Nuclear explosion debris. The first man made nuclear explosion occurred on July 16, 1945 at 5:50 am on the Trinity Test Site near Alamogordo, New Mexico in the United States, an area now known as the White Sands Missile Range. The event involved the full-scale testing of an implosion-type fission atomic bomb. In a memorandum to the U.S. Secretary of War, General Leslie Groves describes the yield as equivalent to 15,000 to 20,000 tons of TNT. Following this test, a uranium-gun type nuclear bomb (Little Boy) was dropped on the Japanese city of Hiroshima on August 6, 1945, with a blast yield
Nagasaki Atomic Bomb Museum an atomic bomb on Japan had been made by 1943, and a shortlist of candidate target cities was in place in 1945. At the time, it was argued that an atomic bombing would bring about a more rapid end to the war. Hiroshima, the first target, was selected to show the power of America's new weapon. The second bombing, of Nagasaki, was intended to demonstrate that the USA had a large arsenal. At 11:02 A.M. local time on August 9, 1945, the atomic bomb, nicknamed Fat Man as its code name by Robert Serber in the United States (after Sydney