Is There an Ice-Spewing Volcano on Titan? : Big Pic

Dec. 15, 2010 -- It's been a long-standing theory that the frozen dwarf planets and moons of the outer solar system may possess geological mechanisms that create cryovolcanoes. Now, scientists working with data beamed back by the NASA Cassini Equinox mission think they've spotted strong evidence of an "ice volcano" on the Saturnian moon Titan.

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Cryovolcanoes aren't like any volcano you find on Earth, even though planetary scientists think they might look similar. On Titan, the only solar system satellite massive enough to hold on to a substantial atmosphere, the temperature hovers at around 94 K (or -290 Fahrenheit).

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These frigid conditions ensure that elements that can be found in gaseous form on Earth are in liquid or even solid form on Titan's surface. Indeed, Titan is the only other solar system body apart from Earth to have liquid lakes -- but these lakes aren't filled with water, they're filled with liquid methane.

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Beneath the ice-rich Titan surface, it is assumed that geological processes may cause heating, thus melting these subterranean ices. Like the volcanoes on Earth, the heated material needs to be vented to the surface. But unlike Earth's molten rock, it's a slushy ice mix that is thought to ooze out of cryovolcanoes, creating 1,000 meter-high peaks, deep volcanic craters and finger-like flows.

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Using 3D elevation data from Cassini (visualized above), scientists think they've spotted a suspicious-looking mountain feature on Titan that could be one of these cryovolcanoes.

"This is the very best evidence, by far, for volcanic topography anywhere documented on an icy satellite," said Jeffrey Kargel, a planetary scientist at the University of Arizona, Tucson, at this week's American Geophysical Union (AGU) meeting in San Francisco. "It's possible the mountains are tectonic in origin, but the interpretation of cryovolcano is a much simpler, more consistent explanation."

The feature in question is located in Titan's Sotra Facula region and, if confirmed to be a cryovolcano, it may explain why Titan's atmosphere is so methane rich.

"Cryovolcanoes help explain the geological forces sculpting some of these exotic places in our solar system," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "At Titan, for instance, they explain how methane can be continually replenished in the atmosphere when the sun is constantly breaking that molecule down."

Image credit: NASA/JPL-Caltech/USGS/University of Arizona.

-- Ian O'Neill, Discovery News