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Leo Szilard creates the idea of creating a chain reaction by splitting neutrons from an atom's nuclei, and introduced the idea of using this to create a bomb.
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Otto Frisch coins the term 'fission' (the splitting of an atom) after discovering fission fragments in an ionized chamber.
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J. Robert Oppenheimer realizes that the amount of neutrons expelled through fission could be used to create Szilard's idea of the creation of a bomb through a chain reaction.
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President Roosevelt received a letter from Albert Einstein and Leo Szilard warning that there will most definitely be an atomic bomb created in the near future.
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The National Defense Research Committee is created to organize scientific research for war purposes in the United States.
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Winston Churchill allows the British Chiefs of Staff to begin development on an atomic bomb.
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President Roosevelt allows Arthur H. Compton to create the Metallurgical Laboratory at the University of Chicago for the purpose of producing an atomic bomb.
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Authorized by president Franklin D. Roosevelt, the Manhattan Project was created to bring together the top scientists and military leaders in an effort to create a nuclear weapon.
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Igor Kurchatov becomes the director of a secret program to produce an atomic bomb.
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The very first sample of plutonium in metal form is produced at the Chicago Metal Lab. Plutonium is one of the two isotopes used in the production of an atomic bomb.
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A B-29 bomber is being modified to be able to transport and drop an atomic bomb.
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A B-29 begins test drops of dummy atomic bombs.
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Testing of a wire detonator began to ensure precise, reliable, and simultaneous detonation for implosion.
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The bomb that would be dropped on Hiroshima is made, just lacking the U-235 core that is predicted to be produced before August 1st.
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The first successful test of an atomic bomb was preformed at the Trinity test site in New Mexico.
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The united States continues to test nuclear weapons to stay ahead of the Soviet Union in the technology war during the Cold War.
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The 509th Composite Group begins flying practice missions over Japan.
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Little Boy is fully assembled and ready to be used.
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Fat Man explodes at 1950 feet near the perimeter of the city. The yield is estimated to be 21Kt. This second bombing forced Japan to surrender in the war.
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the Soviet union holds their first successful nuclear bomb test.
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The United kingdom holds its first successful testing of an atomic bomb.
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Little Boy is released at an altitude of 31,060 feet above Hiroshima. Little Boy explodes at an altitude of 1,850 feet, 550 feet from the target area, Aioi Bridge, with an estimated yield of 15 Kt.
