Search Results - Nuclear weapon

In the history of warfare, only two nuclear weapons have been detonated offensively; both by the United States of America during the closing days of World War II. The first was detonated on the morning of 6 August 1945, when the United States dropped a (uranium) gun-type device code-named "Little Boy" on the Japanese city of Hiroshima. The second was detonated three days later when the United States dropped a plutonium implosion-type device code-named "Fat Man" on the city of Nagasaki, Japan. These bombings resulted in the immediate deaths of around 120,000 people from injuries sustained from the explosion and acute radiation sickness, and even more deaths from long-term effects of (ionising) radiation. The use of these weapons was and remains controversial. (See Atomic bombings of Hiroshima and Nagasaki for a full discussion.)

Since the Hiroshima and Nagasaki bombings, nuclear weapons have been detonated on over two thousand occasions for testing purposes and demonstration purposes. The only countries known to have detonated nuclear weapons — and that acknowledge possessing such weapons — are (chronologically) the United States, the Soviet Union (succeeded as a nuclear power by Russia), the United Kingdom, France, the People's Republic of China, India, Pakistan, and North Korea. Israel is also widely believed to possess nuclear weapons, though it does not acknowledge having them. For more information on these states' nuclear programs, as well as other states that formerly possessed nuclear weapons or are suspected of seeking nuclear weapons, see List of states with nuclear weapons.

The first nuclear weapons were created in the United States by an international team, involving many displaced scientists from central Europe, which included Germany, with assistance from the United Kingdom and Canada during World War II as part of the top-secret Manhattan Project. While the first weapons were developed primarily out of fear that Nazi Germany would develop them first, they were eventually used against the Japanese cities of Hiroshima and Nagasaki. The first test was conducted on July 16, 1945 at a site near Alamogordo, New Mexico.^[2] The Soviet Union developed and tested their first nuclear weapon in 1949, based partially on information obtained from Soviet espionage in the United States. Both the U.S. and USSR would go on to develop weapons powered by nuclear fusion (thermonuclear bombs) by the mid-1950s. With the invention of reliable rocketry during the 1960s, it became possible for nuclear weapons to be delivered anywhere in the world on a very short notice, and the two Cold War superpowers adopted a strategy of deterrence to maintain a shaky peace.^[3]