Nuclear weapon
hideA nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion comparable to the detonation of more than a billion kilograms of conventional high explosive. Even small nuclear devices can devastate a city. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major aspect of international policy since their debut.
In the history of warfare, only two nuclear weapons have been detonated offensively, both near the end 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 (mostly civilians) from injuries sustained from the explosion and acute radiation sickness, and even more deaths from long-term effects of ionizing 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.)
For more information about Nuclear weapon, read the full article at
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News tagged with nuclear
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First Neutrino Events Observed at T2K Near Detector
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(PhysOrg.com) -- Physicists from the Japanese-led multi-national T2K neutrino collaboration announced today that over the weekend they detected the first events generated by their newly built neutrino beam ...
Spitzer Telescope Observes Baby Brown Dwarf
Nov 23, 2009 |
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(PhysOrg.com) -- NASA's Spitzer Space Telescope has contributed to the discovery of the youngest brown dwarf ever observed -- a finding that, if confirmed, may solve an astronomical mystery about how these ...
Nuclear weapons: Predicting the unthinkable
Nov 22, 2009 |
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If a nuclear weapon were detonated in a metropolitan area, how large would the affected area be? Where should first responders first go? According to physicist Fernando Grinstein, we have some initial understanding to address ...
Genetic analysis helps dissect molecular basis of cardiovascular disease
Nov 20, 2009 |
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Using highly precise measurements of plasma lipoprotein concentrations determined by nuclear magnetic resonance spectroscopy (NMR), researchers led by Daniel Chasman at Brigham and Women's Hospital and Harvard Medical School ...
An atomic-level look at an HIV accomplice
Nov 19, 2009 |
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(PhysOrg.com) -- Since the discovery in 2007 that a component of human semen called SEVI boosts infectivity of the virus that causes AIDS, researchers have been trying to learn more about SEVI and how it works, in hopes of ...
Doubts raised on nuclear industry viability
Nov 19, 2009 |
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(PhysOrg.com) -- The investment in nuclear power has been growing around the world over the last few years, being viewed as a means for countries to control their energy security, avoid the price fluctuations ...
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Like surfers on monster waves, electrons can ride waves of plasma to very high energies in a very short distance. Scientists have proven that plasma acceleration works. Now they're developing it as a way to ...
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(PhysOrg.com) -- While politicians debate the best ways to cut global carbon dioxide emissions, researchers at Idaho National Laboratory's Center for Advanced Energy Studies are charging ahead on a strategy ...
Advanced nuclear fuel sets global performance record
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(PhysOrg.com) -- Idaho National Laboratory scientists have set a new world record with next-generation particle fuel for use in high temperature gas reactors (HTGRs).
Acute heart attack patients receiving high ionizing radiation dose
Nov 16, 2009 |
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Acute heart attack patients received an average total dose of ionizing radiation equal to 725 chest X-rays from medical tests during their hospital stay, according to research presented at the American Heart Association's ...
Chromosomes dance and pair up on the nuclear membrane (w/ Video)
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(PhysOrg.com) -- Meiosis - the pairing and recombination of chromosomes, followed by segregation of half to each egg or sperm cell - is a major crossroads in all organisms reproducing sexually. Yet, how the ...
Two Earth-sized bodies with oxygen rich atmospheres found -- but they're stars not planets
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(PhysOrg.com) -- Astrophysicists at the University of Warwick and Kiel University have discovered two earth sized bodies with oxygen rich atmospheres - however there is a bit of a disappointing snag for anyone ...
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Medicine & Health / HIV & AIDS
Nov 12, 2009 |
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Structural biologists at the University of Pittsburgh School of Medicine have described the architecture of the complex of protein units that make up the coat surrounding the HIV genome and identified in it a "seam" of functional ...
Stars Fueled by Dark Matter Could Hold Secrets to the Universe
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(PhysOrg.com) -- The first stars in the universe may have been very different from the stars we see today, yet they may hold clues to understanding some of the mysterious features of the universe. These "dark ...
