Possible Shore Line Spotted On Saturn's Moon

According to a NASA release, images from NASA's Cassini spacecraft show what appears to be a large shore line cutting across the southern hemisphere of Titan, Saturn's largest moon.

"This is the area where liquid or a wet surface has most likely been present, now or in the recent past," said Steve Wall, radar deputy team leader from NASA's Jet Propulsion Laboratory. "Titan probably has episodic periods of rainfall or massive seepages of liquid from the ground."

The news appeared to validate earlier theories that Titan once had large oceans of liquid methane (as opposed to water.) There may even still be some liquid present at or near the surface, according to project scientists.

"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 Wall.

Until Cassini entered orbit around Saturn last year and began taking images of the large moon, Titan was presumed to hold large active seas or oceans of liquid methane. No evidence has actually been found of any amounts of liquid on the surface, although discovery of the shore line might indicate such liquid existed in the past.

The images show what appears to be a shore line, dividing two distinct regions -- one bright and possibly rough, the other dark and smooth. The region is approximately 1050 miles long by 105 miles wide. Scientists say bright patterns within the dark region may indicate past flooding that has since receded.

Two distinct types of drainage and channel formation have been identified from the images, as well as those taken from two other passes in October 2004 and February 2005. Think of the difference between the scythe-like effects of rushing water on the formation of the Grand Canyon, versus a light rain. Channels etched into the icy crust of Titan appear to be evidence of the former, while wide smooth areas indicate evidence of past pools of liquid methane.

Scientists believe Titan's environment is somewhat similar to Earth's, before biological activity took over and altered the composition of our atmosphere. Titan's low temperature and the absence of water are significant differences.

FMI: www.nasa.gov