Saturn's moon, Titan, is one of the most exotic places in the Solar System, with large lakes filled with nearly pure, liquid methane, a thick atmosphere that provides surface pressures similar to those on Earth, and very cold temperatures of about -180 degrees Celsius. Aside from Earth, Titan is the only body in the Solar System with liquid on its surface.

This has always tantalized astrobiologists who have wondered about the possibility of some kind of unknown life living in those methane lakes. Now scientists have found some solid theoretical reasons to believe that some of the complex chemistry in Titan's atmosphere could support life on the world.

Citing experimental and observational data, the researchers note the abundance of hydrogen cyanide in Titan's atmosphere. This is a hydrogen-bonding molecule that may combine with other molecules on the surface to form polymers, including polyimine. Using quantum mechanical calculations, the scientists demonstrated that polyimine has electronic and structural properties at very cold temperatures that could potentially facilitate prebiotic chemistry in conditions like those on the surface of Titan, especially in tidal pools near the large seas.

"Possibilities like this... are very speculative and intended as a suggestion of the kinds of structures that might occur, rather than a specific prediction," the authors wrote in their paper, published this week in the early edition of Proceedings of the National Academy of Sciences. "Because they are impossible to form naturally in a warmer world containing water and oxygen, only future exploratory missions to Titan can test the hypothesis that natural chemical systems evolve chemical complexity in almost any circumstance."

We are all for a lander being sent to Titan. Ars sat in on one meeting at the Jet Propulsion Laboratory in 2015 where famed ocean explorer Robert Ballard, who found the Titanic wreck, was learning about the possibilities of exploring subsea oceans on Europa and the surface lakes of Titan for signs of life. When he heard about the methane lakes on Saturn's moon, Ballard exclaimed, "Oh man, you've got to go there."

PNAS, 2016. DOI: 10.1073/pnas.1606634113 (About DOIs).