History and Physics of the Manhattan Project and the Bombings of Hiroshima and Nagasaki

One of the defining characteristics of the Manhattan Project was its secrecy, from the initial self-censorship campaign by physicists in the United States after the discovery of nuclear fission, through the creation of the Atomic Energy Commission in the early postwar period. In this talk, I will discuss the various phases of secrecy that characterized the work during World War II, and the reactions that various scientists within the project, especially physicists, had to working under these information control regimes. It will furthermore explore the way in which a number of key project physicists — including Leo Szilard, Niels Bohr, J. Robert Oppenheimer, Henry DeWolf Smyth, and Edward Teller — conceptualized and engaged with what was termed the "problem of secrecy" in the postwar period, as the ad hoc wartime arrangements were transformed into a more permanent legal structure.