Saturn’s rings may be ‘recently’ added after icy moons collided

SATURN’S rings were created when two icy moons crashed together unleashing a frozen debris field that encircled the planet, a study has suggested.

Previous theories included the notion that the rings were formed from pieces of comets or asteroids that were torn apart by Saturn’s powerful gravity field and left suspended in orbit soon after the planet formed. However, new research by Nasa and the universities of Durham and Glasgow suggests the rings were created only a few hundred million years ago when two ice moons collided and shattered.

That would mean that for most of its existence, Saturn did not have rings.

Experts say the two culprits would have been similar in size to two of Saturn’s current moons, Dione and Rhea, which have a radius of 348 and 474 miles respectively.

Dr Vincent Eke, associate professor in the department of physics at Durham, said: “We tested a hypothesis for the recent formation of Saturn’s rings and have found an impact of icy moons is able to send enough material near to Saturn to form the rings we see now.”

Saturn has seven rings composed of chunks of ice, most of which are no bigger than a boulder. They were first spotted by Italian astronomer Galileo Galilei in 1610. In the 1800s, Scottish scientist James Clerk Maxwell determined that they were made up of individual pieces.

Although Saturn is around 4.5 billion years’ old, recent data from Nasa’s Cassini mission show its rings are almost pure ice and fairly dust free, suggesting they are far younger than the planet.

Dust is a good indicator of how long an object has been in place because it accumulates in layers over time but the icy chunks in Saturn’s rings are sparkling clean, meaning they cannot have been there since the birth of the planet.

For the new study, which is published in The Astrophysical Journal, the team simulated nearly 200 different collision scenarios and found that two moons coming together would scatter the right amount of ice to form the rings. Explanations involving comets and asteroids struggled to explain why there is almost no rock present.