Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2006 February 8
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The Great Basin on Tethys
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: Some moons wouldn't survive the collision. Tethys, one of Saturn's larger moons at about 1000 kilometers in diameter, survived the collision, but sports today the expansive impact crater Odysseus. Sometimes called the Great Basin, Odysseus occurs on the leading hemisphere of Tethys and shows its great age by the relative amount of smaller craters that occur inside its towering walls. The density of Tethys is similar to water-ice. The above digitally enhanced image was captured late last year by the robot Cassini spacecraft in orbit around Saturn as it swooped past the giant ice ball.

Tomorrow's picture: NGC 1309 and friends

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