Part of the show Sex Chromosomes, Genetics and Food Webs
The holy grail of finding extraterrestrial life has been the discovery of an Earth-sized planet with just the right temperature for liquid water to exist on the surface. However a new study has shown that we should actually be looking at moons rather than planets. Europa, one of Jupiter's moons, is regarded as one of the best prospects for extraterrestrial life in our solar system despite being covered in kilometres of water ice. Jupiter's gravity is strong enough to distort the shape of Europa in a similar way to how our Moon's gravity creates tides. This distortion is equivalent to rapidly stretching and releasing an elastic band, and results in the generation of heat. This heat warms up Europa's frosty interior, allowing a layer of liquid water to form underneath the ice crust. The study suggests that cold gas giants larger than Jupiter may harbour warm moons with thoroughly thawed surfaces or underground seas, and that these could be the perfect breeding ground for extraterrestrial life.