It seems improbable that a satellite designed to monitor polar ice sheets and floating sea ice could accurately measure a disturbance in Earth’s magnetic field. But that is just what ESA’s CryoSat mission did earlier this year.
Europa is not supposed to look the way it does. Jupiter's icy moon is scarred by a chaotic patchwork of fractured terrain, criss crossed ridges, and disrupted surface regions that suggest something dynamic is happening beneath its frozen shell. Scientists have long suspected that a vast liquid ocean, kept warm by the gravitational kneading of Jupiter's enormous gravity, lies hidden beneath that ice. Now, a new study using the James Webb Space Telescope is adding a crucial piece to the puzzle, and the implications reach right to the heart of astrobiology.

