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.

2004 December 17
See Explanation.  Clicking on the picture will download
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Prometheus and the Rings of Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

Explanation: In Greek Mythology, Prometheus was known for stealing fire from the gods. Ironically, in a story for more modern times Prometheus may also become known for stealing, but this time for stealing icy particles from Saturn's rings. This eerie close-up from the Cassini spacecraft shows the 100 kilometer-long Saturnian moon Prometheus orbiting near the inner edge of Saturn's F ring. The dramatic view clearly resolves the potato-shaped moon and multiple strands of the narrow F ring. It also reveals a faint strand of material connecting Prometheus with the rings. One possibility is that the tiny moon's gravity is indeed drawing off particles from the rings and is influencing the formation of the gaps and kinks seen in the ring structure.

Tomorrow's picture: ice line

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