The goal this time would be 100 million electron volts, the threshold of energy believed to hold atomic nuclei together. For the boys, Lawrence’s new machine held out not only the promise of exciting discoveries in science but something more personal: a chance at redemption.
That spring, during a nationally broadcast radio lecture, Lawrence spoke for the first time publicly of his plans for a gargantuan super-cyclotron. Fully two months before the 60-inch began operating at the brand-new Crocker Laboratory—its pencil-thin blue beam of light reminding the assembled journalists of a science-fiction death ray—Ernest had already moved well beyond the medical cyclotron in his mind.
Lawrence calculated that the next machine would require a 2,000-ton magnet. Artist’s drawings commissioned for a lecture tour showed a beam 140 feet long, compared to the 60-inch’s 4-foot beam. There was, as yet, no structure on the Berkeley campus big enough to house the mammoth machine, nor any charitable foundation willing to bear its projected million-dollar cost.
But Ernest’s hope was that his new machine might yield answers to some of the fundamental questions that the experiment in Germany had raised. Among them, whether other elements could be made to fission, and whether the number and energy of neutrons released by splitting uranium atoms would be sufficient to sustain a chain reaction. On the resolution of that last question, physicists realized, lay the answer to whether atomic energy could be used to propel ships and power industry—or to build a bomb.96
True to type, Lawrence chose to focus on the brighter prospect. “We are trying to find out whether neutrons are generally given off in the splitting of uranium; and, if so, prospects for useful nuclear energy become very real!” he enthused in a February 1940 letter to scientists at the Cavendish. Although it went unmentioned, between the lines was Ernest’s hope that the vindication of his long-deferred dream at Solvay might be at hand. “It may be that the day of useful nuclear energy is not so far distant after all,” he mused.97
By contrast, Oppenheimer remained wary and pessimistic. Writing to friends at the University of Michigan, he professed to find uranium and fission more worrisome than exciting, and the potential consequences ominous indeed: “So I think it really not too improbable that a ten [centimeter] cube of uranium deuteride … might very well blow itself to hell.”98
2
A PRACTICAL PHILOSOPHER’S STONE
LAWRENCE’S OPTIMISM EXTENDED to politics. “I still think war is going to be avoided. All this discussion certainly must mean that Hitler is backing down,” he wrote to his parents on August 29, 1939, three days before the Germans invaded Poland, sparking the Second World War.1
A few weeks earlier, other physicists—European born and hence preternaturally more inclined toward pessimism—had sent a warning letter to President Franklin Roosevelt that proved far closer to the mark.
Leo Szilard was a Hungarian theorist who had fled Germany in 1933, only days before the border was closed to Jews, and found a sinecure at Columbia University. Eugene Wigner, a friend of Szilard’s from Budapest, joined Princeton’s physics faculty in 1930. Another fellow countryman and theoretician, Edward Teller, had come to the United States in 1935. A professor at George Washington University, Teller in summer 1939 was teaching at Columbia during the day and discussing fission with Szilard at night.2 Albert Einstein, the German-born physics theorist, was the oldest and by far the best known of their number.
While their leader was Szilard—the letter was his idea—the driving force was Teller, literally.3 Since Szilard lacked an operator’s license, he relied upon Teller and the latter’s temperamental 1935 Plymouth to get him to Einstein.
At thirty-one, Teller already had a dark and somewhat moody visage, famously prominent eyebrows, and a noticeable limp, the result of a streetcar accident years earlier in Munich, where he had lost part of his right foot. He possessed an agile, self-deprecating wit, but his easy and high-pitched laugh hid a large and surprisingly fragile ego. (Overprotected by his mother, he “reached adolescence still a serious child with no sense of humor,” Teller later wrote. He found the taunts of his schoolmates “intolerable.”) Once, in 1934, while Teller was a student at Niels Bohr’s famous physics salon in Copenhagen, he had been casually reprimanded by the master for a careless comment. The rebuke was not intended as an insult, and the moment quickly passed. But Bohr’s students were surprised to see Teller left pale and shaken by the incident.4
Teller’s colleagues then, and later, would remark upon his restless, seemingly driven energy. (Teller himself described his personality type as neither “melancholic” nor “sanguine” but “choleric,” or quick to anger. Fermi thought Teller the only monomaniac he knew who had several manias.) This peculiar intensity was evident not only in Teller’s work but even in his piano playing: friends observed that he played all of Mozart’s pieces fortissimo.
Late one evening in March 1939, Teller and a violin accompanist had been in the middle of a Mozart sonata at Edward’s home when they were interrupted by an urgent telephone call from Szilard. “I have found the neutrons,” Szilard announced melodramatically, in Hungarian—their secret code—before hanging up. Since Teller knew that his colleague’s most recent experiments concerned chain reactions in uranium, he had reason to suspect, with Szilard, that the world was headed for grief.5
At the end of July, Szilard asked Teller to drive him to Einstein. Despite Edward’s car breaking down and another stop along the way to ask directions of a child, the pair finally made it to the famous physicist’s summer house on the north fork of Long Island. While Einstein served tea, Szilard persuaded the author of the relativity theory to sign the letter he had drafted, which warned FDR that since “the element uranium may be turned into a new and important source of energy in the immediate future,” … “it is conceivable … extremely powerful bombs of a new type may thus be constructed.”6
The letter was forwarded to a contact of Szilard’s at the White House.
