Liquid water on Europa
Jupiter's moon Europa probably contains liquid water. The laws of electromagnistism stipulate that a varing magnetic field cause an induced magnetic field if the body withing the original magnetic field is conductive. Europa is within Jupeters magnetic field and the Galileo probe's mesuments of Europa's induced magnetic field suggets it has a global conductive layer near the icy surface. The best possibility to explain this would be a below surface salty ocean. [1]