The origin of Saturn's beautiful rings and the reason for the planet's unusually large 27 degree-tilt on its axis has puzzled astronomers for decades. Scientists had initially believed that the rings had been a part of the planet since its formation billions of years ago. However, recent research indicates that the planet acquired them sometime between 100 and 200 million years ago.
They had also theorized that Saturn's tilt was the result of a gravitational pull from Neptune. But data from NASA's Cassini mission showed that Saturn had fallen outside Neptune's grasp at some point in the past. Now, a new study published in the journal Science on September 16, 2022 suggests that an extinct moon may be responsible for the rings and the unusual tilt.
Jack Wisdom, a planetary science professor at the Massachusetts Institute of Technology, and his team assert that Saturn, which currently has 83 moons, once had at least one more. They speculate the satellite, nicknamed Chrysalis, was tugging at the planet in a way that allowed it to have gravitational interaction with Neptune.
However, about 160 million years ago, Chrysalis got too close to Saturn, causing it to rip apart and fall into the planet. The loss of the Moon was enough to remove Saturn from Neptune's grasp and leave it with its present-day tilt. Wisdom and his team further hypothesize that fragments from the destroyed Moon settled into the planet's orbit and formed its iconic rings. This theory also helps explain why the rings are far younger than the planet.
"We like it because it's a scenario that explains two or three different things that were previously not thought to be related," says Wisdom. "The rings are related to the tilt, who would ever have guessed that?"
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