New ring discovered around Saturn |
New ring discovered around Saturn |
Oct 7 2009, 12:25 AM
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Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
QUOTE The newly discovered ring spans from 128 to 207 times the radius of Saturn – or farther – and is 2.4 million kilometres thick. It was found using NASA's Spitzer Space Telescope, which revealed an infrared glow thought to come from sun-warmed dust in a tenuous ring. The discovery was announced on Tuesday at a meeting of the American Astronomical Society's Division of Planetary Sciences in Fajardo, Puerto Rico. "This is a unique planetary ring system, because it's the largest planetary ring in the solar system," team leader Anne Verbiscer of the University of Virginia in Charlottesville told the meeting. The source of the ring's material seems to be Saturn's far-flung moon Phoebe, which orbits the planet at an average distance of 215 times the radius of Saturn. When Phoebe is hit by wayward space rocks, the impacts could generate debris that fills the rings. http://www.newscientist.com/article/dn1792...und-saturn.html |
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Oct 7 2009, 10:13 PM
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Senior Member Group: Moderator Posts: 3241 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
I don't think there is anything special about Phoebe. It just happens to be large enough to throw enough material into space with micrometeorite impacts that its co-orbital ring is visible to Spitzer. I would not be surprised if the other small detritus out in the outer Saturn system (and the other outer planet systems) have similar, but much fainter, rings. Keep in mind that the proposed scenario put out be Verbiscer et al. is akin to what is going on at Janus and Epimetheus, Pallene, Methone and Anthe, Aegaeon, Mab, and Adrastea and Metis.
The reason it doesn't happen on the Moon is that the Moon is massive enough that most impact ejecta re-accretes back onto the Moon. For these little guys, like Phoebe, they are too small to hold on to much of the ejecta from micrometeorite impacts, and dust from these impacts goes into orbit around the parent planet. -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Oct 7 2009, 10:19 PM
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#3
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
Maybe Neptune's large irregular Nereid also has a ring associated with it.
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