Alien Ocean

This enhanced color image shows cracks and ridges on Europa’s surface that reveal a detailed geologic history. Some ridges, such as the prominent one at top right, develop into long, arc-shaped “cycloids” that may be related to changing tidal forces as Europa orbits Jupiter. The wall of this ridge stands perhaps a third of a […]

Scientists think there is an ocean within Jupiter’s moon Europa. NASA-JPL astrobiologist Kevin Hand explains why scientists are so excited about the potential of this ice-covered world to answer one of humanity’s most profound questions.