The Cassini space probe has discovered a variety of complex hydrocarbons and carbon-nitrogen compounds in the upper atmosphere of Titan. Described by the Jet Propulsion Laboratory as an “organic ‘factory’ of hydrocarbons” the upper atmosphere seems to be an unlikely spot for such high levels of these compounds, since they should condense and rain out on the moon’s surface. The mechanism by which these compounds are created likely includes ultraviolet radiation from the sun, although the exact details are not well understood.
The graph below shows the presence of compounds containing 1, 2, 3, 4, 5, 6, and 7 carbons in their molecular structure, some of which are hydrocarbons (carbon combined with hydrogen) and others that are carbon-nitrogen compounds. Titan’s atmosphere is composed mostly of nitrogen and a significant amount of methane (CH4).
This discovery is not that same as discovering life, but complex hydrocarbons are known precursors to the building blocks that somehow lead to life. Scientists hope data about organic chemistry on Titan will give them a better understand of how life may have started on our own planet.