August 2, 1939: Einstein sends his first letter to President Roosevelt, warning him that Uranium is a potentially dangerous energy source.
September 1, 1939: Beginning of World War II. October 9 - December 6, 1941: President Franklin Roosevelt approves the development of the atomic bomb (Manhattan Project). December 7, 1941: Japan bombs Pearl Harbor. September 23, 1942: J. Robert Oppenheimer is named the project's scientific director. May 5, 1943: Japan is named the number one target for any potential atomic bomb attacks. April 12, 1945: Harry Truman becomes the 33rd president of the United States. April 27, 1945: Four cities in Japan are named as possible targets (Niigati, Hiroshima, Kikura, Kyota). |
July 16, 1945: Atomic bomb first tested in New Mexico (Trinitiy). Eye wittness acounts say the blast was the equivalent of 10'000 tons of dinamite.
July 17, 1945: Leo Szilard and 69 other scientists sign a petition and send to President Truman, asking him to consider asking Japan to surrender before bombing them. July 26, 1945: United States calls for surrender from Japan. July 28, 1945: Japan rejects surrender. August 6, 1945: An atomic bomb is dropped on Hiroshima, Japan August 7, 1945: Pamphlets are dropped on cities in Japan asking them to petition for surrender, and warning them to evacuate immediately. August 9, 1945: An atomic bomb was dropped on Nagasaki. September 2, 1945: Japan surrenders. (Many historians mark this as the end of the war.) |
The creation and usage of the atomic bomb was the height of destruction during World War II for the United States and Japan. It was a desperate last resort to end the war, and it was succesful. (Notice that Japan surrenders a month after the atomic bomb is dropped on Nagasaki, and the war ends soon after that).