Goodbye to Saturn’s rings

Saturn’s wide, iconic rings make this planet the telescopic showpiece of the solar system, but new research confirms the planet’s rings are only temporary. The new work was published December 17, 2018, in the peer-reviewed journal Icarus. It describes a process whereby ice particles from the rings are being pulled by gravity onto Saturn, falling as a dusty ring rain.

James O’Donoghue of NASA’s Goddard Space Flight Center is lead author of the new study. O’Donoghue said in a statement:

We estimate that this ‘ring rain’ drains an amount of water products that could fill an Olympic-sized swimming pool from Saturn’s rings in half an hour.

Saturn’s rings consists of countless separate particles with sizes ranging from pea-sized to that of giant boulders. These particles are composed mainly of water ice, with a trace of rocky material. There are two basic possibilities for how Saturn got its rings. It is conceivable that Saturn formed with the rings from the great cloud of gas and dust that also formed our sun and the other planets, 4 1/2 billion years ago. Or – as now seems more likely – the rings started out as moons for Saturn that collided, or a moon that came too close (within Saturn’s Roche limit) and was shattered by tidal forces.

The new research favors the idea that the rings are recent and temporary. Like some previous studies, it suggests a much younger age for the rings than 4 1/2 billion years. The ring rain alone indicates that the rings will last no more than 300 million years, these scientists said. Earlier research suggested an even shorter timeframe for the rings, giving them less than 100 million years to live. O’Donoghue said:

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