Diana Preston - Before the Fallout

After further discussion together and in small groups, they retired to bed. None of them got much sleep. Otto Hahn was clearly very depressed and agitated. According to Erich Bagge’s diary, “At 2 am there was a knock on our door and Mr. von Laue entered. ‘We must do something; I am very worried about Otto Hahn. This news has shaken him horribly, and I fear the worst.’ We stayed awake a long time, and only when we were able to tell from the next room that Mr. Hahn had finally fallen asleep did we all go to bed.”

The transcribed discussions on both 6 and 7 August reveal fundamental misunderstandings on the part of the German scientists about how a bomb could be made to work. Heisenberg stated on 6 August that “a ton” of U-235 would be required to produce the critical mass necessary for an explosion. In his explanation of why this was so he used an irrelevant (and arithmetically incorrect) calculation. His description also omitted any discussion of the effect of heat gasifying the material and causing only some 2 percent of it to be consumed. Had Heisenberg realized this, his calculation would have produced an even higher figure of fifty tons. While inaccuracy in calculation can be forgiven in the heat of discussion and the stress of just having heard about Hiroshima, Heisenberg’s account seems to miss too many fundamental points for there to be any doubt that the German project was some way from understanding even the theory of an atomic bomb, never mind the engineering practicalities of separating enough fissile material and of constructing one.

Over the next few days the transcripts reveal that the scientists, under the leadership of von Weizsacker, began to develop a rationale of why their work had failed, perhaps designed to protect them against three kinds of criticism: from Germans who thought they should have done better to protect their fatherland; from Allied scientists who could not understand how they could have worked for Hitler on an atomic bomb; and self-criticism based on doubts about their own scientific abilities and moral values. Von Weizsacker’s statement that they did not do it because they did not want to formed one of the two key strands of what Max von Laue called their “version” (Lesart in German) of events, from which he distanced himself. The other justification, not entirely compatible with the first but more pragmatic, was that it was impossible to produce a bomb during the expected duration of the war with the resources available to them. Von Laue noted that during their discussions Heisenberg was “mostly silent.”

The sense of purpose that had fueled Robert Oppenheimer ended with the war. He confessed that there was “not much left in me at the moment.” Determined to return to academe, he resigned from Los Alamos. In the immediate postwar years he remained an influential adviser to the U.S. Atomic Energy Commission (AEC)—the successor to the Manhattan Project. However, he did not support the AEC’s plans to build the world’s first hydrogen bomb based on the release of energy caused by the fusing of hydrogen atoms, believing the fission bomb quite powerful enough for America’s military needs.

Some other scientists, especially Edward Teller, resented Oppenheimer’s attitude. The passionately anticommunist Teller feared the Russians would soon acquire the capability to build an atomic bomb and had devoted himself to what he called the “sweet technology” of the hydrogen bomb. His supporters included Ernest Lawrence, and the project went ahead. On 1 November 1952 the United States conducted the H-bomb equivalent of the Trinity test over the Pacific. The device destroyed an island a mile in diameter, exploding with a force five hundred times greater than Little Boy. To an observer it seemed like “gazing into eternity, or into the gates of hell.”

The news depressed Oppenheimer deeply and convinced him he had lost all influence. Before long he fell victim to the prevailing mood of anticommunist hysteria centered around the Republican senator Joe McCarthy. On 12 April 1954 the New York Times reported that the AEC had suspended Oppen­heimer’s security clearance and planned a hearing that day to consider charges that Oppenheimer’s left-wing contacts and activities in the 1930s made him unfit to have access to classified information.

The AEC hearing was held in private and lasted more than three weeks. Op­penheimer was the first witness to appear before the three-man board. Many others followed and, as the transcripts show, most gave him their wholehearted support, but some, including Edward Teller, did not. Under cross-examination Teller stated, “If it is a question of wisdom and judgment, as demonstrated by actions since 1945, then I would say one would be wiser not to grant clearance.” By “actions” Teller was no doubt referring to Oppenheimer’s overt opposition to the H-bomb, which he interpreted as unpatriotic. The board recommended by two to one that Oppenheimer’s security clearance should not be renewed. The AEC endorsed that view but emphasized, somewhat ambiguously perhaps, that though they considered him a security risk, Oppenheimer’s personal loyalty was not in question.

Oppenheimer was deeply wounded but refrained from public denunciation of his detractors. He continued as director of the Institute for Advanced Study in Princeton—a post he had taken up in 1947—and in 1963 the AEC, in a gesture of rehabilitation, awarded him the Enrico Fermi Award for outstanding contributions to atomic energy. Throat cancer prompted the chain­smoking Oppenheimer’s resignation from the institute in 1966, and he died in his elegant Princeton home the following year at the age of sixty-two. Enrico Fermi himself had returned to the University of Chicago but had died in 1954, aged just fifty-three, seven months after testifying in Oppenheimer’s defense.

Oppenheimer had always remained on good terms with Leslie Groves. Groves retired from the army in 1948 when General Dwight D. Eisenhower, then chief of staff, who thought Groves insensitive, arrogant, and ruthless, made it plain both that Groves would no longer exercise the same influence on nuclear policy as he had during the war and that he would not be appointed the army’s next chief of engineers. Instead, the fifty-one-year-old Groves joined the Remington Rand Corporation. At the 1954 AEC hearings Groves did his best to support Oppenheimer, the man he had always considered a genius, asserting that he “would be astounded” if Oppenheimer had ever committed a disloyal act. However, under cross-examination he admitted that, under a strict interpretation of the AEC’s security rules, Oppenheimer should not be given security clearance. Groves would die of a heart attack in 1970.

Ernest Lawrence excused himself from testifying at the Oppenheimer hearings on health grounds. Some colleagues claimed this was simply an excuse—he had been intending to testify against Oppenheimer but could not bring himself to go through with it. Others believed the excuse was genuine—he was suffering from severe ulcerative colitis. Lawrence spent his postwar career raising ever-larger sums for ever-larger cyclotrons. He finally overreached himself with plans for a device that contravened the special theory of relativity and was physically unachievable. His futile strivings to make it work undermined his already frail health. He died in 1958.

Edward Teller was longer lived. He became the inspiration behind President Ronald Reagan’s “Star Wars” strategy—the building of a defensive shield in space to ward off missile attack. Some also thought him and his views the inspiration for the movie Dr. Strangelove. He died in 2003 at the age of ninety-five.

Among the many young American scientists who contributed to the Manhattan Project, the mercurially brilliant, safecracking, wisecracking Richard Feynman stands out. He became a highly influential figure in many areas of postwar science. He was awarded the Nobel Prize for Physics for his work on the theory of quantum electrodynamics and played a decisive role in diagnosing the fatal flaw that destroyed the Challenger space shuttle in 1986. Feynman died two years later.