Titan (or Saturn VI) is the largest moon of Saturn. It is the only natural satellite known to have a fully developed dense atmosphere, and the only object other than Earth for which clear evidence of stable bodies of surface liquid has been found. The atmospheric composition in the stratosphere is 98.4% nitrogen—the only dense, nitrogen-rich atmosphere in the Solar System aside from the Earth’s—with the remaining 1.6% composed of mostly of methane (1.4%) and hydrogen (0.1–0.2%).
Above: True-color image of layers of haze in Titan’s atmosphere.
Below: A graph detailing temperature, pressure, and other aspects of Titan’s climate. The atmospheric haze lowers the temperature in the lower atmosphere, while methane raises the temperature at the surface. Cryovolcanoes erupt methane into the atmosphere, which then rains down onto the surface, forming lakes.