This global view of Io was obtained by NASA's Galileo spacecraft. Io's surface is covered with volcanic deposits that are thought to contain ordinary silicate rock, along with various sulfur-rich compounds that give the satellite its distinctive color. The reddest and blackest areas are closely associated with active volcanic regions and recent surface deposits. The yellow areas may correspond to sulfur. In the white or slightly blue areas the surface may be coated with frosts of sulfur dioxide. The color is composed of images taken in the near-infrared, green, and violet filters of the Solid State Imaging (CCD) system, and has been enhanced to emphasize the variations in color and brightness that characterize Io's surface. North is to the top and the smallest features which can be discerned are 6 kilometers in size. These images were taken at a range of 580,000 kilometers.
* Image credit and text - JPL
