Rhea and Dione (false colors)

Original caption:"Saturn's cratered, icy moons, Rhea and Dione, come alive with vibrant color that reveals new information about their surface properties. To create these false-color views, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superimposed over a clear-filter image of each moon. The combination of color map and brightness image shows how the colors vary across the moon's surface in relation to geologic features. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil. (...) The images have not been scaled to show the moons' proper relative sizes".