Stock Photo - A blue halo glows around Pluto’s receding crescent in this highest-resolution color departure shot taken from NASA's New Horizons spacecraft from 120,000 miles (200,000 kilometers) away from Pluto on July 14, 2015. Shown in approximate true color, the picture was constructed from a mosaic of six black-and-white images from the Long Range Reconnaissance Imager, with color added from a lower resolution Ralph/Multispectral Visible Imaging Camera color image. Scientists believe the haze is a smog resulting from the action of sunlight on methane and other molecules in Pluto's atmosphere. This reaction produces a complex mixture of hydrocarbons that accumulate into small haze particles which scatter blue light. As they settle down through the atmosphere, the haze particles form numerous intricate horizontal layers that extend to altitudes of over 120 miles (200 kilometers). Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute via CNP. - Baltimore/Maryland/