Reporting by Michael Kahn; Editing by Maggie Fox

Reuters - Mon Sep 22, 9:54 PM ET

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[Above: The most detailed look ever at Saturn's rings, obtained by the Cassini spacecraft, is shown in this handout image released by NASA May 24, 2005. (NASA/JPL/Reuters)]

Saturn's rings may be older than thought

LONDON (Reuters) - Saturn's rings may be more massive and older than previously thought, researchers said on Tuesday.

Findings to be presented at the European Planetary Science Congress in Germany bolster the possibility that the rings were formed billions of years ago.

Because the rings appear so clean and bright, some scientists had argued the they were much younger than Saturn, possible as little as 100 million years.

But closer examination shows the rings are rougher than they look.

"Because they are clumpy, the previous estimates of the mass of the rings are incorrect," Larry Esposito of the University of Colorado said in a telephone interview. "With more mass they can be older and still appear bright."

The rings encircling Saturn are one of the most dramatic features of the solar system. The other gaseous planets in the solar system -- Jupiter, Uranus and Neptune -- also are encircled by rings, but they are not as spectacular.

There is scientific debate over the origins of Saturn's rings. One idea is that the material that makes up the rings is debris from collisions involving moons orbiting the giant planet.

Another theory holds that the rings were formed at the same time as Saturn and from some of the same material that created the second-largest planet in the solar system.

Using a computer model and information from the U.S.-European Cassini spacecraft mission, Esposito and his team simulated colliding particles in Saturn's rings and their erosion by meteorites.

"Both Cassini observations and theoretical calculations can allow the rings of Saturn to be billions of years old," Esposito said in a statement.

Article link w/images:
http://news.yahoo.com/s/nm/20080923/ts_nm/us_saturn_rings

By Seth Borenstein - AP Science Writer - November 26, 2008

Plumes spewing from Saturn moon may contain water


[AP This file image provided by NASA on Oct. 10, 2007, shows geyser-like eruptions of ice particles and water]

WASHINGTON Astronomers looking at the spectacular supersonic plumes of gas and dust shooting off one of Saturn's moons say there are strong hints of liquid water, a key building block of life.

Their research, appearing in Thursday's issue of the journal Nature, adds to the growing push to explore further the moon Enceladus, as one of the solar system's most compelling places for potential life.

Using images from NASA's Cassini probe, astronomers had already figured that the mysterious plumes shooting from Enceladus' icy terrain contain water vapor. New calculations suggesting the gas and dust spew at speeds faster-than-sound make the case for liquid, said study lead author Candice Hansen of NASA's Jet Propulsion Lab in California. Her team calculated the plumes travel more than 1,360 mph.

Reaching that speed "is hard to do without liquids," Hansen said. While her paper offers more evidence building on what others have found, she added that her research is not the final proof of liquid water on Enceladus (pronounced en-SELL-ah-dus).

Other planetary scientists, such as Andrew Ingersoll at the California Institute of Technology, said the research is good, but that it is possible to achieve such speeds with ice particles and at cooler temperatures. So Hansen hasn't proven her case yet, he and other scientists said.

Carolyn Porco, the head of the Cassini camera team and an astronomer who didn't take part in Hansen's research, said "the evidence in my mind is building on liquid water." That moon, one of 60 circling Saturn, "has become the go-to place" for exploration in the outer planets, she said.

Europa, a moon of Jupiter, may have a liquid ocean beneath its frozen surface. But Enceladus, thought responsible for producing one of Saturn's rings, is more accessible, Hansen said. "Enceladus is sort of helpfully spewing out its innards," she said.

On the Net:
http://www.nature.com/nature/index.html

Yahoo News Link:
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