New NASA research confirms that Saturn is losing its iconic rings at the maximum rate estimated from Voyager 1 & 2 observations made decades ago. The rings are being pulled into Saturn by gravity as a dusty rain of ice particles under the influence of Saturn’s magnetic field. Right now, it’s raining 10,000 kilograms of ring rain on Saturn per second. Fast enough to fill an Olympic-sized pool in half an hour.
“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. “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.” O’Donoghue is lead author of a study on Saturn’s ring rain appearing in Icarus December 17.
If you were to pick Saturn out of a lineup you’d probably recognize it by its iconic rings. They’re the biggest, brightest rings in our solar system. Extending over 280,000 km from the planet; wide enough to fit 6 Earths in a row. But Saturn won’t always look this way. Because its rings are disappearing.
Scientists have long wondered if Saturn was formed with the rings or if the planet acquired them later in life. The new research favors the latter scenario, indicating that they are unlikely to be older than 100 million years, as it would take that long for the C-ring to become what it is today assuming it was once as dense as the B-ring. “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!” O’Donoghue added.
Saturn’s rings are mostly made up of chunks of ice and rock. Which are under constant bombardment: Some by UV radiation from the Sun and others by tiny meteoroids.
When these collisions take place, the icy particles vaporize, forming charged water molecules that interact with Saturn’s magnetic field; ultimately, falling toward Saturn, where they burn up in the atmosphere.
Now, we’ve known about ring rain since the 1980s when NASA’s Voyager mission first noticed mysterious, dark bands that turned out to be ring rain caught in Saturn’s magnetic fields. Back then, researchers estimated the rings would totally drain in 300 million years. But observations by NASA’s former Cassini spacecraft give a darker prognosis. Before its death dive into Saturn in 2017, Cassini managed to get a better look at the amount of ring-dust raining on Saturn’s equator.
And discovered that it was raining heavier than previously thought. With these clearer observations, scientists calculated the rings had only 100 million years left to live. Now, it’s tough to imagine a ringless Saturn.
But for much of its existence, the planet was as naked as Earth. While Saturn first formed around 4.5 BILLION years ago, studies suggest the rings are only 100- 200 million years old, tops. That’s younger than some dinosaurs.