Titan's Northern Lakes Caused by Saturn's Eccentric Orbit

Images taken by the Cassini space probe have indicated over the years that there are numerous liquid hydrocarbon lakes on Saturn's largest moon, Titan. With more research came the knowledge that the distribution of lakes between the two poles was highly uneven. In fact, the North Pole appears to be hosting about 20 times more lakes, dry lake beds, and partially filled craters than its southern counterpart. Many theories have been set forth to explain the difference, but none of them has managed to do so in a satisfactory manner. Now, experts propose a very interesting alternative, Space reports.

“We propose that, in this orbital configuration, the difference between evaporation and precipitation is not equal in opposite seasons, which means there is a net transport of methane from south to north,” expert Oded Aharonson, a California Institute of Technology (Caltech) associate professor of planetary science, says. He and his team base their claims on data obtained by the Synthetic Aperture Radar (SAR) instrument aboard Cassini. The group argues that the eccentricities in Saturn's orbit around the Sun, which have already been exhaustively studied, may be forcing the change on its moon as well.

The team, however, underlines that the process is only temporary on a geological time scale. Over tens of thousands of years, this methane/ethane transport network, which now functions from South to North, may reverse. A similar process is thought to occur on Earth as well, when periodical, long-term shifts in orbit push the planet further from the Sun, causing ice ages. This is believed to be the case with Titan as well. As it stands, it would appear that it is now at the height of one of its variations.

“Like Earth, Titan has tens-of-thousands-of-year variations in climate driven by orbital motions. On Titan, there are long-term climate cycles in the global movement of methane that make lakes and carve lake basins. In both cases we find a record of the process embedded in the geology. We may have found an example of present-day climate change, analogous to Milankovitch climate cycles on Earth, on another object in the solar system,” the expert concludes.