Published: September 20, 2005
Cassini Radar Images Show Dramatic "Shoreline" on Titan
Saturn moon might have been wet, liquid could still be present, NASA says
Images returned during Cassini's recent flyby of Saturn’s moon Titan show evidence of what appears to be a large shoreline cutting across the smoggy moon's southern hemisphere.
According to a September 16 NASA press release, this hints that the area was once wet, or that some kind of liquid is now present.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and Agenzia Spaziale Italiana, the Italian space agency.
"We've been looking for evidence of oceans or seas on Titan for some time," said Steve Wall, radar deputy team leader from NASA's Jet Propulsion Laboratory in California.
"This radar data is among the most telling evidence so far for a shoreline," he added.
The images show what looks like a shoreline dividing a distinct bright and dark region roughly 1,700 kilometers long by 170 kilometers wide. Directly to the right of a bright and possibly rough area is one that is very dark and smooth.
"Titan probably has episodic periods of rainfall or massive seepages of liquid from the ground," Wall said.
Brightness patterns in the dark area indicate that Titan might once have been flooded with liquid that now has partially receded. Bay-like features also lead scientists to speculate that the bright-dark boundary is most likely a shoreline.
Taken together with two other radar passes in October 2004 and February 2005, these images have identified at least two distinct types of drainage and channel formation on Titan.
Titan’s current environment is believed by scientists to be somewhat similar to that of Earth before biological activity forever altered the composition of Earth's atmosphere.
The major differences between Earth and Titan are the absence of liquid water and the very low temperature of the latter.
With a thick, nitrogen-rich atmosphere, Titan was until recently presumed to hold large seas or oceans of liquid methane. Cassini has been orbiting Saturn for a year and has found no evidence of these large seas.
This was Cassini's eighth of 45 Titan flybys planned during the spacecraft’s four-year tour. The next radar pass will be October 26.
The new radar images are available on NASA’s Web site.
Source: U.S. Department of State
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