Like Jupiter's Moon Ganymede, Titan is larger than the planet Mercury.
Titan is the only moon in the solar system which holds on to a thick atmosphere.
The atmospheric pressure near Titan's surface is nearly twice that of Earth. As on Earth, the most abundant gas in Titan's atmosphere is nitrogen. Methane is the second most abundant gas, and may play a role similar to water on the Earth. Methane condenses to form clouds . It may fall as rain, and form puddles on the surface.