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IMAGES OF IMPACT CRATER CHAINS ON CALLISTO
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A portion of a chain of impact craters on Jupiter's moon Callisto is
seen in this image taken by the Galileo spacecraft on November 4, 1996.
This crater chain on Callisto is believed to result from the impact of
a split object, similar to the fragments of Comet Shoemaker- Levy 9
which smashed into Jupiter's atmosphere in July of 1994.
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Impact Crater Chain On Callisto
Galileo Image
November 4, 1996
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This high-
resolution view, taken by Galileo's solid state imaging television
camera during its third orbit around Jupiter, is of Callisto's northern
hemisphere at 35 degrees north, 46 degrees west, and covers an area of
about eight miles (13 kilometers) across. The smallest visible crater
is about 140 yards (130 meters) across. The image was taken at a range
of 974 miles (1,567 kilometers).
On a global scale, Callisto is heavily cratered, indicating the great
age of its surface. At the scale of this image, it was anticipated that
the surface would be heavily cratered as well; however, there is a
surprising lack of small craters, suggesting that one or more processes
have obliterated these and other small-scale features. For example,
downslope movement of ice-rich debris could bury small craters. The
bright slopes visible in this picture represent places where downslope
movement has taken place, exposing fresh ice surfaces.
The Jet Propulsion Laboratory manages the Galileo mission for NASA's
Office of Space Science, Washington, DC.
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Gipul Catena Crater Chain On Callisto
Voyager 1 Image
March 1979
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This Voyager 1 image of Gipul Catena, on Callisto, was obtained in March,
1979. Seven other crater chains have been mapped on Callisto to date. The
discovery of Shoemaker-Levy 9 in 1993 solved the mystery of the origin of
these chains. These chains formed when the fragments of comets split by
Jovian tides hit the large Jovian satellites. Crater size and chain
morphologies are being studied to determine the masses of comet fragments
and nuclei and to assess models for the break up of comet nuclei. Gipul
Catena is 620 km long and located near Callisto's north pole.
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Impact Crater Chain On Callisto
Voyager Image
Photo Credit:
Paul Schenk/Lunar & Planetary Institute
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This image taken by the Voyager spacecraft of an unnamed crater chain is one
of the longest of 12 or so such chains on Callisto, one of Jupiter's 4
planet-sized satellites. It is 360 kilometers long and the largest
individual crater is approximately 24 kilometers across. Jay Melosh and Paul
Schenk, reporting in the October 21, 1993, issue of Nature, propose that
these and similar mysterious crater chains on Ganymede and Callisto probably
formed from the past impact of comets tidally disrupted during close passage
of Jupiter, similar to comet Shoemaker-Levy 9 which will strike Jupiter in
July, 1994. They conclude that tidal splitting of comets is relatively
common and can occur roughly once per century.
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