produce a string of papers, with a particular emphasis oions ofEarth and their effe climate.
Croll was the first to suggest that cyclical ges in the shape of Earth’s orbit, fromelliptical (which is to say slightly oval) to nearly circular to elliptical again, might explain theo areat of ice ages. No one had ever thought before to sider an astronomicalexplanation for variations ih’s weather. Thanks almost eo Croll’s persuasivetheory, people in Britain began to beore respoo the notion that at some formertime parts of the Earth had been in the grip of ice. When his iy and aptitude werereized, Croll was given a job at the Geological Survey of Scotland and widely honored:
he was made a fellow of the Royal Society in London and of the New York Academy ofSd given an honorary degree from the Uy of St. Andrews, among much else.
Unfortunately, just as Agassiz’s theory was at last beginning to find verts in Europe, hewas busy taking it into ever more exotic territory in America. He began to find evidence flaciers practically everywhere he looked, includihe equator. Eventually he becamevihat ice had once covered the whole Earth, extinguishing all life, which God hadthen re-created. None of the evidence Agassiz cited supported such a view. heless, inhis adopted try his stature grew and grew until he was regarded as only slightly below adeity. When he died in 1873 Harvard felt it necessary to appoint three professors to take hisplace.
Yet, as sometimes happens, his theories fell swiftly out of fashiohan a decade afterhis death his successor in the chair of geology at Harvard wrote that the “so-called glacialepoch . . . so popular a few years ago among glacial geologists may now be rejected withouthesitation.”
Part of the problem was that Croll’s putations suggested that the most ret ice ageoccurred eighty thousand years ago, whereas the geological evidencreasingly indicatedthat Earth had undergone some sort of dramatic perturbation much more retly than that.
Without a plausible explanation for what might have provoked an ice age, the whole theoryfell into abeyahere it might have remained for some time except that in the early 1900sa Serbian academiamed Milutin Milankovitch, who had no background iial motionsat all—he was a meical engineer by training—developed an ued i ier. Milankovitch realized that the problem with Croll’s theory was not that it wasincorrect but that it was too simple.
As Earth moves through space, it is subjeot just to variations in the length and shape ofits orbit, but also to rhythmic shifts in its angle of orientation to the Sun—its tilt and pitdwobble—all affeg the length and iy of sunlight falling on any patch of land. Inparticular it is subject to three ges in position, known formally as its obliquity,precession, and etricity, over long periods of time. Milankovitch wondered if there mightbe a relationship between these plex cycles and the ings and goings of ice ages. Thedifficulty was that the cycles were of widely differehs—of approximately 20,000,40,000, and 100,000 years, but varying in each case by up to a few thousand years—whichmeant that determining their points of interse over long spans of time involved a nearlyendless amount of devoted putation. Essentially Milankovitch had to work out the angleand duration of ining solar radiation at every latitude oh, in every season, for amillion years, adjusted for three ever-ging variables.
Happily this recisely the sort of repetitive toil that suited Milankovitch’stemperament. For the wenty years, even while on vacation, he worked ceaselessly withpencil and slide rule puting the tables of his cycles—work that now could be pleted ina day or two with a puter. The calculations all had to be made in his spare time, but in1914 Milankovitch suddenly got a great deal of that when World War I broke out and he wasarrested owing to his position as a reservist in the Serbian army. He spent most of the four years under loose house arrest in Budapest, required only to report to the police aweek. The rest of his time ent w in the library of the Hungarian Academy ofSces. He ossibly the happiest prisoner of war in history.
The eventual oute of his diligent scribblings was the 1930 book MathematicalClimatology and the Astronomical Theory of Climatic ges. Milankovitch was right thatthere was a relationship between ice ages and plaary wobble, though like most people heassumed that it was a gradual increase in harsh wihat led to these long spells ofess. It was a Russian-Germaeist, Wladimir K?ppen—father-in-law of ourteic friend Alfred Wegener—who saw that the process was more subtle, and rather moreunnerving, than that.
The cause of ice ages, K?ppen decided, is to be found in cool summers, not brutal winters.
If summers are too cool to melt all the snow that falls on a given area, more ining sunlightis bounced back by the reflective surface, exacerbating the cooling effed encimore snow to fall. The sequence would tend to be self-perpetuating. As snow accumulatedinto an ice sheet, the region would grow cooler, prompting more ice to accumulate. As theglaciologist Gwen Schultz has noted: “It is not necessarily the amount of snow that causes icesheets but the fact that snow, however little, lasts.” It is thought that an ice age could startfrom a single unseasonal summer. The leftover snow reflects heat and exacerbates the chillingeffect. “The process is self-enlarging, unstoppable, and ohe ice is really growing itmoves,” says McPhee. You have advang glaciers and an ice age.
In the 1950s, because of imperfect dating teology, stists were uo correlateMilankovitch’s carefully worked-out cycles with the supposed dates of ice ages as thenperceived, and so Milankovitd his calculations increasingly fell out of favor. He died in1958, uo prove that his cycles were correct. By this time, write John and Mary Gribbin,“you would have been hard pressed to find a geologist or meteist wharded themodel as being anything more than an historical curiosity.” Not until the 1970s and therefi of a potassium-argohod for dating a seafloor sediments were histheories finally vindicated.
The Milankovitch cycles alone are not enough to explain cycles of ice ages. Many otherfactors are involved—not least the disposition of the tis, in particular the presence oflandmasses over the poles—but the specifics of these are imperfectly uood. It has beensuggested, however, that if you hauled North America, Eurasia, and Greenland just threehundred miles north we would have perma and inescapable ice ages. We are very lucky, itappears, to get any good weather at all. Even less well uood are the cycles ofparative balminess within ice ages, known as interglacials. It is mildly unnerving toreflect that the whole of meaningful human history—the development of farming, the creationof towns, the rise of mathematid writing and sd all the rest—has taken placewithin an atypical patch of fair weather. Previous interglacials have lasted as little as eightthousand years. Our own has already passed its ten thousandth anniversary.
The fact is, we are still very mu an ice age; it’s just a somewhat shrunkehoughless shruhan many people realize. At the height of the last period of glaciation, arouy thousand years ago, about 30 pert of the Earth’s land surface was under ice. Tenpert still is—and a further 14 pert is in a state of permafrost. Three-quarters of all thefresh water oh is locked up in ice even now, and we have ice caps at both poles—asituation that may be unique ih’s history. That there are snowy wihrough much ofthe world and perma glaciers even in temperate places such as New Zealand may seemquite natural, but in fact it is a most unusual situation for the pla.
For most of its history until fairly ret times the general pattern for Earth was to be hotwith no perma iywhere. The current ice age—ice epoch really—started about fortymillion years ago, and has ranged from murderously bad to not bad at all. Ice ages tend towipe out evidence of earlier ice ages, so the further back you go the more sketchy the picturegrows, but it appears that we have had at least seventeen severe glacial episodes in the last 2.5million years or so—the period that cides with the rise of Homo erectus in Africafollowed by modern humans. Two only cited culprits for the present epoch are the riseof the Himalayas and the formation of the Isthmus of Panama, the first disrupting air flows,the sed o currents. India, on island, has pushed two thousand kilometers into theAsian landmass over the last forty-five million years, raising not only the Himalayas, but alsothe vast Tibetan plateau behind them. The hypothesis is that the higher landscape was notonly cooler, but diverted winds in a way that made them flow north and toward NorthAmerica, making it more susceptible to long-term chills. Then, beginning about five millionyears ago, Panama rose from the sea, closing the gap between North and South America,disrupting the flows of warming currents between the Pacifid Atlantid gingpatterns of precipitation across at least half the world. One sequence was a drying out ofAfrica, which caused apes to climb down out of trees and go looking for a new way of livingon the emerging savannas.
At all events, with the os and tis arranged as they are now, it appears that icewill be a long-term part of our future. Acc to John McPhee, about fifty mlacialepisodes be expected, each lasting a huhousand years or so, before we hope fora really long thaw.
Before fift..y million years ago, Earth had nular ice ages, but when we did have themthey teo be colossal. A massive freezing occurred about 2.2 billion years ago, followedby a billion years or so of warmth. Then there was another ice age even larger than the first—se that some stists are now referring to the age in which it occurred as theCryogenian, or super ice age. The dition is more popularly known as Snowball Earth.
“Snowball,” however, barely captures the murderousness of ditions. The theory is thatbecause of a fall in solar radiation of about 6 pert and a dropoff in the produ (orretention) of greenhouse gases, Earth essentially lost its ability to hold on to its heat. Itbecame a kind of all-over Antarctica. Temperatures plunged by as much as 80 degreesFahre. The entire surface of the pla may have frozen solid, with o ice up to half amile thick at higher latitudes and tens of yards thick even iropics.
There is a serious problem in all this in that the geological evidendicates iceeverywhere, including around the equator, while the biological evidence suggests just asfirmly that there must have been open water somewhere. For ohing, obacteriasurvived the experience, and they photosynthesize. For that they needed sunlight, but as youwill know if you have ever tried to peer through it, ice quickly bees opaque and after onlya few yards would pass on no light at all. Two possibilities have been suggested. One is that alittle o water did remain exposed (perhaps because of some kind of localized warming ata hot spot); the other is that maybe the ied in such a way that it remairanslut—a dition that does sometimes happen in nature.
If Earth did freeze over, then there is the very difficult question of how it ever got warmagain. An icy pla should refleuch heat that it would stay frozen forever. It appearsthat rescue may have e from our molten interior. Once again, we may be ied toteics for allowing us to be here. The idea is that we were saved by voloes, whichpushed through the buried surface, pumping out lots of heat and gases that melted the snowsand re-formed the atmosphere. Iingly, the end of this hyper-frigid episode is marked bythe Cambrian outburst—the springtime event of life’s history. In fact, it may not have been astranquil as all that. As Earth warmed, it probably had the wildest weather it has everexperienced, with hurries powerful enough to raise waves to the heights of skyscrapersand rainfalls of indescribable iy.
Throughout all this the tubeworms and clams and other life forms adhering to deep ovents undoubtedly went on as if nothing were amiss, but all other life oh probably cameas close as it ever has to cheg out entirely. It was all a long time ago and at this stage wejust don’t know.
pared with a Cryogenian outburst, the ice ages of more ret times seem pretty smallscale, but of course they were immensely grand by the standards of anything to be found oh today. The Wissian ice sheet, which covered much of Europe and North America,was two miles thi places and marched forward at a rate of about four hundred feet a year.
What a thing it must have been to behold. Even at their leading edge, the ice sheets could benearly half a mile thick. Imagianding at the base of a wall of ice two thousa high.
Behind this edge, over an area measuring in the millions of square miles, would be nothingbut more ice, with only a few of the tallest mountain summits poking through. Wholetis sagged uhe weight of so much id even now, twelve thousand years afterthe glaciers’ withdrawal, are still rising bato place. The ice sheets didn’t just dribble outboulders and long lines of gravelly moraines, but dumped entire landmasses—Long Islandand Cape Cod and Nantucket, among others—as they slowly swept along. It’s little wohat geologists befassiz had trouble grasping their moal capacity to reworklandscapes.
If ice sheets advanced again, we have nothing in our armory that could deflect them. In1964, at Prince William Sound in Alaska, one of the largest glacial fields in North Americawas hit by the stro earthquake ever recorded on the ti. It measured 9.2 on theRichter scale. Along the fault lihe land rose by as much as twenty feet. The quake was soviolent, in fact, that it made water slosh out of pools in Texas. And what effect did thisunparalleled outburst have on the glaciers of Prince William Sound? all. They justsoaked it up a on moving.
For a long time it was thought that we moved into and out of ice ages gradually, overhundreds of thousands of years, but we now know that that has not been the case. Thanks toice cores from Greenland we have a detailed record of climate for something over a huhousand years, and what is found there is not f. It shows that for most of its rethistory Earth has been nothing like the stable and tranquil place that civilization has known,but rather has lurched violently between periods of warmth and brutal chill.
Toward the end of the last big glaciation, some twelve thousand years ago, Earth began towarm, and quite rapidly, but then abruptly plunged bato bitter cold for a thousand yearsor so in a known to sce as the Younger Dryas. (The name es from the arctit the dryas, which is one of the first to reize land after an ice sheet withdraws. Therewas also an Older Dryas period, but it wasn’t so sharp.) At the end of this thousand-yearonslaught average temperatures leapt again, by as much as seven degrees iy years,which doesn’t sound terribly dramatic but is equivalent to exging the climate ofSdinavia for that of the Mediterranean in just two decades. Locally, ges have beeneven more dramatic. Greenland ice cores show the temperatures there ging by as much asfifteen degrees in ten years, drastically altering rainfall patterns and growing ditions. Thismust have been uling enough on a thinly populated plaoday the sequenceswould be pretty well unimaginable.
What is most alarming is that we have no idea—none—what natural phenomena could soswiftly rattle Earth’s thermometer. As Elizabeth Kolbert, writing in the New Yorker, hasobserved: “No knowernal force, or even any that has been hypothesized, seems capableof yanking the temperature bad forth as violently, and as often, as these cores haveshown to be the case.” There seems to be, she adds, “some vast and terrible feedback loop,”
probably involving the os and disruptions of the normal patterns of o circulation, butall this is a long way from being uood.
Oheory is that the heavy inflow of meltwater to the seas at the beginning of theYounger Dryas reduced the saltiness (and thus density) of northern os, causing the GulfStream to swerve to the south, like a driver trying to avoid a collision. Deprived of the GulfStream’s warmth, the northern latitudes returo chilly ditions. But this doesn’t begin toexplain why a thousand years later when the Earth warmed once again the Gulf Stream didn’tveer as before. Instead, we were given the period of unusual tranquility known as theHoloe, the time in which we live now.
There is no reason to suppose that this stretch of climatic stability should last much longer.
In fact, some authorities believe that we are in for even worse than what went before. It isnatural to suppose that global warming would act as a useful terweight to the Earth’stendency to plunge bato glacial ditions. However, as Kolbert has pointed out, whenyou are fronted with a fluctuating and uable climate “the last thing you’d want todo is duct a vast unsupervised experiment on it.” It has even been suggested, with moreplausibility than would at first seem evident, that an ice age might actually be induced by arise in temperatures. The idea is that a slight warming would enhance evaporation rates andincrease cloud cover, leading in the higher latitudes to more persistent accumulations of snow.
In fact, global warming could plausibly, if paradoxically, lead to powerful localized cooling inNorth Amerid northern Europe.
Climate is the product of so many variables—rising and falling carbon dioxide levels, theshifts of tis, solar activity, the stately wobbles of the Milankovitch cycles—that it is asdifficult to prehend the events of the past as it is to predict those of the future. Much issimply beyond us. Take Antarctica. For at least twenty million years after it settled over theSouth Pole Antarctica remained covered in plants and free of ice. That simply shouldn’t havebeen possible.
No less intriguing are the knes of some late dinosaurs. The British geologistStephen Drury hat forests within 10 degrees latitude of the North Pole were home togreat beasts, including Tyrannosaurus rex. “That is bizarre,” he writes, “for such a highlatitude is tinually dark for three months of the year.” Moreover, there is now evide these high latitudes suffered severe winters. Oxygen isotope studies suggest that theclimate around Fairbanks, Alaska, was about the same ie Cretaceous period as it isnow. So what was Tyrannosaurus doing there? Either it migrated seasonally over enormousdistances or it spent much of the year in snowdrifts in the dark. In Australia—which at thattime was more polar in its orientation—a retreat to warmer climes wasn’t possible. Howdinosaurs mao survive in such ditions only be guessed.
Ohought to bear in mind is that if the ice sheets did start tain for whateverreason, there is a lot more water for them to draw on this time. The Great Lakes, Hudson Bay,the tless lakes of ada—these weren’t there to fuel the last ice age. They were createdby it.
Oher hand, the phase of our history could see us melting a lot of ice rather thanmaking it. If all the ice sheets melted, sea levels would rise by two hundred feet—the heightof a twenty-story building—and every coastal city in the world would be inundated. Morelikely, at least in the short term, is the collapse of the West Antarctic ice sheet. In the past fiftyyears the waters around it have warmed by 2.5 degrees tigrade, and collapses haveincreased dramatically. Because of the underlying geology of the area, a large-scale collapseis all the more possible. If so, sea levels globally would rise—and pretty quickly—by betweenfifteen and twenty feet on average.
The extraordinary fact is that we don’t know which is more likely, a future us eonsof perishing frigidity or one giving us equal expanses of steamy heat. Only ohing iscertain: we live on a knife edge.
In the long run, ially, ice ages are by no means bad news for the plahey grindup rocks and leave behind new soils of sumptuous riess, and gouge out fresh water lakesthat provide abundant nutritive possibilities for hundreds of species of being. They act as aspur to migration ahe pla dynamic. As Tim Flannery has remarked: “There is onlyone question you need ask of a ti in order to determihe fate of its people: ‘Did youhave a good ice age?’ ” And with that in mind, it’s time to look at a species of ape that trulydid.
28 THE MYSTERIOUS BIPED
JUST BEFORE CHRISTMAS 1887, a young Dutch doctor with an un-Dutame, MarieEugène Fran?ois Thomas Dubois, arrived in Sumatra, ich East Indies, with theiion of finding the earliest human remains oh.
1Several things were extraordinary about this. To begin with, no one had ever gone lookingfor a human bones before. Everything that had been found to this point had been foundactally, and nothing in Dubois’s background suggested that he was the ideal didate tomake the process iional. He was an anatomist by training with no background iology. Nor was there any special reason to suppose that the East Indies would holdearly human remains. Logic dictated that if a people were to be found at all, it would beon a large and long-populated landmass, not in the parative fastness of an archipelago.
Dubois was driven to the East Indies on nothing strohan a hunch, the availability ofemployment, and the knowledge that Sumatra was full of caves, the enviro in whichmost of the important hominid fossils had so far been found. What is most extraordinary in allthis—nearly miraculous, really—is that he found what he was looking for.
At the time Dubois ceived his plan to search for a missing link, the human fossil recordsisted of very little: five inplete Neaal skeletons, one partial jawbone of uainprovenance, and a half-dozen ice-age humaly found by railway workers in a cave at acliff called agnon near Les Eyzies, France. Of the Neaal spes, the bestpreserved was sitting unremarked on a shelf in London. It had been found by workers blastingrock from a quarry in Gibraltar in 1848, so its preservation was a wonder, but unfortunatelyno o appreciated what it was. After being briefly described at a meeting of the GibraltarStific Society, it had beeo the Hunterian Museum in London, where it remainedundisturbed but for an occasional light dusting for over half a tury. The first formaldescription of it wasn’t written until 1907, and then by a geologist named William Sollas“with only a passing peten anatomy.”
So ihe name and credit for the discovery of the first early humao theNeander Valley in Germany—not unfittingly, as it happens, for by uny cideneander in Greek means “new man.” There in 1856 workmen at another quarry, in a cliff faceoverlooking the Düssel River, found some curious-looking bones, which they passed to alocal schoolteacher, knowing he had an i in all things natural. To his great credit theteacher, Johann Karl Fuhlrott, saw that he had some ype of human, though quite what itwas, and how special, would be matters of dispute for some time.
Many people refused to accept that the Neaal bones were a at all. August Mayer,a professor at the Uy of Bonn and a man of influence, insisted that the bones were1Though Dutch, Dubois was from Eijsden, a town b the French-speaking part of Belgium.
merely those of a Mongolian Cossack soldier who had been wounded while fighting inGermany in 1814 and had crawled into the cave to die. Hearing of this, T. H. Huxley inEngland drily observed how remarkable it was that the soldier, though mortally wounded, hadclimbed sixty feet up a cliff, divested himself of his clothing and personal effects, sealed thecave opening, and buried himself uwo feet of soil. Another anthropologist, puzzlihe Neaal’s heavy bre, suggested that it was the result of long-term frowningarising from a poorly healed forearm fracture. (In their eagero reject the idea of earlierhumans, authorities were often willing to embrace the most singular possibilities. At about thetime that Dubois was setting out for Sumatra, a skeleton found in Périgueux was fidentlydeclared to be that of an Eskimo. Quite what an a Eskimo was doing in southwestFrance was never fortably explained. It was actually an early agnon.)It was against this background that Dubois began his search for a human bones. Hedid no digging himself, but instead used fifty victs lent by the Dutch authorities. For a yearthey worked on Sumatra, then transferred to Java. And there in 1891, Dubois—or rather histeam, for Dubois himself seldom visited the sites—found a se of a human iumnow known as the Trinil skullcap. Though only part of a skull, it showed that the owner hadhad distinctly nonhumaures but a much larger brain than any ape. Dubois called itAnthropithecus erectus (later ged for teical reasons to Pithethropus erectus) anddeclared it the missing liween apes and humans. It quickly became popularized as “JavaMan.” Today we know it as Homo erectus.
The year Dubois’s workers found a virtually plete thighbohat lookedsurprisingly modern. In fact, many anthropologists think itis modern, and has nothing to dowith Java Man. If it is aus bo is unlike any other found sinoheless Duboisused the thighboo deduce—correctly, as it turned out—that Pithethropus walkedupright. He also produced, with nothing but a scrap of ium and oooth, a model of theplete skull, which also proved unily accurate.
In 1895, Dubois returo Europe, expeg a triumphal reception. In fact, he met nearlythe opposite reaost stists disliked both his clusions and the arrogant manner inwhich he presehem. The skullcap, they said, was that of an ape, probably a gibbon, andnot of any early human. Hoping to bolster his case, in 1897 Dubois allowed a respectedanatomist from the Uy of Strasbustav Schwalbe, to make a cast of the skullcap.
To Dubois’s dismay, Schwalbe thereupon produced a monograph that received far moresympathetic attention than anything Dubois had written and followed with a lecture tour inwhich he was celebrated nearly as warmly as if he had dug up the skull himself. Appalled atered, Dubois withdrew into an undistinguished position as a professor of geology at theUy of Amsterdam and for the wo decades refused to let anyone examine hisprecious fossils again. He died in 1940 an unhappy man.
Meanwhile, and half a world away, in late 1924 Raymond Dart, the Australian-born head ofanatomy at the Uy of the Witwatersrand in Johannesburg, was sent a small butremarkably plete skull of a child, with an intact face, a lower jaw, and what is known asan endocast—a natural cast of the brain—from a limestone quarry on the edge of the KalahariDesert at a dusty spot called Taung. Dart could see at ohat the Taung skull was not of aHomo erectus like Dubois’s Java Man, but from an earlier, more apelike creature. He placedits age at two million years and dubbed it Australopithecus afrius, or “southern ape man ofAfrica.” In a report to Nature, Dart called the Taung remains “amazingly human” andsuggested the need for airely new family, Homo simiadae (“the man-apes”), toaodate the find.
The authorities were even less favorably disposed to Dart than they had been to Dubois.
Nearly everything about his theory—indeed, nearly everything about Dart, it appears—ahem. First he had proved himself lamentably presumptuous by dug theanalysis himself rather than calling on the help of more worldly experts in Europe. Even hischosen name, Australopithecus, showed a lack of scholarly application, bining as it didGreek and Latin roots. Above all, his clusions flew in the face of accepted wisdom.
Humans and apes, it was agreed, had split apart at least fifteen million years ago in Asia. Ifhumans had arisen in Africa, why, that would make us Negroid, foodness sake. It wasrather as if someone w today were to annouhat he had found the aral bones ofhumans in, say, Missouri. It just didn’t fit with what was known.
Dart’s sole supporter of note was Robert Broom, a Scottish-born physi andpaleontologist of siderable intelled cherishably etriature. It was Broom’shabit, for instao do his fieldwork naked when the weather was warm, which was often.
He was also known for dug dubious anatomical experiments on his poorer and moretractable patients. Wheients died, which was also often, he would sometimes burytheir bodies in his back garden to dig up for study later.
Broom was an aplished paleontologist, and since he was also resident in South Africahe was able to exa?99ｌib.mihe Taung skull at first hand. He could see at ohat it ortant as Dart supposed and spoke out vigorously on Dart’s behalf, but to no effect. Forthe fifty years the received wisdom was that the Taung child e and nothingmore. Most textbooks didn’t eveion it. Dart spent five years w up a monograph,but could find no oo publish it. Eventually he gave up the quest to publish altogether(though he did tinue hunting for fossils). For years, the skull—today reized as ohe supreme treasures of anthropology—sat as a paperweight on a colleague’s desk.
At the time Dart made his annou in 1924, only four categories of a hominidwere known—Homo heidelbergensis, Homo rhodesiensis, Neaals, and Dubois’s JavaMan—but all that was about to ge in a very big way.
First, in a, a gifted adian amateur named Davidson Black began to poke around ata place, Dragon Bone Hill, that was locally famous as a hunting ground for old bones.
Unfortunately, rather than preserving the bones for study, the ese ground them up tomake medies. We only guess horiceless Homo erectus bones ended up as asort of ese equivalent of bicarbonate of soda. The site had been much denuded by thetime Black arrived, but he found a single fossilized molar and on the basis of that alone quitebrilliantly annouhe discovery of Sinanthropus pekinensis, which quickly became knoeking Man.
At Black’s urging, more determined excavations were uaken and many other bonesfound. Unfortunately all were lost the day after the Japaa Pearl Harbor in 1941when a ti of U.S. Marirying to spirit the bones (and themselves) out of thetry, was intercepted by the Japanese and imprisoned. Seeing that their crates held nothingbut bohe Japanese soldiers left them at the roadside. It was the last that was ever seen ofthem.
In the meantime, ba Dubois’s old turf of Java, a team led by Ralph von Koenigswaldhad found anroup of early humans, which became known as the Solo People from thesite of their discovery on the Solo River at Ngandong. Koenigswald’s discoveries might havebeen more impressive still but for a tactical error that was realized too late. He had offeredlocals tes for every piece of hominid bohey could e up with, then discovered tohis horror that they had beehusiastically smashing large pieces into small oomaximize their ine.
In the following years as more bones were found and identified there came a flood of newnames—Homnasis, Australopithecus transvaalensis, Paranthropus crassidens,Zinjanthropus boisei,and scores of others, nearly all involving a new genus type as well as anew species. By the 1950s, the number of named hominid types had risen to fortably overa huo add to the fusion, individual forms ofte by a succession of differentnames as paleoanthropologists refined, reworked, and squabbled over classifications. SoloPeople were known variously as Homo soloensis, Homenius asiaticus, Homoneahalensis soloensis, Homo sapiens soloensis, Homo erectus erectus, and, finally, plainHomo erectus .
In an attempt to introdue order, in 1960 F. Clark Howell of the Uy ofChicago, following the suggestions of Ernst Mayr and others the previous decade, proposedcutting the number of geo just two—Australopithecus and Homo —and rationalizingmany of the species. The Java and Peking men both became Homo erectus. For a time orderprevailed in the world of the hominids.
2It didn’t last.
After about a decade of parative calm, paleoanthropology embarked on another periodof swift and prolific discovery, which hasn’t abated yet. The 1960s produced Homo habilis,thought by some to be the missing liween apes and humans, but thought by others not tobe a separate species at all. Then came (among many others) Homaster, Homolouisleakeyi, Homo rudolfensis, Homo microus, and Homo antecessor, as well as a raft ofaustralopithees: A.afarensis, A. praegens, A. ramidus, A. walkeri, A. anamensis, and stillothers. Altogether, some twenty types of hominid are reized ierature today.
Unfortunately, almost no two experts reize the same twenty.
Some tio observe the two hominid genera suggested by Howell in 1960, but othersplae of the australopithees in a separate genus called Paranthropus , and still othersadd an earlier group called Ardipithecus. Some put praegens into Australopithecus and someinto a new classification, Homo antiquus, but most don’t reize praegens as a separatespecies at all. There is ral authority that rules ohings. The only way a namebees accepted is by sensus, and there is often very little of that.
A big part of the problem, paradoxically, is a she of evidence. Sihe dawn of time,several billion human (or humanlike) beings have lived, each tributing a little geicvariability to the total human stock. Out of this vast he whole of our uandingof humaory is based on the remains, often exceedingly fragmentary, of perhaps fivethousand individuals. “You could fit it all into the back of a pickup truck if you didn’t mind2Humans are put in the lamely Homimdae. Its members, traditionally called hominids, include any creatures(includiines) that are more closely related to us than to any surviving chimpahe apes,meanwhile, are lumped together in a family called Pongidae. Many authorities believe that chimps, gorillas, andutans should also be included in this family, with humans and chimps in a subfamily called Homininae.
The upshot is that the creatures traditionally called hominids bee, uhis arra, hominins. (Leakeyand others insist on that designation.) Hominoidea is the name of the aue sunerfamily whicludes us.
how much you jumbled everything up,” Ian Tattersall, the bearded and friendly curator ofanthropology at the Ameri Museum of Natural History in New York, replied when I askedhim the size of the total world archive of hominid and early human bones.
The she wouldn’t be so bad if the bones were distributed evenly through time andspace, but of course they are not. They appear randomly, often in the most tantalizing fashion.
Homo erectus walked the Earth for well over a million years and inhabited territory from theAtlantic edge of Europe to the Pacific side of a, yet if yht back to life everyHomo erectus individual whose existence we vouch for, they wouldn’t fill a school bus.
Homo habilis sists of even less: just two partial skeletons and a number of isolated limbbones. Something as short-lived as our own civilization would almost certainly not be knownfrom the fossil record at all.
“In Europe,” Tattersall offers by way of illustration, “you’ve got hominid skulls in Geiadated to about 1.7 million years ago, but then you have a gap of almost a million years beforethe remains turn up in Spain, right oher side of the ti, and then you’ve gotanother 300,000-year gap before you get a Homo heidelbergensis in Germany—and none of.them looks terribly much like any of the others.” He smiled. “It’s from these kinds mentary pieces that you’re trying to work out the histories of entire species. It’s quite atall order. We really have very little idea of the relationships between many a species—which led to us and which were evolutionary dead ends. Some probably don’t deserve tarded as separate species at all.”
It is the patess of the record that makes eaew find look so sudden and distinct fromall the others. If we had tens of thousands of skeletons distributed at regular intervals throughthe historical record, there would be appreciably more degrees of shading. Whole new speciesdon’t emerge instantaneously, as the fossil record implies, but gradually out of other, existingspecies. The closer you go back to a point of divergehe closer the similarities are, so thatit bees exceedingly difficult, and sometimes impossible, to distinguish a late Homoerectus from an early Homo sapiens, si is likely to be both aher. Similardisagreements often arise over questions of identification frmentary remains—deg, for instance, whether a particular bone represents a female Australopithecus boiseior a male Homo habilis.
With so little to be certain about, stists often have to make assumptions based on otherobjects found nearby, and these may be little more than valiant guesses. As Alan Walker andPat Shipman have drily observed, if you correlate tool discovery with the species of creaturemost often found nearby, you would have to clude that early hand tools were mostly madeby antelopes.
Perhaps nothier typifies the fusion than the fragmentary bundle of tradisthat was Homo habilis. Simply put, habilis bones make no sense. When arranged in sequehey show males and females evolving at different rates and in different dires—the malesbeing less apelike and more human with time, while females from the same period appearto be moving away from humareater apeness. Some authorities don’t believehabilis is a valid category at all. Tattersall and his colleague Jeffrey Schwartz dismiss it as amere “wastebasket species”—oo whirelated fossils “could be vely swept.”
Even those who see habilis as an indepe species don’t agree oher it is of the samegenus as us or is from a side branch that never came to anything.
Finally, but perhaps above all, human nature is a factor in all this. Stists have a naturaltendency to interpret finds in the way that most flatters their stature. It is a rare paleontologistindeed who annouhat he has found a cache of bones but that they are nothing to getexcited about. Or as John Reader uatedly observes in the book Missing Links, “It isremarkable how often the first interpretations of new evidence have firmed thepreceptions of its discoverer.”
All this leaves ample room fuments, of course, and nobody likes tue more thahropologists. “And of all the disciplines in sce, paleoanthropology boasts perhapsthe largest share of egos,” say the authors of the ret Java Man —a book, it may be hat itself devotes long, wonderfully unselfscious passages to attacks on the inadequaciesof others, in particular the authors’ former close colleague Donald Johanson. Here is a smallsampling:
In our years of collaboration at the institute he [Johanson] developed a well-deserved, if unfortunate, reputation for uable and high-decibel personalverbal assaults, sometimes apanied by the tossing around of books orwhatever else came vely to hand.
So, bearing in mind that there is little you say about humaory that won’t bedisputed by someone somewhere, other than that we most certainly had one, what we thinkwe know about who we are and where we e from is roughly this:
For the first 99.99999 pert of our history as anisms, we were in the same aralline as chimpanzees. Virtually nothing is known about the prehistory of chimpanzees, butwhatever they were, we were. Then about seven million years ago something major happened.
A group of new beings emerged from the tropical forests of Afrid began to move abouton the open savanna.
These were the australopithees, and for the five million years they would be theworld’s dominant hominid species. (Austral is from the Latin for “southern” and has noe in this text to Australia.) Australopithees came in several varieties, someslender and gracile, like Raymond Dart’s Taung child, others more sturdy and robust, but allwere capable of walking upright. Some of these species existed for well over a million years,others for a more modest few huhousand, but it is worth bearing in mind that even theleast successful had histories many times lohan we have yet achieved.
The most famous hominid remains in the world are those of a 3.18-million-year-oldaustralopithee found at Hadar ihiopia in 1974 by a team led by Donald Johanson.
Formally known as A.L. (for “Afar Locality”) 288–1, the skeleton became more familiarlyknown as Lucy, after the Beatles song “Lu the Sky with Diamonds.” Johanson has neverdoubted her importance. “She is our earliest aor, the missing liween ape andhuman,” he has said.
Lucy was tiny—just three and a half feet tall. She could walk, though how well is a matterof some dispute. She was evidently a good climber, too. Much else is unknown. Her skull wasalmost entirely missing, so little could be said with fidence about her brain size, thoughskull fragments suggested it was small. Most books describe Lucy’s skeleton as being 40pert plete, though some put it closer to half, and one produced by the AmeriMuseum of Natural History describes Lucy as two-thirds plete. The BBC television seriesApe Man actually called it “a plete skeleton,” even while showing that it was anythingbut.
A human body has 206 bones, but many of these are repeated. If you have the left femurfrom a spe, you don’t he right to know its dimensions. Strip out all the redundantbones, and the total you are left with is 120—what is called a half skeleton. Even by this fairlyaodating standard, and even ting the slightest fragment as a full bone, Lustituted only 28 pert of a half skeleton (and only about 20 pert of a full one).
In The Wisdom of the Bones, Alan Walker rets how he once asked Johanson how hehad e up with a figure of 40 pert. Johanson breezily replied that he had disted the106 bones of the hands a—more than half the body’s total, and a fairly important half,too, one would have thought, since Lucy’s principal defining attribute was the use of thosehands ao deal with a ging world. At all events, rather less is known about Lucythan is generally supposed. It isn’t even actually known that she was a female. Her sex ismerely presumed from her diminutive size.
Two years after Lucy’s discovery, at Laetoli in Tanzania Mary Leakey found footprints leftby two individuals from—it is thought—the same family of hominids. The prints had beenmade when two australopithees had walked through muddy ash following a voliceruption. The ash had later hardened, preserving the impressions of their feet for a distance ofover twenty-three meters.
The Ameri Museum of Natural History in New York has an abs diorama thatrecords the moment of their passing. It depicts life-sized re-creations of a male and a femalewalking side by side across the a Afri plain. They are hairy and chimplike indimensions, but have a bearing and gait that suggest humanness. The most strikiure ofthe display is that the male holds his left arm protectively around the female’s shoulder. It is atender and affeg gesture, suggestive of close bonding.
The tableau is doh such vi that it is easy to overlook the sideration thatvirtually everything above the footprints is imaginary. Almost every external aspect of thetwo figures—degree of hairiness, facial appendages (whether they had human noses or chimpnoses), expressions, skin color, size and shape of the female’s breasts—is necessarilysuppositional. We ’t even say that they were a couple. The female figure may in fact havebeen a child. Nor we be certain that they were australopithees. They are assumed to beaustralopithees because there are no other known didates.
I had been told that they were posed like that because during the building of the dioramathe female figure kept toppling over, but Ian Tattersall insists with a laugh that the story isuntrue. “Obviously we don’t know whether the male had his arm around the female or not,but we do know from the stride measurements that they were walking side by side and closetogether—close enough to be toug. It was quite an exposed area, so they were probablyfeeling vulnerable. That’s why we tried to give them slightly worried expressions.”
I asked him if he was troubled about the amount of lise that was taken in restrugthe figures. “It’s always a problem in making re-creations,” he agreed readily enough. “Youwouldn’t believe how much discussion go into deg details like whether Neaalshad eyebrows or not. It was just the same for the Laetoli figures. We simply ’t know thedetails of what they looked like, but we vey their size and posture and make somereasonable assumptions about their probable appearance. If I had it to do again, I think I mighthave made them just slightly more apelike and less human. These creatures weren’t humans.
They were bipedal apes.”
Until very retly it was assumed that we were desded from Lud the Laetolicreatures, but now many authorities aren’t so sure. Although certain physical features (theteeth, for instance) suggest a possible liween us, other parts of the australopitheeanatomy are more troubling. In their book Extinct Humans, Tattersall and Schwartz point outthat the upper portion of the human femur is very like that of the apes but not of theaustralopithees; so if Lucy is in a direct liween apes and modern humans, it meanswe must have adopted an australopithee femur for a million years or so, then gone back toan ape femur when we moved on to the phase of our development. They believe, in fact,that not only was Luot our aor, she wasn’t even much of a walker.
“Lud her kind did not loote in anything like the modern human fashion,” insistsTattersall. “Only when these hominids had to travel between arboreal habitats would they findthemselves walking bipedally, ‘forced’ to do so by their own anatomies.” Johansoaccept this. “Lucy’s hips and the muscular arra of her pelvis,” he has written, “wouldhave made it as hard for her to climb trees as it is for modern humans.”
Matters grew murkier still in 2001 and 2002 when four exceptional new spes werefound. One, discovered by Meave Leakey of the famous fossil-hunting family at LakeTurkana in Kenya and called Kenyanthropus platyops (“Kenyan flat-face”), is from about thesame time as Lud raises the possibility that it was our aor and Lucy was anunsuccessful side branch. Also found in 2001 were Ardipithecus ramidus kadabba, dated atbetween 5.2 million and 5.8 million years old, and Orrorin tugenensis, thought to be 6 millionyears old, making it the oldest hominid yet found—but only for a brief while. In the summerof 2002 a French team w in the Djurab Desert of Chad (ahat had never beforeyielded a bones) found a hominid almost 7 million years old, which they labeledSahelanthropus tchadensis. (Some critics believe that it was not human, but an early ape andtherefore should be called Sahelpithecus.) All these were early creatures and quite primitivebut they walked upright, and they were doing so far earlier than previously thought.
Bipedalism is a demanding and risky strategy. It means refashioning the pelvis into a fullload-bearing instrument. To preserve the required strength, the birth al must beparatively narrow. This has two very signifit immediate sequences and one loerm one. First, it means a lot of pain for any birthing mother and a greatly increased dangerof fatality to mother and baby both. Moreover to get the baby’s head through such a tightspace it must be born while its brain is still small—and while the baby, therefore, is stillhelpless. This means long-term infant care, whi turn implies solid male–female bonding.
All this is problematiough when you are the intellectual master of the pla, but whenyou are a small, vulnerable australopithee, with a brain about the size of an e,3therisk must have been enormous.
3Absolute brain size does not tell you everything-or possibly sometimes even much. Elephants and whales bothhave brains larger than ours, but you wouldnt have much trouble outwitting them in traegotiations. It isrelative size that matters, a point that is often overlooked. As Gould notes, A. afrius had a brain of only 450cubitimeters, smaller than that of a gorilla. But a typical afrius male weighed less than a hundredpounds, and a female much less still, whereas gorillas easily top out at 600 pounds (Gould pp. 181-83).
So why did Lud her kind e down from the trees and out of the forests? Probablythey had no choice. The slow rise of the Isthmus of Panama had cut the flow of waters fromthe Pacifito the Atlantic, diverting warming currents away from the Arctid leading tothe o of an exceedingly sharp ice age in northern latitudes. In Africa, this would haveproduced seasonal drying and cooling, gradually turning juo savanna. “It was not somuch that Lud her like left the forests,” John Gribbin has written, “but that the forestsleft them.”
But stepping out onto the open savanna also clearly left the early hominids much moreexposed. An upright hominid could see better, but could also be seeer. Even now as aspecies, we are almost preposterously vulnerable in the wild. Nearly every large animal you care to name is stronger, faster, and toothier than us. Faced with attack, modern humanshave only two advantages. We have a good brain, with which we devise strategies, andwe have hands with which we fling or brandish hurtful objects. We are the only creaturethat harm at a distance. We thus afford to be physically vulnerable.
All the elements would appear to have been in place for the rapid evolution of a potentbrain, ahat seems not to have happened. For over three million years, Lud herfellow australopithees scarcely ged at all. Their brain didn’t grow and there is no signthat they used even the simplest tools. What is straill is that we now know that forabout a million years they lived alongside other early hominids who did use tools, yet theaustralopithees ook advantage of this useful teology that was all around them.
At one poiween three and two million years ago, it appears there may have been asmany as six hominid types coexisting in Africa. Only one, however, was fated to last: Homo,which emerged from the mists beginning about two million years ago. No one knows quitewhat the relationship was between australopithees and Homo, but what is known is thatthey coexisted for something over a million years before all the australopithees, robust andgracile alike, vanished mysteriously, and possibly abruptly, over a million years ago. No oneknows why they disappeared. “Perhaps,” suggests Matt Ridley, “we ate them.”
ventionally, the Homo line begins with Homo habilis, a creature about whom we knowalmost nothing, and cludes with us, Homo sapiens (literally “mahinker”). Iween, and depending on which opinions you value, there have been half a dozen otherHomo species: Homaster, Homo neahalensis, Homo rudolfensis, Homoheidelbergensis, Homo erectus, and Homo antecessor.
Homo habilis (“handy man”) was named by Louis Leakey and colleagues in 1964 and wasso called because it was the first hominid to use tools, albeit very simple ones. It was a fairlyprimitive creature, much more chimpahan human, but its brain was about 50 pertlarger than that of Lu gross terms and not much less large proportionally, so it was theEinstein of its day. No persuasive reason has ever been adduced for why hominid brainssuddenly began to grow two million years ago. For a long time it was assumed that big brainsand upright walking were directly related—that the movement out of the forests atedirategies that fed off of or promoted braininess—so it was something of asurprise, after the repeated discoveries of so many bipedal dullards, to realize that there wasno apparent e betwee all.
“There is simply no pelling reason we know of to explain why human brains ge,” says Tattersall. Huge brains are demanding ans: they make up only 2 pert of thebody’s mass, but devour 20 pert of its energy. They are also paratively picky in whatthey use as fuel. If you e another morsel of fat, your brain would not plainbecause it won’t touch the stuff. It wants glucose instead, and lots of it, even if it means short-ging ans. As Guy Brown notes: “The body is in stant danger of> beied by a greedy brain, but ot afford to let the brain go hungry as that would rapidlylead to death.” A big brain needs more food and more food means increased risk.
Tattersall thinks the rise of a big brain may simply have been an evolutionary act. Hebelieves with Stephen Jay Gould that if you replayed the tape of life—even if you ran it baly a relatively short way to the dawn of hominids—the ces are “quite unlikely” thatmodern humans or anything like them would be here now.
“One of the hardest ideas for humans to accept,” he says, “is that we are not theculmination of anything. There is nothing iable about our being here. It is part of ourvanity as humans that we tend to think of evolution as a process that, in effect, rogrammed to produce us. Even anthropologists teo think this way right up until the1970s.” Indeed, as retly as 1991, in the popular textbook The Stages of Evolution, C.
L Brace stuck doggedly to the linear cept, aowledging just one evolutionary deadend, the robust australopithees. Everything else represented a straightforrogression—each species of hominid carrying the baton of development so far, then handingit on to a younger, fresher runner. Now, however, it seems certain that many of these earlyforms followed side trails that didn’t e to anything.
Luckily for us, one did—a group of tool users, which seemed to arise from out of nowhereand overlapped with the shadowy and much disputed Homo habilis. This is Homo erectus, thespecies discovered by Eugène Dubois in Java in 1891. Depending on which sources yousult, it existed from about 1.8 million years ago to possibly as retly as twenty thousandor so years ago.
Acc to the Java Man authors, Homo erectus is the dividing line: everything thatcame before him elike in character; everything that came after was humanlike. Homoerectus was the first to hunt, the first to use fire, the first to fashion plex tools, the first toleave evidence of campsites, the first to look after the weak and frail. pared with all thathad gone before, Homo erectus was extremely human in form as well as behavior, itsmembers long-limbed and lean, very strong (much strohan modern humans), and withthe drive and intelligeo spread successfully e areas. To other hominids, Homoerectus must have seemed terrifyingly powerful, fleet, and gifted.
Erectus was “the velociraptor of its day,” acc to Alan Walker of Penn StateUy and one of the world’s leading authorities. If you were to look one in the eyes, itmight appear superficially to be human, but “you wouldn’t ect. You’d be prey.”
Acc to Walker, it had the body of an adult human but the brain of a baby.
Although erectus had been known about for almost a tury it was known only fromscattered fragments—not enough to e even close to making one full skeleton. So it wasn’tuntil araordinary discovery in Afri the 1980s that its importance—or, at the veryleast, possible importance—as a precursor species for modern humans was fully appreciated.
The remote valley of Lake Turkana (formerly Lake Rudolf) in Kenya is now one of theworld’s most productive sites for early human remains, but for a very long time no one hadthought to look there. It was only because Richard Leakey was on a flight that was divertedover the valley that he realized it might be more promising than had been thought. A teamwas dispatched to iigate, but at first found nothing. Then late oernoon KamoyaKimeu, Leakey’s most renowned fossil hunter, found a small piece of hominid brow on a hillwell away from the lake. Such a site was uo yield much, but they dug anyway out ofrespect for Kimeu’s instincts and to their astonishment found a nearly plete Homo erectusskeleton. It was from a boy aged between about nine and twelve who had died 1.54 millionyears ago. The skeleton had “airely modern body structure,” says Tattersall, in a way thatwas without pret. The Turkana boy was “very emphatically one of us.”
Also found at Lake Turkana by Kimeu was KNM-ER 1808, a female 1.7 million years old,which gave stists their first clue that Homo erectus was more iing and plexthan previously thought. The woman’s bones were deformed and covered in crowths,the result of an agonizing dition called hypervitaminosis A, which e only fromeating the liver of a ivore. This told us first of all that Homo erectus was eati.
Even more surprising was that the amount of growth showed that she had lived weeks or evenmonths with the disease. Someone had looked after her. It was the first sign of tenderness inhominid evolution.
It was also discovered that Homo erectus skulls tained (or, in the view of some, possiblytained) a Broca’s area, a region of the frontal lobe of the brain associated with speech.
Chimps don’t have such a feature. Alan Walker thinks the spinal al didn’t have the sizeand plexity to enable speech, that they probably would have unicated about as wellas modern chimps. Others, notably Richard Leakey, are vihey could speak.
For a time, it appears, Homo erectus was the only hominid species oh. It was hugelyadventurous and spread across the globe with what seems to have beeaking rapidity.
The fossil evidence, if taken literally, suggests that some members of the species reached Javaat about the same time as, or even slightly before, they left Africa. This has led some hopefulstists to suggest that perhaps modern people arose not in Africa at all, but in Asia—whichwould be remarkable, not to say miraculous, as no possible precursor species have ever beenfound anywhere outside Africa. The Asian hominids would have had to appear, as it were,spontaneously. And anyway an Asian beginning would merely reverse the problem of theirspread; you would still have to explain how the Java people then got to Africa so quickly.
There are several more plausible alternative explanations for how Homo erectus mao turn up in Asia so soon after its first appearan Africa. First, a lot of plus-or-minusinggoes into the dating of early human remains. If the actual age of the Afri bones is at thehigher end of the range of estimates or the Java the lower end, or both, then there isplenty of time for Afri erects to find their way to Asia. It is also entirely possible that oldererectus bones await discovery in Africa. In addition, the Javan dates could be wrongaltogether.
Now for the doubts. Some authorities don’t believe that the Turkana finds are Homoerectus at all. The snag, ironically, was that although the Turkana skeletons were admirablyextensive, all othererectus fossils are inclusively fragmentary. As Tattersall and JeffreySchwartz note iinct Humans, most of the Turkana skeleton “couldn’t be pared withanything else closely related to it because the parable parts weren’t known!” The Turkaons, they say, look nothing like any Asian Homo erectus and would never have beensidered the same species except that they were poraries. Some authorities insist oncalling the Turkana spes (and any others from the same period) Homaster.
Tattersall and Schwartz don’t believe that goes nearly far enough. They believe it wasergaster“or a reasonably close relative” that spread to Asia from Africa, evolved intoHomo erectus,and then died out.
What is certain is that sometime well over a million years ago, some new, parativelymodern, upright beings left Afrid boldly spread out auch of the globe. Theypossibly did so quite rapidly, increasing their range by as much as twenty-five miles a year onaverage, all while dealing with mountain ranges, rivers, deserts, and other impediments andadapting to differences in climate and food sources. A particular mystery is how they passedalong the west side of the Red Sea, an area of famously punishing aridity now, but even drierin the past. It is a curious irony that the ditions that prompted them to leave Africa wouldhave made it much more difficult to do so. Yet somehow they mao find their wayaround every barrier and to thrive in the lands beyond.
And that, I’m afraid, is where all agreement ends. What happened in the history ofhuman development is a matter of long and rancorous debate, as we shall see in the chapter.
But it is worth remembering, before we move on, that all of these evolutionary jostlingsover five million years, from distant, puzzled australopithee to fully modern human,produced a creature that is still 98.4 pert geically indistinguishable from the modernchimpahere is more differeween a zebra and a horse, or between a dolphin anda porpoise, than there is between you and the furry creatures your distant aors left behihey set out to take over the world.
29 THE RESTLESS APESOME
TIME ABOUT A million and a half years ago, some fotten genius of the hominidworld did an ued thing. He (or very possibly she) took oone and carefully used itto shape ahe result was a simple teardrop-shaped hand axe, but it was the world’sfirst piece of advaeology.
It was so superior to existing tools that soon others were following the ior’s lead andmaking hand axes of their owually whole societies existed that seemed to do littleelse. “They made them ihousands,” says Ian Tattersall. “There are some places inAfrica where you literally ’t move without stepping on them. It’s strange because they arequite intensive objects to make. It was as if they made them for the sheer pleasure of it.”
From a shelf in his sunny workroom Tattersall took down an enormous cast, perhaps a footand a half long a inches wide at its widest point, and ha to me. It was shapedlike a spearhead, but ohe size of a stepping-stone. As a fiberglass cast it weighed only afew ounces, but the inal, which was found in Tanzania, weighed twenty-five pounds. “Itwas pletely useless as a tool,” Tattersall said. “It would have taken two people to lift itadequately, and eve would have been exhausting to try to pound anything with it.”
“What was it used for then?”
Tattersall gave a genial shrug, pleased at the mystery of it. “No idea. It must have had somesymbolic importance, but we only guess what.”
The axes became known as Acheulean tools, after St. Acheul, a suburb of Amiens innorthern France, where the first examples were found in the eenth tury, and trastwith the older, simpler tools known as Oldowan, inally found at Olduvai Ge inTanzania. In older textbooks, Oldowan tools are usually shown as blunt, rounded, hand-sizedstones. In fact, paleoanthropologists now tend to believe that the tool part of Oldowan rockswere the pieces flaked off these larger stones, which could then be used for cutting.
Now here’s the mystery. When early modern humans—the ones who would eventuallybee us—started to move out of Afriething over a huhousand years ago,Acheulean tools were the teology of choice. These early Homo sapiens loved theirAcheulean tools, too. They carried them vast distances. Sometimes they even took unshapedrocks with them to make into tools later on. They were, in a word, devoted to the teology.
But although Acheulean tools have been found throughout Africa, Europe, aern aral Asia, they have almost never been found in the Far East. This is deeply puzzling.
In the 1940s a Harvard paleontologist named Hallum Movius drew something called theMovius line, dividing the side with Acheulean tools from the ohout. The line runs in asoutheasterly dire across Europe and the Middle East to the viity of modern-dayCalcutta and Bangladesh. Beyond the Movius line, across the whole of southeast Asia andinto a, only the older, simpler Oldowan tools have been found. We know that Homosapie far beyond this point, so why would they carry an advanced and treasured stoeology to the edge of the Far East and then just abandon it?
“That troubled me for a long time,” recalls Alan Thorne of the Australian NationalUy in berra. “The whole of modern anthropology was built round the idea thathumans came out of Afri two waves—a first wave of Homo erectus, which became JavaMan and Peking Man and the like, and a later, more advanced wave of Homo sapiens, whichdisplaced the first lot. Yet to accept that you must believe thatHomo sapiens got so far withtheir more modern teology and then, for whatever reason, gave it up. It was all verypuzzling, to say the least.”
As it turned out, there would be a great deal else to be puzzled about, and one of the mostpuzzling findings of all would e from Thorne’s own part of the world, iback ofAustralia. In 1968, a geologist named Jim Bowler oking around on a long-dried lakebedcalled Mungo in a parched and lonely er of western New South Wales when somethingvery ued caught his eye. Stig out of a crest-shaped sand ridge of a type knownas a lue were some human bones. At the time, it was believed that humans had been inAustralia for no more than 8,000 years, but Mungo had been dry for 12,000 years. So whatwas anyone doing in su inhospitable place?
The answer, provided by carbon dating, was that the bones’ owner had lived there whenLake Mungo was a much mreeable habitat, a dozen miles long, full of water and fish,fringed by pleasant groves of casuarina trees. To everyone’s astonishment, the bour to be 23,000 years old. Other bones found nearby were dated to as much as 60,000 years.
This was ued to the point of seeming practically impossible. At no time sininids first arose oh has Australia not been an island. Any human beings who arrivedthere must have e by sea, in large enough o start a breeding population, aftercrossing sixty miles or more of open water without having any way of knowing that ave landfall awaited them. Having lahe Mungo people had then found their waymore than two thousand miles inland from Australia’s north coast—the presumed point ofentry—which suggests, acc to a report in the Proceedings of the National Academy ofSces, “that people may have first arrived substantially earlier than 60,000 years ago.”
How they got there and why they came are questions that ’t be answered. Acc tomost anthropology texts, there’s no evidehat people could even speak 60,000 years ago,much less engage in the sorts of cooperative efforts necessary to build o-worthy craft andize island tis.
“There’s just a whole lot we don’t know about the movements of people before recordedhistory,” Alan Thorold me when I met him in berra. “Do you know that wheeenth-tury anthropologists first got to Papua New Guihey found people in thehighlands of the interior, in some of the most inaccessible terrain oh, growing sweetpotatoes. Sweet potatoes are native to South America. So how did they get to Papua NewGuinea? We don’t know. Don’t have the fai idea. But what is certain is that people havebeen moving around with siderable assuredness for lohan traditionally thought, andalmost certainly sharing genes as well as information.”
The problem, as ever, is the fossil record. “Very few parts of the world are even vaguelyameo the long-term preservation of human remains,” says Thorne, a sharp-eyed manwith a white goatee and an i but friendly manner. “If it weren’t for a few productiveareas like Hadar and Olduvai i Africa we’d knhteningly little. And when youlook elsewhere, often wedo knhteningly little. The whole of India has yielded just onea human fossil, from about 300,000 years ago. Between Iraq and Vietnam—that’s adistance of some 5,000 kilometers—there have been just two: the one in India and aNeaal in Uzbekistan.” He grinned. “That’s not a whole hell of a lot to work with. You’releft with the position that you’ve got a few productive areas for human fossils, like the GreatRift Valley in Afrid Mungo here in Australia, and very little iween. It’s notsurprising that paleontologists have trouble eg the dots.”
The traditional theory to explain human movements—and the oill accepted by themajority of people in the field—is that humans dispersed across Eurasia in two waves. Thefirst wave sisted of Homo erectus, who left Africa remarkably quickly—almost as soon asthey emerged as a species—beginning nearly two million years ago. Over time, as they settledin different regions, these early erects further evolved into distinctive types—into Java Manand Peking Man in Asia, and Homo heidelbergensis and finally Homo neahalensis inEurope.
Then, something over a huhousand years ago, a smarter, lither species of creature—the aors of every one of us alive today—arose on the Afri plains and began radiatingoutward in a sed wave. Wherever they went, acc to this theory, these new Homosapiens displaced their duller, less adept predecessors. Quite how they did this ha>s alwaysbeen a matter of disputation. No signs of slaughter have ever been found, so most authoritiesbelieve the newer hominids simply outpeted the older ohough other faay alsohave tributed. “Perhaps we gave them smallpox,” suggests Tattersall. “There’s no real wayof telling. The oainty is that we are here now and they aren’t.”
These first modern humans are surprisingly shadowy. We know less about ourselves,curiously enough, than about almost any other line of hominids. It is odd indeed, as Tattersallnotes, “that the most ret major event in human evolution—the emergence of our ownspecies—is perhaps the most obscure of all.” Nobody even quite agree where trulymodern humans first appear in the fossil record. Many books place their debut at about120,000 years ago in the form of remains found at the Klasies River Mouth in South Africa,but not everyone accepts that these were fully modern people. Tattersall and Schwartzmaintain that “whether any or all of them actually represent our species still awaits definitiveclarification.”
The first undisputed appearance of Homo sapiens is in the eastererranean, aroundmodern-day Israel, where they begin to show up about 100,000 years ago—but evehey are described (by Trinkaus and Shipman) as “odd, difficult-to-classify and poorlyknown.” Neaals were already well established in the region and had a type of tool kitknown as Mousterian, which the modern humans evidently found worthy enough to borrow.
No Neaal remains have ever been found in north Africa, but their tool kits turn up allover the place. Somebody must have takehere: modern humans are the onlydidate. It is also known that Neaals and modern humans coexisted in some fashionfor tens of thousands of years in the Middle East. “We don’t know if they time-shared thesame space or actually lived side by side,” Tattersall says, but the moderns tinued happilyto use Neaal tools—hardly ving evidence of overwhelming superiority. No lesscuriously, Acheulean tools are found in the Middle East well over a million years ago, butscarcely exist in Europe until just 300,000 years ago. Again, why people who had theteology didn’t take the tools with them is a mystery.
For a long time, it was believed that the agnons, as modern humans in Europebecame known, drove the Neaals before them as they advanced across the ti,eventually f them to its western margins, where essentially they had no choice but tofall in the sea o extinct. In fact, it is now known that agnons were in the far west ofEurope at about the same time they were also ing in from the east. “Europe rettyempty pla those days,” Tattersall says. “They may not have entered each other allthat often, even with all their ings and goings.” One curiosity of the agnons’ arrivalis that it came at a time known to paleoclimatology as the Boutellier interval, when Europelunging from a period of relative mildness into yet another long spell of punishing cold.
Whatever it was that drew them to Europe, it wasn’t the glorious weather.
In any case, the idea that Neaals crumpled in the face of petition from newlyarrived agnons strains against the evide least a little. Neaals were nothing ifnot tough. For tens of thousands of years they lived through ditions that no modern humanoutside a few polar stists and explorers has experienced. During the worst of the ice ages,blizzards with hurrie-force winds were on. Temperatures routinely fell to 50 degreesbelow zero Fahre. Polar bears padded across the snowy vales of southern England.
Neaals naturally retreated from the worst of it, but even so they will have experiencedweather that was at least as bad as a modern Siberian wihey suffered, to be sure—aNeaal who lived much past thirty was lucky indeed—but as a species they weremagnifitly resilient and practically iructible. They survived for at least a huhousand years, and perhaps twice that, over aretg from Gibraltar to Uzbekistan,which is a pretty successful run for any species of being.
Quite who they were and what they were like remain matters of disagreement anduainty. Right up until the middle of the tweh tury the accepted anthropologicalview of the Neaal was that he was dim, stooped, shuffling, and simian—thequintessential caveman. It was only a painful act that prodded stists to residerthis view. In 1947, while doing fieldwork in the Sahara, a Franco-Algerian paleontologistnamed Camille Aramb te from the midday sun uhe wing of his lightairplane. As he sat there, a tire burst from the heat, and the plaipped suddenly, striking hima painful blow on the upper body. Later in Paris he went for an X-ray of his neck, and noticedthat his owebrae were aligly like those of the stooped and hulking Neaal.
Either he hysiologically primitive or Neaal’s posture had been misdescribed. Infact, it was the latter. Neaal vertebrae were not simian at all. It ged utterly how weviewed Neaals—but only some of the time, it appears.
It is still only held that Neaals lacked the intelligence or fiber to pete onequal terms with the ti’s slender and more cerebrally nimble newers, Homosapiens. Here is a typical ent from a ret book: “Modern humaralized thisadvahe Neaal’s siderably heartier physique] with better clothing, better firesaer shelter; meanwhile the Neaals were stuck with an oversize body that requiredmore food to sustain.” In other words, the very factors that had allowed them to survivesuccessfully for a huhousand years suddenly became an insuperable handicap.
Above all the issue that is almost never addressed is that Neaals had brains that weresignifitly larger than those of modern people—1.8 liters for Neaals versus 1.4 formodern people, acc to one calculation. This is more than the differeweenmodern Homo sapiens and late Homo erectus , a species we are happy tard as barelyhuman. The argument put forward is that although our brains were smaller, they weresomehow more effit. I believe I speak the truth when I observe that nowhere else inhuman evolution is su argument made.
So why then, you may well ask, if the Neaals were so stout and adaptable andcerebrally well endowed, are they no longer with us? One possible (but much disputed)answer is that perhaps they are. Alan Thorne is one of the leading propos of an alternativetheory, known as the multiregional hypothesis, which holds that human evolution has beentinuous—that just as australopithees evolved into Homo habilis and Homoheidelbergensis became over time Homo neahalensis, so modernHomo sapiens simplyemerged from more a Homo forms.Homo erectus is, on this view, not a separate speciesbut just a transitional phase. Thus modern ese are desded from a Homo erectusforebears in a, modern Europeans from a European Homo erectus, and so on.
“Except that for me there are no Homo erectus,” says Thorne. “I think it’s a term which hasoutlived its usefulness. For me, Homo erectus is simply an earlier part of us. I believe onlyone species of humans has ever left Africa, and that species isHomo sapiens.”
Oppos of the multiregional theory reject it, in the first instance, on the grounds that itrequires an improbable amount of parallel evolution by hominids throughout the Old World—in Africa, a, Europe, the most distant islands of Indonesia, wherever they appeared. Somealso believe that multiregionalism ences a racist view that anthropology took a very longtime to rid itself of. In the early 1960s, a famous anthropologist named Carleton of theUy of Pennsylvania suggested that some modern races have different sources in, implying that some of us e from more superior stock than others. This hearkenedbafortably to earlier beliefs that some modern races such as the Afri “Bushmen”
(properly the Kalahari San) and Australian Abines were more primitive than others.
Whatever ay personally have felt, the implication for many people was that someraces are ily more advanced, and that some humans could essentially stitutedifferent species. The view, so instinctively offensive noidely popularized in manyrespectable places until fairly ret times. I have before me a popular book published byTime-Life Publications in 1961 called The Epian based on a series of articles in Lifemagazine. In it you find suents as “Rhodesian man . . . lived as retly as25,000 years ago and may have been an aor of the Afriegroes. His brain size wasclose to that of Homo sapiens.” In other words black Afris were retly desded fromcreatures that were only “close” to Homo sapiens.
Thorne emphatically (and I believe sincerely) dismisses the idea that his theory is in anymeasure racist and ats for the uniformity of human evolution by suggesting that therewas a lot of movement bad forth between cultures and regions. “There’s no reason tosuppose that people only went in one dire,” he says. “People were moving all over theplace, and where they met they almost certainly shared geic material throughinterbreeding. New arrivals didn’t replace the indigenous populations, they joihem. Theybecame them.” He likens the situation to when explorers like Coellan enteredremote peoples for the first time. “They weren’t meetings of different species, but of the samespecies with some physical differences.”
What you actually see in the fossil record, Thorne insists, is a smooth, tinuoustransition. “There’s a famous skull from Petralona in Greece, dating from about 300,000 yearsago, that has been a matter of tention among traditionalists because it seems in some waysHomo erectus but in other ways Homo sapiens. Well, what we say is that this is just what youwould expect to find in species that were evolving rather than being displaced.”
Ohing that would help to resolve matters would be evidence of interbreeding, but that isnot at all easy to prove, or disprove, from fossils. In 1999, archeologists in Pal found theskeleton of a child about four years old that died 24,500 years ago. The skeleton was modernoverall, but with certain archaic, possibly Neaal, characteristics: unusually sturdy legboeeth bearing a distinctive “s..t>hoveling” pattern, and (though not everyone agrees on it)an iion at the back of the skull called a suprainiac fossa, a feature exclusive toNeaals. Erik Trinkaus of Washington Uy in St. Louis, the leading authority onNeaals, annouhe child to be a hybrid: proof that modern humans and Neaalsinterbred. Others, however, were troubled that the Neaal and moderures weren’tmore blended. As one critic put it: “If you look at a mule, you don’t have the front endlooking like a donkey and the bad looking like a horse.”
Ian Tattersall declared it to be nothing more than “a ky modern child.” He accepts thatthere may well have been some “hanky-panky” between Neaals and moderns, butdoesn’t believe it could have resulted in reproductively successful offspring.
1“I don’t knowof any twanisms from any realm of biology that are that different and still in the samespecies,” he says.
With the fossil record so unhelpful, stists have turned increasingly to geic studies,in particular the part known as mitodrial DNA. Mitodrial DNA was only discoveredin 1964, but by the 1980s some ingenious souls at the Uy of California at Berkeley hadrealized that it has two features that lend it a particular venience as a kind of molecularclock: it is passed on only through the female line, so it doesn’t bee scrambled withpaternal DNA with eaew geion, and it mutates about twenty times faster than normalnuclear DNA, makin?9９ｌｉｂ?g it easier to deted follow geic patterns over time. By trag therates of mutation they could work out the geic history aionships of whole groups ofpeople.
In 1987, the Berkeley team, led by the late Allan Wilson, did an analysis of mitodrialDNA from 147 individuals and declared that the rise of anatomically modern humansoccurred in Africa within the last 140,000 years and that “all present-day humans aredesded from that population.” It was a serious blow to the multiregionalists. But thenpeople began to look a little more closely at the data. One of the most extraordinary points—almost too extraordinary to credit really—was that the “Afris” used iudy wereactually Afri-Ameris, whose genes had obviously been subjected to siderablemediation in the past few hundred years. Doubts also soon emerged about the assumed ratesof mutations.
By 1992, the study was largely discredited. But the teiques of geialysistio be refined, and in 1997 stists from the Uy of Munich maoextrad analyze some DNA from the arm bone of the inal Neaal man, and thistime the evideood up. The Munich study found that the Neaal DNA was unlike anyDNA found oh now, strongly indig that there was iioweenNeaals and modern humans. Now this really was a blow to multiregionalism.
1One possibility is that Neaals and agnons had different numbers of osomes, a plicationthat only arises when species that are close but not quite identical join. In the equine world, forexample, horses have 64 osomes and donkeys 62. Mate the two and you get an offspring with areproductively useless number of osomes, 63. You have, in short, a sterile mule.
Then in late 2000 Nature and other publicatioed on a Swedish study of themitodrial DNA of fifty-three people, which suggested that all modern humans emergedfrom Africa within the past 100,000 years and came from a breeding stock of no more than10,000 individuals. Soon afterward, Erider, director of the WhiteheadInstitute/Massachusetts Institute of Teology ter fenome Research, annouhatmodern Europeans, and perhaps people farther afield, are desded from “no more than afew hundred Afris who left their homeland as retly as 25,000 years ago.”
As we have noted elsewhere in the book, modern human beings show remarkably littlegeic variability—“there’s more diversity in one social group of fifty-five chimps than iire human population,” as ohority has put it—and this would explain why.
Because we are retly desded from a small founding population, there hasn’t been timeenough or people enough to provide a source of great variability. It seemed a pretty severeblow to multiregionalism. “After this,” a Penn State academic told the Washington Post,“people won’t be too ed about the multiregional theory, which has very littleevidence.”
But all of this overlooked the more or less infinite capacity for surprise offered by thea Mungo people of western New South Wales. In early 2001, Thorne and his colleaguesat the Australian National Uy reported that they had recovered DNA from the oldest ofthe Mungo spes—now dated at 62,000 years—and that this DNA proved to be“geically distinct.”
The Mungo Man, acc to these findings, was anatomically modern—just like you a carried ainct geieage. His mitodrial DNA is no longer found inliving humans, as it should be if, like all other modern people, he was desded from peoplewho left Afri the ret past.
“It turned everything upside down again,” says Thorh undisguised delight.
Then other even more curious anomalies began to turn up. Rosalind Harding, a populatioicist at the Institute of Biological Anthropology in Oxford, while studyiaglobingenes in modern people, found two variants that are ong Asians and theindigenous people of Australia, but hardly exist in Africa. The variant genes, she is certain,arose more than 200,000 years ago not in Africa, but i Asia—long before modern Homosapiens reached the region. The only way to at for them is to say that aors ofpeople now living in Asia included archaiinids—Java Man and the like. Iingly,this same variahe Java Man gene, so to speak—turns up in modern populations inOxfordshire.
fused, I went to see Harding at the institute, whihabits an old brick villa onBanbury Road in Oxford, in more or less the neighborhood where Bill to hisstudent days. Harding is a small and chirpy Australian, from Brisbane inally, with the rareknack for being amused and ear at the same time.
“Don’t know,” she said at once, grinning, when I asked her how people in Oxfordshireharbored sequences of betaglobin that shouldn’t be there. “On the whole,” she went on moresomberly, “the geic record supports the out-of-Africa hypothesis. But then you find theseanomalous clusters, which most geicists prefer not to talk about. There’s huge amounts ofinformation that would be available to us if only we could uand it, but we don’t yet.
We’ve barely begun.” She refused to be drawn out on what the existence of Asian-ingenes in Oxfordshire tells us other than that the situation is clearly plicated. “All we say at this stage is that it is very untidy and we don’t really know why.”
At the time of our meeting, in early 2002, another Oxford stist named Bryan Sykes hadjust produced a popular book called The Seven Daughters of Eve in which, using studies ofmitodrial DNA, he had claimed to be able to traearly all living Europeans back to afounding population of just seven women—the daughters of Eve of the title—who livedbetween 10,000 and 45,000 years ago iime known to sce as the Paleolithic. To eachof these women Sykes had given a name—Ursula, Xenia, Jasmine, and so on—and eveailed personal history. (“Ursula was her mother’s sed child. The first had been taken bya leopard when he was only two. . . .”)When I asked Harding about the book, she smiled broadly but carefully, as if not quitecertaio go with her answer. “Well, I suppose you must give him some credit forhelping to popularize a difficult subject,” she said and paused thoughtfully. “And thereremains the remote possibility that he’s right.” She laughed, the on more ily:
“Data from any single gene ot really tell you anything so definitive. If you follow themitodrial DNA backwards, it will take you to a certain place—to an Ursula or Tara orwhatever. But if you take any other bit of DNA, any ge all, and traceit back, it will takeyou someplace else altogether.”
It was a little, I gathered, like following a road random９9ｌib.t>ly out of London and finding thateventually it ends at John O’Groats, and cluding from this that anyone in London musttherefore have e from the north of Scotland. They might have e from there, of course,but equally they could have arrived from any of hundreds of other places. In this sense,acc t, every gene is a different highway, and we have only barely begun tomap the routes. “No single gene is ever going to tell you the whole story,” she said.
So geic studies aren’t to be trusted?
“Oh you trust the studies well enough, generally speaking. What you ’t trust are thesweeping clusions that people often attach to them.”
She thinks out-of-Africa is “probably 95 pert correct,” but adds: “I think both sides havedone a bit of a disservice to sce by insisting that it must be ohing or the other. Thingsare likely to turn out to be not shtforward as either camp would have you believe. Theevidence is clearly starting to suggest that there were multiple migrations and dispersals indifferent parts of the woing in all kinds of dires and generally mixing up the genepool. That’s never going to be easy to sort out.”
Just at this time, there were also a number of reports questioning the reliability of claimsing the recovery of very a DNA. An academic writing in Nature had noted hoaleontologist, asked by a colleague whether he thought an old skull was varnished or not,had licked its top and annouhat it was. “In the process,” he Nature article, “largeamounts of modern human DNA would have been transferred to the skull,” rendering ituseless for future study. I asked Harding about this. “Oh, it would almost certainly have beeninated already,” she said. “Just handling a bone will i. Breathing on itwill i. Most of the water in our labs will i. We are all swimming infn DNA. In order to get a reliably spe you have to excavate it in sterileditions and do the tests on it at the s?
ite. It is the trickiest thing in the world not toinate a spe.”
So should such claims be treated dubiously? I asked.
Harding nodded solemnly. “Very,” she said.
If you wish to uand at once why we know as little as we do about human ins, Ihave the place for you. It is to be found a little beyond the edge of the blue Ngong Hills inKenya, to the south a of Nairobi. Drive out of the city on the main highway toUganda, and there es a moment of startling glory when the ground falls away and you arepresented with a hang glider’s view of boundless, pale green Afri plain.
This is the Great Rift Valley, which arcs across three thousand miles of east Africa,marking the teic rupture that is setting Africa adrift from Asia. Here, perhaps forty milesout of Nairobi, along the baking valley floor, is an a site called esailie, whicestood beside a large and pleasant lake. In 1919, long after the lake had vanished, a geologistnamed J. W. Gregory was scouting the area for mineral prospects when he came across astretch of open ground littered with anomalous dark stohat had clearly been shaped byhuman hand. He had found one of the great sites of Acheulean tool manufacture that IanTattersall had told me about.
Uedly iumn of 2002 I found myself a visitor to this extraordinary site. Iwas in Kenya for another purpose altogether, visiting some projects run by the charity CAREIional, but my hosts, knowing of my i in humans for the present volume, hadied a visit to esailie into the schedule.
After its discovery by Gregory, esailie lay undisturbed for over two decades beforethe famed husband-and-wife team of Louis and Mary Leakey began an excavation that isn’tpleted yet. What the Leakeys found was a site stretg to ten acres or so, where toolswere made in incalculable numbers fhly a million years, from about 1.2 million yearsago to 200,000 years ago. Today the tool beds are sheltered from the worst of the elemeh large tios and fenced off with chi wire to disce opportunisticsging by visitors, but otherwise the tools are left just where their creators dropped themand where the Leakeys found them.
Jillani Ngalli, a keen young man from the Kenyan National Museum who had beendispatched to act as guide, told me that the quartz and obsidian rocks from which the axeswere made were never found on the valley floor. “They had to carry the stones from there,” hesaid, nodding at a pair of mountains in the hazy middle distance, in opposite dires fromthe site: esailie and Ol Esakut. Each was about ten kilometers, or six miles, away—along way to carry an armload of stone.
Why the early esailie people went to such trouble we only guess, of course. Notonly did they lug hefty stones siderable distao the lakeside, but, perhaps even moreremarkably, they then ahe site. The Leakeys’ excavations revealed that there wereareas where axes were fashioned and others where blunt axes were brought to be resharpened.
esailie was, in short, a kind of factory; ohat stayed in business for a million years.
Various replications have shown that the axes were tricky and labor-intensive objects tomake—even with practice, an axe would take hours to fashion—a, curiously, they werenot particularly good for cutting or chopping or scraping or any of the other tasks to whichthey were presumably put. So we are left with the position that for a million years—far, farlohan our own species has even been ience, much less engaged in tinuouscooperative efforts—early people came in siderable o this particular site to makeextravagantly large numbers of tools that appear to have been rather curiously pointless.
And who were these people? We have no idea actually. We assume they were Homoerectus because there are no other known didates, which means that at their peak—theirpeak —the esailie workers would have had the brains of a modern infant. But there is nophysical eviden which to base a clusioe over sixty years of searg, nohuman bone has ever been found in or around the viity of esailie. However muchtime they spent there shaping rocks, it appears they went elsewhere to die.
“It’s all a mystery,” Jillani Ngalli told me, beaming happily.
The esailie people disappeared from the se about 200,000 years ago when the lakedried up and the Rift Valley started to bee the hot and challenging place it is today. Butby this time their days as a species were already numbered. The world was about to get itsfirst real master race, Homo sapiens . Things would never be the same again.
30 GOOD-BYE
IN THE EARLY 1680s, at just about the time that Edmond Halley and his friends ChristopherWren and Robert Hooke were settling down in a London coffeehouse and embarking on thecasual wager that would result eventually in Isaaewton’s Principia , Henry dish’sweighing of the Earth, and many of the other inspired and endable uakings thathave occupied us for much of the past four hundred pages, a rather less desirable milestonewas being passed on the island of Mauritius, far out in the Indian O some eight hundredmiles off the east coast of Madagascar.
There, some fotten sailor or sailor’s pet was harrying to death the last of the dodos, thefamously flightless bird whose dim but trusting nature and lack of leggy zip made it a ratherirresistible target for bored young tars on shore leave. Millions of years of peaceful isolationhad not prepared it for the erratid deeply unnerving behavior of human beings.
We don’t know precisely the circumstances, or even year, attending the last moments of thelast dodo, so we don’t know which arrived first, a world that tained a Principia or ohathad no dodos, but we do know that they happe more or less the same time. You wouldbe hard pressed, I would submit, to find a better pairing of occurreo illustrate the divineand felonious nature of the human being—a species anism that is capable of unpigthe deepest secrets of the heavens while at the same time pounding iin, f９9lｉb?or nopurpose at all, a creature that never did us any harm and wasn’t eveely capable ofuanding what we were doing to it as we did it. Indeed, dodos were so spectacularlyshort on insight, it is reported, that if you wished to find all the dodos in a viity you hadonly to cate a to squawking, and all the others would waddle along to see what.
The indigo the poor dodo didn’t end quite there. In 1755, some seventy years afterthe last dodo’s death, the director of the Ashmolean Museum in Oxford decided that theinstitution’s stuffed dodo was being unpleasantly musty and ordered it tossed on abohis was a surprising decision as it was by this time the only dodo ieuffed or otherwise. A passing employee, aghast, tried to rescue the bird but could save onlyits head and part of one limb.
As a result of this and other departures from on sense, we are not irely surewhat a living dodo was like. We possess much less information than most people suppose—ahandful of crude descriptions by “uific voyagers, three or four oil paintings, and a fewscattered osseous fragments,” in the somewhat aggrieved words of the eenth-turynaturalist H. E. Strid. As Strid wistfully observed, we have more physical evidenceof some a sea monsters and lumbering saurapods than we do of a bird that lived intomodern times and required nothing of us to survive except our absence.
So what is known of the dodo is this: it lived on Mauritius, lump but not tasty, andwas the biggest-ever member of the pigeon family, though by quite what margin is unknownas its weight was never accurately recorded. Extrapolations from Strid’s “ossements” and the Ashmolean’s modest remains show that it was a little over two and a halffeet tall and about the same distance from beak tip to backside. Being flightless, it ed onthe ground, leaving its eggs and chicks tragically easy prey fs, dogs, and monkeysbrought to the island by outsiders. It robably extinct by 1683 and was most certainlygone by 1693. Beyond that we know almost nothing except of course that we will not see itslike again. We know nothing of its reproductive habits and diet, where it ranged, what soundsit made in tranquility or alarm. We don’t possess a single dodo egg.
From beginning to end our acquaintah animate dodos lasted just seventy years. Thatis a breathtakingly sty period—though it must be said that by this point in our history wedid have thousands of years of practice behind us iter of irreversible eliminations.
Nobody knows quite how destructive human beings are, but it is a fact that over the last fiftythousand years or so wherever we have gone animals have teo vanish, in oftenastonishingly large numbers.
In America, thirty genera of large animals—some very large indeed—disappearedpractically at a stroke after the arrival of modern humans on the ti between ten ay thousand years ago. Altogether North and South America between them lost aboutthree quarters of their big animals once man the hunter arrived with his flint-headed spearsand keen anizational capabilities. Europe and Asia, where the animals had had looevolve a useful wariness of humans, lost between a third and a half of their big creatures.
Australia, for exactly the opposite reasons, lost han 95 pert.
Because the early hunter populations were paratively small and the animal populationstruly moal—as many as ten million mammoth carcasses are thought to lie frozen iundra of northern Siberia alone—some authorities think there must be other explanations,possibly involving climate ge or some kind of pandemic. As Ross MacPhee of theAmeri Museum of Natural History put it: “There’s no material be to huntingdangerous animals more often than you o—there are only so many mammoth steaksyou eat.” Others believe it may have been almost criminally easy to catd clobberprey. “In Australia and the Americas,” says Tim Flannery, “the animals probably didn’t knowenough to run away.”
Some of the creatures that were lost were singularly spectacular and would take a littlemanaging if they were still around. Imagine ground sloths that could look into an upstairswindow, tortoises nearly the size of a small Fiat, monitor lizards twenty feet long baskingbeside desert highways iern Australia. Alas, they are gone and we live on a muchdiminished plaoday, across the whole world, only four types of really hefty (a metrior more) land animals survive: elephants, rhinos, hippos, and giraffes. Not for tens of millionsof years has life oh been so diminutive and tame.
The question that arises is whether the disappearances of the Stone Age and disappearanore ret times are in effect part of a siin event—whether, in short, humansare ily bad news for other living things. The sad likelihood is that we may well be.
Acc to the Uy of Chicago paleontologist David Raup, the background rate ofextin oh throughout biological history has been one species lost every four yearson average. Acc to o calculation, human-caused extin now may berunning as much as 120,000 times that level.
In the mid-1990s, the Australian naturalist Tim Flannery, now head of the South AustralianMuseum in Adelaide, became struck by how little we seemed to know about mains, includiively ret ones. “Wherever you looked, there seemed to be gapsin the records—pieces missing, as with the dodo, or not recorded at all,” he told me whe him in Melbourne a year or so ago.
Flannery recruited his frieer Schouten, an artist and fellow Australian, and togetherthey embarked on a slightly obsessive quest to scour the world’s major colles to find outwhat was lost, what was left, and what had never been known at all. They spent four yearspig through old skins, musty spes, old drawings, and written descriptions—whatever was available. Schouten made life-sized paintings of every animal they couldreasonably re-create, and Flannery wrote the words. The result was araordinary bookcalled A Gap in Nature, stituting the most plete—and, it must be said, moving—catalog of animal extins from the last three hundred years.
For some animals, records were good, but nobody had done anything much with them,sometimes for years, sometimes forever. Steller’s sea cow, a walrus-like creature related tothe dugong, was one of the last really big animals to go extinct. It was truly enormous—anadult could reach lengths of nearly thirty feet and weigh ten tons—but we are acquainted withit only because in 1741 a Russian expedition happeo be shipwrecked on the only placewhere the creatures still survived in any numbers, the remote and foggy ander Islandsin the Bering Sea.
Happily, the expedition had a naturalist, Ge Steller, who was fasated by the animal.
“He took the most copious notes,” says Flannery. “He even measured the diameter of itswhiskers. The only thing he wouldn’t describe was the male genitals—though, for somereason, he was happy enough to do the female’s. He even saved a piece of skin, so we had agood idea of its texture. We weren’t always so lucky.”
The ohing Steller couldn’t do was save the sea cow itself. Already huo the brinkof extin, it would be googether withiy-seven years of Steller’s discovery ofit. Many other animals, however, couldn’t be included because too little is known about them.
The Darling Downs hopping mouse, Chatham Islands swan, Assion Island flightless crake>,at least five types of large turtle, and many others are forever lost to us except as names.
A great deal of extin, Flannery and Schouten discovered, hasn’t been cruel or wanton,but just kind of majestically foolish. In 1894, when a lighthouse was built on a lonely rockcalled Stephens Island, iempestuous strait between the North and South Islands of NewZealand, the lighthouse keeper’s cat kept bringing him stratle birds that it had caught.
The keeper dutifully sent some spes to the museum in Wellington. There a curatrewvery excited because the bird was a relic species of flightless wrens—the only example of aflightless perg bird ever found anywhere. He set off at once for the island, but by the timehe got there the cat had killed them all. Twelve stuffed museum species of the Stephens Islandflightless wren are all that .
At least we have those. All too often, it turns out, we are not much better at looking afterspecies after they have gohan we were before they went. Take the case of the lovelyCarolina parakeet. Emerald green, with a golden head, it was arguably the most striking aiful bird ever to live in North America—parrots don’t usually venture so far north, asyou may have noticed—and at its peak it existed in vast numbers, exceeded only by thepassenger pigeon. But the Carolina parakeet was also sidered a pest by farmers and easilyhunted because it flocked tightly and had a peculiar habit of flying up at the sound of gunfire(as you would expect), but theurning almost at oo che fallen rades.
In his classic Ameriithology, written in the early eenth tury, CharlesWillson Peale describes an occasion in which he repeatedly empties a shotgun into a tree inwhich they roost:
At each successive discharge, though showers of them fell, yet the affe of thesurvivors seemed rather to increase; for, after a few circuits around the place, they againalighted near me, looking down on their slaughtered panions with such masymptoms of sympathy and , as entirely disarmed me.
By the sed decade of the tweh tury, the birds had been so relentlessly huhat only a few remained alive in captivity. The last one, named Inca, died in the atiZoo in 1918 (not quite four years after the last passenger pigeon died in the same zoo) andwas reverently stuffed. And where would you go to see poor Inow? Nobody knows. Thezoo lost it.
What is both most intriguing and puzzling about the story above is that Peale was a lover ofbirds, a did not hesitate to kill them in large numbers for er reason than that itied him to do so. It is a truly astounding fact that for the loime the people whowere most intensely ied in the world’s living things were the ones most likely toextinguish them.
No one represehis position on a larger scale (in every sehan Lionel WalterRothschild, the sed Baron Rothschild. S of the great banking family, Rothschild was astrange and reclusive fellow. He lived his entire life in the nursery wing of his home at Tring,in Bughamshire, using the furniture of his childhood—even sleeping in his childhoodbed, though eventually he weighed three hundred pounds.
His passion was natural history and he became a devoted accumulator of objects. He senthordes of trained men—as many as four hu a time—to every quarter of the globe toclamber over mountains and hack their way through jungles in the pursuit of newspes—particularly things that flew. These were crated or boxed up a back toRothschild’s estate at Tring, where he and a battalion of assistants exhaustively logged andanalyzed everything that came before them, produg a stant stream of books, papers, andmonographs—some twelve hundred in all. Altogether, Rothschild’s natural history factoryprocessed well over two million spes and added five thousand species of creature to thestific archive.
Remarkably, Rothschild’s colleg efforts were her the most extensive nor the mostgenerously funded of the eenth tury. That title almost certainly belongs to a slightlyearlier but also very wealthy British collector named Hugh g, who became sopreoccupied with accumulating objects that he built a large ogoing ship and employed acrew to sail the world full-time, pig up whatever they could find—birds, plants, animalsof all types, and especially shells. It was his unrivaled colle of barhat passed toDarwin and served as the basis for his seminal study.
However, Rothschild was easily the most stific collector of his age, though also themrettably lethal, for in the 1890s he became ied in Hawaii, perhaps the mosttemptingly vulnerable enviro Earth has yet produced. Millions of years of isolation hadallowed Hawaii to evolve 8,800 unique species of animals and plants. Of particular ioRothschild were the islands’ colorful and distinctive birds, often sisting of very smallpopulations inhabitiremely specifiges.
The tragedy for many Hawaiian birds was that they were not only distinctive, desirable, andrare—a dangerous bination in the best of circumstances—but also oftebreakinglyeasy to take. The greater koa finch, an innoember of the honeycreeper family, lurkedshyly in the opies of koa trees, but if someone imitated its song it would abandon its coverat ond fly down in a show of wele. The last of the species vanished in 1896, killedby Rothschild’s ace collector Harry Palmer, five years after the disappearance of its cousin thelesser koa finch, a bird so sublimely rare that only one has ever beehe one shot forRothschild’s colle. Altogether during the decade or so of Rothschild’s most intensivecolleg, at least nine species of Hawaiian birds vanished, but it may have been more.
Rothschild was by no means alone in his zeal to capture birds at more or less any cost.
Others in fact were more ruthless. In 1907 when a well-known collector named AlansonBryan realized that he had shot the last three spes of black mamos, a species of forestbird that had only been discovered the previous decade, he hat the news filled him with“joy.”
It was, in short, a difficult age to fathom—a time when almost any animal ersecuted ifit was deemed the least bit intrusive. In 1890, New York State paid out over one hundredbounties for eastern mountain lions even though it was clear that the much-harassed creatureswere on the brink of extin. Right up until the 1940s many states tio paybounties for almost any kind of predatory creature. West Virginia gave out an annual collegescholarship to whoever brought in the most dead pests—and “pests” was liberally interpretedto mean almost anything that wasn’t grown on farms or kept as pets.
Perhaps nothing speaks more vividly for the strangeness of the times thae of thelovely little Ba’s warbler. A native of the southern Uates, the warbler wasfamous for its unusually thrilling song, but its population numbers, never robust, graduallydwindled until by the 1930s the warbler vanished altogether a unseen for many years.
Then in 1939, by happy ce two separate birdihusiasts, in widely separatedlocations, came across lone survivors just two days apart. They both shot the birds, and thatwas the last that was ever seen of Ba’s warblers.
The impulse to exterminate was by no means exclusively Ameri. In Australia, bountieswere paid oasmanian tiger (properly the thylae), a doglike creature with distinctive“tiger” stripes across its back, until shortly before the last one died, forlorn and nameless, in aprivate Hobart zoo in 1936. Go to the Tasmanian Museum today and ask to see the last of thisspecies—the only large ivorous marsupial to live into modern times—and all they show you are photographs. The last surviving thylae was thrown out with the weekly trash.
I mention all this to make the point that if you were designing an anism to look after lifein our lonely os, to monitor where it is going and keep a record of where it has been, youwouldn’t choose human beings for the job.
But here’s aremely salient point: we have been chosen, by fate or Providence orwhatever you wish to call it. As far as we tell, we are the best there is. We may be allthere is. It’s an unnerving thought that we may be the living universe’s supreme achievementand its worst nightmare simultaneously.
Because we are so remarkably careless about looking after things, both when alive andwhen not, we have no idea—really all—about how many things have died offpermaly, or may soon, or may never, and what role layed in any part of theprocess. In 1979, in the book The Sinking Ark, the author Norman Myers suggested thathuman activities were causing about two extins a week on the pla. By the early 1990she had raised the figure to some six hundred per week. (That’s extins of all types—plants, is, and so on as well as animals.) Others have put the figure even higher—to wellover a thousand a week. A United Natio of 1995, oher hand, put the totalnumber of knowins in the last four hundred years at slightly under 500 for animalsand slightly over 650 for plants—while allowing that this was “almost certainly aimate,” particularly with regard to tropical species. A few interpreters think mostextin figures are grossly inflated.
The fact is, we d?on’t know. Don’t have any idea. We don’t know whearted doingmany of the things we’ve done. We don’t know what we are doing right now or how ourpresent as will affect the future. What we do know is that there is only one plao do iton, and only one species of being capable of making a sidered difference. Edward O.
Wilson expressed it with unimprovable brevity in The Diversity of Life: “One pla, oneexperiment.”
If this book has a lesson, it is that we are awfully lucky to be here—and by “we” I meanevery living thing. To attain a９９lｉb?ny kind of life in this universe of ours appears to be quite anachievement. As humans we are doubly lucky, of course: We enjoy not only the privilege ofexiste also the singular ability to appreciate it and even, in a multitude of ways, tomake it better. It is a talent we have only barely begun to grasp.
We have arrived at this position of eminen a stunningly short time. Behaviorallymodern human beings—that is, people who speak and make art and anize plexactivities—have existed for only about 0.0001 pert of Earth’s history. But surviving foreven that little while has required a nearly endless string of good fortune.
We really are at the beginning of it all. The trick, of course, is to make sure we never findthe end. And that, almost certainly, will require a good deal more than lucky breaks.天涯在线书库《www.tianyabook.com》