In June, chemists at the University of Arizona reported that they had produced large organic molecules in a gas designed to mimic the composition of Titan's atmosphere. Like Earth's, Titan's gaseous envelop is mostly nitrogen, with a pinch of methane as well. The question: What happens to this mix when ultraviolet radiation from the sun hits it?
In the experiment, led by Hiroshi Imanaka, the nitrogen shifted quite smartly from a gas into tiny particles called aerosols – and into a form that reacts readily with other chemicals.
Such particles eventually settle out of the atmosphere. On Titan's surface, they would make a more-reactive form of nitrogen available to build more-complex pre-biotic molecules.
Still, researchers aren't sure if the aerosols in Titan's atmospheric haze contain nitrogen, so for now, it's not clear that the chemistry that took place in the lab is taking place at Saturn. If some of those aerosols do contain nitrogen, however, prospects for pre-biotic chemistry on Titan would brighten.