Saturn’s rings may be no more than 400 million years old
Saturn’s rings might have formed while trilobites scuttled about on Earth. Space dust has been accumulating on the icy halos for no more than 400 million years, researchers report in the May 12 Science Advances. The 4.5-billion-year-old planet appears to have acquired its iconic ornamentation relatively recently, says physicist Sascha Kempf of the University of Colorado Boulder. “We’re quite lucky to see a ring in the first place.” The rings of Saturn are made of countless icy particles, which become covered with dust as tiny meteoroids strike them. These dustings darken the rings’ complexion, like mud sullies snow on roads in winter. This cosmic staining was key to the new analysis, as was the now-defunct Cassini spacecraft’s Cosmic Dust Analyzer. From 2004 to 2017, the instrument caught dust-sized micrometeoroids moving around Saturn, measuring their velocity, mass, charge and composition. Kempf and colleagues identified about 160 particles — out of millions — that could have...