Moon Math Shifts Again: Saturn Adds 11, Jupiter Cracks 101 in a Discovery Surge

A New Moon Count for the Gas Giants

The solar system’s moon tally has been officially updated. Astronomers have discovered 15 new moons orbiting Jupiter and Saturn, bringing the ringed planet’s total to 285 and pushing Jupiter past the century mark to 101 known moons .

The discoveries, formally reported by the International Astronomical Union’s Minor Planet Center, raise the total number of known moons orbiting planets in the solar system to 442 .

Tiny, Distant, and Hard to Spot

The newly identified moons are tiny by celestial standards—each averaging about 3 kilometers (less than 2 miles) in diameter . They orbit far from their parent planets, much farther than the well-known large moons like Europa or Titan.

Because of their small size and distant orbits, these moons are incredibly faint, with brightness levels falling between magnitude 25 and 27. For context, Earth’s moon shines at magnitude -12.6—literally billions of times brighter . Spotting them required the most powerful ground-based telescopes available, and they remain invisible to even advanced backyard equipment.

Jupiter’s four new moons were discovered by astronomers Scott Sheppard of the Carnegie Institution for Science and David Tholen of the University of Hawaii. They used the 6.5-meter Magellan-Baade Telescope in Chile and the 8-meter Subaru Telescope in Hawaii .

Saturn’s 11 new moons were found by a team led by Edward Ashton of the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan, using the 3.6-meter Canada-France-Hawaii Telescope on Mauna Kea . Ashton’s team previously discovered 128 new Saturnian moons in 2025 .

What’s Next for the Moon Race?

While Saturn currently holds a commanding lead, the moon race is far from over. Two major missions—NASA’s Europa Clipper and the European Space Agency’s JUICE (Jupiter Icy Moons Explorer) —are currently en route to Jupiter and will arrive in the early 2030s . Their close-up surveys are expected to reveal many more small moons around the gas giant that ground-based telescopes cannot detect .

For now, Saturn remains the undisputed “moon king” of the solar system, with 285 known satellites—nearly three times Jupiter’s count .

Solar System Moon Count (Updated)