Diana Preston - Before the Fallout

Edward Teller saw a continuing “conflict between Heisenberg’s patriotism and Heisenberg’s thorough unwillingness to help the Nazis.” He also recalled, “I could not imagine that he would support the Nazis willingly, much less do so enthusiastically.” Teller’s remarks are typically clear-cut and the reality perhaps less so. Heisenberg and von Weizsacker made compromises with the authorities when, as von Weizsacker stated in a private conversation with Heisenberg at Farm Hall, they were aware that “the right [correct] position [for us] would really have been in a concentration camp [as protestors] and there are people who chose that.” Heisenberg remained involved because, like many others, he was a German patriot w ho feared the consequences of defeat particularly by the Russians at least as much as those of victory. Heisenberg was also naive and tactless and entirely unable to appreciate the perspectives of others and hence the impact of his words and actions upon them. In the words of Sam Goudsmit to Rudolf Peierls, long after the war, the problem was that “this great physicist, our idol, wasn’t any better [morally] than we are.”

Levels of commitment fluctuated with the progress of the war. When Heisenberg visited Niels Bohr in Copenhagen in autumn 1941, when the Germans seemed to have nearly won the war, one of Heisenberg’s messages was that Bohr must accept the reality of a German victory. At around that time too, Houtermans, despite previously leaking information to the Allies at great personal risk, told his superiors and others of his work on plutonium instead of attempting to conceal it. Perhaps scientific conceit played a part, but there was also an element of accommodating to the likely outcome of the war. Such pragmatism seems to have influenced most of the Germans who remained, with the notable exception of Max von Laue, who did not work on the German bomb project and gave moral support to Jewish former colleagues. According to Houtermans, when he told von Laue that he was worried about the possibility of Germany making a bomb during the war, von Laue’s ambiguous reply was “An invention is not made which one doesn’t want to make.”

The two waiters of the memorandum that spurred Britain and the United States to action—Otto Frisch and Rudolf Peierls—both commented in 1965 about the attitude of the German scientists they had known well before the war. Peierls suggested, “In the west, we all felt that this was our war and that for Hitler to acquire complete domination of the world would be a disaster. The German scientists, I think, were not so identified with their own regime…. it may be that as a result they were less active in thinking about these possibilities.” Peierls, however, added a sentence suggesting plausibly that scientific curiosity might have kept them involved despite themselves: “The possibility was a very exciting thing for any physicist, whatever you decide to do with it.”

Otto Frisch thought similarly: “In the first place I think it is true to say that all the best scientists did not wish to have such a frightful weapon in Hitler’s hands. I think that many of them hoped that once the war was over and won the Nazi regime could be disposed of, or softened or civilized… but they didn’t want them to get the tremendous power that would go with possession of such a weapon. Second, there were very bad relations on the whole between scientists and government and military in Germany. The scientists regarded the government simply as a source of revenue to be otherwise kept at arm’s length.”

If we accept that most German scientists had misgivings about producing a bomb which may have unconsciously inhibited their work, does this mean that the full implication of their “version” of events, developed at Farm Hall and later, should be accepted—that is, that if they had been fully committed, they could have made a bomb on the same timescale as the Allies and even that some of the scientists tried to sabotage the war effort? There is no evidence to substantiate any sabotage. There is, however, considerable evidence that the Germans did not understand the physics necessary to make a bomb, such as that revealed by Heisenberg’s failure to describe the physics at Farm Hall, and in particular to identify the correct critical mass, and by Bothe’s disregard of the potential of graphite as a moderator. As one of them said at Farm Hall, they also looked down on essential isotope-separation work perhaps as more chemical engineering than physics.

The German project was, as admitted in the recorded conversations at Farm Hall, riven by personality differences and rivalries. Competition between the army, the Reich Research Council, and the Kaiser Wilhem Society fragmented rather then focused the German program, and scientists competed against each other for scarce supplies of heavy water. Heisenberg was undoubtedly a great physicist, but he was not a great leader or project manager in the way that Groves was. Until the war he never oversaw any major project. He was not an enthusiastic experimentalist, as evinced by his near failure in his doctoral exams when questioned about how experiments and equipment worked. He was also not renowned for skill at undertaking mathematical calculations to back up his brilliant insights. “Though a brilliant theoretician,” according to Rudolf Peierls, “he was always very casual about numbers.”

The German project never employed more than about one hundred scientists. Even multiplying this figure ten or fifteen times to allow for technicians and other workers produces a total workforce of only around 1 percent of the Manhattan Project. Even had German scientists shown more commitment and pressed for greater resources from Speer and others, it is by no means clear they would have been forthcoming. The V-1 and V-2 rocket programs and the jet aircraft program had both begun before the war and had clear priority. In 1941, when the scientists seem to have had the greatest commitment, the very reason for that increase in commitment—the perceived proximity of a German victory—would have worked against them because they could not claim a bomb would have been finished in time to end the war.

One reason why Britain moved its work to the United States was a lack of resources. Another was fear that German bombing might destroy any facilities constructed. Similarly, the Germans at Farm Hall and elsewhere recognized that, had they increased their resources, the British and Americans would have quickly become aware of this and destroyed their plants, just as they attacked the Vemork heavy water factory and the laboratories in Berlin. They were right. Not only did the Allies have a committed agent in Paul Rosbaud, they also had excellent photoreconnaissance aircraft, which would have been bound to identify any large-scale plant. They were also prepared to contemplate abduction or assassination of key personnel such as Heisenberg.

Therefore, leaving any moral queasiness on the scientists’ part aside, it is highly unlikely that Germany would have been able to make an atom bomb before it was defeated. It may well have been able to make a “dirty bomb,” which, attached to a V-1 or V-2 rocket, could have distributed radioactive material over London, as feared by several of the scientists at Los Alamos, or along the Normandy invasion beaches, as General Groves warned General Eisenhower. However, for whatever reason, in practice no one in Germany seems to have considered this option.

A final question addresses the human element in the story. What if Niels Bohr had not mumbled? All an individual’s attributes are important to whether they succeed in their chosen task. Leo Szilard said after his unsuccessful meeting with Secretary of State James Byrnes that it might have been better for the world if he, Szilard, had been secretary of state and Byrnes a physicist. Hans Bethe said that the Manhattan Project “changed everything; it took scientists into politics.” The requirement on scientists to understand the wider world applies in reverse, of course, to politicians and laypeople in regard to science. Rudolf Peierls said in 1986, “I’m afraid forty years ago we overestimated the capacity of those in power to understand the implications of what we had created.”