Nuclear weapons testing in the context of Nuclear state

Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1 January 1950 as the commencement date (epoch) of the age scale, with 1950 being labelled as the "standard year". The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must account for when using radiocarbon dating for dates of origin that may fall after this year.

In a convention that is not always observed, many sources restrict the use of BP dates to those produced with radiocarbon dating; the alternative notation "RCYBP" stands for the explicit "radio carbon years before present".

An earthquake, also called a quake, tremor, or temblor, is the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at a particular location in the Earth is the average rate of seismic energy release per unit volume.

In its most general sense, the word earthquake is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining, fracking, and nuclear weapons testing. The initial point of rupture is called the hypocenter or focus, while the ground level directly above it is the epicenter. Earthquakes are primarily caused by geological faults, but also by volcanism, landslides, and other seismic events.

A mannequin (sometimes spelled as manikin and also called a dummy, lay figure, or dress form) is a doll, often articulated, used by artists, tailors, dressmakers, window dressers and others, especially to display or fit clothing and show off different fabrics and textiles. Alternatively the term refers, or referred to, a live human fashion model.

Life-sized mannequins with simulated airways are used in the teaching of first aid, CPR, and advanced airway management skills such as tracheal intubation. During the 1950s, mannequins were used in nuclear tests to help show the effects of nuclear weapons on humans. Also referred to as mannequins are the human figures used in computer simulation to model the behavior of the human body.

The nuclear arms race was an arms race competition for supremacy in nuclear warfare between the United States, the Soviet Union, and their respective allies during the Cold War. During this same period, in addition to the American and Soviet nuclear stockpiles, other countries developed nuclear weapons, though no other country engaged in warhead production on nearly the same scale as the two superpowers.

The race began during World War II, dominated by the Western Allies' Manhattan Project and Soviet atomic spies. Following the atomic bombings of Hiroshima and Nagasaki, the Soviet Union accelerated its atomic bomb project, resulting in the RDS-1 test in 1949. Both sides then pursued an all-out effort, realizing deployable thermonuclear weapons by the mid-1950s. The arms race in nuclear testing culminated with the 1961 Tsar Bomba. Atmospheric testing was ended in the 1963 Partial Nuclear Test Ban Treaty. Subsequent work focused on the miniaturization of warheads at LLNL and VNIITF, and the neutron bomb.

Israel is widely believed to possess nuclear weapons. Estimates of Israel's stockpile range from 90 to 400 warheads, and the country is believed to possess a nuclear triad of delivery options: by F-15 and F-16 fighters, by Dolphin-class submarine-launched cruise missiles, and by the Jericho series of medium to intercontinental range ballistic missiles. Its first deliverable nuclear weapon is estimated to have been completed in late 1966 or early 1967, which would make it the sixth of nine nuclear-armed countries.

Israel maintains a policy of deliberate ambiguity, neither formally denying nor admitting to having nuclear weapons, instead repeating over the years that "Israel will not be the first country to introduce nuclear weapons to the Middle East". Israel interprets "introduce" to mean it will not test or formally acknowledge its nuclear arsenal. Western governments, including the United States, similarly do not acknowledge the Israeli capacity. Israeli officials, including prime ministers, have made statements that seemed to imply that Israel possesses nuclear weapons, including discussions of use in the Gaza war.

Nuclear proliferation is the spread of nuclear weapons to additional countries, particularly those not recognized as nuclear-weapon states by the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT. Nuclear proliferation occurs through the spread of fissile material, and the technology and capabilities needed to produce it and to design and manufacture nuclear weapons. In a modern context, it also includes the spread of nuclear weapons to non-state actors. Proliferation has been opposed by many nations with and without nuclear weapons, as governments fear that more countries with nuclear weapons will increase the possibility of nuclear warfare (including the so-called countervalue targeting of civilians), de-stabilize international relations, or infringe upon the principle of state sovereignty. Conversely, supporters of deterrence theory argue that controlled proliferation decreases conflict rates via nuclear peace.

Nuclear weapons were initially researched during World War II, jointly by the United States, United Kingdom and Canada, and separately by Germany, Japan, the Soviet Union, and France. The United States was the first and is the only country to have used a nuclear weapon in war, when it used two bombs against Japan in August 1945. After surrendering, Germany and Japan ceased to be involved in any nuclear weapon research. A nuclear arms race followed, with further countries developing and testing nuclear weapons. The US primarily competed with the Soviet Union, which carried out their first test in 1949. Seven other countries developed nuclear weapons during the Cold War. The UK and France, both NATO members, developed fission and fusion weapons throughout the 1950s, and 1960s, respectively. China developed both against the backdrop of the Sino-Soviet split.

Trinity was the first detonation of a nuclear weapon, conducted by the United States Army at 5:29 a.m. Mountain War Time (11:29:21 GMT) on July 16, 1945, as part of the Manhattan Project. The test was of an implosion-design plutonium bomb, or "gadget" – the same design as the Fat Man bomb later detonated over Nagasaki, Japan, on August 9, 1945. Concerns about whether the complex Fat Man design would work led to a decision to conduct the first nuclear test. The code name "Trinity" was assigned by J. Robert Oppenheimer, the director of the Los Alamos Laboratory. The name was possibly inspired by the poetry of John Donne.

Planned and directed by Kenneth Bainbridge, the test was conducted in the Jornada del Muerto desert about 35 miles (56 km) southeast of Socorro, New Mexico, on what was the Alamogordo Bombing and Gunnery Range, but was renamed the White Sands Proving Ground just before the test. The only structures originally in the immediate vicinity were the McDonald Ranch House and its ancillary buildings, which scientists used as a laboratory for testing bomb components.

Helium-3 (He see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and hydrogen-1 are the only stable nuclides with more protons than neutrons. It was discovered in 1939. Helium-3 atoms are fermionic and become a superfluid at the temperature of 2.491 mK.

Helium-3 occurs as a primordial nuclide, escaping from Earth's crust into its atmosphere and into outer space over millions of years. It is also thought to be a natural nucleogenic and cosmogenic nuclide, one produced when lithium is bombarded by natural neutrons, which can be released by spontaneous fission and by nuclear reactions with cosmic rays. Some found in the terrestrial atmosphere is a remnant of atmospheric and underwater nuclear weapons testing.

The anti-nuclear movement is a social movement that opposes various nuclear technologies. Some direct action groups, environmental movements, and professional organisations have identified themselves with the movement at the local, national, or international level. Major anti-nuclear groups include Campaign for Nuclear Disarmament, Friends of the Earth, Greenpeace, International Physicians for the Prevention of Nuclear War, Peace Action, Seneca Women's Encampment for a Future of Peace and Justice and the Nuclear Information and Resource Service. The initial objective of the movement was nuclear disarmament, though since the late 1960s opposition has included the use of nuclear power. Many anti-nuclear groups oppose both nuclear power and nuclear weapons. The formation of green parties in the 1970s and 1980s was often a direct result of anti-nuclear politics.

Scientists and diplomats have debated nuclear weapons policy since before the atomic bombings of Hiroshima and Nagasaki in 1945. The public became concerned about nuclear weapons testing from about 1954, following extensive nuclear testing including the Castle Bravo disaster. In 1963, many countries ratified the Partial Test Ban Treaty which prohibited atmospheric nuclear testing.

Nuclear weapons testing is the act of experimentally and deliberately firing one or more nuclear devices in a controlled manner pursuant to a military, scientific or technological goal. This has been done on test sites on land or waters owned, controlled or leased from the owners by one of the eight nuclear nations: the United States, the Soviet Union, the United Kingdom, France, China, India, Pakistan and North Korea, or has been done on or over ocean sites far from territorial waters. There have been 2,121 tests done since the first in July 1945, involving 2,476 nuclear devices. As of 1993, worldwide, 520 atmospheric nuclear explosions (including eight underwater) have been conducted with a total yield of 545 megatons (Mt): 217 Mt from pure fission and 328 Mt from bombs using fusion, while the estimated number of underground nuclear tests conducted in the period from 1957 to 1992 is 1,352 explosions with a total yield of 90 Mt. As a result of the 1996 Comprehensive Nuclear-Test-Ban Treaty, there were no declared tests between the 1998 Pakistani Chagai-II and the 2006 North Korean test, and none outside North Korea to date.

Very few unknown tests are suspected at this time, the Vela incident being the most prominent. Israel is the only country suspected of having nuclear weapons but not confirmed to have ever tested any.

Enewetak Atoll (/ɛˈniːwəˌtɔːk, ˌɛnɪˈwiːtɔːk/; also spelled Eniwetok Atoll or sometimes Eniewetok; Marshallese: Ānewetak, [ænʲeːwɛːdˠɑk], or Āne-wātak, [ænʲeːwæːdˠɑk]; known to the Japanese as Brown Atoll or Brown Island; Japanese: ブラウン環礁) is a large coral atoll of 40 islands in the Pacific Ocean and with its 296 people (as of 2021) forms a legislative district of the Ralik Chain of the Marshall Islands. With a land area total less than 5.85 square kilometers (2.26 sq mi), it is no higher than 5 meters (16.4 ft) and surrounds a deep central lagoon, 80 kilometers (50 mi) in circumference. It is the second-westernmost atoll of the Ralik Chain and is 305 kilometers (190 mi) west from Bikini Atoll.

It was held by the Japanese from 1914 until its capture by the United States in February 1944 during World War II, then became Naval Base Eniwetok. Nuclear testing by the US, totaling the equivalent of over 30 megatons of TNT, took place during the Cold War; in 1977–1980, a concrete dome (the Runit Dome) was built on Runit Island to deposit radioactive soil and debris.

The Partial Test Ban Treaty (PTBT), formally known as the 1963 Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water, prohibited all test detonations of nuclear weapons except for those conducted underground. It is also abbreviated as the Limited Test Ban Treaty (LTBT) and Nuclear Test Ban Treaty (NTBT), though the latter may also refer to the Comprehensive Nuclear-Test-Ban Treaty (CTBT), which succeeded the PTBT for ratifying parties.

Negotiations initially focused on a comprehensive ban, but that was abandoned because of technical questions surrounding the detection of underground tests and Soviet concerns over the intrusiveness of proposed verification methods. The impetus for the test ban was provided by rising public anxiety over the magnitude of nuclear tests, particularly tests of new thermonuclear weapons (hydrogen bombs), and the resulting nuclear fallout. A test ban was also seen as a means of slowing nuclear proliferation and the nuclear arms race. Though the PTBT did not halt proliferation or the arms race, its enactment did coincide with a substantial decline in the concentration of radioactive particles in the atmosphere.

There are currently nine sovereign states that are generally understood to possess nuclear weapons, though only eight formally acknowledge possessing them. In order of first successful nuclear test, the world's nine nuclear-armed states are the United States (1945), Russia (1949), the United Kingdom (1952), France (1960), China (1964), India (1974), Pakistan (1998), and North Korea (2006); Israel is believed to have acquired nuclear weapons around 1967, but has never openly tested or formally acknowledged having them. Under the Non-Proliferation Treaty (NPT), the United States, Russia, the United Kingdom, France, and China are recognized "nuclear-weapons states" (NWS). They are also the five permanent members of the United Nations Security Council. Israel, India, and Pakistan never signed the NPT, while North Korea acceded to it in 1985 before announcing withdrawal in 2003.

South Africa developed nuclear weapons by 1982 but dismantled them around 1989 and joined the NPT in 1991. Following the dissolution of the Soviet Union in 1991, the former Soviet republics of Ukraine, Kazakhstan, and Belarus had nuclear weapons deployed on their territories, but agreed to transfer them to Russia (which inherited the Soviet Union's international rights and obligations) and join the NPT as non-nuclear-weapon states.

Under the Manhattan Project, the United States was the first country to manufacture nuclear weapons and is the only country to have used them in combat, with the bombings of Hiroshima and Nagasaki in World War II against Japan. In total it conducted 1,054 nuclear tests, and tested many long-range nuclear weapons delivery systems.

The United States currently deploys 1,770 warheads, mostly under Strategic Command, to its nuclear triad: Ohio-class submarines with Trident II submarine-launched ballistic missiles, silo-based Minuteman III intercontinental ballistic missiles, and B-2 Spirit and B-52 Stratofortress bombers armed with B61 and B83 bombs and AGM-86B cruise missiles. The US maintains a limited anti-ballistic missile capability via the Ground-Based Interceptor and Aegis systems. The US plans to modernize its triad with the Columbia-class submarine, Sentinel ICBM, and B-21 Raider, from 2029.