Titan lightning - An energy source for biochemistry

Possible lightning on Saturn's moon Titan, with its dense nitrogen-methane atmosphere, may provide additional energy for the formation of some trace species, including prebiotic molecules in the troposphere, where other chemical processes are inactive. Although thunderclouds may be a rare phenomenon on Titan, a rapid development of a thick, extensive CH4 cloud in the troposphere would attract a high number of free electrons, which are present due to the low abundance of electrophilic species. The entirely negative charge of the cloud may cause temporary maximum electric fields in excess of the breakdown field to initiate Earth-like cloud-to-ground lightning flashes in the lowest 20 km of Titan's atmosphere. It is suggested that the electromagnetic energy radiated by possible lightning should be sufficient to produce some long-lived hydrocarbons and nitriles, preferentially at low latitudes, where the CH4 abundance and the lightning frequency may be higher than at higher latitudes. (Author)