In the race for the title of the planet with the most moons, Saturn may have overtaken Jupiter for the final time.
Earlier this year, Jupiter had 12 new moons added to its total, which is now 95, making it our solar system’s frontrunner—Saturn only had 83 confirmed moons at the time. But over the last couple of weeks, astronomers have announced the discoveries of 62 additional moons of Saturn, raising its number to 145, according to a statement from the University of British Columbia (UBC) in Canada.
Now, researchers think Jupiter has no chance to catch up. “Saturn will win by miles,” Mike Alexandersen, an astronomer at the Center for Astrophysics, Harvard & Smithsonian, who contributed to the findings, tells the New York Times’ Jonathan O’Callaghan. “I don’t think it’s a contest anymore.”
Astronomers continued to discover more moons over the centuries. And from 2004 to 2017, a spacecraft named after Cassini studied Saturn up close and discovered more moons, according to the European Space Agency.
Two groups of astronomers made the new sightings, per the New York Times. One detected moons around Saturn in the mid-2000s using the Subaru Telescope in Hawaii. The other observed Saturn from 2019 to 2021 using the Canada-France-Hawaii Telescope atop Hawaii’s Mauna Kea volcano.
While the possible moons were first detected several years ago, it takes that long to track the objects and confirm they are indeed orbiting the planet. In total, the researchers discovered 63 new moons, with the first discovery announced in 2021.
“Saturn not only has nearly doubled its number of moons, it now has more moons than all the rest of the planets in the solar system combined,” Brett Gladman, one of the researchers involved in the discovery and an astronomer at UBC, tells the Guardian’s Hannah Devlin and Nicola Davis.
The newly discovered satellites are all irregular moons, meaning that they have large and tilted orbits, according to UBC’s statement. They revolve around the planet from between six million and 18 million miles away, per the New York Times.
Saturn now has 121 known irregular moons and 24 known regular moons. The smallest of the newly announced moons is just about 1.6 miles in diameter, while Titan, Saturn’s largest moon, is 3,200 miles in diameter.
Some of the researchers estimated in a 2021 paper that Saturn has about 150 irregular moons that are at least two miles wide, writes Sky & Telescope’s Jeff Hecht. “There are about 30 left [undiscovered] in this size range [and] likely many hundreds, if not thousands, of Saturnian moons with smaller sizes,” Edward Ashton, who led the research with the Canada-France-Hawaii Telescope and now works at the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, tells the publication.
Saturn’s irregular moons have coalesced in three orbital groups based on their tilted paths, per UBC’s statement. Scientists think older moons collided and broke apart, forming the moons we see today.
“These moons are pretty key to understanding some of the big questions about the solar system,” Bonnie Buratti, a planetary scientist at NASA’s Jet Propulsion Laboratory, tells the New York Times. “They have the fingerprints of events that took place in the early solar system.”