Agencies SYDNEY

Saturn's moon count surged by 128, reaching 274, the most in our solar system, thanks to discoveries by Edward Ashton's team at Academia Sinica. The International Astronomical Union officially recognized these new moons, solidifying Saturn's dominance over Jupiter. Historically, Jupiter led with Galileo's 1610 discovery of its four largest moons. Forty-five years later, Saturn’s first known moon, Titan, was discovered by Dutch astronomer Christiaan Huygens.

The recent 128 moons were found by stacking images from the Canada France Hawaii telescope. Past discoveries also came from spacecraft like Voyager 1 and Cassini, and "ring-plane crossings”. Voyager 1 identified Atlas, while Cassini added seven more. A ring-plane crossing –when Saturn's rings appear to vanish from Earth – reveals hidden moons. Titan and 12 others were found during these events. Two more ring-plane crossings are expected in in March and November, 2025.

The newly discovered moons are small, just kilometers across, and are all "irregular". Unlike regular moons formed with their planet, irregular moons are captured planetesimals, later fragmented by collisions. This influx establishes Saturn's unprecedented lunar dominance. In 2019, Saturn surpassed Jupiter with the discovery of 20 new moons. This took the count to 82 for Saturn and 79 for Jupiter.

Just a few years later, in February 2023, Jupiter took the lead with 12 new moons, beating Saturn's 83 moons at the time. Only a short time later, still in 2023, the same astronomers who discovered the recent 128 moons discovered 62 moons orbiting Saturn. This placed the ringed planet firmly in the lead.