Titan, Saturn's largest moon and the second-biggest natural satellite in the solar system, is an unquestionably interesting place. It's a world with a thick atmosphere and with lakes, fog and rainfall—only with liquid hydrocarbons rather than liquid water.

Titan would be even more interesting if a speculation made five years ago proved out: that the moon could be teeming with extraterrestrial life. Titan-based (Titanate? Titanic?) life could dwell in liquid methane and breathe gaseous hydrogen, just as so much Earthly life dwells in liquid water and breathes gaseous oxygen. Such organisms would consume hydrocarbons such as acetylene near Titan's surface, so their presence might be recognizable by a dearth of acetylene and hydrogen at the surface,
Chris McKay and Heather Smith noted in Icarus in 2005.

A pair of new studies provide evidence for such depletions of acetylene and hydrogen, stirring up a sudden frenzy of public interest in Titan, including a characteristically bombastic treatment from the British press.
The Telegraph grabbed readers' attention with the headline, "Titan: Nasa scientists discover evidence 'that alien life exists on Saturn's moon'." On Twitter, Carolyn Porco, lead scientist on the imaging team for NASA's Cassini spacecraft, bemoaned the headline and reported that she "just got an e-mail from someone 'applying' to be among those folks we send to Titan."

Now McKay, of the NASA Ames Research Center in Moffett Field, Calif., has seen fit to clear the air himself, making plain that extraterrestrial life on Titan is but one possible explanation of many—and far from the most likely.

To read the rest of the article, click here.