Little Boy and Fat Man
Little Boy was the first nuclear weapon used in warfare. It exploded approximately 1,800 feet over Hiroshima, Japan, on the morning of August 6, 1945, with a force equal to 13,000 tons of TNT. Immediate deaths were between 70,000 to 130,000.
Fat Man was the second nuclear weapon used in warfare. Dropped on Nagasaki, Japan, on August 9, 1945, Fat Man devastated more than two square miles of the city and caused approximately 45,000 immediate deaths.
Major Charles W. Sweeney piloted the B-29, #77 that dropped Fat Man. After the nuclear mission, #77 was christened Bockscar after its regular Command Pilot, Fred Bock.
While Little Boy was a uranium gun-type device, Fat Man was a more complicated and powerful plutonium implosion weapon that exploded with a force equal to 20 kilotons of TNT.
The discovery of fission in early in 1939 made atomic bombs possible. When the great Danish physicist, Niels Bohr, announced the discovery of fission to the world, many scientists became alarmed by the prospect that Germany would use fission to develop a Nazi atomic bomb. Albert Einstein wrote to President Franklin Roosevelt advising the president of such a possibility. Einstein's letter led to the creation of the Manhattan Project as well as the Los Alamos Laboratory.
Berkeley Summer Conference
In the summer of 1942, J. Robert Oppenheimer convened a study conference in his University of California offices to explore the possibility of developing an atomic bomb. Attended by such notable physicists as Hans Bethe and Edward Teller, the conferees concluded that an...