This roughly true color picture was constructed from a mosaic of six black-and-white images from the Long Range Reconnaissance Imager aboard the New Horizons space craft when it was about 200,000 km beyond Pluto. The color added from a lower resolution Ralph/Multispectral Visible Imaging Camera color image.

The haze is a smog resulting from the action of sunlight on methane and other molecules in Pluto’s atmosphere producing a complex mixture of hydrocarbons that accumulate into small haze particles. As the particles settle down through the atmosphere scattering blue light from the Sun, the smogs forms layers extending to altitudes of over 200 km.

Image Credit: NASA

This mosaic is composed of the sharpest views of Pluto that NASA’s New Horizons spacecraft obtained during its flyby of the distant planet on July 14, 2015.

Here’s NASA’s description of the image:

This mosaic is composed of the sharpest views of Pluto that NASA’s New Horizons spacecraft obtained during its flyby of the distant planet on July 14, 2015. The pictures are part of a sequence taken near New Horizons’ closest approach to Pluto, with resolutions of about 250-280 feet (77-85 meters) per pixel — revealing features smaller than half a city block on Pluto’s diverse surface. The images include a wide variety of spectacular, cratered, mountainous and glacial terrains — giving scientists and the public alike a breathtaking, super-high resolution window on Pluto’s geology. The images form a strip 50 miles (80 kilometers) wide trending from Pluto’s jagged horizon about 500 miles (800 kilometers) northwest of the informally named Sputnik Planum, across the al-Idrisi mountains, onto the shoreline of Sputnik Planum and then across its icy plains. They were made with the telescopic Long Range Reconnaissance Imager (LORRI) aboard New Horizons, over a timespan of about a minute centered on 11:36 UT on July 14 — just about 15 minutes before New Horizons’ closest approach to Pluto — from a range of just 10,000 miles (17,000 kilometers). They were obtained with an unusual observing mode; instead of working in the usual “point and shoot,” LORRI snapped pictures every three seconds while the Ralph/Multispectral Visual Imaging Camera (MVIC) aboard New Horizons was scanning the surface. This mode requires unusually short exposures to avoid blurring the images.

Image Credit: NASA

New Horizons was about 21,000 kilometers beyond Pluto, about 19 minutes after its closest approach, when it took this picture. The image also reveals Pluto’s tenuous and complex layers of hazy atmosphere. The crescent twilight landscape near the top of the frame are areas on the south of the planet including the nitrogen ice plains informally known as Sputnik Planum and rugged mountains of water-ice in the Norgay Montes.

Image Credit: NASA

This image from the New Horizons spacecraft is our first look at Pluto’s atmosphere in infrared wavelengths. It was taken after the spacecraft was beyond Pluto’s orbit, so the planet is backlit with sunlight coming from above and behind. New Horizons was about 180,000 km beyond Pluto. The false color image codes wavelengths around 1.25 µm as blue, 2.5 µm as red, and intermediate wavelengths as green. North in this image is at roughly 10 o’clock.

The blue band is the result of sunlight being scattered by haze particles in the planet’s atmosphere, haze which is suspected of being photochemical smog caused by the action of sunlight on methane and other molecules. These form hydrocarbons such as acetylene and ethylene which accumulate into small particles. The µm-sized scatter sunlight giving the haze its blue tint. It looks blue in visible light too.

The whitish patches around Pluto’s limb are from sunlight bouncing off more reflective or smoother areas on its surface.

Image Credit: NASA