Saturn’s rings are remarkably young, new study delivers strongest evidence yet

A new study has upended our understanding of the age of Saturn's magnificent icy rings, revealing that they are far younger than previously thought.

For decades, scientists have been boggled by the origin and age of these iconic rings. The latest research, led by physicist Sascha Kempf at CU Boulder, has delivered the strongest evidence yet that Saturn's rings are remarkably youthful - no more than 400 million years old.

The team came to this conclusion by studying dust. According to Kempf, an associate professor in the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder, the tiny grains of rocky material wash through Earth's solar system on an almost constant basis. In some cases, this flux can leave behind a thin layer of dust on planetary bodies, including on the ice that makes up Saturn's rings.

To find out the age of Saturn's rings, Kempf and his colleagues studied how rapidly this layer of dust builds up - a bit like telling how old a house is by running your finger along its surfaces.

The journey was arduous: between 2004 and 2017, the team diligently utilized the Cosmic Dust Analyzer, an instrument on NASA's Cassini spacecraft, to scrutinize minuscule particles of dust traversing Saturn's vicinity. Over those years, the researchers managed to amass a mere 163 grains originating from regions far beyond the planet's immediate surroundings. On the basis of their calculations, Saturn's majestic rings have likely been accumulating dust for a relatively short span of a few hundred million years.

For most of the 20th Century, scientists assumed that the rings likely formed at the same time as Saturn, Kempf said. However, this research concludes that the rings are much younger than the planet itself, which is about 4.5 billion years old.

The fate of Saturn's rings is uncertain. A recent study found that Saturn's rings are falling in on the planet as icy rain due to the planet's intense gravity.