🪐 The catastrophic origin of Saturn's rings becomes clearer

Saturn's magnificent rings, much younger than previously thought, might owe their existence to the destruction of an ancient moon. This same event could also explain why the planet is tilted today. This hypothesis, presented at a scientific conference, offers a coherent answer to two long-standing questions.

According to this hypothesis, a moon named Chrysalis would have accompanied Saturn for billions of years. However, about 100 million years ago, its orbit is thought to have become destabilized, causing it to spiral towards the planet. The extreme gravitational forces would then have torn this satellite apart, scattering its debris into space.


Computer simulations indicate that during this close approach, Saturn's tidal forces mostly ripped off Chrysalis's icy mantle, largely preserving its rocky core. This mechanism accounts for the current composition of the rings, which are almost exclusively made of water ice and practically devoid of rock, matching observations.

Furthermore, Saturn's tilt of about 26.7 degrees would also be explained by this scenario. Until now, it was attributed to a gravitational resonance with Neptune.

Saturn's other moons, like Titan, have also influenced the evolution of the rings. Their gravitational attractions likely eliminated up to 70% of the rings' initial mass over time. Thus, the original ring must have been much more massive than the one we see today.

Today, scientists are questioning the fate of Chrysalis's residual core and searching for marks of this episode on Saturn's other satellites. Future missions could detect abnormal impacts, providing new elements to reconstruct the full story.

This theory builds on earlier work, notably a study published in Science in 2022, which had already highlighted Chrysalis's role. The recent modeling clarifies the formation mechanisms, strengthening the plausibility of this origin for the rings.