Heisenberg’s War: The Secret History of the German Bomb
During World War II the scientists and technicians in Britain and the US who were building an atom bomb feared that Nazi Germany might produce such a weapon first. Yet at the end of the war it became clear that there had been no such threat. Not only was no German bomb under construction, but no extensive effort was being made to develop one. Why was that so?
The first answer was given by the physicist Sam Goudsmit, who was sent to Europe in 1947 on what was called the “Alsos” mission to discover the fact about the German project. In his book Alsos he attributed the failure to gross incompetence on the part of the scientists. In particular he claimed that Heisenberg did not know the difference between a bomb and a reactor. This last statement he later withdrew, but he remained convinced that Heisenberg, the most famous German physicist, did his best to develop a bomb, but his best was not good enough.
Another explanation was put forward in 1956 by Robert Jungk in his book Brighter Than a Thousand Suns, and supported by Walter Kaempfert of The New York Times. According to them, the German scientists refrained from making a bomb for moral reasons. I know of no evidence that Heisenberg made this claim himself in public, and it is not clear whether he really took that position in his interview with Jungk. But he also never repudiated it publicly.
Heisenberg later gave his own explanation in articles in scientific journals and in his autobiographical book Physics and Beyond. While he and his colleagues knew a bomb to be possible in principle, he wrote, they saw that the effort to develop it was far too great to be undertaken by Germany in wartime. (In retrospect this seems reasonable, because even the Americans, who had greater technological resources and were not subject to air raids, did not complete the bomb before V-E day.) As a result the German scientists did not ask for a crash program, and took as their goal the construction of an experimental reactor, in order to prove the feasibility of a chain reaction and to prepare the way for a future nuclear power program. They felt relieved that they did not have to make a decision on whether to work on a weapon. It is anybody’s guess whether they would have worked on a bomb if they had regarded this as a practical possibility.
I find this explanation convincing; it seems consistent with the evidence I have seen. It is true that Heisenberg was known to allow his memory to be colored by what he would like to be true, but I have learned from experience that one should never discount the possibility that a person might actually mean what he is saying.
The recently released “Farm Hall Transcripts,” of recorded conversations of German atomic scientists who were interned in England shortly after the war, firmly ruled out the …