Oceans, clouds, rain, bubbles: all are phenomena familiar in the terrestrial environment, thanks to the aqueous character of our planet. But no longer do they seem limited to this sole locale in the Solar System. Liquid water exists too on some of the tidally heated moons of the giant planets, par-ticularly Jupiter's Europa and Saturn's Ence-ladus, which are considered in consequence two of the most promising environments for astrobiological searches. On Saturn's moon Titan, meanwhile, rain of liquid hydrocarbons falls onto alkane lakes or seas; Venus is shrouded in clouds composed from droplets of sulfuric acid. The science that describes the properties of droplets, bubbles and liquid films -namely capillarity, pioneered by Pierre-Simon Laplace at the start of the nineteenth century - therefore has relevance beyond our planet. Some of the implications for extraterrestrial environments are explored by Cordier and colleagues1.
展开▼
