At 5:30 a.m. on July 16, 1945, Los Alamos scientists detonated a plutonium bomb at a test site located on the U.S. Air Force base at Alamogordo, New Mexico, some 120 miles south of Albuquerque. Oppenheimer chose the name “Trinity” for the test site, inspired by the poetry of John Donne. The test had been scheduled for 4 a.m., but when the time came it was raining, and the appointed hour was pushed back to 5:30. Tensions ran high at the test site, where those assembled included the scientist Enrico Fermi–who had directed the first nuclear chain reaction in December 1942–U.S. Army Brigadier General Leslie Groves, Bush, Oppenheimer and others.
When the bomb was finally detonated atop a steel tower, an intense light flash and sudden wave of heat was followed by a great burst of sound echoing in the valley. A ball of fire tore up into the sky and then was surrounded by a giant mushroom cloud stretching some 40,000 feet across. With a power equivalent to around 21,000 tons of TNT, the bomb completely obliterated the steel tower on which it rested. The nuclear age had begun.
