Titan's Surface Could Hide Ocean

March 20, 2008 -- An ocean may be hiding below the crust of Saturn's biggest moon, Titan, teaming up with its dense atmosphere to cause shifts on the moon's surface, a study said Thursday.

Years worth of radar observations from the Cassini probe showed that features of Titan's geology had drifted from a fixed point of reference, indicating that the moon's rotation had temporarily sped up, the study said.

Powerful winds could be rocking Titan back and forth around its axis, meaning the moon's massive atmosphere speeds up its rotation speed and slows it down later in the year, said the study, published in the journal Science.

But for the atmosphere to be able to change the moon's surface, it would need help from an underground ocean flowing between Titan's crust and core, wrote researchers from Johns Hopkins University, led by astronomer Ralph Lorenz.

Titan is the second-largest moon in the solar system and is about 50 percent larger than Earth's moon.

An ocean may also be hiding under the surface of another Saturn moon, Enceladus, according to NASA.

A close overflight by Cassini on March 12 found ice geysers erupting between the cracks of Enceladus'frozen south pole. Ice samples and other material collected by Cassini may also indicate the presence of organic molecules.

Cassini, a NASA spacecraft, was launched in 1997 attached to the European Space Agency's Huygens probe. The joint Cassini-Huygens mission is the first devoted to the exploration of Saturn.

Huygens separated from Cassini in December 2004 to land on Titan, while Cassini went into orbit around Saturn after a seven-year voyage across some 2.2 billion miles of space.

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