Titan has always excited planetary astronomers and science-fiction writers. For good reason. It’s a romantic place, orbiting lovely Saturn, the ringed celebrity of the solar system, and its the only moon with a thick atmosphere. Titan has an active surface carved by wind and rain dotted with oceans and rivers where natural gas falls in big fat droplets and volcanoes spew water like lava. In fact Titan is composed of so much icy stuff that if it were as close to the sun as Mars about half the moon would evaporate into a giant puffball, by some guestimates growing to half the size of Uranus, before the volatile gases took flight on the solar wind and blew away in a massive cometary tail. It would make for a spectacular sight!

But those icy layers offer a possible alien refuge for life, and to understand a hypothetical Titanian biosphere we don’t have to look into deep space for evil green slime, we only have to look beneath our own oceans for exotic microbes and bizarre metazoans. [Read more…]