I think the youthful rings (see next post) must be made and destroyed all the time, but the mass is considerable, which suggests either an external source (capture), an internal source (shed by Saturn), or recycling (10 million unseen moonlets have been suggested).
SaturnThey range in size from a centimeter or so to several meters. A few kilometer-sized objects are also likely.
by Bill Arnett
The Nine Planets
Saturn's rings are extraordinarily thin: though they're 250,000 km or more in diameter they're less than one kilometer thick. Despite their impressive appearance, there's really very little material in the rings -- if the rings were compressed into a single body it would be no more than 100 km across.
The ring particles seem to be composed primarily of water ice, but they may also include rocky particles with icy coatings.
Voyager confirmed the existence of puzzling radial inhomogeneities in the rings called "spokes" which were first reported by amateur astronomers (left). Their nature remains a mystery, but may have something to do with Saturn's magnetic field...
The origin of the rings of Saturn (and the other jovian planets) is unknown. Though they may have had rings since their formation, the ring systems are not stable and must be regenerated by ongoing processes, perhaps the breakup of larger satellites. The current set of rings may be only a few hundred million years old.Saturn's Rings: FormationThe prevailing theory as to how Saturn's rings were formed comes from the 19th century astronomer Edouard Roche. Roche predicted that if an object such as a moon were to come too close to a large planet such as Saturn, eventually it would be torn apart by tidal forces - the uneven gravitational pull upon an object due to its size.
Adler Planetarium
2005
Under a tidal force, an object experiences a greater gravitational pull on its nearer side than its farther side. If the difference in force is great enough, this can cause a strain which literally breaks an object apart. Scientists now call this limit where an object will be torn apart by tidal forces the Roche Limit.Saturn's rings may be youngWhen the Voyager spacecraft swept past Saturn, they radioed back photos of a complex, very dynamic system of rings -- thousands of rings. Studies of these rings have led some astronomers to wonder if they are really as old as Saturn itself. Two lines of thinking suggest a recent origin:
by William R. Corliss
May-Jun 1985
(1) The rings are composed of both light material (very likely water ice) and dark material (probably rocks and dust). The rocky fragments, according to the prevailing nebular theory, should have condensed early in solar-system history, and then been swept gravitationally into the planet as they were slowed by friction with the uncondensed nebular material. Yet, dark material is still in the rings. (2) The incessant bombardment of the rings by meteorites should have pulverized the rings, sending fragments and vaporized material in all directions. In just 10 million years the rings should have been largely erased. They are still there.
(Cuzzi, Jeffrey N.; "Ringed Planets: Still Mysterious -- II," Sky and Telescope, 69:19, 1985.)
Small Comets and Our Origins
University of Iowa | circa 1999 | Louis A. Frank
Posted on 10/20/2004 2:13:25 AM EDT by SunkenCiv
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