Based on a new research paper, penned by O'Donoghue and six other researcher from institutions across the United States and United Kingdom, the combined effect of these two mechanisms is causing ring material to rain down onto Saturn at what NASA calls the "worst-case-scenario" rate of the estimates provided by the Voyager data.
"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", lead study author James O'Donoghue, a NASA fellow at the Goddard Space Flight Center, said in a statement.
Saturn's rings are mostly chunks of water ice ranging in size from microscopic dust grains to boulders several yards (meters) across. "This is relatively short, compared to Saturn's age of over four billion years".
It ain't St. Louis without the Gateway Arch, it ain't Mount Rushmore without the Presidents, and it sure ain't Saturn without the 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.
"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", O'Donoghue said.
This means the rings are disappearing at an "alarming speed" - and could be gone within 100 million years.
"It's not out of the question, I would say, that the rings might degrade on this kind of time scale", said Jeff Cuzzi of NASA's Ames Research Center in Moffett Field, California, who was not involved in the research. 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". The ring rain that falls into the gas giant is so abundant that the icy bands could disappear in 300 million years, or even sooner.
Once there, the icy ring particles vaporize and the water can react chemically with Saturn's ionosphere.
Research has already shown that Saturn's rings are fairly young. In October, NASA released findings from the hair-raising dive its Cassini spacecraft made between the innermost edge of Saturn's rings and the uppermost reaches of its atmosphere, shortly before its planned suicide plunge into the planet in September of 2017.
The team also discovered a glowing band at a higher latitude in the southern hemisphere. Solar radiation and clouds of plasma from space rock impacts continuously bombard the water ice and other particles that make up the rings.
The spacecraft took a census of the particles it encountered that were falling toward the planet; the amount of ring rain Cassini caught is "completely consistent" with O'Donoghue's measurements, Spilker said. Since ultraviolet light from the Sun charges the ice grains and makes them respond to Saturn's magnetic field, varying exposure to sunlight should change the quantity of ring rain.
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It's likely the combination of the two that prompted selling - not least concerns over growth stemming from the U.S. Energy Information Administration.