re: Why so far away?
Cassini Finds an Active, Watery World at Saturn's Enceladus
Saturn's tiny icy moon Enceladus, which ought to be cold and dead, instead displays evidence for active ice volcanism.
NASA's Cassini spacecraft has found a huge cloud of water vapor over the moon's south pole, and warm fractures where evaporating ice probably supplies the vapor cloud. Cassini has also confirmed Enceladus is the major source of Saturn's largest ring, the E-ring.
Additional information and graphics on these results are available at:
http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .