spaceSpace and Physics

Saturn's "Ring Rain" Is Actually More Of A Downpour, Say Scientists


Jonathan O'Callaghan

Senior Staff Writer


Scientists have discovered that Saturn’s rings are dumping way more material than we thought onto the planet.

Published in the journal Science, six studies used data from the finale of the Cassini mission, which was sent diving between the rings and Saturn before its demise in September 2017.


In total Cassini orbited 22 times between the rings and Saturn, using its instrument to probe this previously unexplored region of space. And the most surprising finding is just how much material from the rings is making its way to the planet, 10 times more than thought.

“This confirms that ring material is finding its way into Saturn's atmosphere,” Bill Kurth from the University of Iowa, one of the paper’s co-authors, told IFLScience.

This is called “ring rain”, and it has been theorized before. It was thought to be mostly water ice, dropping in earnest quantities onto the planet, but now we’ve found signs of organic compounds dropping too.

"Turns out, ring rain is more like a ring downpour," said Hunter Waite from the Southwest Research Institute in Texas, one of the paper’s lead authors, in a statement. “Water ice, along with the newly discovered organic compounds, is falling out of the rings way faster than anyone thought – as much as 10,000 kilograms of material per second."


Organics refers to molecules that contain carbon, in this case things like butane and propane, commonly used as fuel for a stove on Earth. The findings suggest Saturn’s rings play a dramatic role in shaping the composition of the planet’s upper atmosphere.

Cassini was sent swooping between the rings and the planet towards the end of its mission. NASA/JPL-Caltech

"This is a new element of how our Solar System works," Thomas Cravens from the University of Kansas, and a co-author on one of the papers, said in a statement. “The quality and quantity of the materials the rings are putting into the atmosphere surprised me."

The findings have a number of fascinating implications. For example, it now suggests that material from different parts of the rings may replenish other parts, such as the innermost D ring.

From the amount of material being released, it may also be that the rings have a shorter lifespan than thought. In an absence of new material, rings like these probably drain away over time – and perhaps already did so for other worlds like Jupiter.


And the research could help us solve how a planet gets rings in the first place. It’s not clear if Saturn’s rings herald from the dawn of the Solar System, for example, or are a more recent addition.


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