The moon Europa, like Goldilocks' porridge, might be juuuuust right. I would go so far as to say that if there is an ocean on Europa, it is the most exobiologically interesting place in the solar system. That is to say, there might be life there.
Worms thrive in similar environments.
Of the planets in our Solar System, Earth, Kasting and his colleagues calculated, is the only one close enough to the Sun to be warm enough for liquid water, yet not so close that the water boils away. Mars is one such world. Another, in some ways even more tantalizing, is Europa . The lure of Europa Fourth largest of the 16 known satellites of Jupiter , Europa is a chunk of rock and metal about as big as Earth's Moon, sheathed in ice. Voyager photographs taken 20 years ago show a smooth surface scored heavily with cracks, like a favorite skating pond in late winter.