europa than there is in the world, on earth. so consequently, that water which is being harbored underneath the ice shell may indeed contain all types of life. so we're anxious to go there. we're anxious to study it. and we're anxious to see how that life could survive over these billions of years. >> another potential target, a little closer in, saturn's moon of titan. what can we find there? >> well, titan is another fabulous world. it's got a hefty atmosphere. it also has -- it's the only body in the solar system beyond eartha actually has liquid on its surface. it has lakes maybe even as large as seas of methane. and in fact, i can tell you, we're observing rain of methane going on right now in the southern hemisphere of the titan. it's a fabulous world that we want to study. we believe it's a lot like what early earth would be and we're quite interested in seeing much