In its final moments in space, NASA’s Cassini spacecraft made its last dive into Saturn’s atmosphere, giving scientists the information they needed to make an astonishing discovery. Using the measurements Cassini sent back, scientists were able to determine that Saturn didn’t always have rings, putting to rest an age-old scientific debate, according to a statement issued by researchers at the University of California, Berkeley. Saturn without rings? My childhood mind is totally blown.
The researchers say Saturn’s rings most likely formed around 10 million to 100 million years ago, which is around the time the dinosaurs were around, according to NASA. But the planet itself formed 4.5 billion years ago, says NASA, which is when our solar system was young itself. The scientists were able to figure out the age of the rings by having Cassini measure the rings’ mass during its 22 deep-dives between the planet and the rings, according to NASA. The level of the gravitational pull between the rings and the planet, says NASA, told the scientists how much mass the planet and the rings have — a lower mass means the rings are younger.
The scientific community has been debating how old Saturn’s rings are for a long time, according to BBC News. Some people thought the rings formed when the planet did, says BBC News, while others thought the rings formed relatively recently, perhaps by a crushed-up moon or a passing comet that got into a collision. "Previous estimates of the age of Saturn's rings required a lot of modelling [sic] and were far more uncertain,” Luciano Iess from Sapienza University of Rome, Italy, told BBC News. “But we now have direct measurements that allows us to constrain the age very well.”
Regardless of how old Saturn’s rings are, the sad reality for astronomy enthusiasts is that the rings are temporary. At least, on a cosmic scale. In December 2018, researchers published a study in the journal Icarus showing that Saturn is shedding its rings. Astronomers have known Saturn is losing its rings since the 1980s, but this new study reveals just how fast that process is happening, NBC News reports. At the rate the planet is shedding those beautiful swirls of rock and ice, says NBC News, they’ll be gone within 100 million to 300 million years. That’s unimaginably long for humans, but a mere blink-and-you-missed-it moment on the cosmic level, according to NBC News.
“The rings are basically being eaten away from the inside,” James O’Donoghue, a postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study, told NBC News. O’Donoghue’s findings also support these new findings out of UC Berkeley. Back in December 2018, he even told NBC News that their findings suggested that the rings were younger than Saturn. “If [the rings are] decaying fast now, they can’t have been around that long. The rings probably formed at the same time that the dinosaurs were about to be wiped out.”
Cassini concluded its 20-year mission with its last dive into Saturn, running out of fuel and destroying itself as it fell into the planet’s atmosphere, according to the news release. But the data it sent back in its final days offered the world some truly breakthrough information.
“These measurements were only possible because Cassini flew so close to the surface in its final hours,” Burkhard Militzer, a professor of earth and planetary science at the University of California, Berkeley, said in the news release. “It was a classic, spectacular way to end the mission.”