- Saturn's moon count rises to 285 with the discovery of 11 new moons
- Jupiter surpasses 100 moons, reaching a total of 101 with four new finds
- Solar system's total known moons now stand at 442, says Minor Planet Center
Astronomers have discovered 11 new moons orbiting Saturn, raising its total number of known satellites to 285. Meanwhile, Jupiter has crossed a major milestone, with its moon count surpassing 100 for the first time after four new moons were identified. With the addition of four newly detected moons, Jupiter's total has now reached 101. The official number of known moons in our solar system has now reached 442.
According to an announcement by the Minor Planet Center, the newly discovered moons are "irregular" satellites, meaning they are small (averaging about 3 km across) and have distant, often eccentric orbits. They have super wide orbits, way wider than Jupiter's and Saturn's bigger moons, and are really faint – between magnitude 25 and 27. To put that in perspective, our moon is at magnitude -12.6, so these are way beyond backyard telescopes. Given their small size and lack of scientific significance, they've been given alphanumeric designations instead of formal names, following International Astronomical Union guidelines.
Astronomers now use a "shift and stack" method, where multiple images of the same sky area are combined to strengthen the signal of very faint objects moving in orbit. Jupiter's new moons were identified by Scott Sheppard and David Tholen, while Saturn's batch was found by a team led by Edward Ashton.
Updated Planetary Moon Counts
- Saturn: 285 confirmed moons. Saturn remains the "Moon King," having gained 11 new moons
- Jupiter: 101 moons. The discovery of four new moons pushes Jupiter past the 100-moon milestone for the first time.
- Other Planets: The counts for other planets remain stable: Uranus (28), Neptune (16), Mars (2), and Earth (1). Mercury and Venus have no moons.
Why the Count Keeps Rising?
Advances in telescope technology and computational methods, such as the "shift and stack" technique, allow astronomers to track faint objects over time by layering multiple long-exposure images. Many of these moons are believed to be captured asteroids or fragments from ancient collisions.
