9 THE MIGHTY ATOM

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    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<bdo>藏书网</bdo>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<samp>藏书网</samp>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.

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