It seems that the more we look, the more we find. The solar system is awash in water, sort of: Mars, our next-door neighbor; Jupiter’s moon, Europa; the two Saturnian offspring, Titan and Enceladus.
Joining that A-list now, is Ganymede, the solar system’s largest moon, bigger than even Mercury. It’s also the only moon that has a magnetic field, generated by a swirling molten-iron core.
Auroral bands, ringing its polar regions—which would appear red to anyone standing on Ganymede, and looking up at the night sky—observed by the Hubble Space Telescope, suggest the presence of a briny ocean deep beneath its surface.
But unlike the hidden oceans on Europa and Enceladus, which are sandwiched between rock and ice, Ganymede’s sea is trapped between two layers of ice.
h/t: NATIONAL GEOGRAPHIC