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Title: Scientists Find Seas on Saturn's Moon
Source:
Associated Press
URL Source: [None]
Published: Mar 13, 2007
Author: Associated Press
Post Date: 2007-03-13 21:12:49 by Brian S
Keywords: None
Views: 66
Comments: 3
(03-13) 17:37 PDT LOS ANGELES, (AP) -- 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. "They're very obvious. There's nothing subtle about them," said Cassini scientist Jonathan Lunine of the University of Arizona, Tucson. 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. While there's no scientific definition of what constitutes a lake or sea on Titan, the newly found features are significantly larger than previously discovered bodies of liquid on the frigid moon and should be considered seas, Lunine 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. Judging by their sizes and depths, Lunine said the newly discovered seas likely aren't responsible for replenishing the long-term methane found in the moon's atmosphere. Instead, Lunine said that source likely comes from underground methane reservoirs that vent to the surface. 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. ___ On the Net: Cassini mission: saturn.jpl.nasa.gov/home/index.cfm
Poster Comment: 
(1 image)Titan Sea and Lake Superior
March 13, 2007Full-Res: PIA09184
This side-by-side image shows a Cassini radar image (on the left) of what is the largest body of liquid ever found on Titan's north pole, compared to Lake Superior (on the right). This close-up is part of a larger image (see Titan (T25) Viewed by Cassini's Radar - Feb. 22, 2007) and offers strong evidence for seas on Titan. These seas are most likely liquid methane and ethane.
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#3. To: Brian S (#0)
Judging by their sizes and depths, Lunine said the newly discovered seas likely aren't responsible for replenishing the long-term methane found in the moon's atmosphere. Instead, Lunine said that source likely comes from underground methane reservoirs that vent to the surface Maybe Titans' critters breath out methane... Wouldn't that be awesome.
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Top • Page Up • Full Thread • Page Down • Bottom/LatestTitan 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.
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