Following on Cassini's discoveries, NASA aims to probe Jupiter's Europa for potential life. With every new world we discover, we should look back at our own planet with awe, says Marcelo Gleiser.
"This is the closest we've come, so far, to identifying a place with some of the ingredients needed for a habitable environment," NASA says. There are signs of a promising reaction under the surface.
If jets of water vapor are indeed erupting from Europa, a spacecraft could potentially fly through them and analyze their chemistry. The moon is believed to have a vast subterranean, saltwater ocean.
Enjoy Juno's trip to Jupiter — after that we'll see a little gap in planetary science missions from the U.S. That's because a NASA budget crunch several years ago left fewer missions in the pipeline.