Saturn’s Rings Age Revealed

Saturn formed in the early years of the Solar System approximately 4.5 billion years ago. Until recently, it seemed to be impossible to figure out the age of its ring system. The new data collected during the final mission of NASA’s Cassini showed that there was the time when Saturn existed without its rings.

Having used a coherent radio link between Earth and the Cassini spacecraft, a researcher of Sapienza University of Rome, Luciano Iess, acquired new information about Saturn’s gravitational field. Diving between the planet and its rings, the probe collected useful gravity data, which allowed scientists to determine that the rings may have formed later than the planet itself. Based on remote-sensing data, they separated gravity of Saturn from the gravitational effect of its rings and finally found the rings’ mass.

Luciano Iess’s research is based on a connection between the mass and the age of the rings previously made by scientists. Lower mass points to a younger age, because the rings, which are bright and mostly made of ice, would have been contaminated and darkened by interplanetary debris over a longer period. According to the findings they are contemporaries of dinosaurs and were formed in the last 100 million years.

Scientists are currently working on the issue of how Saturn's rings formed. The new evidence of young rings lends credence to theories that they formed from a comet that wandered too close and was torn apart by Saturn's gravity — or by an event that broke up an earlier generation of icy moons.