Saturn’s Rings Have an Expiration Date

Saturn rings won't last forever

New research says Saturn’s rings are a cosmological ‘blink and you’ll miss it’ moment. Scientists first inkling that Saturn’s rings aren’t a permanent structure came during Voyager 1 & 2’s observations decades ago. Now, a paper confirms the majestic rings of Saturn will eventually disappear.

But don’t worry, Saturn will still be an incredible sight from your backyard telescope. While the gas giant’s ring system is a cosmological ‘blink and you’ll miss it’ moment, people will enjoy Saturn’s rings for generations to come.

The new NASA research says Saturn’s ring system will be a shadow of its former self in less than 100 million years.

What’s happening? Gravity and Saturn’s magnetic field are creating a ‘ring rain.’ And it’s pulling in a whole bunch of water. UV light from the sun and plasma clouds caused by tiny meteor strikes charge the icy particles. They then become attracted to Saturn’s magnetic field, and the planet’s intense gravity does the rest.

“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,” said James O’Donoghue of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

O’Donoghue, the lead author on the paper, added, “From this alone, the entire ring system will be gone in 300 million years, but add to this the Cassini-spacecraft measured ring-material detected falling into Saturn’s equator, and the rings have less than 100 million years to live. This is relatively short, compared to Saturn’s age of over 4 billion years.”

Saturn’s rings look nice and smooth at a distance, but they are made up of countless pieces of ice ranging from dust-grain sized to boulders spanning several years across.

The new research also points to Saturn gaining its beautiful ring system well after becoming a gas giant. They may be no older than 100 million years. “We are lucky to be around to see Saturn’s ring system, which appears to be in the middle of its lifetime. However, if rings are temporary, perhaps we just missed out on seeing giant ring systems of Jupiter, Uranus and Neptune, which have only thin ringlets today!” says O’Donoghue.

Okay, but how would Saturn acquire its rings? One theory points to small, icy moons around Saturn smashing into each other. And the debris from these collisions forming the rings we see today.

There’s still more scientists can learn about Saturn’s ‘ring rain.’ As Saturn goes through multi-year long seasons (thanks to a 29.4-year orbit), its rings get varying exposure to the Sun. Since UV light is one of the main mechanisms for ‘ring rain’ it should change how much it rains depending on the season.

Nothing is forever, but losing Saturn’s rings stings. But who knows how the solar system will look in another 100 million years. A passing comet or asteroid might have set the pieces in motion for Saturn to get its rings. It could happen again.

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