The Solar System's largest moon-- bigger than Mercury-- may have an ocean
Hubble has found more evidence that Ganymede has a subsurface ocean. This hypothesis is not new-- that icy moons that have a rock-ice interface could have oceans-- but this is more evidence that this is the case, and on Ganymede no less-- the biggest moon in our solar system. Not only does the evidence suggest an ocean, but the biggest ocean found to date-- bigger than those on Europa and Enceledus. Very interesting.