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Heavy Hydrogen discovered
Harold C. Urey discovers Heavy Hydrogen (deuterium). -
Proving Einstein's Theory of Relativity.
John Crockcroft and E.T.S. Walton, of Great Britain, split the atom, thereby proving Einstein's Theory of Relativity. -
Possibilities of a Nuclear Reaction are Realized.
Leo Szilard, a Hungarian physicist, realizes the possibility of a nuclear chain reaction. -
World War II Begins
Timeline of Hitler’s march to conquer the world -
First Nuclear Fission
Enrico Fermi, of Italy, produces the first nuclear fission. -
Theory of Nuclear Fission
Lise Meitner and Otto Frisch announce the Theory of Nuclear Fission. -
Neutrality Act
The Neutrality Act was put in place to keep the U.S. out of the war, so the cash and carry system was created to enable the U.S. to help allies without getting involved. -
Discovery of Fission
Niels Bohr announces the discovery of fission in a conference at George Washington University.Robert Oppenheimer then realizes the military possibilities of nuclear fission. -
Einstein Letter
Albert Einstein writes to President Franklin Roosevelt concerning the use of uranium as a new source of energy and urging the development of an atomic research program. Roosevelt did not see the use of such a program, but did agree to proceed with the idea, leading to the formation of the Committee on Uranium. -
Plutonium is discovered
Glenn Seaborg discovers Plutonium. -
Lend Lease Act
The Lend lease act passed congress, which was proposed by FDR to improve the U.S. economy and help their allies even more by lending them military supplies. -
The Process begins
FDR gives the go-ahead for the development of an atomic weapon. -
The "Manhattan Project" Begins
FDR authorizes the Manhattan Engineering District for the purpose of creating an atomic bomb, and the American effort to design and build an atomic bomb revives its code name, "The Manhattan Project" -
Attack on Pearl Harbor
Japanese bombed Pearl Harbor, Hawaii, destroying nearly the entire U.S. Pacific fleet, hundreds of airplanes, and killing about 2,500 military personnel and civilians. -
U.S. Declares war on Japan
U.S. congress declares war on Japan at the request of FDR in response to the bombing of Pearl Harbor. -
Germany and Italy Declares war on U.S.
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Colonel Leslie Groves is placed in charge
Manhattan Project is placed under the control of Colonel Leslie Groves and J. Robert Oppenheimer becomes the Project's Scientific Director. -
The Chicago Pile
First controlled nuclear fission reaction is produced by Enrico Fermi at the University of Chicago. -
Japan becomes the primary target
According to the Military Policy Committee of the Manhattan Project, for any future atomic bomb, Japan would be the primary target -
D-Day
Invasion of Normandy. -
Harry Truman is named President
Franklin Roosevelt dies a few hours after suffering a massive cerebral hemorrhage. Harry Truman is named the 33rd President of the US. -
Manhattan Project selects possible targets
The Target Committee of the Manhattan Project selected four cities as possible targets for the atomic bomb. They are: Kyoto, Hiroshima, Kokura, and Niigata. -
War ends in Europe.
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Leo Szilard attempts to warn President Truman
Leo Szilard attempts to warn President Truman in person concerning the dangers of atomic weapons. -
Leo Szilard begins a petition
Leo Szilard begins a petition to get President Truman to call off using the atomic bomb in Japan. -
Trinity Test
The world's first atomic detonation takes place in the 'Trinity Test' at Alamogordo, New Mexico. -
Here comes the Bombs
President Truman orders atomic bombs to be used. Considered to be the most difficult decision of his life. -
Potsdam Declaration
Potsdam Declaration is issued, demanding an unconditional surrender by Japan. -
Potsdam Declaration Denied
Japan refused the declaration even with the threat of total destruction. -
Hiroshima
The First atomic bomb named "Little Boy" was dropped from the plane "Enola Gay" on Hiroshima, Instantly killing 70,000 Japanese/ -
Warning
U.S. decides to drop warning pamphlets on Japanese cities. -
Nagasaki
The second atomic bomb named "Fat Man" was dropped on Nagasaki, instantly killing 80,000 Japanese. Original target was Kokura, but poor weather forced the target to change. -
Impossible Threats
U.S. drops warning leaflets concerning another atomic bomb on Nagasaki, the day after the bomb was dropped, even though the U.S. was out of atomic bombs and had no way of producing any more at the time. -
The Japanese Surrendered
