Europa
From Slackerpedia Galactica
Europa is an ice-covered moon of Jupiter that is believed to have a salt water ocean which could possibly contain life. Europa is not to be confused with Europe.
Attempt no landings there.
Europa is largely rock, with a 100km deep layer of water on top. The top layer is frozen, likely 5-20 km deep. The rest is either liquid water or a liquid-ice slush. It is beleived to be convective, that is warmer areas rise to the surface, cool and then sink. The cracks in the surface ice could be caused by warmer water rising and melting parts of the surface. Those parts then freeze, expands and creates cracks elsewhere. If a lander is ever sent to Europa, it would likely land near one of those cracks so it could get to the ocean easier. The heat that keeps the water warm is thought to come from tidal stretching and compression of Europa caused by Jupiter's gravity.
The ocean is believed to be salty because of magnetic readings by the Gallileo spacecraft, which could be best explained by a moving body of salt water.
There are conditions on Earth, deep in the oceans, which are similar to the conditions predicted to exist in the oceans on Europa. On Earth at least, life flourishes in these places ("extremophiles").
NASA has has many missions to Europa on its drawing board. These missions get strong support from congress, but for keep getting axed by NASA HQ, probably to pay for Bush's Vision for Space Exploration.
