New Horizons finds 6 Pluto landslides, with debris aprons that could bury a small city

Space missions tend to leave us with artifacts, not mysteries you can still actively solve. But Pluto keeps refusing to go quiet. In 2015, NASA’s New Horizons flew past the dwarf planet and took high-resolution imagery of its surface. Now, a team led by geologist Marco Emanuele Discenza has pulled something striking out of those images: evidence for six landslides on Pluto.

These landslides are down the inner walls of three craters on the western edge of Sputnik Planitia, Pluto’s heart-shaped, defining region. The team used New Horizons’ LORRI (Long-Range Reconnaissance Imager), which was capable of detecting surface features as small as 984 feet (300 meters). Within that scale limit, they identified convincing landslide evidence in six separate events, including a landslide in Pluto’s Coughlin crater that fell 1.4 miles (2.2 kilometers), plus two more in Giclas crater and three in a third, unnamed crater.

So what exactly did they see? Landslides leave behind debris aprons, and on Pluto those aprons spilled onto the crater floors. The distance the landslide material traveled ranged between 6.3 and 9 miles (10.1 and 14.5 km). Some of the debris aprons looked bumpy, which suggests large boulders of solid ice are mixed into the rubble. Meanwhile, the source regions show well-defined, concave-shaped cliffs, where material appears to have broken away and tumbled down Pluto’s steep crater walls.

The largest apron is the one that really jumps off the page: it covers 50 square miles (130 square kilometers). The researchers note that this would be large enough to bury a small city or a large town on Earth. That is an enormous scale for geology, especially for a world that, until recently, many people assumed would be more like a frozen relic than an active engine. Landslides also help shape planetary surfaces by transporting material across distances, and Pluto is now joining a lineup of bodies where this process is documented, including Mars, Ceres, icy moons of the gas giants, and even Pluto’s companion, Charon. The key difference here is simple and consequential: these are the first landslides found on Pluto.

The “how” is where the story gets more interesting, because the trigger is not yet clear. For the landslide in Coughlin, the team identified a plausible culprit: a smaller impact nearby that may have triggered the bigger slope failure. But for the other five, the origins are less certain. One possibility the study raises is thermal stress in Pluto’s surface ice. Pluto has volatile materials like molecular nitrogen, carbon monoxide, and methane. As Pluto subtly heats up and cools down along its elliptical orbit, those volatiles can periodically sublimate and then condense again. That cycle could stress the surface ice enough to encourage cracking and slope failure, without needing an external shove.

There is also evidence suggesting more landslides elsewhere on Pluto. However, New Horizons’ coverage was limited because the spacecraft hurriedly flew past on July 4, 2015. The imagery needed to confirm additional landslides is lacking, so the team’s current catalog is bounded by what the mission captured. This detail matters for how we interpret the discovery: the “six” may be what they can prove confidently with the available LORRI data and its detection capability, not necessarily the maximum number of landslides Pluto has experienced.

Finally, the study was published in the journal Icarus. From an executive-briefing standpoint, the business-relevant takeaway is not that Pluto has geology. It is that mission data can still yield brand-new, high-impact scientific findings years after launch, and those findings can adjust baseline assumptions about where activity can exist in the solar system. For organizations tracking space research, science instrumentation, and long-term mission planning, Pluto’s landslides are a reminder that “still active, on geological timescales” can apply even to faraway, cold worlds. That changes the questions future missions should bring: what other processes are currently hidden behind limited coverage, resolution constraints, and timing windows, and how quickly could the next surprise appear once someone decides to look harder at the images we already have?