Scientists using New Horizons images of Pluto's surface to make 3-D topographic maps have discovered that two of Pluto's mountains, informally named Wright Mons and Piccard Mons, could possibly be ice volcanoes. The color is shown to depict changes in elevation, with blue indicating lower terrain and brown showing higher elevation; green terrains are at intermediate heights. http://photojournal.jpl.nasa.gov/catalog/PIA20050