Astronomers discover 128 new moons orbiting Saturn

Saturn has cemented its status as the planet with the most moons, leaving Jupiter trailing behind. Astronomers have confirmed the discovery of 128 additional moons orbiting Saturn, bringing its total to an astonishing 274. This surge in moon count nearly doubles what was previously known and is more than all the other planets’ moons combined.

The findings, led by an international team of astronomers using the Canada-France-Hawaii Telescope (CFHT), were officially recognized by the International Astronomical Union (IAU) and published in the journal arXiv.

The research team, which included scientists from Taiwan, Canada, the U.S., and France, used a technique called "shift and stack" to detect these small celestial bodies.

By repeatedly observing the same sky regions between 2019 and 2021 and later in 2023, they stacked multiple images together to enhance the visibility of faint moons. This painstaking process resulted in the detection of 128 new moons, all classified as irregular moons.

Unlike regular moons, which formed around their host planet in near-circular, equatorial orbits, irregular moons follow highly elliptical and inclined paths. These moons were likely captured by Saturn’s gravity billions of years ago and have since been shaped by violent cosmic events. Their erratic orbits are a stark contrast to moons like Earth’s, which formed through a massive collision and remain relatively stable.

“These moons are a few kilometers in size and are likely all fragments of a smaller number of originally captured moons that were broken apart by violent collisions, either with other Saturnian moons or with passing comets,” said Dr. Brett Gladman, a professor in the University of British Columbia’s (UBC) Department of Physics and Astronomy.

Among Saturn’s irregular moons, astronomers have identified three distinct orbital groups: the Inuit, Gallic, and Norse groups. The Norse group, which consists of moons following retrograde orbits, dominates in both number and variation in inclination. The latest discoveries add significantly to this population, reinforcing the theory that a massive collision occurred in Saturn’s system within the last 100 million years.

Astronomers have long suspected that Saturn’s irregular moon system has a history of catastrophic impacts. The discovery of so many new moons near the Mundilfari subgroup, a cluster of retrograde moons, strengthens this hypothesis. The Mundilfari moons, named after a figure in Norse mythology, likely formed when a larger captured moon shattered into smaller fragments due to a collision.

In a 2021 paper, Dr. Edward Ashton and colleagues hypothesized that a recent large-scale collision in the Saturnian system shaped its current moon distribution. “We hypothesize that the steep Saturnian size distribution, from D = 4 km down to 3 km, is a signature of a significant 'recent' collision (or collisions) in its irregular moon system,” Ashton stated. These findings suggest that Saturn’s irregular moons are dynamic remnants of a once more massive moon population.

The discovery is also significant in understanding how giant planets capture and retain moons over time. “These studies reveal that the giant planets captured some moderate-sized moons more than 4 billion years ago as the giant planets formed, and we are now seeing moons that are mostly the fragments of those originally captured moons,” said Dr. Gladman.

With 274 confirmed moons, Saturn’s reign as the planet with the most moons seems secure, at least for now. Jupiter currently has 95 confirmed moons, and while more discoveries may emerge, it is unlikely to surpass Saturn.

“Based on our projections, I don’t think Jupiter will ever catch up,” Ashton remarked. Advances in observational technology may reveal additional small moons, but for now, the limits of detection appear to have been reached.

“With current technology, I don’t think we can do much better than what has already been done for moons around Saturn, Uranus, and Neptune,” said Ashton.

Saturn’s extensive moon system remains one of the most intriguing aspects of the solar system. Many of its moons, both large and small, interact with its iconic rings, shaping them and creating gaps like the Cassini Division. Some researchers believe that Saturn’s rings themselves may have originated from past moon destruction events.

As exploration continues, new insights into these celestial bodies will further our understanding of planetary formation and the dynamic history of the outer solar system.

Note: Materials provided above by The Brighter Side of News. Content may be edited for style and length.

Like these kind of feel good stories? Get The Brighter Side of News' newsletter.