Question

What are the chances of a biochemistry occuring on Titan--even though temperatures are very small.

We have yet to find out. Indeed, Titan is very cold—about -178°C (-289°F) to be exact—far too cold for liquid water to exist, one of the key ingredients to life as we know it. However, we have known for decades that Titan harbors organic chemistry in its atmosphere and perhaps more on its surface. Many believe that the abundance of nitrogen, methane, and other hydrocarbon-rich elements in Titan’s atmosphere would inevitably condense to fill the lakes (maybe even oceans) that we suspect cover Titan’s surface. These surface organics of nitriles, hydrocarbons, and tholins would readily combine to form amino acids (the building blocks of protein!) if they ever came in contact with liquid water. But how would liquid water ever exist in such a cold place? Many scientists have suggested the transient scenarios of meteorite impacts and cryo-volcanism, both of which would melt the surrounding ice and provide enough liquid water to enable these organic reactions. If ammonia were present, which is likely in the Titan environment, the melted water would take up to 10,000 years to refreeze! If any biochemistry exists or ever existed on Titan (possibly preserved in ice), we hope to soon find out when the Cassini-Huygens spacecraft arrives in 2004 and takes its complete inventory of the surface. Maybe then we will come to unravel some of Titan’s chemical mysteries! If you would like to keep up with the Cassini-Huygens Saturn/Titan mission, please visit: http://saturn.jpl.nasa.gov/cassini/index.shtml For more information on the proposed study of Titan, you can view the current prospectus of our new Titan Focus Group at: http://nai.arc.nasa.gov/library/downloads/focus_groups/titan_prospectus.pdf Anna Lee Strachan, NASA Astrobiology Institute
May 27, 2002