NASA’s New Horizon space probe, which flew by Pluto last July, continues to send data and images that amaze and awe. Thursday, the space agency released an image of Pluto’s North Pole taken by the probe’s Ralph/Multispectral Visible Imaging Camera (MVIC). The image shows, as has previous images of other regions of the so-called dwarf planet, that Pluto is a diverse world with an active geology. The North Pole of Pluto is characterized by long canyons that are covered in yellow methane ice. The canyons show how the dwarf planet had, and perhaps still has active tectonics.
“Long canyons run vertically across the polar area—part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons (yellow in the image below) – is about 45 miles (75 kilometers) wide and runs close to the north pole. Roughly parallel subsidiary canyons to the east and west (in green) are approximately 6 miles (10 kilometers) wide. The degraded walls of these canyons appear to be much older than the more sharply defined canyon systems elsewhere on Pluto, perhaps because the polar canyons are older and made of weaker material. These canyons also appear to represent evidence for an ancient period of tectonics.
“A shallow, winding valley (in blue) runs the entire length of the canyon floor. To the east of these canyons, another valley (pink) winds toward the bottom-right corner of the image. The nearby terrain, at bottom right, appears to have been blanketed by material that obscures small-scale topographic features, creating a ‘softened’ appearance for the landscape.”
The image suggests that a lot of Pluto’s geological processes have been driven by the melting and freezing of ice over billions of years.
“Large, irregularly-shaped pits (in red), reach 45 miles (70 kilometers) across and 2.5 miles (4 kilometers) deep, scarring the region. These pits may indicate locations where subsurface ice has melted or sublimated from below, causing the ground to collapse.
“The color and composition of this region – shown in enhanced color – also are unusual. High elevations show up in a distinctive yellow, not seen elsewhere on Pluto. The yellowish terrain fades to a uniform bluish gray at lower elevations and latitudes. New Horizons’ infrared measurements show methane ice is abundant across Lowell Regio, and there is relatively little nitrogen ice.”
New Horizons took nine and a half years from its launch from Earth to voyage across the solar system before it achieved its brief flyby of Pluto. Because of the slow transmission times from beyond the orbit of Pluto, the NASA probe is taking many months to return the images and data that it acquired during that short encounter. Thus far, New Horizons has proven to be the most fruitful and celebrated space probe of the 21st Century. The probe has transformed Pluto from a fuzzy dot seen only through telescopes to a fully realized world, with features and processes not seen before by the eyes of humans.
The mission of New Horizons is not complete yet. The probe is currently hurtling deep into the Kuiper Belt, a region of rock and ice that surrounds the solar system. New Horizons is due to encounter one of those Kuiper Belt objects sometime in 2019.