A flurry of new moons have made their presence known around Jupiter and Saturn, bringing their moon populations to 101 and 285 respectively.
The new discoveries also provide the total number of known moons orbiting planets and dwarf planets the solar system to 442 – and that doesn’t include the many moon leaves that come with different ones asteroids or small Kuiper belt objects.
The newly discovered moons — four for Jupiter and 11 for Saturn – was announced by the Minor Planet Center, which is the clearing house for astronomical discoveries of asteroids, cometscentaurs and indeed moons.
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None of the newly discovered moons are very large, averaging about 3 kilometers in diameter. They have very wide orbits, far wider than the larger moons of Jupiter and Saturn, and are extremely faint, between magnitudes 25 and 27. (For context, our moon is at -12.6.) This puts them well beyond the reach of backyard telescopes.
Instead, it took intense observations from some of our largest ground-based telescopes to capture them. The four new moons of Jupiter were all found by astronomers Scott Sheppard of the Carnegie Institution for Science and David Tholen of the University of Hawaii, using the 6.5-meter Magellan-Baade telescope at Las Campanas Observatory in Chile and the 8-meter Subaru telescope atop Mauna Kea in Hawaii.
Meanwhile, the 11 new moons of Saturn were discovered thanks to a team led by Edward Ashton at the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan. They used the 3.5 meter Canada–France–Hawaii telescope on Mauna Kea. This comes after Ashton led a team to discover 128 new moons of Saturn as late as 2025.
In particular, both Sheppard and Ashton are prodigious discoverers of solar system moons, with over 200 each to their name, many of them co-discoveries.
While Jupiter lags behind Saturn in the lunar stakes by quite a large number, Europa Clipper and the Jupiter Icy Moons Explorer (JUICE) missions, currently bound for Jupiter, could redress the balance when they arrive in the Jovian system in the early 2030s.
To summarize, the current numbers are that of the planets, Earth has a moon, March has two, Jupiter has 101, Saturn has 285, Uranus have 28 and Neptune has 16 while Venus and Mercury have none. For the dwarf planets, Pluto have five Eris have one, Makemake has one, Haumea has two and Ceres has none.
The new moons of Jupiter were announced in the Minor Planet Electronic Circulars MPEC 2026-F09, F10, F11 and F12and the 11 new moons of Saturn were declared in MPEC 2026-F14.
