|Otto Hahn, Fritz Strassmann, Lise Meitner, Otto Robert Frisch, Rudolf Peierls, Enrico Fermi physics|
When neutrons hit uraniums split releasing neutrons and energy exponentially.
In 1934, Hahn and Strassmann discovered neutrons fired into uranium produced barium. In 1939, Meitner and Frisch explained that, when split, uranium atoms release energy. In 1940, Frisch and Peierls showed how an atomic bomb could be triggered. During WW II, the U.S. feared Germany would produce the bomb. Fermi built the first self-sustaining nuclear reactor in Chicago in 1942. The U.S. hired thousands and spent billions to make the bombs dropped on Hiroshima and Nagasaki in 1945.
The bombs murdered 166,000 people in Hiroshima and 80,000 in Nagasaki from thermal radiation, falling debris, general conflagration, radiation sickness, and subsequent cancers. Most were civilians, including students from Malaya, 22,000 Korean and Chinese forced laborers, 20 Allied POWs, and 3,200 Japanese Americans.