QUESTION:
What do the current data suggest about the possibility of liquid
water existing on Europa?

ANSWER from FAQ on March 4, 1997:
Europa is about the size of Earth's Moon and is covered largely with
smooth white and brownish-tinted ice, instead of large craters like
so many other bodies in the Solar System. Scientists believe its
cracked cue-ball appearance is due to stressing caused by the
contorting tidal effects of Jupiter's strong gravity. They speculate
that the warmth generated by tidal heating may have been sufficient
to soften or even liquefy some portion of Europa's icy covering.

Images of the moon also indicate the some large ice pieces have broken
off from main masses and have moved possibly indicating a ocean
underneath the ice.

For more information, visit the Europa page at NASA JPL:
http://www.jpl.nasa.gov/galileo/europa/