Titan Computer artwork of the surface of Titan the largest of Saturns moons The planet is seen in the sky Larger than the planet Mercury Titan is the second biggest moon in the solar system and the only one with a planetlike atmosphere Its surface is hidden by a dense blanket of orange methanerich clouds from which a rain of organic compounds is thought to fall The moon is probably made of a mixture of ice and rock and seas of ethane and methane may exist on its surface It is thought the mixture of organic compounds in Titans atmosphere might resemble that of the primitive Earth and could hold clues about the origin of life from simple organic compounds