The hydrocarbon lakes that have recently been discovered on Saturn's moon Titan are not distributed equally across the hemispheres, reports a study online this week in Nature Geoscience. The difference in lake coverage between the hemispheres could be the result of seasonal variations in Saturn's orbit around the Sun.

Oded Aharonson and colleagues quantified the distribution of the lakes and basins that had been identified by the Cassini orbiter on Titan's surface. They found that in the northern hemisphere, the fraction of the surface covered with lakes and basins is much higher than in the southern hemisphere.

The authors propose that Titan is governed by a vigorous hydrological cycle that varies on a timescale of tens of thousands of years and leads to modification of the planet's surface ― similar to the Earth's glacial cycles.