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75th anniversary of WWII official end

The Lab’s role in helping end the fighting.
August 28, 2020
The Gadget is shown here before its successful detonation during the Trinity test on July 16, 1945. This plutonium implosion-style device was the precursor to the Fat Man weapon deployed above Nagasaki on Aug. 9, 1945. Information related to these world-changing events are part of the collections in the National Security Research Center, the Lab’s classified library.

The Gadget is shown here before its successful detonation during the Trinity test on July 16, 1945. This plutonium implosion-style device was the precursor to the Fat Man weapon deployed above Nagasaki on Aug. 9, 1945. Information related to these world-changing events are part of the collections in the National Security Research Center, the Lab’s classified library.

 

By National Security Research Center staff 

It was the deadliest conflict in history and Sept.2 is the 75th anniversary of its end.

World War II began in 1939 and involved more than 30 countries, including all the greatest global powers. The United States entered the war in 1941 following the Japanese attack on Pearl Harbor. Meanwhile, in 1943 a secret lab was formed in Los Alamos under the leadership physicist J. Robert Oppenheimer. The goal: To build the world’s first nuclear weapons. 

In what is one of the greatest scientific achievements ever, the Los Alamos scientists created the Gadget, Little Boy and Fat Man. The war ended shortly thereafter. 

  • July 16, 1945: The Gadget plutonium implosion weapon is successfully detonated during the Trinity test.
  • 6, 1945: The Enola Gay delivers the Little Boy uranium gun-type weapon above Hiroshima.
  • 8, 1945: The Soviets declare war on Japan.
  • 9, 1945: Bockscar delivers the Fat Man plutonium implosion weapon above Nagasaki.
  • 14, 1945: Japan announces its surrender.
  • 2, 1945: Japan signs formal surrender documents aboard the USS Missouri, officially ending six years of global war.

The uranium, gun-type weapon Little Boy was the first atomic weapon to be used in combat when it was deployed above Hiroshima on Aug. 6, 1945. It was the first of two nuclear weapons ever used in combat. Shortly thereafter, Japan surrendered and World War II officially ended on Sept. 2, 1945.
The uranium, gun-type weapon Little Boy was the first atomic weapon to be used in combat when it was deployed above Hiroshima on Aug. 6, 1945. It was the first of two nuclear weapons ever used in combat. Shortly thereafter, Japan surrendered and World War II officially ended on Sept. 2, 1945.