When was the first nuclear bomb discovered?

Answer 1

1. In 1896 Becquerel discovered the phenomenon of natural radioactivity.
2. In 1933 Szilard in London invented the concept of nuclear chain reactions, necessary for both bombs and reactors. However no material was known that could support this reaction.
3. In 1934 Szilard patented the concept of the chain reaction, including claims covering both atomic bombs and atomic reactors.
4. In 1936 Szilard signed his patent over to the British Admiralty, to keep it out of the hands of Nazi Germany. It became a classified secret.
5. In 1938 Otto Frisch, in Berlin discovered the phenomenonof nuclear fission in Uranium-235. This provided a material that finally made Szilard's patent practical.
6. In 1942 the US began the Manhattan Project, with the goal of beating the Germans to the bomb.
7. In 1945, the first 3 atomic bombs were detonated, one in New Mexico as a test and two over Japan in combat.

Total time span 1896 to 1945 = 49 years.

Answer 2

Do you think fission bombs are lying around someplace waiting to be discovered and used? The fission bomb was invented by Leo Szilard in 1933 while crossing a London street. He patentedhis invention in 1934 (Great Britain patent 630,726). The Manhattan Project in the US developed two different practical implementations of that bomb between 1942 and 1945, testingthe plutonium based design on July 16, 1945. The uranium based design was tested in combat on Hiroshima on August 6, 1945 and a duplicate of the previously tested plutonium based design was used in combat on August 9, 1945.

It took over a decade of hard theoretical and experimental work, secret political lobbying, industrial infrastructure development, and hand crafted prototype construction to go from initial invention to usable prototype weapon implementations in the case of the fission bomb. And a few more years after the war to make factory manufacturable models.