The true nature of Heisenberg’s role in the Nazi atomic bomb effort is a fascinating question, and dramatic enough to have inspired a well-received 1998 theatrical play, “Copenhagen.” The real story, however, may never be completely unraveled. Heisenberg was the scientific leader of the German bomb program up until its cancellation in 1942, when the German military decided that it was too ambitious a project to undertake in wartime, and too unlikely to produce results.
Some historians believe that Heisenberg intentionally delayed and obstructed the project because he secretly did not want the Nazis to
get the bomb. Heisenberg’s apologists point out that he never joined the Nazi party, and was not anti-Semitic. He actively resisted the government’s Deutsche-Physik policy of eliminating supposed Jewish in-fluences from physics, and as a result was denounced by the S.S. as a traitor, escaping punishment only because Himmler personally declared him innocent. One strong piece of evidence is a secret message carried to the U.S. in 1941, by one of the last Jews to escape from Berlin, and eventually delivered to the chairman of the Uranium Committee, which was then studying the feasibility of a bomb. The message stated “…that a large number of German physicists are working intensively on the problem of the uranium bomb under the direction of Heisenberg, that Heisenberg himself tries to delay the work as much as possible, fearing the catastrophic results of success. But he cannot help fulfill-ing the orders given to him, and if the problem can be solved, it will be solved probably in the near future. So he gave the advice to us to hurry
up if U.S.A. will not come too late.” The message supports the view that Heisenberg intentionally misled his government about the bomb’s tech-nical feasibility; German Minister of Armaments Albert Speer wrote that he was convinced to drop the project after a 1942 meeting with Heisen-berg because “the physicists themselves didn’t want to put too much into it.” Heisenberg also may have warned Danish physicist Niels Bohr personally in September 1941 about the existence of the Nazi bomb effort.
On the other side of the debate, critics of Heisenberg say that he clearly wanted Germany to win the war, that he visited German-occupied territories in a semi-official role, and that he simply may not have been very good at his job directing the bomb project. On a visit to the occupied Netherlands in 1943, he told a colleague, “Democracy cannot develop sufficient energy to rule Europe. There are, therefore, only two alternatives: Germany and Russia. And then a Europe under German leadership would be the lesser evil.” Some historians argue that the real point of Heisenberg’s meeting with Bohr was to try to convince the U.S. not to try to build a bomb, so that Germany, possessing a nuclear monopoly, would defeat the Soviets — this was after the June 1941 entry of the U.S.S.R. into the war, but before the December 1941 Pearl Harbor attack brought the U.S. in. Bohr apparently considered Heisen-berg’s account of the meeting, published after the war was over, to be inaccurate. The secret 1941 message also has a curious moral passivity to it, as if Heisenberg was saying “I hope you stop me before I do something bad,” but we should also consider the great risk Heisenberg
would have been running if he actually originated the message.
Story from physicist Szilard said that, Bohr carried out information from Germany to U.S. that Heisenberg was able to make a controlled fission. General Spears has been providing underground lab for Heisenberg. But Heisenberg declared that creating atomic bombs had not been possible. It is said that Heisenberg had hell to Nazi moral reason not to use the atomic bomb. Meanwhile, the Manhattan project succeeded. But before using it, Germany lost the war trigger. Heisenberg, Hahn, etc., held captive in England. When finally the atomic bomb detonated at Hiroshima, Heisenberg showed disbelief. He showed that the bomb was to Hahnshould have radius critically half a meter, so the volume is half a cubic meter, and a hundred pounds of mass. And U-238 heavy as it could have been produced in recent years, with the purification of the U-235. But Heisenberg miscalculated. Bombs droppedon Hiroshima, U-238 mass was only 1 kg. Weight of 1 kg can be produced in a matter of days in America.
In the end, we have 2 conclusions. Whether the Germany atomic bomb failed because of Heisenberg’s moral reason or miscalculation. Uncertain. And the murder plans against Heisenberg? It is still uncertain why Borg or Bethe didn’t kill him. It is all about Heisenberg, and it must be uncertain.
A Historical Perspective on Copenhagen, David C. Cassidy, Physics Today,July 2000, p. 28, http://www.aip.org/pt/vol-53/iss-7/p28.html
Bohr drafted several replies, but never published them for fear of hurting Heisenberg and his family. Bohr’s papers were to be sealed for 50 years after his death, but his family released them early, in February 2002.