SerpApi.Org
Pluto, once seen as a frozen dot at the edge of the solar system, has turned out to be a geologically dynamic place where whole crater walls can collapse.
Pluto’s surface is so cold that water behaves like icy rock. But a fresh look at NASA’s New Horizons images shows that parts of that frozen landscape have collapsed anyway. Researchers have identified six giant landslides inside three impact craters, where ice and debris fell more than 2 kilometers and slid as far as 14 kilometers. The finding gives scientists new insight into how Pluto’s rugged surface changes over time.
Looking Back
The evidence came from images taken in July 2015, when New Horizons swept past Pluto and gave scientists their first close view of its surface. The spacecraft’s Long-Range Reconnaissance Imager, or LORRI, captured terrain at about 300 meters per pixel—sharp enough to reveal crater walls, scarps, and broad debris fields.
Marco Emanuele Discenza of Geoservizi s.r.l. and his colleagues combined the LORRI images with elevation maps from the flyby. They focused on steep crater walls and nearby cliffs, then looked for the basic signs of a landslide: gaps where material had broken loose, blocks that had shifted downhill, and debris piled across the crater floor.
They found one landslide in Coughlin crater, two in Giclas crater and three in an unnamed crater. The slides dropped between 1.5 and 2.2 kilometers, then ran as far as 14.5 kilometers across crater floors. The largest covered about 130 square kilometers—enough to bury a small city.
“These observations have enabled, for the first time, landslides to be recognized on one of the most prominent icy bodies in the Kuiper Belt,” the study authors wrote.
Long Slides
Landslides are familiar on Earth, where rain, melting snow, earthquakes, and volcanic eruptions can send even entire mountainsides crashing downhill. But this can happen on any world. Planetary scientists have also seen them on Mars, Mercury, Ceres, Vesta, icy moons, and even Pluto’s large moon Charon.
But Pluto, being so far away, had so far kept its landslides out of view. Scientists had suspected its steep crater rims and rugged ice terrain could fail, yet earlier work had not confirmed landslides in the strict sense.
The newly identified features look unusually mobile. In simple terms, the fallen material traveled a long way for how far it dropped. That may reflect Pluto’s low gravity and slippery icy debris. It may also point to volatile ices—nitrogen, carbon monoxide and methane—that can shift between solid and gas as Pluto’s surface temperature changes.
“The landslides we identified on Pluto travelled relatively long distances, suggesting that the displaced material moved very efficiently,” Discenza told Discover. “Studying this behavior may provide clues about the properties of Pluto’s surface and subsurface materials, including the possible influence of ice and volatile substances.”
Unclear Triggers
The team cannot yet say what set the landslides in motion. One candidate is impact shaking. In Coughlin crater, a smaller, younger crater sits near the older crater’s rim, and the study suggests that impact may have helped trigger the slide there.
The other five cases remain harder to explain. Tectonic stress, erosion, cryovolcanism, unloading of slopes, and heat-driven changes in ice could all play a role. An impact might also heat nearby surface layers, causing ice to melt or sublimate and lowering friction after the initial shock.
New Horizons changed Pluto from a blur into a landscape with its own geology. The new study adds landslides to that picture. In at least three craters, parts of the inner walls appear to have failed, sending ice and debris across the floors below. It is another sign that Pluto’s surface has not simply sat unchanged in the deep cold.
Better images and topographic maps might reveal many more landslides, showing where Pluto’s surface has failed and where future landers, if they ever go, might face unstable ground.
“Landslides can represent a potential hazard for future exploration missions, particularly in areas with steep slopes or signs of past instability,” Discenza explained. “Studying where they occur and how large they can become can help identify potentially critical areas and support safer decisions when selecting landing sites or planning surface operations.”
The study was published in the journal Icarus.
This story originally appeared on ZME Science. Want to get smarter every day? Subscribe to our newsletter and stay ahead with the latest science news.
