2016/09/09 by Klaus Gottstein, Gottstein, Klaus
Arts and Humanities · Physics and Astronomy · #FOS: Physical sciences #History and Philosophy of Physics (physics.hist-ph) #Physics and Society (physics.soc-ph) #Twentieth Century Scientific Developments #physics.hist-ph #physics.soc-ph
paper · pdf · doi:10.48550/arxiv.1609.02775
20 pages
arxiv created 2016/09/09 · openalex publication_date 2016/09/09 · arxiv updated 2016/09/12 · openalex created_date 2016/09/23 · openalex updated_date 2026/07/28
The results of a careful analysis of all the available information on the activities of Heisenberg and of his talks during the years 1939 to 1945 can be summarized in the following way. Like several other German physicists Heisenberg was drafted by German Army Ordnance when war began in Europe in September 1939 to investigate whether the energy from splitting Uranium nuclei by neutrons could be used for technical and military purposes. Heisenberg found that this is possible in principle but that military use would require such enormous industrial expenditures that it would take many years and would be impracticable while the war lasted. The project was therefore dropped by the Nazi government in 1942. Heisenberg even refrained from calculating a precise value for the critical mass of U 235. He was relieved that he was thus spared a moral decision between obeying an order to build the bomb or risking his life by refusing to be involved in the project or sabotaging it. He was happy to be confined to a project of building a small test reactor under civilian administration that the government had approved. In 1941 Heisenberg tried to get the opinion of Niels Bohr in Copenhagen on what the international community of nuclear physicist could possibly do or prevent regarding the long-range technical feasibility of making nuclear weapons. Bohr completely misunderstood the cautious approach of Heisenberg.