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meteor
meteor appearance of a small particle flying through space that interacts with the earth's upper atmosphere. While still outside the atmosphere, the particle is known as a meteoroid. Countless meteoroids of varying sizes are moving about the solar system at any time. Perhaps a billion meteoroids a day enter the atmosphere, their speeds ranging from 10 to 45 mi (16-72 km) per sec. They experience friction due to collisions with the atmosphere; by the time they reach 50 to 75 mi (80-120 km) from the earth's surface, they have been heated to incandescence through friction and are visible as "shooting stars," or "falling stars." Most disintegrate completely before they reach the earth; those large enough to reach the ground are called meteorites . A meteor of considerable duration and brightness is known as a fireball ; a fireball that breaks apart with an explosion is a bolide. The brightest fireball ever recorded fell in the Tunguska Basin, Siberia, in 1908, causing the destruction of forest over an area of about 770 sq mi (2,000 sq km). Meteoroids are composed of stone, iron, or a mixture of stone and iron, with other metals present in very small proportions. Other meteoroids, the carbonaceous chondrites, are stony with a large amount of carbon. Although most meteoroids are quite small, and even though only a very small fraction of them reach the earth's surface, their large quantity accounts for several tons of matter falling on the earth each day. A single observer under a dark sky can see an average of 5 to 10 meteors per hour; more during a meteor shower . More meteors are visible after midnight because the earth's rotation has then positioned the observer's part of the earth in the direction of the earth's motion about the sun. The frequency of meteors also increases when the earth passes through certain swarms of particles that intersect the earth's orbit. Such meteor showers are named for the constellation from which they appear to originate. |
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"meteor." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "meteor." The Columbia Encyclopedia, 6th ed.. 2008. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1E1-meteor-ent.html "meteor." The Columbia Encyclopedia, 6th ed.. 2008. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-meteor-ent.html |
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meteor
meteor A brief streak of light in the Earth's upper atmosphere between altitudes of 85 and 115 km, produced by the high-speed entry of a small fragment of interplanetary debris (a meteoroid). An estimated 100 million meteors are visible to the naked eye over the whole Earth in an average 24-hour period. Meteoroids enter the atmosphere at velocities of 11–72 km/s. A typical naked-eye meteor of magnitude +2 is produced by a meteoroid about 8 mm in diameter. Over 0.1–0.2 s, its kinetic energy is converted principally to heat and ionization; only a small proportion is converted to visible light. The surface of a meteoroid is rapidly vaporized by the process of ablation. Material eroded from the meteoroid's surface goes on to collide further with atmospheric particles, producing excitation and ionization along a column perhaps 20–30 km long. The excess energy imparted to the atmospheric particles is re-emitted in a fraction of a second as visible light.
Meteors may be produced by particles sharing an orbit around the Sun (a meteor stream), or by solitary, random particles (sporadic meteors). During a meteor shower, more meteors will be seen. Most meteors are faint. The naked eye can detect events down to about magnitude +5, while binoculars show meteors as faint as magnitude +8. Smaller material gives rise to radio meteors or radar meteors, perhaps equivalent to visual magnitudes around magnitude +12. Occasionally, the arrival of a more substantial piece of debris produces an extremely bright fireball. |
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"meteor." A Dictionary of Astronomy. 1997. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "meteor." A Dictionary of Astronomy. 1997. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O80-meteor.html "meteor." A Dictionary of Astronomy. 1997. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-meteor.html |
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meteor
meteor † atmospheric phenomenon XV; fireball, shooting star XVI. — modL. meteōrum or Gr. metėōron, sb. use of n. of metéōros raised up, lofty, f. metā META- + *eōr-, var. of base of aeírein raise.
Hence, or partly — medL. meteōricus, meteoric † elevated, lofty XVII; † pert. to the atmosphere XVIII; pert. to meteors XIX. meteorite XIX. meteorology XVII. — F. or modL. — Gr. meteōrologíā. meteorological XVI. |
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T. F. HOAD. "meteor." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "meteor." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O27-meteor.html T. F. HOAD. "meteor." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-meteor.html |
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meteor
meteor (shooting star) Brief streak of light in the night sky caused by a meteoroid entering the Earth's upper atmosphere at high speed from space. A typical meteor lasts from a few tenths of a second to a few seconds, depending on the meteoroid's impact speed, which can vary from c.11–70km/s (7–45mi/s). At certain times of the year there are meteor showers, when meteors are more numerous than usual.
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"meteor." World Encyclopedia. 2005. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "meteor." World Encyclopedia. 2005. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O142-meteor.html "meteor." World Encyclopedia. 2005. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-meteor.html |
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meteor
meteor Transient, incandescent trail of a meteoroid entering the Earth's atmosphere. All the material burns up before reaching the ground. It is popularly referred to as a ‘shooting star’. A very bright meteor is called a fireball. Compare METEORITES.
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AILSA ALLABY and MICHAEL ALLABY. "meteor." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "meteor." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O13-meteor.html AILSA ALLABY and MICHAEL ALLABY. "meteor." A Dictionary of Earth Sciences. 1999. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-meteor.html |
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meteor
me·te·or / ˈmētēər; -ēˌôr/ • n. a small body of matter from outer space that enters the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light. |
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"meteor." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "meteor." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O999-meteor.html "meteor." The Oxford Pocket Dictionary of Current English. 2009. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-meteor.html |
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meteor
meteor •astrantia • Bastia
•Dei gratia, hamartia
•poinsettia
•in absentia, Parmentier
•Izvestia
•meteor, wheatear
•Whittier • cottier • Ostia
•consortia, courtier
•protea • Yakutia • frontier • Althea
•Anthea • Parthia
•Pythia, stichomythia
•Carinthia, Cynthia
•forsythia • Scythia • clothier • salvia
•Latvia • Yugoslavia • envier
•Flavia, Moldavia, Moravia, Octavia, paviour (US pavior), Scandinavia, Xavier
•Bolivia, Livia, Olivia, trivia
•Sylvia • Guinevere • Elzevir
•Monrovia, Segovia
•Retrovir • effluvia • colloquia
•Goodyear • yesteryear • brassiere
•Abkhazia
•Anastasia, aphasia, brazier, dysphasia, dysplasia, euthanasia, fantasia, Frazier, glazier, grazier, gymnasia, Malaysia
•amnesia, anaesthesia (US anesthesia), analgesia, freesia, Indonesia, Silesia, synaesthesia
•artemisia, Kirghizia, Tunisia
•ambrosia, crozier, hosier, osier, symposia
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"meteor." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 11 Feb. 2012 <http://www.encyclopedia.com>. "meteor." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (February 11, 2012). http://www.encyclopedia.com/doc/1O233-meteor.html "meteor." Oxford Dictionary of Rhymes. 2007. Retrieved February 11, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-meteor.html |
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