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This is an image showing a linear string of craters which may have been created when a broken comet such as SL-9 struck the surface.
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NASA/NSSDC and the Space Telescope Science Institute

Craterchains

Observations such as these now suggest that moons of Jupiter have been struck in the past by strings of broken comet material such as that of comet SL-9. The craterchain shown here is found on Jupiter's moon Callisto.

Other craterchains that have been found are:

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Comet Hale-Bopp

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The Jupiter family of comets

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The trajectory of Comet Shoemaker-Levy 9 over time

Mathematical theory suggests that comet Shoemaker-Levy 9 was likely a short-period comet which was captured into orbit around Jupiter in 1929 and began to execute the trajectory plotted in this diagram....more

The Comet Coma

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF