NASA Says Saturn Is Losing Its Rings, and They Will Be Gone in 300 Million Years

NASA has said Saturn's iconic rings will be gone in 300 million years—a blink of an eye cosmically speaking. A study by scientists from the space agency found the planet had been losing mass from its rings at the maximum rate predicted—enough to fill an Olympic swimming pool in just half an hour.

Scientists had previously found Saturn's rings were losing mass from data sent back from the Voyager 1 and 2 spacecraft. The rate of loss was further refined by Cassini, which completed its mission by plummeting through Saturn's rings in September last year.

Read more: NASA's Cassini discovers big, 'empty' void between Saturn's rings

The latest research, published in the journal Icarus, provided new analysis of Saturn from observations obtained with the Keck telescope located on Mauna Kea, Hawaii. The team looked at previous research about the planet's "ring rain" that tracked how much mass was being lost. They then used measurements from Keck to "confirm and expand on existing models." In doing so, they discovered Saturn's rings were losing mass at a "worst case scenario" rate, NASA said.

"We estimate that this 'ring rain' drains an amount of water products that could fill an Olympic-size swimming pool from Saturn's rings in half an hour," lead author James O'Donoghue, from NASA's Goddard Space Flight Center, said in a statement. "From this alone, the entire ring system will be gone in 300 million years, but add to this the Cassini-spacecraft measured ring-material detected falling into Saturn's equator, and the rings have less than 100 million years to live. This is relatively short, compared with Saturn's age of over four billion years."

Saturn's rings are being dragged into its main body by gravitational pull from the planet. It is not clear if the rings, which are mostly made up of water-ice, formed at the same time as the planet, or if Saturn gained them at some point later in its history. If they were acquired at a later date—which the latest findings suggest—it is thought they could have formed when small moons, asteroids and comets got caught up by the intense gravitational pull and collided.

The latest study indicates that Saturn got its rings less than 100 million years ago, so anyone observing the planet before this would have seen a very different celestial body. "We are lucky to be around to see Saturn's ring system, which appears to be in the middle of its lifetime," O'Donoghue said. "However, if rings are temporary, perhaps we just missed out on seeing giant ring systems of Jupiter, Uranus and Neptune, which have only thin ringlets today."

Researchers now hope to see how the ring rain changes during different seasons—ultraviolet light from the sun might change the quantity of the mass being lost. Concluding, the team wrote: "Assuming that our Saturn northern Spring measurement represents all seasons, and that the rings are able to reorganize over time, the ring rain mechanism alone will drain Saturn's rings to the planet in 292 million years."

Saturn rings
Artist's impression of how Saturn could look in the next 100 million years. NASA/Cassini/James O'Donoghue