Galileo Orbiter observes volcanic eruptions in progress on Io
Image: NASA/JPL/University of Arizona
Two plumes of material rising from separate volcanic eruptions appear in this image of Jupiterís moon Io, taken by the Galileo Orbiter. The first plume from the erupting caldera, Pillan Patera, appears to have a blue color, as it extends off the left edge of the moon. The second plume, from the Prometheus caldera, is colored red and is near the center of the image. The Prometheus caldera is marked by bright and dark rings. Two other volcanoes, Surya Patera and Culann Patera, are also shown here.