Cassini Mission Reveals Saturn's Moon has Earthly Features

Washington, 24 Jul 2006

A region on the surface of Saturn’s moon, Titan, appears to look much like Earth, with rivers, lakes and plains, according to radar images transmitted by NASA’s Cassini spacecraft.

“Surprisingly, this cold, faraway region has geological features remarkably like Earth,” said Jonathan Lunine, the mission’s interdisciplinary scientist at the University of Arizona-Tucson.

The mission, managed by NASA’s Jet Propulsion Laboratory (JPL) in California, is a cooperative project among NASA, the European Space Agency (ESA) and Agenzia Spaziale Italiana, the Italian space agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate.

The unmanned, scientific mission launched in 1997, and reached the ringed planet in 2004 on a four-year mission to study Saturn and its 31 moons. Cassini sent the ESA's Huygens probe drifting down to the surface of Titan in 2005. (See related article .)

The region of current interest is known as Xanadu, first discovered by NASA’s Hubble Space Telescope in 1994, according to a July 19 JPL news release. Infrared imaging reveals it as a striking bright spot with a surface modified by winds, rain and the flow of liquids, probably methane or ethane.

Located in the outer reaches of the solar system, Titan is much colder than Earth, with an estimated average surface temperature of 191 below zero Celsius, NASA says.

"Although Titan gets far less sunlight and is much smaller and colder than Earth, Xanadu is no longer just a mere bright spot, but a land where rivers flow down to a sunless sea," Lunine said.

Observations by the Huygens probe and by NASA's Voyager strongly hint that both methane rain and dark orange hydrocarbon solids fall like soot from the moon's dark skies.

On Xanadu, liquid methane might fall as rain or trickle from springs. Rivers of methane might carve the channels and carry off grains of material to accumulate as sand dunes elsewhere on Titan.

"This land is heavily tortured, convoluted and filled with hills and mountains," said Steve Wall, the Cassini radar team's deputy leader at JPL.

"There appear to be faults, deeply cut channels and valleys,” he added. “Also, it appears to be the only vast area not covered by organic dirt. Xanadu has been washed clean. What is left underneath looks like very porous water ice, maybe filled with caverns.”

Over the next two years, Cassini will fly by Titan 29 times, providing future opportunities for scientists to study what Wall likens to “a newly discovered continent.”

The text of the press release is available on the JPL Web site.

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