The latest images from the Galileo orbiter seem to show that ice-spewing volcanoes and the movement of tectonic plates have completely reshaped the surface of Jupiter's moon Europa. The images were gathered on a December 19, 1996, flyby that brought the spacecraft within 692 km of the moon's surface, more than 200 times closer than Voyager 2 flew in 1979.
The new images do not show active ice volcanoes or geysers, but they do reveal flows of material on the surface. “This is the first time we've seen actual ice flows on any of the moons of Jupiter,” said Ronald Greeley, a member of the Galileo imaging team and a planetologist from Arizona State University. “These flows, as well as dark scarring on some of Europa's cracks and ridges, appear to be remnants of ice volcanoes or geysers.” (See Figure 1.)