Does a New Theory Finally Explain the Mysteries of the Planet Saturn?

“Saturn and some of its 274 moons are pretty weird,” writes Smithsonian magazine:

[Saturn moon] Titan has strangely few impact craters, Hyperion is tiny and misshapen, and Iapetus has a tilted orbit. What’s more, planets tend to wobble along their rotational axes as they spin, like an off-kilter spinning top in the moments before it topples over. Formally called precession, scientists have long thought that Saturn’s wobble rate should match Neptune’s because they’re probably gravitationally linked. However, data from NASA’s Cassini spacecraft, which studied the ringed planet from 2004 to 2017, revealed that Saturn’s precession rate is slightly speedier than Neptune’s.

In 2022, some researchers suggested that the destruction of a hypothetical moon, called Chrysalis, around 160 million years ago may have knocked Saturn out of sync and formed the pieces that became the planet’s rings. But this work implied that Chrysalis probably would’ve crashed into Titan, posing a major problem, study co-author Matija Äuk, an astronomer at the SETI Institute, tells New Scientist‘s Leah Crane. In that case, Chrysalis’ debris couldn’t have become the rings, he says.

So, Äuk and his colleagues used computer simulations to investigate what would happen if Chrysalis did smack into Titan. If that happened around 400 million years ago, they found, the crash would’ve wiped away Titan’s craters and made its orbit more elliptical. The altered path may have slowly pushed the trajectories of other moons, which then scraped against one another and left chunks of ice and rock that now make up Saturn’s rings. The timing seems to align with the rings’ estimated age of roughly 100 million years. Additionally, one piece of kicked-up debris may have formed the weird moon Hyperion, which may have subsequently tilted the orbit of the moon Iapetus, according to the analysis. The scenario could also resolve Saturn’s unexpected wobble, which is currently “a little bit too fast,” Äuk tells Jacopo Prisco at CNN.
The study has been accepted for publication in the Planetary Science Journal, and is already available on the preprint server arXiv.