Astronomers know a lot about Saturn’s ring system. They’ve known about it for centuries, ever since Galileo first spotted it with his telescope in 1610. It’s made out of ice and rock particles, some as big as a minivan. And the rings are super flat, like a razor-thin CD that’s 170,000 miles across, but only a couple dozen yards thick.
NASA has explored them, first with the Pioneer and Voyager probes, and more recently, with the Cassini mission. Cassini spent more than a decade circling Saturn, and as its final act, dove between the planet and its rings. It got an awesome new measurement of the planet’s gravitational field, which gave astronomers new info on the mass of the planet and its rings.
But despite all that, there’s still lots we don’t know. Like, how old are Saturn’s rings? And how did they form?
