Shown here is one of the topographic mapping images of Jupiter's moon Io (Latitude: -40 to +90 degrees, Longitude: 210-320 degrees) acquired by NASA's Galileo spacecraft, revealing a great variety of landforms. There are rugged mountains several miles high, layered materials forming plateaus, and many irregular depressions called volcanic calderas. There are also dark lava flows and bright deposits of SO2 frost or other sulfurous materials, which have no discernable topographic relief at this scale. Several of the dark, flow-like features correspond to hot spots, and may be active lava flows. There are no landforms resembling impact craters, as the volcanism covers the surface with new deposits much more rapidly than the flux of comets and asteroids can create large impact craters. The volcano Ra Patera, seen to have an active plume 75 km high during Galileo's first orbit in June 1996, is located on the bright limb of this image but no plume can be seen, so it is now (5 months later) inactive.
North is to the top of the picture and the sun illuminates the surface from the left. The image covers an area about 2800 kilometers wide and the smallest features that can be discerned are 4.1 kilometers in size. This image was taken on November 6th, 1996, at a range of 403,100 kilometers by the Solid State Imaging (CCD) system on the Galileo Spacecraft.
The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.
This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo. Image Credit: NASA/JPL