How did Saturn get its rings?

“Millions of years ago, Saturn has an extra moon, perhaps 400 kilometers across and formed almost entirely of ice. But this moon is doomed. It’s orbiting just too close to resist the immense forces of Saturn’s gravity.”

Where did Saturn’s rings come from? BBC Earth Lab shares this informative clip from The Planets: Saturn, an episode from the 2019 series.

Cassini Mission planetary scientist Linda Spilker explains how an ice moon might have been the source for Saturn’s orbiting debris field:

“The rings probably formed from an object that got too close to Saturn. There’s this invisible boundary around Saturn, called the Roche limit, and that’s the limit, depending on what you’re made of, where Saturn’s gravity is strong enough it will actually pull you apart, that the gravity on the side closer to Saturn is strong enough that compared to the gravity on the other side, it will literally rip you apart. You don’t have enough gravity of your own to stay together.”

And there are a few surprising details in Saturn’s rings: They are younger than the dinosaurs, they form a disk wider than Jupiter that averages just 9 meters (30 feet) thick, and thanks to Cassini, we now know that there are tall peaks rising as high as 2.5 kilometers (1.6 miles) from the planet’s B ring.

In the clip above, planetary scientist Carolyn Porco emphasizes: “I just can’t tell you how surprised we were to see this. It’s just the spectacle of it was just unanticipated.”

Watch these Saturn and Cassini videos next:
• Cassini’s Grand Finale, our daring last months orbiting Saturn
• Around Saturn: The Cassini program’s incredible images animated
• Saturn’s Mysterious Moons
• Brian Cox’s Favorite Wonder: Saturn’s moon Titan
• Postcards from Saturn: The incredible images that Cassini sent home