We Have a New 'Moon King'

Move over, Jupiter: Saturn is the new "moon king," with 274 planetary satellites in orbit, almost half of which were only just discovered. As of 2023, Jupiter was considered the leader among moon-hosting planets in the solar system with 92 confirmed, compared to Saturn's 83. Jupiter now has 95 confirmed moons. But Saturn has almost triple that number, with 128 new moons recognized by the International Astronomical Union on Tuesday, and "based on our projections, I don't think Jupiter will ever catch up," Dr. Edward Ashton of the Academia Sinica's Institute for Astronomy and Astrophysics in Taiwan tells the Guardian.

Ashton and colleagues had identified 62 of Saturn's moons using the Canada-France-Hawaii Telescope in Hawaii before launching into further observations in 2023. Using the "shift and stack" technique to view a set of sequential images in which a moon's movement can become visible, the team discovered 128 new, irregular moons—mostly small, potato-shaped objects just a few miles across and often clumped together, between 6.5 million and 18 million miles from the planet, per the New York Times. They "are likely all fragments of a smaller number of originally captured moons that were broken apart by violent collisions, either with other Saturnian moons or with passing comets," University of British Columbia astronomer Brett Gladman tells the Guardian.

Further observations could offer insights into the distant past, around 100 million years ago, when planets navigated unstable orbits and often banged into things. Forty-seven of the new moons might be the result of a single collision, per the Times. For now, astronomers are "on the hunt for dozens of obscure Viking deities" whose names can be applied to the moons, the Guardian reports. Saturn's moons are all named after Gallic, Norse, and Inuit gods, and most of the new moons fall in the Norse cluster, the outlet notes. But with 128 moons to be named, "eventually the criteria may have to be relaxed a bit," says Ashton, lead author of a paper to be published in Research Notes of the American Astronomical Society. (More discoveries stories.)