jan 1, 1945 - 1945
January - First plutonium reprocessing begins at Hanford.
January 20 - First uranium 235 separated at Oak Ridge, Tennessee.
June 11 - The Franck Report is sent to Secretary of War Stimson.
July 16 - U.S. explodes the world's first atomic bomb, the Trinity test, at Alamogordo, New Mexico.
August 6 - Little Boy, an uranium bomb, was dropped on Hiroshima, Japan. Between 80,000 - 140,000 people are killed.
August 9 - Fat Man, a plutonium bomb, was dropped on Nagasaki, Japan. About 74,000 people are killed.
Added to timeline:
atomic and nuclear physics