Surface of Titan. Computer artwork of rivers on Titan, the largest moon of Saturn (upper centre). The Sun is at upper left. This artwork is based on observations made by the CassiniHuygens probe in December 2004. Titan has traces of complex hydrocarbon compounds in its nitrogen atmosphere. These form as sunlight acts on the methane in Titans upper atmosphere, leading to clouds of ethane, and oily rivers and oceans of hydrocarbons on the surface. Titan orbits over 1.2 million kilometres from Saturn, a ringed gas giant planet that is the sixth planet from the Sun. The gravity on Titan is about a seventh of Earths. Saturn is over 1.4 billion kilometres from the Sun. Surface temperatures on Titan are as cold as 183 degrees Celsius.