Few parts of our galaxy have captured the human imagination like the beautiful, colorful rings of Saturn.
But like all natural things, they will disappear, new research suggests. And so on. However, as soon as 100 million years, in the beginning.
Assuming the human species lives another thousand years, that means the rings will still be around long enough for any possible space tourism.
In the context of the universe’s timeline, however, Saturn’s rings have a much shorter lifespan than previously believed. They probably formed during the last few million years, when dinosaurs roamed the Earth.
This was Cassini’s view from orbit around Saturn on Jan. 2, 2010. Image credit: NASA
That’s according to a new analysis of data from NASA’s Cassini mission, which orbited the gas giant between 2004 and 2017. The study, published on May 15 in the journal Icarus, suggests that the rings formed long after the formation of Saturn itself.
More importantly, Cassini data suggests that the rings are losing tons of mass every second.
With other studies reaching similar conclusions this month — one in Science Advances and a second in Icarus — it’s possible that astronomers can rely on this new view of Saturn’s rings.
“Our inescapable conclusion is that Saturn’s rings must be young by astronomical standards, only a few hundred million years old,” Indiana University Astronomy Professor Emeritus Richard Durisen said in a news release. “If you look at Saturn’s satellite system, there are other possibilities that something spectacular happened there a few hundred million years ago.
Saturn’s rings show their subtle colors in this view taken on August 22, 2009, by NASA’s Cassini spacecraft. Photo: NASA
Controversy about Saturn’s rings
The possible origin of Saturn’s icy rings has long intrigued scientists – even more so than its many moons.
In the new study, Durisen worked with Paul Estrada, a research scientist at NASA’s Ames Research Center. The two have argued for years that Saturn’s rings are small by cosmic standards, as older rings may be darkened by the impact of interplanetary meteoroids, according to a release from Indiana University.
That view holds true in their latest analysis of data collected by NASA’s Cassini spacecraft over the course of 13 years. In its 2017 Grand Finale, the spacecraft made 22 orbits, often passing between Saturn and its rings. The data enabled Durisen and Estrada to estimate the rings’ age and longevity.
The results? Meteoroids will inevitably contaminate Saturn’s rings. They don’t have much time to do that yet because the rings are still young. As the rings suffer repeated impacts from these flying space rocks, their dusty core is slowly eroded, with tons of rings drifting down toward Saturn every second.
Two types of dramatic shadows play across Saturn’s surface in this view from NASA’s Cassini spacecraft from Dec. 6, 2007. Photo: NASA
It’s a view of a cosmic cycle that may have occurred many times across the Milky Way galaxy – long before Earth-orbiting telescopes and NASA spacecraft.
“We have shown that large rings like Saturn’s do not last long,” said Estrada. “One can speculate that the small rings around some of the ice and gas giants in our solar system are the remnants of rings that were once as large as Saturn’s. Perhaps in the not so distant future, astronomically speaking, after the rings of Saturn have been ground down, they will look like the obstacles of Uranus.”
Want to know more? Check out this Indiana University video of Durisen explaining his research.
