Einstein's Genius Club (26 page)

Whether Heisenberg intended to fail or not, we do not know. But to those in Los Alamos, Heisenberg as director of the German effort seemed a distinct threat.

On October 3, 1943, Niels Bohr, the eminent and avuncular “father” of quantum mechanics, donned an ill-fitting aviator's helmet and squeezed into the bomb bay of a twin-engine plane used by England to ferry diplomatic pouches from Stockholm.

Bohr had escaped just days before from his homeland, occupied Denmark, which had become too dangerous for Jews. Until 1943, German Nazis had reluctantly acceded to the Danish monarchy and populace. In return for Denmark's agricultural riches, the occupiers had refrained from their usual tactics. No longer. The tide of the war was beginning to change against Germany, and as it contracted, the pace of the Holocaust quickened. Berlin ordered the arrest of Bohr and his brother Harold, to be followed by the arrest of all Danish Jews. Tipped off, Bohr and his wife casually walked out their door and down to the seaside, where they hid until, under cover of night, they were ferried across the Oresund to Sweden.

Even Sweden was too dangerous. Its streets were crawling with German agents ready to bundle Bohr back to Germany. Intent on brokering a deal to save the Jews of Denmark, Bohr rushed (incognito) to Stockholm, where he appealed to King Gustaf V. At first, the king demurred, having been rebuffed by the Nazis when, in 1940, he offered asylum to the Jews of Norway. Bohr persisted, and with Swedish help, the Danish underground managed to ferry some six thousand refugees (virtually the entire Jewish population of Denmark) across the Oresund.

Within days, Bohr received an official invitation to join fellow scientists in Britain. Certain that his family was safe in Sweden, he accepted. Again, the route out was hazardous. Bohr huddled in the empty bomb bay of a two-engine Mosquito used for diplomatic mail. He was unconscious from oxygen deprivation by the time he arrived in London, but quickly recovered. From there, with his son Aage, he soon traveled with the British contingent to Los Alamos, New Mexico, where J. Robert Oppenheimer and his colleagues were constructing their “completely fantastic” gadget.

Los Alamos was the nerve center of an effort to devise the most destructive “gadget” ever imagined. There, theorists and engineers worked on the explosive mechanisms. Two other locations—Oak Ridge, Tennessee, and Hartford, Washington—housed vast facilities for producing fissionable material. Additional work took place in university laboratories across the country. It was, of course, a secret mission, though its vast size alone made security nearly impossible.

Bohr traveled to Los Alamos by train, along with his son and General Leslie Groves, commanding officer of the Manhattan Project. If Bohr was astonished by the progress in atomic fission, he must have been stupefied by the immensity of the effort. Like Oak Ridge and Hartford, Los Alamos was a small town. In a matter of months, it had grown from a tiny outpost of a few school buildings into a miniature city of tenement apartments, dormitories, mess
halls, physics and chemistry laboratories, warehouses, medical offices, a machine shop, a school, and even a radio station.

The whirlwind construction was overseen by the yin and yang of the American atomic bomb effort: General Groves and J. Robert Oppenheimer. A formidable commander with an ego to match, Groves had trained as an engineer at MIT and West Point, where he graduated fourth in his class. He was aggressive, blustery, and dictatorial—not the sort of man who might endear himself to experimental and theoretical physicists. Indeed, his whirlwind tour of the project laboratories in September 1942, beginning with Pittsburgh and New York and heading west, left egos bruised and Groves increasingly distressed. He was visibly irritated by the prevailing academicism—open-mindedness was valued above efficiency, self-doubt above ambition. “When in doubt, act” was his dictum and constant theme. “How can you work with people like that?” asked Leo Szilard of his fellow physicists in the Chicago Metallurgy Laboratory.
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By the time he reached Berkeley, Groves was desperate for someone who could offer clarity and certitude. What he found was Oppenheimer—his polar opposite in character and intellect. The bookish, leftist, artistic, rail-thin theorist might well have come from a different universe. But the two men had one thing in common: a facility for administration and organization. Oppenheimer had joined the nuclear weapons project officially in February 1942; by May, he was heading various teams at work on the construction of the bomb mechanism. By October, when Groves walked into his office, Oppenheimer and his groups had made great progress in determining the scale, structure, and impact of the bomb and the fission process.

Impressed with what was, for once, a clear and realistic report, Groves invited Oppenheimer to accompany him on the leg back from Chicago. In a small train compartment, Groves, two of his aides, and Oppenheimer dreamed up what was to become Los Alamos: not a cloistered university for scientific speculation and
dialogue (or so Groves would have it), but a single, unified, purposeful laboratory where scientists could exchange ideas freely, without security concerns. For Oppenheimer, the idea of a central laboratory must have seemed quite natural, given the communitarian nature of science. For Groves, rounding up all of those scientists into one place would at least facilitate scrutiny, if not discipline. Oppenheimer had in mind an isolated spot northwest of Santa Fe, New Mexico. For Oppenheimer, it was familiar ground. He had spent vacations horseback riding and hiking through the desert land. He and Groves traveled to New Mexico to find the best site. The first possibility, deep in a valley, lacked not only sunlight but also even the hint of an infrastructure. The second, Oppenheimer's suggestion, came with buildings and infrastructure, in the form of the Los Alamos Boys School, and was high on a plateau—secluded and serene.

Today, such a project might be deemed a boondoggle, a waste of taxpayers' monies. There was no assurance that the bomb could be built, and the expense of building not only laboratories, but the small town that served as living quarters, was enormous.

Groves controlled the purse strings, which he held tight whenever it came to making the town more livable—intersections lacked traffic lights, dwellings consisted of barracks in army issue green, garbage pickups were uncertain. Still, wrote Ruth Marshak, wife of a Los Alamos scientist, the barren landscape had its virtue:

As we neared the top of the mesa, the view was breathtaking. Behind us lay the Sangre de Cristo Mountains, at sunset bathed in changing waves of color—scarlets and lavenders. Below was the desert with is flatness broken by majestic palisades that seemed like the ruined cathedrals and palaces of some old, great, vanished race. Ahead was Los Alamos, and beyond the flat plateau on which it sat was its backdrop, the Jemez Mountain Range. Whenever things went wrong at Los Alamos, and there was never a day when they didn't, we had this one consolation—we had a view.
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However difficult it proved to build and supply a major laboratory in this isolated desert Eden, Los Alamos satisfied Oppenheimer's craving for beauty and Grove's for security.

From a few school buildings, Oppenheimer and Groves created a bustling, makeshift town with a hospital, a school, a town council, ceaseless shortages of housing and water, and a mania for security. Some four thousand civilians and two thousand military personnel were working at Los Alamos by war's end. Those who came in the early days of spring 1943 endured countless deprivations: The laboratories were works in progress, the prefabricated housing turned shabby directly upon being erected, roads were dusty and haphazardly graded, and mail and the rare telephone call were censored.

Still, Oppenheimer managed to recruit, either as residents or as consultants, dozens upon dozens of first-rate scientists: Edward Teller, I. I. Rabi, Enrico Fermi, Ernest Lawrence, Emilio Segré, Hans Bethe, Otto Frisch, Niels Bohr, John von Neumann, and a host of younger men who would become famous, among them Richard Feynman and Robert Wilson. Physically isolated and deprived of cultural distractions (save intense partying and dancing on the weekends), Oppenheimer's scientists worked hard from eight-thirty in the morning until well into the night.

By the winter of 1943, the project moved from theory to construction. Robert Wilson's group had established the “critical mass” of uranium 235—that is, the amount of this type of uranium necessary to create a chain reaction. All that remained was to create sufficient fissionable material, figure out how join two quantities together to create the chain reaction, and test the product. The bomb makers turned from theoretical science to engineering.

Two problems were paramount: manufacturing sufficient fissionable material and creating a mechanism to explode the material. Manufacturing fissionable material proved to be tricky at best. At Tennessee's Oak Ridge, two plants—one using electromagnetic
force, the other gas diffusion—were under construction by the summer of 1943. The first was operational by the fall, but needed constant repairs. The second remained unfinished (and its technology still uncertain) by the year's end.

Constructing an explosive mechanism proved trickier still. Nuclear fission, unlike TNT or other conventional explosives, must begin with sufficient material to achieve critical mass. Of course, the atomic material must remain “subcritical” until the moment of explosion. By the end of 1943, the possibilities had narrowed to two: a “gun” method, whereby an amount of subcritical material is shot into another, producing a supercritical reaction; and an “implosion” method, whereby an amount of subcritical material is imploded into itself by surrounding explosives, thus compressing the fissionable material and turning it supercritical. It would take more than a year to engineer working explosive devices.

Thus, during the winter of 1943–44, Oppenheimer juggled numerous teams at work on designing and arming an atomic bomb. He was seldom away from Los Alamos. Although fond of horseback riding, he rarely took part in the town's social scene.

Bohr arrived at Los Alamos in December 1943. He came with a very tantalizing sketch of a heavy-water reactor given him by Heisenberg during their famous 1941 conversation. Astonished at the successes of the Manhattan Project, Bohr now found his early skepticism about atomic fission evaporating. Could Heisenberg's boxlike drawing be the prototype of a bomb?

A roundtable of Los Alamos physicists pondered the sketch and came to the conclusion that “these Germans were totally crazy,” in the words of Hans Bethe.
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Was this reactor an earnest effort at a nuclear bomb? If so, the Los Alamos scientists could only scratch their heads in wonderment at what was obviously an inefficient and ineffective device. Or was it a smoke screen, intended to lull the Allies, via Bohr, into a false sense of security over Germany's atomic progress?

We now know that Germany, having persecuted and expelled its greatest physicists, lagged far behind in the race to produce a bomb. But at the time, Heisenberg's sketch wasn't enough to settle the matter. Indeed, if the Americans had progressed so far, was it not possible that German physicists, Heisenberg among them, had made equal progress? Thus was born Alsos, an intelligence gathering project aimed at finding out whether Germany might be on the brink of developing an atomic bomb.

Aside from the dubious sketch, Bohr brought to Los Alamos fatherly approbation and a sense of mission. By the winter of 1943, the project had been fully theorized and seemed on its way to certain completion, depending only on the solution to various technical problems. Owing, perhaps, to this seeming confidence, the Los Alamos scientists began to ponder the ethics of their project. Oppenheimer must have voiced his anxieties to Bohr, for he later recalled Bohr's “having made the enterprise hopeful, when many were not free of misgiving.”
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Bohr had little to add to the technical side of the bomb. But he was an éminence grise whose humanity was legendary. He was also an emblem of the rape of Europe. His escape from Hitler's grasp, so dramatic and timely, galvanized the men and women cloistered in the mountains of New Mexico. Later, Oppenheimer remembered Bohr as having spoken of Nazi oppression and of his own “high hope that the outcome would be good.”
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At Los Alamos, Bohr saw the dawn of the nuclear age. Always prescient, he knew almost instantly that the arms race had begun. His answer: a theory of “political” complementarity. The atom bomb was, he felt, the technology that could make war obsolete—but only if its workings were made transparent. In later, fruitless discussions with Roosevelt and Churchill, he proposed sharing atomic information with the Soviets as a gesture of goodwill and diplomacy. Such openness, he argued, would reduce the chance of a postwar arms race. Roosevelt was reported to have listened intently and sympathetically. Churchill, on the other hand, rudely
handed Bohr his hat—and later seems to have persuaded Roosevelt that Bohr and his ideas were dangerously naïve, or simply dangerous.

The danger was yet to come.

Julius Robert Oppenheimer was born in New York in 1904, the son of an affluent German Jewish couple. Precocious, bookish, adventurous, and high-minded (having been schooled at the New York Society for Ethical Culture), he was also petulant and physically lazy, particularly during his teenage years. At eighteen, having delayed entrance to Harvard for a year owing to digestive problems, he spent several weeks camping in New Mexico and Colorado with Herbert Smith, his high school English teacher. Not only did his health improve, but he also fell in love with the rugged landscape and vast mountains. He returned to college much improved in disposition and health. After sailing through Harvard in three years, summa cum laude, he set off for Cambridge, England, and the great experimenter Ernest Rutherford. But he lacked experimental gifts, and soon shifted to theoretical physics at Göttingen. He took his doctorate—in one year—under Max Born in 1927, and meanwhile made his name by publishing sixteen first-rate papers by 1929.