Saturn's Rings: New Explanation for a Spectacular Sight

"Saturn's Rings May Be Remains of Ripped-Apart Moon"
Mike Wall, Space.com (December 12, 2010)

"Saturn's famous rings are the last remaining shards of a huge moon the planet tore apart long ago, a new study suggests.

"A moon about the size of Titan — Saturn's largest satellite — likely spiraled into the giant planet about 4.5 billion years ago, scientists think. As it made its way, Saturn's powerful gravity stripped off the doomed moon's icy outer layers, thus spawning the planet's magnificent rings, according to the research. [Gallery: The Rings and Moons of Saturn]

"And, in death, this lost moon may have given other satellites life, the study suggests. Over the eons, much of the ring material has glommed together, forming the icy inner moons of Saturn.

" 'This model implies that the rings are primordial, that they formed from the same processes that left Titan as Saturn's only large satellite,' said study author Robin Canup of the Southwest Research Institute in Boulder, Colo. "'And it's the only self-consistent explanation for the ice-rich inner satellites.'..."

Part of the puzzle of Saturn's rings is that they're mostly water ice. Which is odd - since mathematical models which do a good job of explaining how the outer planets formed, and observations, show that material available was ice and rock.

The new model involves a moon like Titan, with a rocky core and water ice near the surface, in a decaying orbit around Saturn. The rocky core eventually fell in, but on the way tidal forces stripped water ice off - part of which formed the rings. Some of the rest, again according to this new model, clumped together to form Saturn's inner satellites.

The new model passes the Occam's Razor test:

"..."The other theories have the rings forming from a sort of random event," Canup said. 'This model reduces the number of things that have to happen, which I think makes it more probable.'..."

"Occam's Razor?" Essentially, it's that a simpler solution is more likely to be true. ("THEY are After McCain: Conspiracy Theories, Anyone?," Another War-on-Terror Blog (April 4, 2008))