
Saturn now has a complete of 274 moons
NASA/JPL/House Science Institute
An extra 128 moons have been found orbiting Saturn, bringing the planet’s whole to 274 – greater than there are round all the opposite planets in our photo voltaic system mixed. However as advances in telescope expertise enable us to identify progressively smaller planetary objects, astronomers face an issue: how tiny can a moon be earlier than it’s only a rock?
Edward Ashton at Academia Sinica in Taipei, Taiwan, and his colleagues discovered the brand new moons with the Canada-France-Hawaii Telescope, revealing dozens which have beforehand evaded astronomers. They took hours of pictures of Saturn, adjusted them for the planet’s motion by way of the sky and stacked them on high of one another to disclose objects that may in any other case be too dim to see.
All the brand new moons are between 2 and 4 kilometres in diameter and are prone to have been fashioned lots of of thousands and thousands and even billions of years in the past in collisions between bigger moons, says Ashton.
“These are small little rocks floating in area, so some folks won’t discover it fairly an achievement,” says Ashton. “However I believe it’s essential to have a list of all of the objects within the photo voltaic system.”

The dot on the centre of this picture is among the new “fuzzy blob” moons of Saturn
Edward Ashton et al. (2025)
Regardless of the wealth of information gathered by his staff, these newest moons nonetheless solely seem as “fuzzy blobs”, says Ashton. There are extra highly effective telescopes that would doubtlessly resolve the moons in additional element, though many have smaller fields of view, which might imply taking many extra pictures, he says.
The newly found moons have been recognised by the Worldwide Astronomical Union (IAU), and Ashton and his staff will now get the appropriate to call them. Ashton, who’s Canadian, says he has approached a consultant from Canada’s Indigenous peoples for recommendations, however can also be mulling the concept of some type of public naming contest.
Might there be extra moons on the market? Scientists have spent a long time scanning the realm round Saturn with more and more highly effective telescopes, which has paid off in recent times. In 2019, 20 new moons have been discovered, and Ashton and his colleagues had already discovered 62 in 2023, separate from the 128 they most lately discovered. In the end, it’s seemingly that additional discoveries would require advances in telescope expertise, says Ashton, who believes there are simply 1000’s of moons in orbit round Saturn, even discounting the smaller, rocky particles discovered within the planet’s rings.
Mike Alexandersen on the Minor Planet Middle, which logs planetary our bodies for the IAU, says there are prone to be many extra moons but to be present in our photo voltaic system as enhancements to telescopes enable them to see smaller objects. He says selections should be made about what does and doesn’t rely as a moon.
“I do know that the IAU determined that, as a result of variety of moons which might be prone to exist, they’re not going to prioritise naming something that’s smaller than 1 kilometre. However that’s not the identical as them not recognising it as a moon,” says Alexandersen. “They’ll most likely solely title it if a spacecraft goes to go to it.”
He recommended that the cutoff between what’s a moon and what’s only a rock particle that makes up a part of a planetary ring might be going to be someplace between 1 kilometre and 1 metre in diameter. “Ultimately, it most likely gained’t be my choice, it’ll be the IAU, which is able to make up some cutoff which can be kind of controversial – identical to the lower for what’s a planet or not. And it’s almost definitely going to be comparatively arbitrary,” says Alexandersen.
Elizabeth Day at Imperial School London says that, at some point, there could even be business causes for having correct maps of the photo voltaic system. “We would need to extract sources from asteroids and moons within the photo voltaic system, so having an incredible understanding of what’s the place is essential for that,” says Day.
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Article amended on 12 March 2025
We clarified that Saturn’s whole moon rely is greater than the remainder of the planets mixed
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