The Making of the Atomic Bomb: 25th Anniversary Edition

by Richard Rhodes

It is still an unending source of surprise for me to see how a few scribbles on a blackboard or on a sheet of paper could change the course of human affairs. Stanislaw Ulam

Polanyi asked straightforward questions. How were scientists chosen? What oath of allegiance did they swear? Who guided their research—chose the problems to be studied, approved the experiments, judged the value of the results? In the last analysis, who decided what was scientifically “true”? Armed with these questions, Polanyi then stepped back and looked at science from outside.

The practice of science was not itself a science; it was an art, to be passed from master to apprentice as the art of

“What do we mean by ‘understanding’ something?” Feynman asked innocently.100 His amused sense of human limitation informs his answer: We can imagine that this complicated array of moving things which constitutes “the world” is something like a great chess game being played by the gods, and we are observers of the game. We do not know what the rules of the game are; all we are allowed to do is to watch the playing. Of course, if we watch long enough, we may eventually catch on to a few of the rules. The rules of the game are what we mean by fundamental physics. Even if we know every rule, however . . . what we really can explain in terms of those rules is very limited, because almost all situations are so enormously complicated that we cannot follow the plays of the game using the rules, much less tell what is going to happen next. We must, therefore, limit ourselves to the more basic question of the rules of the game. If we know the rules, we consider that we “understand” the world.

Becoming a scientist is necessarily an act of profound commitment to the scientific system and the scientific world view. “Any account of science which does not explicitly describe it as something we believe in is essentially incomplete and a false pretense. It amounts to a claim that science is essentially different from and superior to all human beliefs that are not scientific statements—and this is untrue.” Belief is the oath of allegiance that scientists swear.102 That was how scientists were chosen and admitted to the order. They constituted a republic

It was clear, then, who among scientists judged the value of scientific results: every member of the group, as in a Quaker meeting. “The authority of scientific opinion remains essentially mutual; it is established between scientists, not above them.” There were leading scientists, scientists who worked with unusual fertility at the growing points of their fields; but science had no ultimate leaders.106 Consensus ruled.

Not that every scientist was competent to judge every contribution. The network solved that problem too. Suppose Scientist M announces a new result. He knows his highly specialized subject better than anyone in the world; who is competent to judge him? But next to Scientist M are Scientists L and N. Their subjects overlap M’s, so they understand his work well enough to assess its quality and reliability and to understand where it fits into science. Next to L and N are other scientists, K and O and J and P, who know L and N well enough to decide whether to trust their judgment about M. On out to Scientists A and Z, whose subjects are almost completely removed from M’s. “This network is the seat of scientific opinion,” Polanyi emphasized; “of an opinion which is not held by any single human brain, but which, split into thousands of different fragments, is held by a multitude of individuals, each of whom endorses the other’s opinion at second hand, by relying on the consensual chains which link him to all the others through a sequence of overlapping neighborhoods.”

How scientific consensus works

Apprentices learned three broad criteria of scientific judgment.109 The first criterion was plausibility. That would eliminate crackpots and frauds. It might also (and sometimes did) eliminate ideas so original that the orthodox could not recognize them, but to work at all, science had to take that risk.

But notice that the mathematical analogy begins to embed the problem of doubt within the framework of language, identifying doubt as a specialized form of verbal ambiguity, and notice that it seeks to clarify ambiguities by isolating their several variant meanings on separate, disconnected planes.

As far back as Bohr’s doctoral dissertation he had decided that some of the phenomena he was examining could not be explained by the mechanical laws of Newtonian physics. “One must assume that there are forces in nature of a kind completely different from the usual mechanical sort,” he wrote then.276 He knew where to look for these different forces: he looked to the work of Max Planck and Albert Einstein.

Planck, a thoroughgoing conservative, had no taste for pursuing the radical consequences of his radiation formula. Someone else did: Albert Einstein. In a paper in 1905 that eventually won for him the Nobel Prize, Einstein connected Planck’s idea of limited, discontinuous energy levels to the problem of the photoelectric effect. Light shone on certain metals knocks electrons free; the effect is applied today in the solar panels that power spacecraft. But the energy of the electrons knocked free of the metal does not depend, as common sense would suggest, on the brightness of the light. It depends instead on the color of the light—on its frequency. Einstein saw a quantum condition in this odd fact. He proposed the heretical possibility that light, which years of careful scientific experiment had demonstrated to travel in waves, actually traveled in small individual packets—particles—which he called “energy quanta.” Such photons (as they are called today), he wrote, have a distinctive energy hv and they transfer most of that energy to the electrons they strike on the surface of the metal. A brighter light thus releases more electrons but not more energetic electrons; the energy of the electrons released depends on hv and so on the frequency of the light. Thus Einstein advanced Planck’s quantum idea from the status of a convenient tool for calculation to that of a possible physical fact.

But no one understood what produced the lines. At best, mathematicians and spectroscopists who liked to play with wavelength numbers were able to find beautiful harmonic regularities among sets of spectral lines.

Using his formula, Balmer was able to predict the wavelengths of lines to be expected for parts of the hydrogen spectrum not yet studied. They were found where he said they would be.

The Balmer formula then became a special case of the more general Rydberg equation, which was built around a number called the Rydberg constant. That number, subsequently derived by experiment and one of the most accurately known of all universal constants, takes the precise modern value of 109,677 cm−1. Bohr would have known these formulae

Mechanistic physics had become authoritarian. It had outreached itself to claim universal application, to claim that the universe and everything in it is rigidly governed by mechanistic cause and effect.

He apologized similarly for his tentative, rambling habit of speech: “I try not to speak more clearly than I think.”

Funny

Much of the difficulty was language, that slippery medium in which Bohr saw us inextricably suspended.

They were thirteen, perhaps fourteen years old. They would be soldiers soon enough.

Is this how do capitalists look at us? Hurry and grow up so you can work for me?

committing His Majesty’s government to a Jewish homeland in Palestine at some indefinite future time, “it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine.”335 can hardly be counted an unseemly reward for saving the guns of the British Army and Navy from premature senility. Chaim Weizmann’s experience was an early and instructive example of the power of science in time of war. Government took note. So did science.

Chemists among the men who survived the attack recognized chlorine quickly enough, however, and knew how easy it was to neutralize; within a week the women of London had sewn 300,000 pads of muslin-wrapped cotton for soaking in hyposulfite—the first crude gas masks.

After she married Haber and bore him a son, a neglected housewife with a child to raise, she withdrew progressively from science and into depression. Her husband’s work with poison gas triggered even more desperate melancholy. “She began to regard poison gas not only as a perversion of science but also as a sign of barbarism,” a Haber biographer explains. “It brought back the tortures men said they had forgotten long ago. It degraded and corrupted the discipline [i.e., chemistry] which had opened new vistas of life.”351 She asked, argued, finally adamantly demanded that her husband abandon gas work. Haber told her what he had told Hahn, adding for good measure, patriot that he was, that a scientist belongs to the world in times of peace but to his country in times of war.352 Then he stormed out to supervise a gas attack on the Eastern Front. Dr. Clara Immerwahr Haber committed suicide the same night.

John Masefield, the British poet, was there and lived to report: “They came on in a monstrous mass, packed shoulder to shoulder, in some places eight deep, in others three or four deep.” On the left flank “the Turks got fairly in among our men with a weight which bore all before it, and what followed was a long succession of British rallies to a tussle body to body, with knives and stones and teeth, a fight of wild beasts in the ruined cornfields of The Farm.”358 Harry Moseley, in the front line, lost that fight. When he heard of Moseley’s death, the American physicist Robert A. Millikan wrote in public eulogy that his loss alone made the war “one of the most hideous and most irreparable crimes in history.”

The shells, if they were not loaded with shrapnel in the first place, were designed to fragment when they exploded on impact; they produced by far the most horrible mutilations and dismemberings of the war, faces torn away, genitals torn away, a flying debris of arms and legs and heads, human flesh so pulped into the earth that the filling of sandbags with that earth was a repulsive punishment. Men cried out against the monstrousness on all sides.

Richard Jordan Gatling, who correctly located the machine gun among automated systems. “It bears the same relation to other firearms,” Gatling noted, “that McCormack’s Reaper does to the sickle, or the sewing machine to the common needle.”374 The military historian John Keegan writes:

“The War had become undisguisedly mechanical and inhuman,” Siegfried Sassoon allows a fictional infantry officer to see. “What in earlier days had been drafts of volunteers were now droves of victims.”378 Men on every front independently discovered their victimization.

Whatever its ostensible purpose, the end result of the complex organization that was the efficient software of the Great War was the manufacture of corpses. This essentially industrial operation was fantasized by the generals as a “strategy of attrition.” The British tried to kill Germans, the Germans tried to kill British and French and so on, a “strategy” so familiar by now that it almost sounds normal. It was not normal in Europe before 1914 and no one in authority expected it to evolve, despite the pioneering lessons of the American Civil War. Once the trenches were in place, the long grave already dug (John Masefield’s bitterly ironic phrase), then the war stalemated and death-making overwhelmed any rational response.

But the death machine had only sampled a vast new source of raw material: the civilians behind the lines. It had not yet evolved equipment efficient to process them, only big guns and clumsy biplane bombers. It had not yet evolved the necessary rationale that old people and women and children are combatants equally with armed and uniformed young men. That is why, despite its sickening squalor and brutality, the Great War looks so innocent to modern eyes.

Budapest, combining Buda, Óbuda and Pest,

The truth is harsher: the Hungarians came to live elsewhere because lack of scientific opportunity and increasing and finally violent anti-Semitism drove them away.

The Minta that Szilard and Teller later attended deeply gratified von Kármán when he went there in the peaceful 1890s. “My father [who founded the school],” he writes, “was a great believer in teaching everything—Latin, math, and history—by showing its connection with everyday living.” To begin Latin the students wandered the city copying down inscriptions from statues and museums; to begin mathematics they looked up figures for Hungary’s wheat production and made tables and drew graphs. “At no time did we memorize rules from a book. Instead we sought to develop them ourselves.”400 What better basic training for a scientist?

They returned in the autumn; by then Admiral Nicholas Horthy had ridden into Budapest on a white horse behind a new national army to install a violent fascist regime, the first in Europe. The Red Terror had come and gone, resulting in some five hundred deaths by execution.418 The White Terror of the Horthy regime was of another order of magnitude: at least 5,000 deaths and many of those sadistic; secret torture chambers; a selective but unrelenting anti-Semitism that drove tens of thousands of Jews into exile.

“I was glad to get out of Hungary,” he writes of his state of mind then. “I felt I had had enough of politicians and government upheavals. . . . Suddenly I was enveloped in the feeling that only science is lasting.”425 That science can be a refuge from the world is a conviction common among men and women who turn to it. Abraham Pais remarks that Einstein “once commented that he had sold himself body and soul to science, being in flight from the ‘I’ and the ‘we’ to the ‘it.’ ”426 But science as a means of escaping from the familiar world of birth and childhood and language when that world mounts an overwhelming threat—science as a way out, a portable culture, an international fellowship and the only abiding certitude—must

Heisenberg nevertheless raised pointed objection to one of Bohr’s statements. Bohr had learned to be alert for bright students who were not afraid to argue. “At the end of the discussion he came over to me and asked me to join him that afternoon on a walk over the Hain Mountain,” Heisenberg remembers. “My real scientific career only began that afternoon.”436 It is the memory of a conversion.

In 1516 a rich silver lode was discovered in Joachimsthal (St. Joachim’s dale), in the territory of the Count von Schlick, who immediately appropriated the mine. In 1519 coins were first struck from its silver at his command. Joachimsthaler, the name for the new coins, shortened to thaler, became “dollar” in English before 1600. Thereby the U.S. dollar descends from the silver of Joachimsthal.

Both of Oppenheimer’s closest college friends, Francis Fergusson and Paul Horgan, agree that he was prone to baroque exaggeration, to making more of things than things could sustain on their own.458 Since that tendency would eventually ruin his life, it deserves to be examined.

Teller generalized it later from his own experience of lost wars and their aftermaths: “Not only do wars create incredible suffering, but they engender deep hatreds that can last for generations.”

What Heisenberg conceived that night came to be called the uncertainty principle, and it meant the end of strict determinism in physics: because if atomic events are inherently blurred, if it is impossible to assemble complete information about the location of individual particles in time and space, then predictions of their future behavior can only be statistical. The dream or bad joke of the Marquis de Laplace, the eighteenth-century French mathematician and astronomer, that if he knew at one moment the precise location in time and space of every particle in the universe he could predict the future forever, was thus answered late at night in a Copenhagen park: nature blurs that divine prerogative away.

The reason both could be accepted as valid is that “particles” and “waves” are words, are abstractions. What we know is not particles and waves but the equipment of our experiments and how that equipment changes in experimental use. The equipment is large, the interiors of atoms small, and between the two must be interposed a necessary and limiting translation. The solution, Bohr went on, is to accept the different and mutually exclusive results as equally valid and stand them side by side to build up a composite picture of the atomic domain. Nur die Fülle führt zur Klarheit: only wholeness leads to clarity. Bohr was never interested in an arrogant reductionism. He called instead—the word appears repeatedly in his Como lecture—for “renunciation,” renunciation of the godlike determinism of classical physics where the intimate scale of the atomic interior was concerned.496

He scolded his distinguished colleague finally in Einstein’s own terms. God does not throw dice? “Nor is it our business to prescribe to God how He should run the world.”502

Comparing helium to hydrogen, nearly 1 percent of the hydrogen mass was missing (4 divided by 4.032 = .992 = 99.2%). “If we were able to transmute [hydrogen] into [helium] nearly 1 percent of the mass would be annihilated. On the relativity equivalence of mass and energy now experimentally proved [Aston refers here to Einstein’s famous equation E = mc2], the quantity of energy liberated would be prodigious. Thus to change the hydrogen in a glass of water into helium would release enough energy to drive the ‘Queen Mary’ across the Atlantic and back at full speed.”

There are those about us who say that such research should be stopped by law, alleging that man’s destructive powers are already large enough. So, no doubt, the more elderly and ape-like of our prehistoric ancestors objected to the innovation of cooked food and pointed out the grave dangers attending the use of the newly discovered agency, fire. Personally I think there is no doubt that sub-atomic energy is available all around us, and that one day man will release and control its almost infinite power. We cannot prevent him from doing so and can only hope that he will not use it exclusively in blowing up his next door neighbor.

Half the experimental physicists studied and fully 84 percent of the theoreticians were the sons of professional men, typically engineers, physicians and teachers, although a minority of experimentalists were farmers’ sons. None of the fathers of the sixty-four scientists, including twenty-two physicists, in the largest of these studies was an unskilled laborer, and few of the fathers of physicists were businessmen. The physicists were almost all either first-born sons or eldest sons. Theoretical physicists averaged the highest verbal IQ’s among all scientists studied, clustering around 170, almost 20 percent higher than the experimentalists.524 Theoreticians also averaged the highest spatial IQ’s, experimentalists ranking second.

The following study of scientists is very interesting

The sixty-four-man study which included twenty-two physicists among its “most eminent scientists in the U.S.” produced this composite portrait of the American scientist in his prime: He is likely to have been a sickly child or to have lost a parent at an early age. He has a very high I.Q. and in boyhood began to do a great deal of reading. He tended to feel lonely and “different” and to be shy and aloof from his classmates. He had only a moderate interest in girls and did not begin dating them until college. He married late . . . has two children and finds security in family life; his marriage is more stable than the average. Not until his junior or senior year in college did he decide on his vocation as a scientist. What decided him (almost invariably) was a college project in which he had occasion to do some independent research—to find out things for himself. Once he discovered the pleasures of this kind of work, he never turned back. He is completely satisfied with his chosen vocation. . . . He works hard and devotedly in his laboratory, often seven days a week. He says his work is his life, and he has few recreations. . . . The movies bore him. He avoids social affairs and political activity, and religion plays no part in his life or thinking. Better than any other interest or activity, scientific research seems to meet the inner need of his nature.525 Clearly this is close to Robert Oppenheimer. The group studied, like the American physics community then, was predomi...

Oppenheimer looked into the subtleties of the invisible cosmic margins, modeled the imploding collapse of dying suns and described theoretical stellar objects that would not be discovered for thirty and forty years—neutron stars, black holes—because the instruments required to detect them, radio telescopes and X-ray satellites, had not been invented yet.550 (Alvarez believes if Oppenheimer had lived long enough to see these developments he would have won a Nobel Prize for his work.) That was originality not so much ahead of its time as outside the frame.

Cool

This very great disparity suggests that the fact that discipline is good for the soul is more fundamental than any of the grounds given for its goodness.

I believe that through discipline, though not through discipline alone, we can achieve serenity, and a certain small but precious measure of freedom from the accidents of incarnation, and charity, and that detachment which preserves the world which it renounces.

“Interested to hear you have had a period of depression. I have them often—sometimes nothing seems to be OK—but I have gotten used to them now. I expect the blues and I endure them. Of course the best palliative is work, but sometimes it is hard to work under the circumstances.”552 That work is only a “palliative,” not a cure, hints at how blue the blues could be. Lawrence was a hidden sufferer, in some measure manic-depressive; he kept moving not to fall

The psychologist who studied scientists at Berkeley with Rorschach and TAT found that “uncommon sensitivity to experiences—usually sensory experiences” is the beginning of creative discovery in science. “Heightened sensitivity is accompanied in thinking by over-alertness to relatively unimportant or tangential aspects of problems. It makes [scientists] look for and postulate significance in things which customarily would not be singled out. It encourages highly individualized and even autistic ways of thinking.”

Most physicists had been content with the seemingly complete symmetry of two particles, the electron and the proton, one negative, one positive. Outside the atom—among the stripped, ionized matter beaming through a discharge tube, for example—two elementary atomic constituents might be enough. But Rutherford was concerned with how each element was assembled. “He had asked himself,” Chadwick continues, “and kept on asking himself, how the atoms were built up, how on earth were you going to get—the general idea being at that time that protons and electrons were the constituents of an atomic nucleus . . . how on earth were you going to build up a big nucleus with a large positive charge? And the answer was a neutral particle.”

Chadwick then went to Vienna. “He found,” write his biographers, “that the scintillation counting was done by three young women—it was thought that not only did women have better eyes than men but they were less likely to be distracted by thinking while counting!” Chadwick observed the young women at work and realized that because they understood what was expected of the experiments they produced the expected results, unconsciously counting nonexistent scintillations.578 To test the technicians he gave them, without explanation, an unfamiliar experiment; this time their counts matched his own. Vienna apologized.