Editing Meteorite (section)

==Fall phenomena==
{{Further|Atmospheric entry|Meteorite fall}}

Most meteoroids disintegrate when entering the Earth's atmosphere. Usually, five to ten a year are observed to fall and are subsequently recovered and made known to scientists.<ref>{{cite web| url = http://www.lpi.usra.edu/meteor/metbull.php?sea=%2A&sfor=names&ants=&falls=yes&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=year&categ=All&mblist=All&rect=&phot=&snew=0&pnt=Normal%20table&dr=&page=1| title = Meteoritical Bulletin| access-date = 28 May 2014| archive-date = 22 August 2016| archive-url = https://web.archive.org/web/20160822210851/http://www.lpi.usra.edu/meteor/metbull.php?sea=%2A&sfor=names&ants=&falls=yes&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=year&categ=All&mblist=All&rect=&phot=&snew=0&pnt=Normal%20table&dr=&page=1| url-status = live}}</ref> Few meteorites are large enough to create large [[impact crater]]s. Instead, they typically arrive at the surface at their [[terminal velocity]] and, at most, create a small pit.
[[File:Oriented Taza Meteorite.jpg|thumb|right|NWA 859 iron meteorite showing effects of atmospheric ablation]]
[[File:Novato Meteorite Impact Pit.jpg|thumb|right|The impact pit made by a 61.9-gram [[Novato meteorite]] when it hit the roof of a house on 17 October 2012.]]
[[File:Flensburg meteorit carsten jonas.jpg|thumb|Meteorite fallen near [[Flensburg]] in 2019.]]

Large meteoroids may strike the earth with a significant fraction of their [[escape velocity]] (second cosmic velocity), leaving behind a [[hypervelocity]] impact crater. The kind of crater will depend on the size, composition, degree of fragmentation, and incoming angle of the impactor. The force of such collisions has the potential to cause widespread destruction.<ref>{{cite report |first1=Clark R. |last1=Chapman |first2=Daniel D. |last2=Durda |first3=Robert E. |last3=Gold |title=The Comet/Asteroid Impact Hazard: A Systems Approach |year=2001 |url=http://www.internationalspace.com/pdf/NEOwp_Chapman-Durda-Gold.pdf |archive-url=https://web.archive.org/web/20160304002442/http://www.internationalspace.com/pdf/NEOwp_Chapman-Durda-Gold.pdf |archive-date=4 March 2016 |publisher=Johns Hopkins University Applied Physics Laboratory |via=International Space Consultants}}</ref><ref>[http://www.lpl.arizona.edu/impacteffects/ Make your own impact at the University of Arizona] {{Webarchive|url=https://web.archive.org/web/20100505045106/http://www.lpl.arizona.edu/impacteffects/ |date=5 May 2010 }}. Lpl.arizona.edu. Retrieved on 17 December 2011.</ref> The most frequent hypervelocity cratering events on the Earth are caused by iron meteoroids, which are most easily able to transit the atmosphere intact. Examples of craters caused by iron meteoroids include [[Barringer Meteor Crater]], [[Odessa Meteor Crater]], [[Wabar craters]], and [[Wolfe Creek crater]]; iron meteorites are found in association with all of these craters. In contrast, even relatively large stony or icy bodies such as small [[comet]]s or [[asteroid]]s, up to millions of tons, are disrupted in the atmosphere, and do not make impact craters.<ref>{{cite journal |last1=Bland|first1=P.A. |last2= Artemieva |year=2006 |first2=Natalya A.|author2-link=Natalia Artemieva |title=The rate of small impacts on Earth |journal= Meteoritics and Planetary Science |volume=41 |issue=4 |pages=607–631 |bibcode=2006M&PS...41..607B |doi=10.1111/j.1945-5100.2006.tb00485.x|s2cid=54627116 |doi-access=free }}</ref> Although such disruption events are uncommon, they can cause a considerable concussion to occur; the famed [[Tunguska event]] probably resulted from such an incident. Very large stony objects, hundreds of meters in diameter or more, weighing tens of millions of [[ton]]s or more, can reach the surface and cause large craters but are very rare. Such events are generally so energetic that the impactor is completely destroyed, leaving no meteorites. (The first example of a stony meteorite found in association with a large impact crater, the [[Morokweng impact structure]] in South Africa, was reported in May 2006.)<ref>{{cite journal |last1=Maier |first1=W.D.
|first2=M. A. G. |last2=Andreoli |first3=I. |last3=McDonald |first4=M. D. |last4=Higgins |first5=A. J.|last5=Boyce |first6=A. |last6=Shukolyukov |first7=G. W. |last7=Lugmair |first8=L. D. |last8=Ashwal |first9=P. |last9=Gräser |title=Discovery of a 25-cm asteroid clast in the giant Morokweng impact crater, South Africa |journal=Nature |volume=441 |pages=203–206|year=2006 |doi=10.1038/nature04751 |pmid=16688173 |issue=7090|bibcode = 2006Natur.441..203M |display-authors=9 |last10=Ripley |first10=E. M. |last11=Hart |first11=R. J. |s2cid=4373614
}}</ref>

Several phenomena are well documented during witnessed meteorite falls too small to produce hypervelocity craters.<ref>{{cite book 
|last1=Sears |first1=D. W. |year=1978|title=The Nature and Origin of Meteorites |publisher=Oxford Univ. Press |location=New York |isbn=978-0-85274-374-4}}</ref> The fireball that occurs as the meteoroid passes through the atmosphere can appear to be very bright, rivaling the sun in intensity, although most are far dimmer and may not even be noticed during the daytime. Various colors have been reported, including yellow, green, and red. Flashes and bursts of light can occur as the object breaks up. Explosions, detonations, and rumblings are often heard during meteorite falls, which can be caused by [[sonic boom]]s as well as [[shock wave]]s resulting from major fragmentation events. These sounds can be heard over wide areas, with a radius of a hundred or more kilometers. Whistling and hissing sounds are also sometimes heard but are poorly understood. Following the passage of the fireball, it is not unusual for a dust trail to linger in the atmosphere for several minutes.

As meteoroids are heated during [[atmospheric entry]], their surfaces melt and experience [[ablation]]. They can be sculpted into various shapes during this process, sometimes resulting in shallow thumbprint-like indentations on their surfaces called [[wikt:regmaglypt|regmaglypt]]s. If the meteoroid maintains a fixed orientation for some time, without tumbling, it may develop a conical "nose cone" or "heat shield" shape. As it decelerates, eventually the molten [[surface layer]] solidifies into a thin fusion crust, which on most meteorites is black (on some [[achondrite]]s, the fusion crust may be very light-colored). On stony meteorites, the [[heat-affected zone]] is at most a few mm deep; in iron meteorites, which are more thermally conductive, the structure of the metal may be affected by heat up to {{Convert|1|cm}} below the surface. Reports vary; some meteorites are reported to be "burning hot to the touch" upon landing, while others are alleged to have been cold enough to condense water and form a frost.<ref>[http://www.lpi.usra.edu/meteor/metbull.php?code=16885 Fall of the Muzaffarpur iron meteorite] {{Webarchive|url=https://web.archive.org/web/20210113072108/https://www.lpi.usra.edu/meteor/metbull.php?code=16885 |date=13 January 2021 }}. Lpi.usra.edu (11 April 1964). Retrieved on 17 December 2011.</ref><ref>[http://www.lpi.usra.edu/meteor/metbull.php?code=15486 Fall of the Menziswyl stone] {{Webarchive|url=https://web.archive.org/web/20210113072017/https://www.lpi.usra.edu/meteor/metbull.php?code=15486 |date=13 January 2021 }}. Lpi.usra.edu (29 July 2006). Retrieved on 17 December 2011.</ref><ref>[http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1934PA.....42...59W&defaultprint=YES&filetype=.pdf The Temperature of Meteorites] {{Webarchive|url=https://web.archive.org/web/20210427233755/http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1934PA.....42...59W&defaultprint=YES&filetype=.pdf |date=27 April 2021 }}. articles.adsabs.harvard.edu (February 1934). Retrieved on 28 May 2014.</ref>

Meteoroids that disintegrate in the atmosphere may fall as meteorite showers, which can range from only a few up to thousands of separate individuals. The area over which a meteorite shower falls is known as its [[strewn field]]. Strewn fields are commonly [[ellipse|elliptical]] in shape, with the major axis parallel to the direction of flight. In most cases, the largest meteorites in a shower are found farthest down-range in the strewn field.<ref>{{Cite book|last1=Norton|first1=O. Richard|url=https://books.google.com/books?id=OMgDhc8d7v4C&q=meteorite+size+distribution+%22strewn+field%22&pg=PA183|title=Field Guide to Meteors and Meteorites|last2=Chitwood|first2=Lawrence|date=2008-05-25|publisher=Springer Science & Business Media|isbn=978-1-84800-157-2|page=184|language=en}}</ref>