Hidden Ocean in Saturn's Moon? New Clues   In 2005, NASA's
Cassini probe, orbiting Saturn, made a tantalizing discovery:
Enceladus, one of Saturn's moons, was venting something --
possibly liquid water -- into the airless space around it.  In
the frozen wastes around Saturn, this was (please forgive the
pun) really cool. How could there be water nearly 900 million
miles from the sun? That's almost 10 times as far out as Earth
is.  Enceladus. Even the name, coming from Greek mythology,
rolls off the tongue mysteriously. En-CELL-a-dus.  It is a small
world, 300 miles in diameter, covered in a thick layer of ice.
It whips around Saturn in 1.4 days, meaning the gravitational
pull of the great ringed planet on the little moon's innards
must be fierce.  Saturn has more than 60 known moons; Enceladus
is the sixth largest. The venting appears to come from fractures
or fissures in the ice near its south pole.  But liquid water?
You can find water in the form of vapor or ice all over the
universe (think of comets, with