Difference between revisions 1211316 and 1211334 on enwikiversity

[[Image:Chain of impact craters on Ganymede.jpg|thumb|right|200px|The image shows a chain of craters on Ganymede. Credit: Galileo Project, Brown University, JPL, NASA.]]
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A '''crater''' may be any large, roughly circular, depression or hole in or beneath the rocky surface of a rocky object.
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[[Image:Yucatan chix crater.jpg|thumb|right|120px|The Chicxulub impact crater is outlined. Credit: NASA/JPL-Caltech, modified by [[w:User:David Fuchs|David Fuchs]].]]
[[Image:Aurora Borealis.jpg|thumb|right|200px|Aurora Borealis is photographed by NASA astronaut Donald R. Pettit. Credit: NASA.]]

[[Image:392171ab.eps.2.gif|thumb|center|300px|The figure shows a reconstruction of the North American (Laurentian) and Eurasian plate positions in the Northern Hemisphere of Earth 214 Myr ago (Mercator projection), with the locations of the five impact structures marked. Credit: John G. Spray, Simon P. Kelley & David B. Rowley.]]⏎
In the image at left is an aerial view of the Barringer Meteor Crater about 69 km east of Flagstaff, Arizona USA. Although similar to the aerial view of the Soudan crater, the Barringer Meteor Crater appears angular at the farthest ends rather than round.

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At right is a natural color photograph of the Aurora Borealis or northern lights and the Manicouagan Impact Crater reservoir (foreground) in Quebec, Canada. They are featured in this photograph taken by astronaut Donald R. Pettit, Expedition Six NASA ISS science officer, on board the International Space Station (ISS).
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"Collisions by fragmented objects result in multiple impacts that can lead to the formation of linear crater chains, or catenae, on planetary surfaces<sup>2</sup>."<ref name=Spray>{{ cite journal
|author=John G. Spray, Simon P. Kelley & David B. Rowley
|title=Evidence for a late Triassic multiple impact event on Earth
|journal=Nature
|month=12 March
|year=1998
|volume=392
|issue=6672
|pages=171-3
|url=http://www.nature.com/nature/journal/v392/n6672/abs/392171a0.html
|arxiv=
|bibcode=
|doi=10.1038/32397
|pmid=
|accessdate=2014-08-06 }}</ref>

"Five terrestrial impact structures have been found to possess comparable ages (214 Myr), coincident with the Norian stage of the Triassic period. These craters are Rochechouart (France), Manicouagan and Saint Martin (Canada), Obolon' (Ukraine) and Red Wing (USA). When these impact structures are plotted on a tectonic reconstruction of the North American and Eurasian plates for 214 Myr before present, the three largest structures (Rochechouart, Manicouagan and Saint Martin) are co-latitudinal at 22.8° (within 1.2°, 110 km), and span 43.5° of palaeolongitude. These structures may thus represent the remains of a crater chain at least 4,462 km long. The Obolon' and Red Wing craters, on the other hand, lie on great circles of identical declination with Rochechouart and Saint Martin, respectively. [...] the five impact structures were [likely] formed at the same time (within hours) during a multiple impact event caused by a fragmented comet or asteroid colliding with Earth."<ref name=Spray/>
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=Moon=
[[Image:Carte Lune mers crateres.jpg|thumb|right|200px|The image is a map in French of the Moon showing the maria and the major craters. Credit: additions made to Lune22h27septembre2004.jpg created by Yves under GFDL by Eric Gaba ([[commons:User:Sting|Sting]] - fr:Sting).]]
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[[Category:Planetary Science]]
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