Saturn's orbit alters Titan's topography

PASADENA, Calif., Nov. 30 (UPI) -- NASA says the eccentricity of Saturn's orbit might have produced the unusually uneven pattern of lakes over the polar regions of Saturn's largest moon, Titan.

Researchers at the California Institute of Technology, NASA's Jet Propulsion Laboratory and other institutions suggest Saturn's oblong orbit around the sun exposes different parts of Titan to different amounts of sunlight, which affect cycles of precipitation and evaporation in those areas.

The researchers say imaging data from NASA's Cassini spacecraft show liquid methane and ethane lakes in Titan's northern high latitudes cover 20 times more area than lakes in the southern high latitudes. The Cassini data also show significantly more partially filled and now-empty lakes in the north.

The researchers say that asymmetry is not likely to be a statistical fluke because of the large amount of data collected by Cassini in its five years surveying Saturn and its moons.

A paper describing the research appears in the early online edition of the journal Nature Geoscience.