Pluto has six confirmed landslides now, and their unusually long runouts are giving scientists a clue about how icy worlds move

Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the Ralph instrument to create this enhanced color global view of Pluto. The images, taken when the spacecraft was 280,000 miles (450,000 kilometers) away, show features as small as 1.4 miles (2.2 kilometers), twice the resolution of the single-image view taken on July 13. | NASA/JHUAPL/SwRI

Four images from New Horizons’ Long Range Reconnaissance Imager (LORRI) were combined with color data from the Ralph instrument to create this enhanced color global view of Pluto. The images, taken when the spacecraft was 280,000 miles (450,000 kilometers) away, show features as small as 1.4 miles (2.2 kilometers), twice the resolution of the single-image view taken on July 13. | NASA/JHUAPL/SwRI

Six landslides were hiding in New Horizons images

The distance travelled may reveal what Pluto is made of

In the northern region of Pluto’s Sputnik Planum, swirl-shaped patterns of light and dark suggest that a surface layer of exotic ices has flowed around obstacles and into depressions, much like glaciers on Earth. | NASA/JHUAPL/SwR

More landslides may still be waiting in the data

Nearly 11 years after NASA’s New Horizons spacecraft made humanity’s first close flyby of Pluto, scientists have returned to its images and identified something that had previously escaped confirmation: six large landslides carved into the dwarf planet’s icy terrain. The features provide the first clear geomorphological evidence of landslides on Pluto itself and, because the material appears to have travelled unusually far for the vertical distance it fell, they may also reveal how debris behaves under the dwarf planet’s low gravity and unusual surface conditions. According to the original study published in Icarus, “First geomorphological evidence of landslides on Pluto,” researchers re-examined high-resolution New Horizons imagery and identified six large-scale features consistent with gravitational slope failure, with drop heights between 1.5 and 2.2 kilometres, runout distances between 10.1 and 14.5 kilometres, and mapped areas reaching approximately 130 square kilometres.Pluto has steep mountains, impact craters, and enough gravity to pull unstable material downslope, yet earlier studies had not unambiguously confirmed conventional landslides on its surface. Researchers led by Marco Emanuele Discenza and Maria Teresa Brunetti looked again for the characteristic signatures left when large masses of material detach from slopes and move downhill, including steep source areas and deposits whose tone and texture differ from the surrounding terrain.All six identified landslides occur along steep inner walls of impact craters near Sputnik Planitia, Pluto’s enormous ice-filled basin. The largest covers about 130 square kilometres, placing it near the upper size range of many terrestrial landslides. According to NASA’s New Horizons mission overview , the spacecraft’s 2015 encounter revealed Pluto as a geologically complex world dominated by diverse icy landscapes, including the roughly 1,000-kilometre-wide Sputnik Planitia. The new analysis shows that gravitational collapse can now be added to the processes known to have reshaped that distant surface.The most intriguing finding is not simply that Pluto has landslides, but how mobile they appear to have been. When researchers compared their drop heights with their horizontal travel distances, the Plutonian landslides generally extended farther than landslides of comparable height elsewhere, suggesting that the moving material experienced relatively low effective friction.That does not yet provide a single explanation for what allowed the debris to travel so efficiently, but landslide mobility can offer indirect information about the physical properties of material that cannot currently be sampled on the ground. Pluto’s surface includes water ice as well as far more volatile nitrogen, methane and carbon monoxide ices, creating conditions unlike those of terrestrial rocky slopes. By measuring the geometry of collapsed material, researchers can therefore begin constraining how icy debris may move under Pluto’s weak gravity. Long-runout landslides are not unique to Pluto. According to a NASA report on New Horizons observations of Charon , scientists previously identified evidence of long-runout landslides on Pluto’s largest moon, making Charon the first known location in the Kuiper Belt where such features had been recognized. The confirmation of six landslides on Pluto now expands the evidence that mass movement is an important geological process even on remote, frozen worlds.The six features are unlikely to represent a complete inventory. New Horizons observed Pluto during a single rapid flyby, and image resolution varies considerably across the surface, meaning smaller or less clearly preserved landslides could remain unidentified.For now, the discovery demonstrates that data collected during one spacecraft encounter can continue producing new findings more than a decade later. Pluto’s landslides also provide scientists with a natural experiment impossible to reproduce on Earth, showing how large masses move across an icy surface under weak gravity and offering another way to reconstruct the mechanical properties and geological evolution of one of the solar system’s most distant explored worlds.