EARTH Magazine: Oceans Revealed on Icy Moons
From EARTH Magazine, 08/03/2015 -- It now appears that, of the many moons of Jupiter and Saturn, two of them may have oceans beneath their icy exteriors. Scientists studying Jupiter's moon Ganymede - the largest moon in the solar system and the only one with its own magnetic field, which frequently sparks aurorae - used the Hubble space telescope to detect ultraviolet light emitted by the aurorae, which were less active than expected, given the moon's magnetic field.