The Ralph/Multispectral Visual Imaging Camera onboard NASA’s New Horizons robotic probe captured this image of Pluto only 19 minutes after closest approach on July 14, 2015.
Pluto’s far side. Image credit: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute.
This image was taken when New Horizons was 13,400 miles (21,550 km) away from Pluto.
The image was obtained at a high phase angle — that is, with the Sun on the other side of the dwarf planet, as viewed by the spacecraft.
Seen here, sunlight illuminates Pluto’s complex haze layers. The southern portions of the icy Sputnik Planum, as well as mountains known as Norgay Montes, can also be seen across Pluto’s crescent at the top of the image.
Looking back at Pluto with images like this gives members of the New Horizons science team information about Pluto’s hazes and surface properties that they can’t get from images taken on approach.
The inset at top right shows a detail of Pluto’s crescent, including an intriguing bright wisp measuring tens of miles across that may be a discreet, low-lying cloud in the dwarf planet’s atmosphere; if so, it would be the only one yet identified in New Horizons imagery.
This ‘cloud’ is visible for the same reason the haze layers are so bright: illumination from the sunlight grazing Pluto’s surface at a low angle.
Atmospheric models suggest that methane clouds can occasionally form in Pluto’s atmosphere.
The inset at bottom right shows more detail on Pluto’s night side. This terrain can be seen because it is illuminated from behind by hazes that silhouette the limb.
The topography here appears quite rugged, and broad valleys and sharp peaks with relief totaling 3 miles (5 km) are apparent.
New Horizons flew through the Pluto system on July 14, 2015, making the first close observations of the dwarf planet and its moons.
According to NASA, the spacecraft is currently 3.23 billion miles (5.2 billion km) from Earth and 242.6 million miles (390.4 million km) beyond Pluto, with all systems healthy and operating normally.
It is on course for a close flyby of the Kuiper Belt object 2014 MU69 on January 1, 2019, pending NASA approval of funding for an extended mission.
