Saturn has 128 newly-discovered moons. Here they are color-coded by their MPEC release. Orange: MPEC 2025 E153, Purple: MPEC 2025-E154, Green: MPEC 2025-E155.
— Tony Dunn (@tony873004.bsky.social) March 11, 2025 at 7:52 PM
128 new Saturn moons
Saturn already had 146 known moons, more than any other planet in our solar system. But on March 11, 2025, the International Astronomical Union’s Minor Planet Center added a whopping 128 new moons to Saturn’s count, bringing its total of moons to 274. The next highest moon count belongs to Jupiter, with a “mere” 95.
A research team, led by Edward Ashton of the Institute for Astronomy and Astrophysics at the Academia Sincia in Taiwan, submitted a paper to the Planetary Science Journal on February 6, 2025, and it became available on arXiv on March 10, 2025. The paper has not yet been accepted and peer reviewed. The science in the paper is based on the publication of 64 new moons of Saturn in 2023. Co-author Brett Gladman of the University of British Columbia told EarthSky:
It was that study … which prompted the more intense search in 2023, which yielded another 128 moons.
The researchers used the Canada-France-Hawaii Telescope atop Mauna Kea in Hawaii for their observations.
The 2025 EarthSky lunar calendar makes a great gift. Get yours today!
I spent almost 2 hours painstakingly copying the orbits of all 128 Saturnian moons from the announcement MPEC and reformatting them for visualization…
Behold, here are the orbits of ALL 128 MOONS OF SATURN. This isn't just a moon system—it's a literal asteroid belt around Saturn! ????
— astrafoxen (@astrafoxen.bsky.social) March 11, 2025 at 7:05 PM
A recent collision led to more moons
The new moons the researchers discovered are all irregular moons. These irregular moons are far away from their host planet and in eccentric orbits. That is, a non-circular orbit where the distance between the orbiting body and the central body varies significantly.
Back in 2021, Ashton authored another paper suggesting that a “recent” collision led to a number of irregular moons of Saturn. And relatively recent in astronomical terms means, in this case, a few hundred million years ago. The researchers suggest that a number of the new moon discoveries were also a result of this collision in Saturn’s past.
The new paper said:
It was initially thought that a single irregular moon group was created by the break up of a larger moon, like the collisional families seen in the asteroid belt. However, some groups are too dispersed to be explained by a single collision. A likely remedy is either multiple independent collisions, second-generation collisions between fragments of the initial collision, or a mixture of the two.
Gladman told EarthSky that a large fraction of the 128 moons’ orbits strongly support the idea that:
a larger moon was destroyed at most 100 million years ago. The collision could have been MORE recent than that, it just can’t be older or all these small (1.2-1.8 miles or 2-3 km) moons would have been running into each other and disappearing.
Names for the moons of Saturn
The largest of Saturn’s moons are named after Titans of Greek mythology and their descendants. Though, as the moon discoveries piled up over the years, the conventions for naming spread out into Gallic, Norse and Canadian Inuit gods. The new moons would likely be named for Viking gods. However, with the large number of discoveries, a new convention might once again be needed.
Saturn’s largest moons, such as Titan, Mimas and Rhea, are big enough to have pulled themselves into a spherical shape. Meanwhile, these new moons are more potato-shaped. They’re more similar in appearance to Mars’ captured asteroid moons, Deimos and Phobos.
The team discovered the first 64 moons between 2019 and 2021. The next three batches of discoveries, of 61 moons, 34 moons and 33 moons, include discoveries up through 2023.
While there is no official definition for what qualifies an object as a moon, some of these new moons are less than 2.5 miles (4 km) in size.
Bottom line: Astronomers have discovered a whopping 128 new Saturn moons. This brings Saturn’s moon total to 274, by far the most of any planet in our solar system.
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