When Was the First Nuclear Weapon Detonated?

On 16 July 1945 at 5:29 AM, the world first nuclear device was detonated at the Trinity test site in the Jornada del Muerto desert of New Mexico, as part of the top-secret Manhattan Project. The plutonium implosion device, nicknamed "Gadget," produced an explosive yield of about 21 kilotonnes of TNT. The fireball reached temperatures hotter than the Sun core, the shock wave was felt 160 km away, and the mushroom cloud rose to 12 km. J. Robert Oppenheimer, scientific director of the project, later recalled the Hindu scripture line: "Now I am become Death, the destroyer of worlds." Three weeks later, atomic bombs were dropped on Hiroshima (6 August) and Nagasaki (9 August), ending World War II.