United States of America · Warfare / World War, 2nd. Chronological records rendered directly from the World History Database.
Leads a team which creates the 1st controlled nuclear reaction. A team led by Enrico Fermi, for whom Fermilab is named, initiate the first artificial self-sustaining nuclear chain reaction in an experimental nuclear reactor named Chicago Pile-1
From 1942-1946 under the control of the US Army Corps of Engineers, under the administration of General Leslie R. Groves
The scientific research is directed by American physicist J. Robert Oppenheimer
Appointed head of the Manhattan Project by Roosevelt to develop the atomic bomb
Successful test of explosive lens for Fat Man
Successful test of explosive lens for Fat Man
Second meeting of the Target Committee, at Los Alamos, which works to finalize the list of cities on which atomic bombs may be dropped
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
President Harry S. Truman discloses to Soviet leader Joseph Stalin that the United States has atomic weapons, Stalin feigns little surprise; he already knows this through espionage
"Little Boy", a gun-type uranium-235 weapon, is used against the city of Hiroshima, Japan
"Little Boy", a gun-type uranium-235 weapon, is used against the city of Hiroshima, Japan
"Fat Man", an implosion-type plutonium-239 weapon, is used against the city of Nagasaki, Japan
General Leslie Groves had commissioned Smyth to write the Report at Los Alamos during the Manhattan Project
General Leslie Groves had commissioned Smyth to write the Report at Los Alamos during the Manhattan Project
The Smyth Report is released to the public, giving the first technical history of the development of the first atomic bombs
Oppenheimer resigns as director of Los Alamos, and is succeeded by Norris Bradbury
"Fat Man", an implosion-type plutonium-239 weapon, is used against the city of Nagasaki, Japan
This factsheet is generated from stored World History Database records matching the country, broad category, detailed category and exact Event value shown above. Duplicate display records are collapsed; database wording is otherwise preserved. Source provenance varies by record, so formal academic citation should be checked against the relevant primary source, archive or specialist historical reference.