This image provided by NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute on Wednesday, Sept. 14, 2016 shows Pluto's moon, Charon, in a mosaic of photographs acquired by the New Horizons spacecraft during its approach to the system from July 7-14, 2016. A new study finds that Pluto is "spray-painting" the red poles of its big moon Charon. The coloration is from Pluto's continually escaping atmosphere and a reaction with solar radiation. (NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute via AP)