Every nice parent tells their kid that they’re good looking, but the truth is that some kids are better looking than others. In the solar system family, that kid is Saturn, the giant, ringed diva of the planetary siblings. The sixth planet’s iconic icy rings swirl around it like a dazzling belt, the most extensive of their kind in the solar system. But as new data from NASA suggests, Saturn’s days in the spotlight are numbered.
Up close, Saturn’s delicate rings are made up of millions of particles of water ice. Their size ranging from microscopic dust grains to huge boulders, these icy chunks are all susceptible to becoming charged by UV light from the sun or nearby plasma clouds, and scientists think that when that happens, the chunks begin to drop out of orbit toward the planet, like flies. As the video above illustrates, the rings slowly dissipate as these chunks rain down into Saturn’s atmosphere.
In about 100 million years, say NASA scientists, there’ll be no more “rain” left to fall.
As "ring rain" continues to fall, Saturn may change like this in the next 100 million years.
The idea that Saturn’s rings are disappearing was first proposed after Voyager 2, one of the two spacecraft NASA sent to explore the outer planets of the solar system, sent home pictures of Saturn in 1981. In the photos, the dark, narrow bands circling the planet suggested the existence of “ring rain,” wrote NASA scientist Jack Connerney, Ph.D., in a 1986 paper. Now, NASA’s new analysis of data collected with the Keck telescope in Mauna Kea, Hawaii in 2011 confirms that ring rain is falling, and it’s falling fast. Saturn’s rings are disappearing at the maximum rate estimated in 1986.
James O’Donoghue, Ph.D., lead author of the new paper in the journal Icarus, said: “We estimate that this ‘ring rain’ drains an amount of water products that could fill an Olympic-sized swimming pool from Saturn’s rings in half an hour.”
Ring rain falls when the charged ice particles get sucked in by Saturn’s enormous magnetic field, which in turn leads them to melt in the upper atmosphere and wash away haze. The highly organized magnetic field causes all this melting to happen in relatively straight lines, which appeared dark in the photos sent home by Voyager 2 (who, by the way, recently left the solar system for good).
This discovery also sheds light on just how old Saturn’s rings are. Nobody is sure where, when, or how the planet got its famous ornaments, but this study supports the theory that the 4-billion-year-old planet picked them up only recently — about 100 million years ago.
Saturn's rings are divided into subsections. Ring C was once as dense as B, an estimated 100 million years ago.
Data on the planet’s B ring and C ring, illustrated above, suggests that the C ring was once as dense as its B ring counterpart, and the newly confirmed rate of “ring rain” suggests it would have taken 100 million years for it to get to that point, assuming both rings started at the same density.
As far as planetary life cycles go, 100 million years is just a blip — not unlike a human’s 15 minutes of fame. Saturn, too long dependent on its good looks, might want to start thinking on a rebrand.
