for National Geographic News
Saturn's moon Enceladus is spewing giant geysers of ice that have sandblasted several nearby moons, making them some of the solar system's most reflective objects, research shows.
A new study published in the journal Science bills Enceladus as "a cosmic graffiti artist, caught in the act."
Last spring NASA's Cassini spacecraft showed what appeared to be geysers streaming out from Enceladus's surface.
(Read related story: "Saturn Moon Has Water Geysers and, Just Maybe, Life" [March 10, 2006].)
One theory suggests that the plumes are created by liquid water below the surface that freezes instantly in the moon's frigid surface climate.
"Enceladus coats itself, snows on itself, and distributes pure water ice particles on its surface," said lead study author Anne Verbiscer, an astronomer at the University of Virginia.
The fluffy texture of this icy coating allows Enceladus to reflect more of the sun's light than any other body in the solar system.
And its neighbor moons are nearly as bright, thanks to the sprays of ice they receive from Enceladus, the researchers say.
"The message seems to be, the closer you are to Enceladus the brighter your surface will be, because it has been coated with fine ice particles from the Enceladus plumes," said Andrew Ingersoll, a planetary meteorologist at the California Institute of Technology, who was not an author of the new study.
"Of course, we still haven't figured out why Enceladus is so special."
Signs of Life?
Like many other scientists, Verbiscer believes that the massive geysers also created Saturn's giant E-ring—the planet's fuzzy-looking outermost ring—and sandblasted many of the other moons orbiting within it.
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