Meteoroid 1

Meteoroid

A Leonid meteor, or a shooting star seen in the2009 Leonid Meteor Shower.

A meteoroid is a sand- to boulder-sized particle of debris in the SolarSystem. The visible path of a meteoroid that enters Earth's (or anotherbody's) atmosphere is called a meteor, or colloquially a shooting staror falling star. If a meteoroid reaches the ground and survives impact,then it is called a meteorite. Many meteors appearing seconds orminutes apart, and appearing to originate from the same fixed point inthe sky, are called a meteor shower. The root word meteor comes fromthe Greek meteōros, meaning "high in the air".

Around 15,000 tonnes of meteoroids, space dust, and debris ofdifferent types enters Earth's atmosphere each year.[1]

Overview

Meteoroid

A slice of a pallasite meteorite fragmentdiscovered in Argentina; on display at the

Museum of Nature, Ottawa, Canada.

As of 2011 the International Astronomical Union officially defines ameteoroid as a solid object moving in interplanetary space, of a sizeconsiderably smaller than an asteroid and considerably larger than anatom".[2][3] Beech and Steel, writing in Quarterly Journal of the RoyalAstronomical Society, proposed a new definition where a meteoroid isbetween 100 µm and 10 m across.[4] Following the discovery andnaming of asteroids below 10 m in size (e.g., 2008 TC3), Rubin andGrossman refined the Beech and Steel definition of meteoroid toobjects between 10 µm and 1 m in diameter.[5] The NEO definitionincludes larger objects, up to 50 m in diameter, in this category. Verysmall meteoroids are known as micrometeoroids (see alsointerplanetary dust).

The Minor Planet Center does not use the term "meteoroid".The composition of meteoroids can be determined as they pass throughEarth's atmosphere from their trajectories and the light spectra of theresulting meteor. Their effects on radio signals also give information,especially useful for daytime meteors which are otherwise verydifficult to observe. From these trajectory measurements, meteoroidshave been found to have many different orbits, some clustering in

Meteoroid 2

streams (see Meteor showers) often associated with a parent comet, others apparently sporadic. Debris frommeteoroid streams may eventually be scattered into other orbits. The light spectra, combined with trajectory and lightcurve measurements, have yielded various compositions and densities, ranging from fragile snowball-like objectswith density about a quarter that of ice,[6] to nickel-iron rich dense rocks.Meteoroids travel around the Sun in a variety of orbits and at various velocities. The fastest ones move at about 26miles per second (42 kilometers per second) through space in the vicinity of Earth's orbit. The Earth travels at about18 miles per second (29 kilometers per second). Thus, when meteoroids meet the Earth's atmosphere head-on (whichwould only occur if the meteors were in a retrograde orbit), the combined speed may reach about 44 miles persecond (71 kilometers per second). Meteoroids moving through the earth's orbital space average about 20 km/s.[7]

Meteor"Meteor" and "Meteors" redirect here. For other uses, see Meteor (disambiguation).

See also Hydrometeor.

Photo of a part of the sky during a meteor showerover an extended exposure time. The meteors

have actually occurred several seconds to severalminutes apart.

Comet 17P/Holmes and Geminid

A meteor is the visible path of a meteoroid that has entered the Earth'satmosphere. Meteors typically occur in the mesosphere, and mostrange in altitude from 76 km to 100 km (46–62 miles).[8] Millions ofmeteors occur in the Earth's atmosphere every day. Most meteoroidsthat cause meteors are about the size of a pebble.

The velocities of meteors result from the movement of the Eartharound the Sun at about 30 km/s (18.5 miles per second),[9] the orbitalspeeds of meteoroids, and the gravitational attraction of the Earth.

Visibility

Meteors become visible between about 75 to 120 kilometers (34–70miles) above the Earth. They disintegrate at altitudes of 50 to 95kilometers (31–51 miles). Meteors have roughly a fifty percent chanceof a daylight (or near daylight) collision with the Earth. Most meteorsare, however, observed at night, when darkness allows fainter objectsto be recognized.

For bodies with a size scale larger than the atmospheric mean free path(10 cm to several metres) the visibility is due to the atmospheric rampressure (not friction) that heats the meteoroid so that it glows andcreates a shining trail of gases and melted meteoroid particles. Thegases include vaporized meteoroid material and atmospheric gases thatheat up when the meteoroid passes through the atmosphere. Mostmeteors glow for about a second. A relatively small percentage ofmeteoroids hit the Earth's atmosphere and then pass out again: theseare termed Earth-grazing fireballs (for example The Great Daylight1972 Fireball).

Meteors may occur in showers, which arise when the Earth passes through a trail of debris left by a comet, or as"random" or "sporadic" meteors, not associated with a specific single cause. A number of specific meteors have beenobserved, largely by members of the public and largely by accident, but with enough detail that orbits of themeteoroids producing the meteors have been calculated. All of the orbits passed through the asteroid belt.[10]

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FireballA fireball is a brighter-than-usual meteor. The International Astronomical Union defines a fireball as "a meteorbrighter than any of the planets" (magnitude −4 or greater).[11] The International Meteor Organization (an amateurorganization that studies meteors) has a more rigid definition. It defines a fireball as a meteor that would have amagnitude of −3 or brighter if seen at zenith. This definition corrects for the greater distance between an observerand a meteor near the horizon. For example, a meteor of magnitude −1 at 5 degrees above the horizon would beclassified as a fireball because if the observer had been directly below the meteor it would have appeared asmagnitude −6.[12] For 2011 there are 4589 fireballs records at the American Meteor Society.[13]

Bolide

A bolide (an especially bright meteor)

Astronomy

The word bolide comes from the Greek βολίς (bolis) [14] which canmean a missile or to flash. The IAU has no official definition of"bolide", and generally considers the term synonymous with "fireball".The term generally applies to fireballs reaching magnitude −14 orbrighter.[15] Astronomers tend to use "bolide" to identify anexceptionally bright fireball, particularly one that explodes (sometimescalled a detonating fireball). It may also be used to mean a fireballwhich creates audible sounds.

Geology

Geologists use the term "bolide" more often than astronomers do: in geology it indicates a very large impactor. Forexample, the USGS uses the term to mean a generic large crater-forming projectile "to imply that we do not knowthe precise nature of the impacting body ... whether it is a rocky or metallic asteroid, or an icy comet forexample".[16]

SuperbolideIf the magnitude of a bolide reaches −17 or brighter it is known as a superbolide.[15][17]

MeteoriteA meteorite is a portion of a meteoroid or asteroid that survives its passage through the atmosphere and impact withthe ground without being destroyed.[18] Meteorites are sometimes, but not always, found in association withhypervelocity impact craters; during energetic collisions, the entire impactor may be vaporized, leaving nometeorites.

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Tektite

Two tektites

Molten terrestrial material "splashed" from a meteorite impact cratercan cool and solidify into an object known as a tektite. These are oftenmistaken for meteorites.

Meteoric dust

Most meteoroids burn up when they enter the atmosphere. Theleft-over debris is called meteoric dust or just meteor dust. Meteordust particles can persist in the atmosphere for up to several months.These particles might affect climate, both by scattering electromagneticradiation and by catalyzing chemical reactions in the upper atmosphere.[19]

Ionization trailsDuring the entry of a meteoroid or asteroid into the upper atmosphere, an ionization trail is created, where themolecules in the upper atmosphere are ionized by the passage of the meteor. Such ionization trails can last up to 45minutes at a time. Small, sand-grain sized meteoroids are entering the atmosphere constantly, essentially every fewseconds in any given region of the atmosphere, and thus ionization trails can be found in the upper atmosphere moreor less continuously. When radio waves are bounced off these trails, it is called meteor burst communications.Meteor radars can measure atmospheric density and winds by measuring the decay rate and Doppler shift of a meteortrail.

ColorThe visible light produced by a meteor may take on various hues, depending on the chemical composition of themeteoroid, and the speed of its movement through the atmosphere. As layers of the meteoroid abrade and ionize, thecolor of the light emitted may change according to the layering of minerals. Possible colors (and elements producingthem) include:•• orange/yellow (sodium)•• yellow (iron)•• blue/green (copper)•• purple (potassium)•• red (silicate)

SoundAny sound generated by a meteor in the upper atmosphere, such as a sonic boom, should not be heard until manyseconds after the meteor disappears. However, in certain instances, for example during the Leonid meteor shower of2001, several people reported sounds described as "crackling", "swishing", or "hissing"[20] occurring at the sameinstant as a meteor flare. Similar sounds have also been reported during intense displays of Earth'sauroras.[21][22][23][24]

Sound recordings made under controlled conditions in Mongolia in 1998 by a team led by Slaven Garaj, a physicistat the Swiss Federal Institute of Technology at Lausanne, support the contention that the sounds are real.[25]

How these sounds could be generated, assuming they are in fact real, remains something of a mystery. It has been hypothesized by some scientists at NASA that the turbulent ionized wake of a meteor interacts with the magnetic field of the Earth, generating pulses of radio waves. As the trail dissipates, megawatts of electromagnetic energy could be released, with a peak in the power spectrum at audio frequencies. Physical vibrations induced by the

Meteoroid 5

electromagnetic impulses would then be heard if they are powerful enough to make grasses, plants, eyeglass frames,and other conductive materials vibrate.[26][27][28][29] This proposed mechanism, although proven to be plausible bylaboratory work, remains unsupported by corresponding measurements in the field.

Frequency of large meteorsThe biggest asteroid to hit Earth on any given day is likely to be about 40 centimeters, in a given year about 4meters, and in a given century about 20 meters. These statistics are obtained by the following:Over at least the range from 5 centimeters (2 inches) to roughly 300 meters (1,000 feet), the rate at which Earthreceives meteors obeys a power-law distribution as follows:

where N(>D) is the expected number of objects larger than a diameter of D meters to hit Earth in a year.[30] This isbased on observations of bright meteors seen from the ground and space, combined with surveys of near Earthasteroids. Above 300 meters in diameter, the predicted rate is somewhat higher, with a two-kilometer asteroid (onemillion-megaton TNT equivalent) every couple of million years — about 10 times as often as the power-lawextrapolation would predict.

Seasonal variation in frequency of fireball sightingsThe frequency of fireball sightings increases by about 10-30% during the weeks of vernal equinox.[31] Evenmeteorite falls are more common during the northern hemisphere's spring season. Although this phenomenon hasbeen known for quite some time, the reason behind the anomaly is not fully understood by scientists. Someresearchers attribute this to an intrinsic variation in the meteoroid population along Earth's orbit, with a peak in bigfireball-producing debris around spring and early summer. Research is in progress for mapping the orbits of themeteors in order to gain a better understanding of the phenomenon.[32]

Notable meteorsPerhaps the best-known meteor/meteorite fall is the Peekskill Meteorite, filmed on October 9, 1992 by at least 16independent videographers.[33]

Eyewitness accounts indicate the fireball entry of the Peekskill meteorite started over West Virginia at 23:48 UT(±1 min). The fireball, which traveled in a northeasterly direction, had a pronounced greenish colour, and attained anestimated peak visual magnitude of −13. During a luminous flight time that exceeded 40 seconds the fireball covereda ground path of some 700 to 800 km.[34]

One meteorite recovered at Peekskill, New York, for which the event and object gained their name, had a mass of12.4 kg (27 lb) and was subsequently identified as an H6 monomict breccia meteorite.[35] The video record suggeststhat the Peekskill meteorite had several companions over a wide area. The companions are unlikely to be recoveredin the hilly, wooded terrain in the vicinity of Peekskill.2008 TC3 was discovered on 6 October 2008 and entered the Earth's atmosphere the next day, striking a remote areaof northern Sudan. It was the first time a meteoroid had been observed in space and tracked prior to impacting Earth.A large fireball was observed in the skies near Bone, Indonesia on October 8, 2009. This was thought to be causedby an asteroid approximately 10 meters in diameter. The fireball contained an estimated energy of 50 kilotons ofTNT, or about twice the Nagasaki atomic bomb. No injuries were reported.[36]

A large bolide was reported on 18 November 2009 over southeastern California, northern Arizona, Utah, Wyoming, Idaho and Colorado. At 12:07 a.m., a security camera at the high altitude W. L. Eccles Observatory (9600 ft above sea level) recorded a movie of the passage of the object to the north.[37][38] Of particular note in this video is the spherical "ghost" image slightly trailing the main object (this is likely a lens reflection of the intense fireball), and the

Meteoroid 6

bright fireball explosion associated with the breakup of a substantial fraction of the object. An object trail can beseen to continue northward after the bright fireball event. The shock from the final breakup triggered sevenseismological stations in northern Utah; a timing fit to the seismic data yielded a terminal location of the object at40.286 N, -113.191 W, altitude 27 km.[39] This is above the Dugway Proving Grounds, a closed Army testing base.

HistoryAlthough meteors have been known since ancient times, they were not known to be an astronomical phenomenonuntil early in the 19th century. Prior to that, they were seen in the West as an atmospheric phenomenon, likelightning, and were not connected with strange stories of rocks falling from the sky. Thomas Jefferson wrote"I would more easily believe that (a) Yankee professor would lie than that stones would fall from heaven."[40] Hewas referring to Yale chemistry professor Benjamin Silliman's investigation of an 1807 meteorite that fell in Weston,Connecticut.[40] Silliman believed the meteor had a cosmic origin, but meteors did not attract much attention fromastronomers until the spectacular meteor storm of November 1833.[41] People all across the eastern United Statessaw thousands of meteors, radiating from a single point in the sky. Astute observers noticed that the radiant, as thepoint is now called, moved with the stars, staying in the constellation Leo.[42]

The astronomer Denison Olmsted made an extensive study of this storm, and concluded it had a cosmic origin. Afterreviewing historical records, Heinrich Wilhelm Matthias Olbers predicted the storm's return in 1867, which drew theattention of other astronomers to the phenomenon. Hubert A. Newton's more thorough historical work led to arefined prediction of 1866, which proved to be correct.[41] With Giovanni Schiaparelli's success in connecting theLeonids (as they are now called) with comet Tempel-Tuttle, the cosmic origin of meteors was now firmlyestablished. Still, they remain an atmospheric phenomenon, and retain their name "meteor" from the Greek word for"atmospheric".[43]

Gallery

Orionid Orionid Two Orionidsand Milky Way

Multi-coloredOrionid

Orionid The brightest meteor, a fireball,leaves a smoky, persistent traildrifting in high-altitude winds,which is seen at the right-hand

side of the image left byOrionid.

Animated illustration ofdifferences between a meteoroid,

meteor and meteorite

A photograph ofa Leonids

meteor showinga meteor, its

afterglow, andits wake

Meteoroid 7

A fireball seen over the desert ofCentral Australia. Although thisoccurred during the Lyrids, its

North-East entry angle indicatesit is sporadic.

Looking down from theInternational Space Station at ameteor as it passes through the

atmosphere

References[1] Stuart Gary - Survey finds not all meteors the same - ABC Science (http:/ / www. abc. net. au/ science/ articles/ 2011/ 12/ 22/ 3396756.

htm?site=science& topic=latest)[2] Millman P.M. (1961). "A report on meteor terminology". JRASC 55: 265–267. Bibcode 1961JRASC..55..265M.[3] "Glossary International Meteor Organization" (http:/ / www. imo. net/ glossary). Imo.net. 2008-11-18. . Retrieved 2011-09-16.[4] Beech, M.; Steel, D. I. (September 1995). "On the Definition of the Term Meteoroid". Quarterly Journal of the Royal Astronomical Society

36 (3): 281–284. Bibcode 1995QJRAS..36..281B.)[5] Rubin, A.E.; Grossman, J.N. (January 2010). "Meteorite and meteoroid: New comprehensive definitions". Meteoritics & Planetary Science

45 (1): 114–122. Bibcode 2010M&PS...45..114R. doi:10.1111/j.1945-5100.2009.01009.x.)[6] Povenmire, H. PHYSICAL DYNAMICS OF THE UPSILON PEGASID FIREBLL – EUROPEAN NETWORK 190882A (http:/ / www. lpi.

usra. edu/ meetings/ lpsc2000/ pdf/ 1183. pdf). Florida Institute of Technology[7] "Report on Orbital Debris" (http:/ / hdl. handle. net/ 2060/ 19900003319). NASA. NASA Technical Reports Server. . Retrieved 1 September

2012.[8] Philip J. Erickson. "Millstone Hill UHF Meteor Observations: Preliminary Results" (http:/ / www. haystack. mit. edu/ ~pje/ meteors/ ). .[9] Williams, David R. (2004-09-01). "Earth Fact Sheet" (http:/ / nssdc. gsfc. nasa. gov/ planetary/ factsheet/ earthfact. html). NASA. . Retrieved

2010-08-09.[10] "Diagram 2: the orbit of the Peekskill meteorite along with the orbits derived for several other meteorite falls" (http:/ / uregina. ca/ ~astro/

mb_5. html). Uregina.ca. . Retrieved 2011-09-16.[11] "MeteorObs Explanations and Definitions (states IAU definition of a fireball)" (http:/ / www. meteorobs. org/ maillist/ msg13871. html).

Meteorobs.org. 1999-07-09. . Retrieved 2011-09-16.[12] "International Meteor Organization - Fireball Observations" (http:/ / www. imo. net/ fireball). Imo.net. 2004-10-12. . Retrieved 2011-09-16.[13] "Fireball Report: 4589 records found between 2011-01-01 and 2011-12-31" (http:/ / www. amsmeteors. org/ fireball2/ public.

php?start_date=2011-01-01& end_date=2011-12-31& submit=Find+ Reports). American Meteor Society. . Retrieved 2012-04-24.[14] http:/ / www. myetymology. com (http:/ / www. myetymology. com/ english/ bolide. html)[15] Belton, MJS (2004). Mitigation of hazardous comets and asteroids (http:/ / books. google. com/ ?id=Dw0A7T0fy6AC). Cambridge

University Press. ISBN 0-521-82764-7. .:156[16] "usgs.gov - What is a Bolide?" (http:/ / woodshole. er. usgs. gov/ epubs/ bolide/ introduction. html). Woodshole.er.usgs.gov. . Retrieved

2011-09-16.[17] Adushkin, Vitaly (2008). Catastrophic events caused by cosmic objects (http:/ / books. google. com/ ?id=3Hd8Lw1hExUC). Springer.

ISBN 1-4020-6451-9. .:133[18][18] The Oxford Illustrated Dictionary. 1976. Second Edition. Oxford University Press. page 533[19] "Climate change: A cosmic connection" (http:/ / www. nature. com/ nature/ journal/ v443/ n7108/ full/ 443141a. html). Nature (journal). 14

September 2006. . Retrieved 2009-05-05.[20] Burdick, Alan (2002). "Psst! Sounds like a meteor: in the debate about whether or not meteors make noise, skeptics have had the upper hand

until now" (http:/ / findarticles. com/ p/ articles/ mi_m1134/ is_6_111/ ai_87854873/ pg_1). Natural History. .[21] Vaivads, Andris (2002). "Auroral Sounds" (https:/ / sites. google. com/ site/ auroralsound/ ). . Retrieved 2011-02-27.[22] "Auroral Acoustics" (http:/ / www. acoustics. hut. fi/ projects/ aurora/ index. html). Laboratory of Acoustics and Audio Signal Processing,

Helsinki University of Technology. . Retrieved 2011-02-17.[23] Silverman, S.M.; T.F. Tuan (1973). "Auroral Audibility". Advance in Geophysics 16: 155–259. doi:10.1016/S0065-2687(08)60352-0.[24] Keay, Colin S.L. (1990). "Chant, C.A. and the Mystery of Auroral Sounds". Journal of the Royal Astronomical Society of Canada 84:

373–382. Bibcode 1990JRASC..84..373K.[25] "Sound of shooting stars" (http:/ / news. bbc. co. uk/ 2/ hi/ science/ nature/ 321596. stm). BBC News. 1999-04-21. . Retrieved 2011-09-16.[26] "Listening to Leonids" (http:/ / science. nasa. gov/ headlines/ y2001/ ast26nov_1. htm). Science.nasa.gov. . Retrieved 2011-09-16.

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[27] "Hearing Sensations in Electric Fields" (http:/ / homepages. tesco. net/ ~John. Dawes2/ extract. htm). Homepages.tesco.net. . Retrieved2011-09-16.

[28] "Human auditory system response to Modulated electromagnetic energy" (http:/ / homepages. tesco. net/ ~John. Dawes2/ frey. htm).Homepages.tesco.net. . Retrieved 2011-09-16.

[29] "Human Perception of Illumination with Pulsed Ultrahigh-Frequency Electromagnetic Energy" (http:/ / homepages. tesco. net/ ~John.Dawes2/ frey2. htm). Homepages.tesco.net. . Retrieved 2011-09-16.

[30] "The flux of small near-Earth objects colliding with the Earth" (http:/ / www. nature. com/ nature/ journal/ v420/ n6913/ full/ nature01238.html). Nature (journal). 21 September 2002. . Retrieved 2009-06-22.

[31] "Spring is Fireball Season" (http:/ / science. nasa. gov/ science-news/ science-at-nasa/ 2011/ 31mar_springfireballs/ ). Science.nasa.gov. .Retrieved 2011-09-16.

[32] "What's Hitting Earth?" (http:/ / science. nasa. gov/ science-news/ science-at-nasa/ 2011/ 01mar_meteornetwork/ ). Science.nasa.gov.2011-03-01. . Retrieved 2011-09-16.

[33] The Peekskill Meteorite [[October 9 (http:/ / aquarid. physics. uwo. ca/ ~pbrown/ Videos/ peekskill. htm)], 1992 Videos][34][34] Brown, P. et al., 1994. Nature, 367, 6524 - 626[35][35] "Meteoritical Bull", by Wlotzka, F. published in "Meteoritics", # 75, 28, (5), 692, 1994[36] Don Yeomans, Paul Chodas and Steve Chesley (October 23, 2009). "Asteroid Impactor Reported over Indonesia" (http:/ / neo. jpl. nasa.

gov/ news/ news165. html). NASA/JPL Near-Earth Object Program Office. . Retrieved 2009-10-30.[37] "W.L Eccles Observatory, Nov 18 2009, North Camera" (http:/ / www. youtube. com/ watch?v=XiL1UGbHXSI). Youtube.com.

2009-11-18. . Retrieved 2011-09-16.[38] "W.L Eccles Observatory, November 18, 2009, North West Camera" (http:/ / www. youtube. com/ watch?v=kE109bKQESw).

Youtube.com. 2009-11-18. . Retrieved 2011-09-16.[39][39] Patrick Wiggins, private communication[40] amsmeteors.org (http:/ / www. amsmeteors. org/ about. html#early) The Early Years of Meteor Observations in the USA[41] meteorshowersonline.com (http:/ / meteorshowersonline. com/ showers/ leonidhis. html) The Leonids and the Birth of Meteor Astronomy[42] Hitchcock, Prof. Edward (January 1834). "On the Meteors of Nov. 13, 1833" (http:/ / books. google. com/ ?id=HjcPAAAAYAAJ&

pg=PA407#PPA405,M1). The American Journal of Science and Arts XXV. .[43] astroprofspage.com (http:/ / astroprofspage. com/ archives/ 318) October's Orionid Meteors

External links• Astronomers spot meteor streaking across central Ontario sky (http:/ / www. cbc. ca/ cp/ science/ 080307/

g030708A. html) - CBC News March 7, 2008• Meteoroids Page (http:/ / solarsystem. nasa. gov/ planets/ profile. cfm?Object=Meteors) at NASA's Solar System

Exploration (http:/ / solarsystem. nasa. gov)• International Meteor Organization fireball page (http:/ / www. imo. net/ fireball)• British Astronomical Society fireball page (http:/ / britastro. org/ baa/ content/ view/ 90/ 121/ )• Live Meteor Screen (http:/ / www. meteorscan. com/ )• Meteor Showers and Viewing Tips (http:/ / stardate. org/ nightsky/ meteors/ )• Meteor shower predictions (http:/ / astroclub. tau. ac. il/ ephem/ Meteors/ )• A Goddard Space Flight Center Science Question of the Week where the answer mentions that a fireball will cast

a shadow. (http:/ / www. gsfc. nasa. gov/ scienceques2005/ 20060406. htm)• Society for Popular Astronomy - Meteor Section (http:/ / www. popastro. com/ sections/ meteor. htm)• Video - Meteor brilliantly lights up sky - and breaks into pieces - Canada - Times Online - November 24, 2008

(http:/ / www. timesonline. co. uk/ tol/ news/ uk/ science/ article5221569. ece)• How meteor showers were linked to comets (http:/ / www. cambridge. org/ catalogue/ catalogue.

asp?isbn=9780521853491& ss=exc)• Science and History of the Perseid Meteor Shower (http:/ / www. space. com/ scienceastronomy/

perseid_history_020806. html)• -A History of Meteors and Other Atmospheric Phenomena (http:/ / www. fireballhistory. com)• how stuff works : atmospheric penetration of meteorites (http:/ / science. howstuffworks. com/ question486. htm)

Article Sources and Contributors 9

Article Sources and ContributorsMeteoroid  Source: http://en.wikipedia.org/w/index.php?oldid=530688771  Contributors: 12dstring, 16@r, 2002:4451:AE0B:1234:225:FF:FEF6:A076,2602:304:100A:3069:A9D9:2A1B:A806:7A90, 77Mike77, 84user, 97chabs, @pple, A More Perfect Onion, ABCD, Aaron north, Ac103051, Acossairt2009, AdamBMorgan, Adaviel, Addshore,Aidarzver, Alansohn, Albertiam, Alecmalenfant, AlexiusHoratius, Allecher, Altaïr, AndrewWTaylor, Anetode, Annddy, Anonymous101, Antandrus, Antoni Barau, Antonio Lopez,Anyeverybody, Arab Dog, ArthurDuhurst, Asd123cumsack, Astronomystars, Autobogg, Awsomezacste, BRUTE, BaconDealer, Banaticus, Bandreus, Basilicofresco, Bebenko, Beefyt, Beland,Bennoro, Bentogoa, Bergsten, Billrush, Bissinger, Bjankuloski06en, Bkonrad, Blakers124, BlueDevil, BlytheG, Bobo192, Bongwarrior, Borgx, Branson03, Brendenkithe81, Brumski, Btafreshi,C m handler, CO, CWenger, CWii, Cactus.man, Calabe1992, Can't sleep, clown will eat me, CanadianLinuxUser, CapPixel, Captin Shmit, Chewie, Clarince63, Clementng23, Cm205, ColdCase,Cole size, Colonies Chris, Comet Tuttle, CommonsDelinker, Cookiesinmytummy1155, Crazy Cool630, Creation7689, Crhipkins, Crunkcar, Cube-X, Cupivistine Noscere?, Curb Chain, Cxz111,D, D. Recorder, DARTH SIDIOUS 2, DMPalmer, Dally Horton, Dan Wylie-Sears 2, Daniel J. 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Image Sources, Licenses and ContributorsFile:Leonid Meteor.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Leonid_Meteor.jpg  License: Creative Commons Attribution 3.0  Contributors: NavicoreFile:Esquel pallasite partial slice.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Esquel_pallasite_partial_slice.jpg  License: Creative Commons Attribution-Sharealike 2.0 Contributors: M. Rehemtulla for the QUOI Media Group.File:Meteor burst.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Meteor_burst.jpg  License: Public Domain  Contributors: NASA Ames Research Center/S. Molau and P.JenniskensFile:Comet holmes and Geminid121307.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Comet_holmes_and_Geminid121307.jpg  License: Creative CommonsAttribution-Sharealike 3.0,2.5,2.0,1.0  Contributors: Brocken Inaglory Original uploader was Brocken InagloryFile:Bolide.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Bolide.jpg  License: Public Domain  Contributors: Boliden-Phasen.jpg: Thomas Grau derivative work: Basilicofresco(msg)File:Two tektites.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Two_tektites.JPG  License: Creative Commons Attribution-ShareAlike 3.0 Unported  Contributors: BrockenInagloryImage:Orionid meteor.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Orionid_meteor.jpg  License: Creative Commons Attribution-Sharealike 3.0,2.5,2.0,1.0  Contributors: -Image:Orionid meteor1.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Orionid_meteor1.jpg  License: Creative Commons Attribution-Sharealike 3.0,2.5,2.0,1.0  Contributors: -Image:Two orionids and milky way.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Two_orionids_and_milky_way.jpg  License: Creative Commons Attribution-Sharealike3.0,2.5,2.0,1.0  Contributors: -Image:Multi colored Orionid.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Multi_colored_Orionid.jpg  License: Free Art License  Contributors: Brocken InagloryImage:Orionids and Orion.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Orionids_and_Orion.jpg  License: Creative Commons Attribution-Sharealike 3.0,2.5,2.0,1.0 Contributors: -Image:Meteor trail.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Meteor_trail.jpg  License: Creative Commons Attribution-Sharealike 3.0,2.5,2.0,1.0  Contributors: -Image:Meteoroid meteor meteorite.gif  Source: http://en.wikipedia.org/w/index.php?title=File:Meteoroid_meteor_meteorite.gif  License: Creative Commons Attribution-Sharealike 3.0 Contributors: AnynobodyImage:Leonid Meteor.jpg  Source: http://en.wikipedia.org/w/index.php?title=File:Leonid_Meteor.jpg  License: Creative Commons Attribution 3.0  Contributors: NavicoreImage:Meteor Bolide.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Meteor_Bolide.JPG  License: Creative Commons Attribution-Sharealike 3.0  Contributors: C m handlerImage:Looking Down on a Shooting Star.JPG  Source: http://en.wikipedia.org/w/index.php?title=File:Looking_Down_on_a_Shooting_Star.JPG  License: Public Domain  Contributors: ISSExpedition 28 crew

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