Even in the pictures, it’s clear that there’s something different about our close neighbor: its rings are twirling at an angle of about 25 degrees to its orbit around the Sun. But it’s less clear how it got tilted, with scientists thinking it probably has something to do with its close neighbor Neptune, as the tilt is similar to its orbit. Now scientists have suggested that the two were once in sync, in a neat alignment or coordination together. That alignment was thrown off at some point in history when a moon wreaked havoc between the two, according to a new study. Today, Saturn has 83 moons. But in the past it may have had an extra satellite, now missing, that scientists named Chrysalis. These many moons orbited Saturn and kept it in alignment with Neptune, scientists say, with this smooth alignment lasting for billions of years. About 160 million years ago, however, Chrysalis felt itself out of this neat alignment and drifted too close to Saturn itself. The moon disintegrated and its loss pulled Saturn away from Neptune and left the planet out of alignment. Additionally, Saturn’s rings may have formed from the pieces that Chrysalis broke into. This helps to explain two mysteries at once. Chrysalis is the cause of the tilt and inexplicable age of the rings, which are only 100 million years old and much younger than the planet itself. “Just like the chrysalis of a butterfly, this satellite was dormant for a long time and suddenly became active and the rings appeared,” said Jack Wisdom, professor of planetary sciences at MIT and lead author of the new study. The team used detailed data about Saturn – including measurements taken when the Cassini probe crashed into the planet – to build an accurate simulation of Saturn. These models showed that the planets could once have been in sync with each other but had fallen out. A moon could be enough to cause these problems, scientists believe. It would orbit Saturn until 200 to 100 million years ago, when it fell into a chaotic orbit that brought it close to other moons and then grazed Saturn, breaking it up. “It’s a pretty good story, but like any other result, it should be looked at by others,” Wisdom said. “But it seems that this lost satellite was just a chrysalis, waiting to have its instability.” The research is described in a paper, “Loss of a Moon Could Explain Saturn’s Obliquity and Young Rings,” published in Science.
