Trinity was the code name of the first detonation of a nuclear device. This test was conducted by the United States Army on July 16, 1945, in the Jornada del Muerto desert about 35 miles southeast of Socorro, New Mexico, at the new White Sands Proving Ground, which incorporated the Alamogordo Bombing and Gunnery Range. The date of the test is usually considered to be the beginning of the Atomic Age. Trinity was a test of an implosion-design plutonium device. The weapon's informal nickname was The Gadget. Using the same conceptual design, the Fat Man device was detonated over Nagasaki, Japan, on August 9, 1945. The Trinity detonation produced the explosive power of about 20 kilotons of TNT.