Are Saturn’s rings young or old?

earthsky.org | 9/17/2019 | Deborah Byrd
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Click For Photo: https://en.es-static.us/upl/2019/09/saturn-cassini-300x130.jpg

View larger. | Saturn, via the Cassini spacecraft. Image via NASA/JPL-Caltech/Space Science Institute/Europlanet.

Four decades ago, when I was first learning astronomy, we all assumed that Saturn’s iconic rings had always been there, as old as the solar system itself. We assumed that Saturn formed with its rings, which are vast and glorious, stretching nearly 200,000 miles (300,000 km) above the planet’s equator. The rings seemed so integral to Saturn itself. But then came the visits to Saturn by Voyagers 1 and 2. Their observations suggested that the rings might be younger than the planet – much younger – a temporary phenomenon, lasting only millions of years in the 4 1/2 billion year lifetime of our solar system. And in recent years, data from the Cassini spacecraft (2004-2017) seemed to nail down the idea that Saturn’s rings are from 10 million to 100 million years old. Now we hear that insight from Cassini wasn’t the final word, either. A team of researchers has reignited the debate about the age of Saturn’s rings with a study that dates the rings as most likely to have formed in the early solar system.

Authors - Dusty - Material - Saturn - Rings

The authors suggest that processes that preferentially eject dusty and organic material out of Saturn’s rings – a “ring rain” that falls in part onto Saturn – could make the rings appear younger than they really are. Cassini, in fact, encountered this ring rain when it dived between Saturn’s rings and its upper atmosphere during its Grand Finale in 2017.

The idea is being discussed this week by astronomers at a joint meeting of the European Planetary Science Congress and the AAS Division for Planetary Sciences in Geneva, Switzerland. It was published just in time for this meeting, on September 16, 2019, in the peer-reviewed journal Nature Astronomy.

Voyager - Images

Voyager 2 captured the images to...
(Excerpt) Read more at: earthsky.org
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