Valley Glaciers on Pluto: Ice (probably frozen nitrogen) that appears to have accumulated on the uplands on the right side of this 390-mile (630-kilometer) wide image is draining from Pluto's mountains onto the informally named Sputnik Planum through the 2- to 5-mile (3- to 8- kilometer) wide valleys indicated by the red arrows in the annotated version. The flow front of the ice moving into Sputnik Planum is outlined by the blue arrows in the annotated version. The origin of the ridges and pits on the right side of the image remains uncertain. The original NASA image was converted from TIFF to JPEG format by the uploader.