Ask anyone who is interested and space and astronomy wise and there’s a good chance that they will tell you that it’s because they once looked through a telescope at Saturn’s rings. It’s a jaw-dropping moment to see them with your own eyes, but new evidence suggests that they exist for but a blink of an eye in cosmic time—and are already in old age.
Saturn’s seven rings—which stretch about 175,000 miles from the planet’s surface and are about 98% ice—are no older than 400 million years, according to a new paper published today in the Science Advances. Saturn itself is about 4.5 billion years old.
They could be gone in 100 million years, according to NASA, pulled into Saturn by gravity.
“If the rings are short lived … why are we seeing them now?” said Sascha Kempf, associate professor in the Laboratory for Atmospheric and Space Physics (LASP) University of Colorado Boulder. “It’s too much luck.”
For most of the 20th century scientists assumed that the rings formed at the same time as the planet, but evidence has been building up in recent years that suggest they are far younger.
Why Saturn has rings remains a mystery. They may have formed when the planet’s gravity tore apart one of its moons about 160 million years ago, claims a paper published in 2022.
They’re the product of dust in the solar system settling on the ice that makes up Saturn’s rings, according to the new research, which arrived at the age for Saturn’s rings by studying how quickly dust builds up in the Saturn system.
The data came from the Cosmic Dust Analyzer instrument on NASA’s Cassini probe, which orbited the ringed planet between 2004 and 2017. It’s estimated that less than a gram of dust per square foot are added to Saturn’s rings each year.
“If you have a clean carpet laid out, you just have to wait,” said Kempf. “Dust will settle on your carpet. The same is true for [Saturn’s] rings.”
Wishing you clear skies and wide eyes.