To the untrained eye, Europa's surface looked scratched. To scientists, those riven lines indicated glacial plates floating on a liquid, probably water. Scientists had suspected Europa was wet, but these images were almost proof. Water, as opposed to ice, is so vital in the search for life because it allows elements to mingle and form the complex organics necessary for all known biology. Warmed by tidal heat, Europa's apparently liquid ocean is prompting intense curiosity about possible life there and whether it might resemble Earth's extremophiles.
Scientists are more cautious.
We need to be able to answer that and a lot of other questions before we start talking about life. The heightened interest in Europa comes at times when scientists are increasingly considering the possibility that several planets and satellites in our solar system contain liquid water and chemical systems evolving in the direction of life. In addition to Europa, two of Saturn's moons look intriguing. Titan has captured attention as a potential incubator of complex organics. Now en route, the Cassini space probe will study Titan for clues about how organics form there.