Pluto’s north pole covered with long, frozen canyons
The latest images sent back by NASA’s New Horizons spacecraft reveal long, frozen canyons running vertically over Pluto’s north polar region, adding yet another level of diversity to the small world’s geologic and topographic features.
Depicted with enhanced color, the north polar region, informally called Lowell Regio, is covered with vertically-running canyons, the widest of which measures 45 miles (75 km) across, highlighted in yellow in an image marked with various colors by members of the New Horizons team to highlight the variety of terrains.
The images were taken by the spacecraft’s Ralph/Multispectral Visible Imaging Camera (MVIC) from a distance of approximately 21,100 miles (33,900 km) from Pluto just 45 minutes before closest approach on July 14, 2015.
Their resolution is approximately 2,230 feet (680 meters) per pixel. The images’ lower edge covers a region measuring about 750 miles (1,200 km) in length.
Lowell Regio is named for Percival Lowell, the founder of Lowell Observatory in Flagstaff, Arizona, where Pluto was discovered in 1930.
Percival Lowell initiated the search for Pluto in the 1890s and had the observatory built in 1894.
On the floor of the large canyon, shown in blue in the marked image, is a winding, shallow valley traversing its entire length.
To the east and west of the largest polar canyons, smaller subsidiary ones about six miles (10 km) wide run on either side. On the marked image, these are depicted in green.
These northern canyons have degraded walls and features much less clearly defined than canyons on other parts of the planet, meaning they are composed of weaker material and are probably much older than their counterparts.
Another valley, shown in pink in the marked images, is visible to the east of all the larger canyons.
Topographic features of adjacent terrain at the bottom right of this second valley are hidden under a layer of surface material, producing a softer, less vivid appearance.
Even further toward the bottom right of the image are huge pits with non-uniform shapes up to 45 miles (70 km) across and 2.5 miles (4 km) deep. On the marked image, these are shown in red.
Mission team members speculate the pits were produced when underground ice caused the ground to collapse either by sublimating or melting from below.
Both the color and the terrain of Pluto’s north polar region are significantly different from those of other surface terrains. Highlighted in false color, the higher elevations have a yellow appearance that becomes less marked at lower levels, which look bluish gray.
According to infrared data taken by New Horizons, this region has high levels of methane ice but little nitrogen ice. This could be key to explaining the color differences, mission scientists think. The canyons located at Lowell Regio appear to be evidence of ancient tectonics.
“One possibility is that the yellow terrains may correspond to older methane deposits that have been more processed by solar radiation than the bluer terrain,” explained Will Grundy of Lowell Observatory, who serves as mission composition team lead.
The New Horizons team also published the latest in a series of blog entries by mission scientists. This week’s, titled “Where’s My Data? Keeping Track of New Horizons’ Treasure of Information,” was written by Science Operations team member Emma Birath of the Southwest Research Institute at Boulder, Colorado.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.