Saturn recycles its rings, creates new ones

Recent thinking suggests that Saturn’s rings are billions of years old, and that Saturn recycles its rings and even creates new ones.

In the 1970s, Voyager 1 provided the first close-up views of Saturn’s rings. Astronomers determined then that the rings were a temporary feature, formed about 100 million years ago when a moon of Saturn was struck by an asteroid. But evidence from the more recent Cassini mission suggests the rings are much older, as old as the solar system itself.

EarthSky spoke with Larry Esposito, principal investigator of the Ultraviolet Imaging Spectrograph on the Cassini mission to Saturn.

Larry Esposito: Now, on Cassini, with even closer views, we see even more rapid processes inconsistent with a single moment when all the rings were created. So there’s a process of continuing creation going on in the rings. When the rings were made by the shattering of a small moon, the pieces can come back together, and the ring can make a moon again. And this recycling, very efficiently uses the ring material so that they can last for the age of the solar system.

Esposito said that, even as we look out at Saturn today, new rings are being formed.

Larry Esposito: In fact there’s structure in the rings that we see today that was not seen 25 years ago by Voyager. Over billions of years, the whole ring system may be created, and recreated.

Our thanks to:
Larry Esposito
Principal Investigator
Ultraviolet Imaging Spectrograph
Cassini Mission to Saturn