Pluto's polar region is dotted with a diverse range of frozen canyons, valleys, and pits, a new NASA photo reveals. The uneven topography is showcased in the latest enhanced color image taken by NASA's New Horizons spacecraft, which flew by Pluto in July of last year.
The various landforms are highlighted in different colors below. The yellow region indicates the pole's largest canyon, spanning 45 miles wide. Within the canyon is a separate valley, highlighted in blue, that snakes along the floor. Smaller companion canyons are shown in green, each stretching about six miles wide. Another valley is shown in pink, and a cluster of oddly shaped pits are colored red in the lower right-hand corner. The pits may be the result of ground collapse, when ice underneath the surface melted or sublimated, NASA thinks.
NASA is a bit baffled at the higher elevations in the image, which show up in a dusty yellow. These yellow landforms aren't seen elsewhere on Pluto, indicating a unique type of surface composition. Infrared measurements from New Horizons indicate this polar region is filled with more methane ice, and less of the nitrogen ice that makes up most of Pluto's surface. NASA thinks these higher, yellow elevations look different because they’ve been exposed to solar radiation longer than the blueish-grey regions.