Only two bodies in the Solar System are known to have persistent surface liquid: Earth and Saturn’s moon Titan. Unlike Earth, Titan’s liquid is methane rather than water, and most of the methane is in the moon’s thick atmosphere instead of on the surface. Therefore, instead of large oceans, Titan possesses smaller, shallower seas in the polar regions. The equatorial region is marked by sand dunes, similar to fields found on Earth. Studies of Titan’s atmosphere show the tropics to be free of precipitation, making it drier than the driest desert on Earth.
However, analysis of Cassini space probe data from 2004 through 2008 may have found as many as five tropical lakes on Titan. Spectral analysis by Caitlin A. Griffith et al. revealed an oval region that absorbs infrared light, an effect consistent with a small lake of liquid methane at least 2 meters deep. They also identified four other candidate lakes, but the data was far less clear. In the absence of rain, the authors suggest the most likely source for these lakes is subsurface—making them desert oases.
Excerpt of an article written by Matthew Francis at Ars Technica. Continue HERE