Printed from: PhysLink.com; http://www.physlink.com/News/Index.cfm?ID=317
Original publication date: Sunday January 8, 2006.
Hubble Finds Additional Moons and Rings Around Uranus
Since dust orbiting Uranus is expected to be depleted by spiraling away, the planet's rings must be continually replenished with fresh material. 'The new discoveries demonstrate that Uranus has a youthful and dynamic system of rings and moons,' said Mark Showalter of the SETI Institute, Mountainview, Calif.
Showalter and Jack Lissauer of NASA's Ames Research Center propose that the outermost ring is replenished by a 12-mile-wide newly discovered moon, named Mab, which they first observed in 2003.
Meteoroid impacts continually blast dust off the surface of Mab. The dust then spreads out into a ring around Uranus. Mab's ring receives a fresh infusion of dust from each impact. Nature keeps the ring supplied with new dust while older dust spirals away or bangs back into the moon.
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