20 new moons found around Saturn, snagging satellite record from Jupiter

Saturn has overtaken Jupiter as the solar system's satellite king.

Astronomers just discovered 20 previously unknown Saturn moons, boosting the ringed planet's tally of known satellites to 82 — three more than Jupiter. And there's more exciting news: You can help name these newfound objects.

All 20 moons are tiny, measuring about 3 miles (5 kilometers) across. Seventeen of them have retrograde orbits, meaning they move around Saturn in the opposite direction to the planet's rotation. These 17 all take more than three Earth years to complete one Saturn lap, and the most far-flung one is the most distant Saturn satellite known, discovery team members said.

An image of Saturn taken in June 2019 showing the planet and some of its largest moons. (Image/SPACE.com)

One of the three newly discovered "prograde" moons has an orbital period of more than three Earth years, while the other two complete one lap every two years or so.

The 17 retrograde moons appear to belong to the "Norse group" of Saturn satellites, which share the same basic orbital parameters. The two innermost prograde objects align with the "Inuit group," and the outermost prograde moon among the new finds may belong to the "Gallic group," but that's unclear at the moment, researchers said.

Each of these satellite groups is likely evidence of a long-ago impact that destroyed a larger moon that had been orbiting in that general area.

"This kind of grouping of outer moons is also seen around Jupiter, indicating violent collisions occurred between moons in the Saturnian system or with outside objects such as passing asteroids or comets," Scott Sheppard, of the Carnegie Institution for Science in Washington, D.C., said in a statement today (Oct. 7) announcing the discovery.

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