Saturn's rings puzzle me

Apparently they puzzle astronomers too.

http://ift.tt/2zbx29l

Quote:

NEW ORLEANS, LOUISIANA—The rings of Saturn seem like permanent fixtures in the solar system, firing the imagination of poets and scientists alike. But observations made this year, in the final months of NASA’s Cassini spacecraft, and reported here at a meeting of the American Geophysical Union (AGU) show they are surprisingly youthful: Until a few hundred million years ago, they did not exist. Saturn acquired its jewels relatively late in life. If any astronomers had gazed at the sky in the time of the dinosaurs, they might have seen a bare and boring Saturn. It was then that some sort of catastrophe struck the gas giant. Perhaps a stray comet or asteroid struck an icy moon, tossing its remnants into orbit. Or maybe the orbits of Saturn’s moons somehow shifted, and the resulting gravitational tug-of-war pulled a moon apart. However it happened, two new lines of evidence from Cassini make it clear that the rings were not around in the early days of the solar system 4.5 billion years ago, as scientists had long believed, says Jeff Cuzzi, a ring specialist at NASA’s Ames Research Center in Mountain View, California. “It rules out the primordial ring story,” Cuzzi says. “That’s what it looks like to me.”

Some of those theories sound ridiculous to me. Particularly the one about somehow the orbits of Saturn's moons shifting and causing a "gravitational tug of war".

A comet colliding with a moon sounds like a good theory to me.

via International Skeptics Forum http://ift.tt/2zc3mJ7