On July 16, 1945, the first atomic bomb was successfully exploded at the Alamogordo Bombing and Gunnery Range in a remote section of desert near Los Alamos, New Mexico. The bomb went off at 5:30 a.m. after a stormy night when the ability to go through with the test was uncertain. The detonation was initially planned for 4:00 am but it was feared that the danger from radiation and fallout would be greatly increased by rain. At 4:45 am a crucial weather report came in favorably, and at 5:10 am the twenty-minute countdown began.
The physicists who worked on the project were both gratified and appalled by the success of the “Trinity” test. J. Robert Oppenheimer, scientific director of the “Manhattan Project,” as the R&D for the atomic bomb was called, quoted the Bhagavad Gita (sacred Hindu scripture), stating, “Now I am become Death, destroyer of worlds.” Trinity Test Director Kenneth Bainbridge’s comment was more prosaic: “Now we are all sons of bitches.”
The effects of the blast sent a mushroom cloud boiling into the sky, both visible and audible for hundreds of miles around. The heat generated at the blast point was described as being 10,000 times hotter than the surface of the sun. The shock wave was felt over 100 miles (160 km) away, and the mushroom cloud reached 7.5 miles (12 km) in height. Three weeks later, on August 6, an atomic bomb was dropped on Hiroshima, Japan, and on August 9, one was dropped on Nagasaki. The atomic bombings of Hiroshima and Nagasaki killed at least 148,000 people immediately and many more over time. By 1950, the death toll was over 340,000.
By 1967 the U.S. had 31,225 operational nuclear warheads. At the end of the Cold War in 1991, the U.S. had an active arsenal of some 23,000 weapons of 26 major types. Since that time nuclear warhead production has been ceased in the U.S., although warhead modification, retrofit, and maintenance activities continue. The current number of operationally deployed weapons (i.e., ready for immediate use) in the U.S. as of 2009, is somewhere between 5100 and 5800. (Note that there are others too, that are designated as “inactive.” Also, it is unclear whether this number includes the stockpile of tactical nuclear weapons the U.S. maintains in Europe and on its territory.) The Soviet arsenal peaked at approximately 45,000 weapons in 1986 but as of 2009 was down to an estimated number between 4800 and 5400. Worldwide, there currently are an estimated 31,000 nuclear warheads deployed or in reserve. The combined explosive yield of these weapons is approximately 5,000 megatons, which is about 200,000 times the explosive yield of the bomb used on Hiroshima.
These numbers could go up as well as down. It takes 55 pounds of weapons-grade uranium to build a nuclear weapon. The global stockpile stands at around 1600 tons, enough for more than 60,000 nuclear weapons. Another 60,000 weapons could also be made from the 500 tons of separated plutonium estimated to exist in the world.