14 DAY TRIAL // Images returned during Cassini's recent flyby of Titan show captivating evidence of what appears to be a large shoreline cutting across the smoggy moon's southern hemisphere. Hints that this area was once wet, or currently has liquid present, are evident.
"We've been looking for evidence of oceans or seas on Titan for some time. This radar data is among the most telling evidence so far for a shoreline," said Steve Wall, radar deputy team leader from NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The images show what looks like a shoreline dividing a distinct bright and dark region roughly 1,700 kilometers long by 170 kilometers wide (1,060 by 106 miles). Directly to the right of a bright and possibly rough area is one that is very dark and smooth.
"This is the area where liquid or a wet surface has most likely been present, now or in the recent past, said Wall. "Titan probably has episodic periods of rainfall or massive seepages of liquid from the ground."
The brightness patterns in the dark area indicate that it may once have been flooded with liquid that may now have partially receded. Bay-like features also lead scientists to speculate that the bright-dark boundary is most likely a shoreline.
Titan has an environment somewhat similar to that of Earth before biological activity forever altered the composition of Earth's atmosphere. The major difference on Titan, however, is the absence of liquid water, and Titan's very low temperature. With a thick, nitrogen-rich atmosphere, Titan was until recently presumed to hold large seas or oceans of liquid methane. Cassini has been in orbit around Saturn for a year and has found no evidence for these large seas.