Hydrocarbon rains may fill lakes in Titan

Washington, Jan 30 (ANI): Recent images from NASA's Cassini spacecraft affirm the presence of lakes of liquid hydrocarbons in Titan, by capturing changes in the lakes brought on by rainfall.

For several years, Cassini scientists have suspected that dark areas near the north and south poles of Saturn's largest satellite might be liquid-filled lakes.

Now, recent pictures of Titan's South Polar region reveals new lake features not seen in images of the same region taken a year earlier.

The presence of extensive cloud systems covering the area in the intervening year suggests that the new lakes could be the result of a large rainstorm and that some lakes may thus owe their presence, size and distribution across Titan's surface to the moon's weather and changing seasons.

The high-resolution cameras of Cassini's Imaging Science Subsystem (ISS) have now surveyed nearly all of Titan's surface at a global scale.

An updated Titan map, released by the Cassini Imaging Team, includes the first near-infrared images of the leading hemisphere portion of Titan's northern "lake district" captured on August 15-16, 2008.

These ISS images complement existing high-resolution data from Cassini's Visible and Infrared Mapping Spectrometer (VIMS) and RADAR instruments.

Such observations have documented greater stores of liquid methane in the northern hemisphere than in the southern hemisphere.

As the northern hemisphere moves toward summer, Cassini scientists predict large convective cloud systems will form there and precipitation greater than that inferred in the south could further fill the northern lakes with hydrocarbons.

Combined with previous analyses, the new observations suggest that underground methane reservoirs must exist.

Titan is the only satellite in the solar system with a thick atmosphere in which a complex organic chemistry occurs.

According to Dr. Elizabeth Turtle, Cassini imaging team associate at the Johns Hopkins University Applied Physics Lab in Laurel, Maryland, "It's unique. How long Titan's atmosphere has existed or can continue to exist is still an open question."

That question and others related to the moon's meteorology and its seasonal cycles may be better explained by the distribution of liquids on the surface. (ANI)