False colour image of the dwarf planet Pluto (left) and it largest moon Charon (right). The colours have been exaggerated to highlight different surface materials and features. Data from the spacecraft's spectroscopic instruments will help scientists determine what these materials are. It is thought that the red colour of Charon's north pole is due to hydrocarbons and tholins, a class of chemicals produced when simple organic compounds are exposed to solar radiation. New Horizons has spent nine and a half years travelling the nearly five billion kilometres to Pluto. Image obtained by New Horizon's Ralph instrument on 13th July 2015.