Scientists have largely agreed that Saturn’s rings are billions of years old, a conclusion based on 10 years of data gathered by NASA’s Cassini probe, which has been orbiting the planet since 2004.
However, new research published in the journal Icarus has indicated that the C ring, one of Saturn’s inner rings, may have formed around the same time dinosaurs walked the Earth.
Attempts to resolve a specific age for Saturn’s rings have been delayed by an ability to ascertain the rings’ specific composition. We know they are mostly made up of water ice chunks, some up to several feet in size. We also know these particles are constantly being ‘polluted’ by micrometeoroids from the outer Solar System’s Kuiper belt. The ratio of these two ingredients could provide details about Saturn’s age, but has proven elusive.
Saturn’s C Ring Proves Difficult to Study
Because the ring ice is opaque to most wavelengths of light, it masks unknown quantities of foreign rocky material. Learning the precise ratio is valuable to researchers because foreign material deposition should have occurred in a predictable way. Also, knowing the average micrometeoroid flux has allowed study researchers reach an approximate of age for the C ring.
Cassini’s Titan Radar Mapper is tuned to the precise wavelength in the microwave end of the electromagnetic spectrum to break through the ice, gauging the complete ring composition, instead of the exterior layers.
Study researchers examined information from Saturn’s C ring, which is the most ‘polluted’ as a result of its relatively low mass, making it simpler to obtain a greater ratio of non-icy material. After many months of going through Cassini information, the study team found most regions in the C ring were comprised of 1 to 2 percent rocky silicates. This ratio combined with estimates of the micrometeoroid flux led researchers to determine the C ring is between 15 and 100 million years old, billions of years younger than previously thought.
“None of the current origin scenarios predict the rings are likely younger than 3.8 billion years old,” study author Zhimeng Zhang, from Cornell University, told Sci-News.com. “This will force a rethinking of ring origin models.”
Image credit: NASA