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Van Allen radiation belts
Van Allen radiation belts two belts (sometimes considered as a single belt of varying intensity) of radiation outside the earth's atmosphere, extending from c.400 to c.40,000 mi (c.650–c.65,000 km) above the earth. Their existence was confirmed from information secured by launching the first U.S. earth satellite, Explorer I, sent up during the International Geophysical Year of 1957–58. The belts were named for James A. Van Allen , the American astrophysicist who first predicted the belts and then was first to interpret the findings of the Explorer satellite. The region of external belts has been given the name of magnetosphere to distinguish it from the atmosphere . The charged particles of which the belts are composed circulate along the earth's magnetic lines of force extending from the area above the equator to the North Pole, to the South Pole, and circles back to the equator. These particles are believed to originate in periodic solar flares. Carried by the solar wind, they become trapped by the earth's magnetic field and are responsible for the aurora borealis seen at polar regions. A part of a belt dips into the upper region of the atmosphere over the South Atlantic to form the Southern Atlantic Anomaly. This can present a dangerous hazard to satellites orbiting the earth. |
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"Van Allen radiation belts." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Van Allen radiation belts." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1E1-VanAllen.html "Van Allen radiation belts." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-VanAllen.html |
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Van Allen radiation belts
Van Allen radiation belts Two rings of radiation trapped by the Earth's magnetic field in the upper atmosphere. The belts contain high-energy, charged particles. The inner belt (of electrons and protons) extends from c.1000 to 4000km (600–2500mi) above the Equator. The outer belt (of electrons) extends from c.15,000 to 25,000km (9000–15,000mi). It is thought that the particles come from solar flares carried by the solar wind. The belts were discovered in 1958 by the US physicist James Van Allen.
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"Van Allen radiation belts." World Encyclopedia. 2005. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Van Allen radiation belts." World Encyclopedia. 2005. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O142-VanAllenradiationbelts.html "Van Allen radiation belts." World Encyclopedia. 2005. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-VanAllenradiationbelts.html |
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Van Allen belt
Van Allen belt Two belts of high-energy, charged particles trapped by the Earth's magnetic field within the magnetosphere. The inner belt starts at an altitude of about 800 km and reaches a maximum intensity at about 2000 km. The outer belt reaches a maximum intensity at between three and four Earth radii (18 000–25 000 km). Although commonly referred to as ‘radiation belts’, they contain particles, not radiation. Their presence was predicted by J. A. Van Allen (1914– ).
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AILSA ALLABY and MICHAEL ALLABY. "Van Allen belt." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "Van Allen belt." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O13-VanAllenbelt.html AILSA ALLABY and MICHAEL ALLABY. "Van Allen belt." A Dictionary of Earth Sciences. 1999. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-VanAllenbelt.html |
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Van Allen Belts
Van Allen Belts Two radiation belts surrounding the Earth, containing trapped charged particles. The inner Van Allen Belt lies around 1.5 Earth radii (9400 km) above the equator, and contains protons and electrons of both solar and ionospheric origin. The outer Van Allen Belt, at an equatorial distance of 4.5 Earth radii (28 000 km), contains mainly electrons from the solar wind. The belts were discovered in 1958 by J. A.Van Allen from measurements obtained by the Explorer 1 satellite.
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"Van Allen Belts." A Dictionary of Astronomy. 1997. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Van Allen Belts." A Dictionary of Astronomy. 1997. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O80-VanAllenBelts.html "Van Allen Belts." A Dictionary of Astronomy. 1997. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-VanAllenBelts.html |
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Van Allen belt
Van Al·len belt • n. each of two regions of intense radiation partly surrounding the earth at heights of several thousand kilometers. |
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"Van Allen belt." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 28 May. 2012 <http://www.encyclopedia.com>. "Van Allen belt." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 28, 2012). http://www.encyclopedia.com/doc/1O999-vanallenbelt.html "Van Allen belt." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 28, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-vanallenbelt.html |
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