20 new moons discovered orbiting Saturn

Saturn now has 82 moons, knocking Jupiter down to second place in the moon count.
By | Published: October 7, 2019 | Last updated on May 18, 2023
An artist’s conception of the 20 newly discovered moons orbiting Saturn.
NASA/JPL-Caltech/Space Science Institute/Paolo Sartorio/Shutterstock

Astronomers have found 20 new moons orbiting Saturn, bumping its total up to 82 moons. That surpasses Jupiter, which was the prior reigning champion with 79 moons. 

One of the new moons has the farthest known orbit around Saturn, and all are similar in size, with diameters around three miles (5 kilometers). Two of the moons take about two years to orbit, while the other 18 take more than three years to do so.

Seventeen of the new moons orbit Saturn backward — or in retrograde — compared to the planet’s other natural satellites. The retrograde moons have orbits resembling some of Saturn’s other already-known moons. And by looking at their inclinations, astronomers suspect these moons could have been part of a much larger moon that broke apart long ago. 

The moons were discovered by a team led by Scott S. Sheppard at the Carnegie Institution for Science and using the Subaru Telescope on Hawaii’s Mauna Kea. 

By studying these small moons and their interactions with our solar system’s large planets, astronomers can answer questions about how these worlds were formed and how they’ve evolved.