The only visible markings are the dark north polar hood and a difference in the brightness and color in the north and south hemispheres. The surface of Titan viewed at infrared wavelengths. Note that the longitudes given are in geographical, as opposed to astronomical, coordinates, so that east longitude increases to the right on maps. Titan is the largest satellite of Saturn and is the only satellite of any planet in our solar system with a significant atmosphere. It has an atmospheric pressure of 1.5 bars or 1.5 x Earth and its atmosphere is a hydrocarbon-rich nitrogen atmosphere.
Titan is the only body in the solar system that appears to have a primitive, unevolved atmosphere.
Its atmosphere is therefore very important as a starting point for studies of the evolutions of all other planetary atmospheres, including Earth. Unfortunately Voyager could not see through Titan's clouds. The Hubble Space telescope has imaged the surface of Titan in the infra-red portion of the spectrum and indicates a variable surface. Titan will next be visited in 2004 with a probe dedicated to descend into its atmosphere that will tell us much more about this important satellite and its atmosphere. Higher-resolution pictures taken later show many fault valleys and ridges parallel to these bands.