How did humans know that atomic bomb could be a thing?

Question

Like we all who built it first and all, but how did the humans know that such a weapon could be possible to build with so much capability? Was there research from older scientists and physicists that led to the idea that such a thing was possible and only needed to be built?

In: 985

Answer 1

If you have time in your hands, Richard Rhodes’s book ‘The Making of the Atomic Bomb’ is a superb story of how a crisis in 19th Century physics led to the discovery of the atom, then the nucleus, then the neutron – and from there how the energy in the uranium nucleus was first liberated through to the destruction of Hiroshima and Nagasaki. It puts the bomb in context and makes it clear that the bomb was inevitable and its use almost certain.

After Hahn and Meitner’s experiment, it was a conversation with Otto Frisch that produced the idea of fission and the very first estimate of how much energy was released when uranium was split. Their work suggested that each fission would release one or two neutrons, and that inspired Leo Szilard who had already come up with the idea of a chain reaction in 1933, but had never considered uranium. In 1939, the idea of a chain reaction in uranium was patented by a team led by Frederic Joliot-Curie – including the idea for a nuclear bomb.

Szilard and Fermi had come to the same conclusion about the same time and alerted the American government to the possibility by a letter signed by Einstein. Meanwhile, the British were taking an early lead; Otto Frisch and Rudolf Peierls had fled Nazi Germany and were working at the University of Birmingham. They produced the first broad outline of a theoretical bomb, including an estimate of the critical mass of uranium needed in early 1940.

Their work became a government project called TUBE ALLOYS which worked out many of the techniques needed to build a uranium bomb, but the UK did not have the spare industrial capacity and was too close to German bombing to realistically build a bomb, so the project was shared with the United States who made up for lost time and actually did it.