After the Voyager encounters with Saturn in the early 80’s, the scientific consensus was that Saturn’s ring system was largely a transient phenomenon. Maybe a hundred million years old, and probably the result of a comet-satellite collision. The sense was that the rings would eventually fade, though likely on a scale of tens to hundreds of million years.
So I read Wednesday’s Cassini news release with interest. “Not so fast,” the ring scientists say. They can date the material in the ring and some of it is as old as the solar system itself.
“The evidence is consistent with the picture that Saturn has had rings all through its history,” said (Larry) Esposito of the University of Colorado‘s Laboratory for Atmospheric and Space Physics. “We see extensive, rapid recycling of ring material, in which moons are continually shattered into ring particles, which then gather together and re-form moons.”
One of the more helpful ways to study the rings is to measure the amount of starlight blocked from the spacecraft’s view. By doing this, researchers have found clumps of material ranging in size from about thirty years to six miles. These objects, many of which are translucent, were nicknamed “Mittens” and “Fluffy” by scientists, who believe them to be relatively short-lived. They seem to break up and reform as they are jostled by one another.