Why is there so much discussion about Europa?
Europa's an amazing place. It's one of the large moons of Jupiter that Galileo discovered way back in the seventeenth century. And it's a strange world. It's got an icy surface, and we've known for a long while that that surface is predominantly winterized. And it has these grooves or cracks in it. And actually they look rather similar to the kind of thing you see in ice flows in Antarctica. If you look at a satellite photo of Antarctica, they look the same. So between that clue and essentially radar measurements at the center of the moon we've discovered that the middle of this thing is liquid. Now it's cold out there in the outer solar system, so it's not heated by the sun. It's actually the energy from Jupiter's gravity as the moon goes around Jupiter. Jupiter's so strong that it keeps the center of the moon liquid. Now why is this exciting? Well it might be a water ocean, warm, very similar to the kind of place that life first appeared on Earth. So, if we're looking for life in the solar system, maybe with Mars is the wrong place to look. That's where people have been focusing. Maybe what we need to do next is go to Europa; and both NASA and the European Space Agency a plot in missions where we go to Europa, land on the surface, and then just drill down through the ice. It might be a couple of meters thick, it might be tens of kilometers thick; but drill down, get into the ocean, and who knows, maybe the first photo they'll send back will be of something large with teeth.
