Scientists around the world have long been trying to uncover the origin of Saturn’s rings, and now, using data from the now-defunct Cassini spacecraft, they are learning about a collection of mini-moons orbiting between Saturn’s rings.
Cassini plunged into Saturn’s atmosphere in September 2017 after skimming past its rings. Researchers have now revealed some of the sophisticated findings from its data in the journal Science. Researchers named the collection of mini-moons for gods from Greek mythology: Pan, Daphnis, Atlas, Pandora and Epimetheus. The mini-moons are estimated to measure between five and 72 miles in diameter. While they vary in shape, they are mostly roundish or resemble potatoes. They are positioned in small gaps between Saturn’s rings.
Cassini spent 13 years in Saturn’s vicinity and focused on the planet’s rings in the last year of its operation. It inserted itself between the rings and sent a lot of valuable data back to Earth before plunging into the atmosphere after 20 years of operation. Although 4,000 scientific articles describing findings from Cassini’s data have been published so far, the well of data has still not run dry.
“I want to work for at least another decade on this stuff,” planetary astronomer Bonnie Buratti of NASA’s Jet Propulsion Laboratory told AFP.
The new study on the collection of mini-moons also targets on a long-held theory which suggests Saturn’s rings and moons may all have come from the same celestial body, which may have collided with another body and then shattered into the pieces which later formed rings.
“The largest fragments became the core of these ring moons,” explained Buratti, “and what happened was the moons continued to accumulate particles from the rings—this is what we saw close up, the accumulation of the ring material onto the moon.”
These findings help researchers explain the gaps behind the moons. The researchers worked on this study for over 30 years, and according to Buratti, it represents a “remarkable collaboration.”
Researchers also want to determine how old the rings actually are. A study published earlier this year suggests the rings may be considerably younger than previously thought. In that study, researchers estimated them to be between 100 million and 1 billion years old. However, other theories have offered different scenarios suggesting they are much older. Another study published in December suggests that the rings are shedding material and could disappear entirely in the future.
“Science is never cut and dried—you never have your final answer,” Buratti said.