Titan: Saturn’s Highly Atmospheric Moon

If Io is the most geologically active moon in the solar system and Ganymede the largest, Saturn’s Titan enjoys the distinction of having the most substantial atmosphere of any moon. No wispy, trace covering, Titan’s atmosphere is mostly nitrogen (90 percent) and argon (nearly 10 percent) with traces of methane and other gases in an atmosphere thicker than the earth’s. The earth’s atmosphere consists of 78 percent nitrogen, 21 percent oxygen, and 1 percent argon. Surface pressure on Titan is about 1.5 times that of the earth. But its surface is very cold, about 90 K. Remember 90 K is –183 C!
Titan’s atmosphere prevents any visible-light view of the surface, though astronomers speculate that the interior of Titan is probably a rocky core surrounded by ice, much like Ganymede and Callisto. Because Titan’s temperature is lower than that of Jupiter’s large moons, it has retained its atmosphere. The presence of an atmosphere thick with organic molecules (carbon monoxide, nitrogen compounds, and various hydrocarbons have been detected in the upper atmosphere) has led to speculation that Titan might support some form of life.