Io's Mountains at Sunset
NASA's Galileo spacecraft captured this dramatic image of mountains on Jupiter's moon Io in February 2000. The image was taken when the sun was low in the sky, illuminating the scene from the left, so it reveals topographic details of Io's surface. A low slope, roughly 820 feet high, runs from the upper left toward the center of the image. Mongibello Mons, the jagged ridge at the left of the image, rises 23,000 feet above the plains of Io, higher than any mountain in North America.
Scientists believe that the mountains are formed when blocks of Io's crust are uplifted along thrust faults. Angular mountains are thought to be younger, while older mountains have more subdued topography, such as the rise near the top center of this image.
Image Credit: NASA/JPL/University of Arizona/Arizona State University