Nuclear weapon yieldThe explosive yield of a nuclear weapon is the amount of energy released such as blast, thermal, and nuclear radiation, when that particular nuclear weapon is detonated, usually expressed as a TNT equivalent (the standardized equivalent mass of trinitrotoluene which, if detonated, would produce the same energy discharge), either in kilotonnes (kt—thousands of tonnes of TNT), in megatonnes (Mt—millions of tonnes of TNT), or sometimes in terajoules (TJ). An explosive yield of one terajoule is equal to .
Nuclear weapons testingNuclear weapons tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength.
Nuclear holocaustA nuclear holocaust, also known as a nuclear apocalypse, nuclear Armageddon, or atomic holocaust, is a theoretical scenario where the mass detonation of nuclear weapons causes globally widespread destruction and radioactive fallout. Such a scenario envisages large parts of the Earth becoming uninhabitable due to the effects of nuclear warfare, potentially causing the collapse of civilization and, in the worst case, extinction of humanity and/or termination of all biological life on Earth.
Peaceful nuclear explosionPeaceful nuclear explosions (PNEs) are nuclear explosions conducted for non-military purposes. Proposed uses include excavation for the building of canals and harbours, electrical generation, the use of nuclear explosions to drive spacecraft, and as a form of wide-area fracking. PNEs were an area of some research from the late 1950s into the 1980s, primarily in the United States and Soviet Union. In the U.S., a series of tests were carried out under Project Plowshare.
Chelyabinsk meteorThe Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural region in Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately diameter, near-Earth asteroid that entered the atmosphere at a shallow 18.3 ± 0.4 degree angle with a speed relative to Earth of 19.16 ± 0.15 kilometres per second (69,000 km/h; 42,690 mph). The light from the meteor was briefly brighter than the Sun, visible as far as away.
Atomic bombings of Hiroshima and NagasakiOn 6 and 9 August 1945, the United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki. The bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the only use of nuclear weapons in an armed conflict. Japan surrendered to the Allies on 15 August, six days after the bombing of Nagasaki and the Soviet Union's declaration of war against Japan and invasion of Japanese-occupied Manchuria. The Japanese government signed the instrument of surrender on 2 September, effectively ending the war.
Castle BravoCastle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of Operation Castle. Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and the first lithium deuteride-fueled thermonuclear weapon ever tested using the Teller-Ulam design. Castle Bravo's yield was , 2.5 times the predicted , due to unforeseen additional reactions involving lithium-7, which led to radioactive contamination in the surrounding area.
Submarine-launched ballistic missileA submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead and allows a single launched missile to strike several targets. Submarine-launched ballistic missiles operate in a different way from submarine-launched cruise missiles.
Neutron bombA neutron bomb, officially defined as a type of enhanced radiation weapon (ERW), is a low-yield thermonuclear weapon designed to maximize lethal neutron radiation in the immediate vicinity of the blast while minimizing the physical power of the blast itself. The neutron release generated by a nuclear fusion reaction is intentionally allowed to escape the weapon, rather than being absorbed by its other components.
Nuclear explosionA nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device. Nuclear explosions are used in nuclear weapons and nuclear testing.
Nuclear winterNuclear winter is a severe and prolonged global climatic cooling effect that is hypothesized to occur after widespread firestorms following a large-scale nuclear war. The hypothesis is based on the fact that such fires can inject soot into the stratosphere, where it can block some direct sunlight from reaching the surface of the Earth. It is speculated that the resulting cooling would lead to widespread crop failure and famine.
ExplosionAn explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully.
HypocenterA hypocenter or hypocentre (), also called ground zero or surface zero, is the point on the Earth's surface directly below a nuclear explosion, meteor air burst, or other mid-air explosion. In seismology, a hypocenter of an earthquake is its point of origin below ground; a synonym is the focus of an earthquake. Generally, the terms ground zero and surface zero are also used in relation to epidemics, and other disasters to mark the point of the most severe damage or destruction.
