Tuesday, March 13, 2007

Hydrocarbon Seas Found on Titan

The Cassini probe, which has been surveying Saturn's largest moon Titan, has spotted what appear to be large, liquid bodies of hyrdrocarbons as large as lakes and small seas. Yahoo News AP wire excerpt:

LOS ANGELES - Scientists for the first time have discovered what appear to be sea-size bodies of liquid on the surface of Saturn's largest moon, including one about as big as the Caspian Sea on Earth.

The discovery by the international Cassini spacecraft was welcomed by researchers, who have long theorized that Titan possessed hydrocarbon seas because of methane and other organic compounds in its thick, largely nitrogen atmosphere. Until now, Cassini had only spotted clusters of small lakes on the planet-size moon.

Researchers using visual and radar imaging uncovered evidence of at least two seas on Titan's hazy north pole. Cassini's camera last month imaged a large, irregular feature stretching 680 miles long with a surface area similar to the landlocked Caspian Sea. Its radar instrument swept over the feature's northern tip and determined it likely contains liquid methane or ethane because of its smooth appearance. However, scientists don't know whether the entire area is filled with liquid.

The spacecraft also discerned another body one-fifth the size of Titan's "Caspian Sea." With a surface area of about 46,000 square miles, it is larger than Lakes Superior and Ontario combined, scientists said.

Results were presented Tuesday at the annual Lunar and Planetary Science Conference in Texas.

Titan is one of the few objects in the outer solar system that possesses a significant atmosphere and scientists have long puzzled over its source. Methane is a flammable gas on Earth but liquid on Titan because of the moon's intense atmospheric pressure and cold.

The discovery raises questions about why hydrocarbon pools are concentrated at Titan's poles, said Carolyn Porco, a Cassini imaging scientist from the Space Science Institute in Boulder, Colo. It also gives researchers confidence that a feature the size of Lake Ontario spied on the moon's south pole two years ago may also be liquid-filled, she said.

In 2005, Cassini launched a probe that parachuted to the surface of Titan where it found evidence of an active world with liquid methane rain and a landscape of ridges, peaks and features formed by erosion. Cassini, on a mission to study the ringed planet and its many moons, is a project of NASA,
the European Space Agency and the Italian Space Agency. The spacecraft is managed by NASA's Jet Propulsion Laboratory in Pasadena.

Cassini has been, and will continue to be an unqualified success. It has shown that this moon, which is nearly as large as Mars, is a dynamic world that has many surprises and promises. With every new finding, Titan's value as a potential base of operations for the outer Solar System grows. Now it is up to us to recognize and take advantage of the opportunity Titan continues to present.

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