Space & Science

Giant Landslides Discovered on Pluto Reveal an Active, Evolving World

When NASA's New Horizons spacecraft swept past Pluto in July 2015, it revealed a breathtakingly complex world of nitrogen glaciers, towering water-ice mountains, and hazy atmospheric layers. Now, eleven years later, scientists have identified something else in that data: six massive landslides that show Pluto is still geologically alive.

• Using high-resolution images from the New Horizons flyby, researchers identified six large landslides within three impact craters on Pluto. The largest debris apron covers an area of 130 square kilometres — big enough to bury a small city. The findings were published in the journal Icarus.
• Pluto's landslides are among the most mobile in the solar system. The debris travelled far greater distances than similar landslides on Earth or Mars, because Pluto's low gravity (one-fifteenth of Earth's) and the low-friction properties of its icy surface allow debris to flow like a slow-moving river of rock and ice.
• The discovery proves that Pluto's surface is still evolving today, long after the impacts that formed its craters. The landslides are likely triggered by the sublimation of nitrogen ice — when subsurface nitrogen turns directly from solid to gas, it destabilises the terrain above, causing crater walls to collapse.

Pluto was long dismissed as a frozen, dead world at the edge of the solar system. The New Horizons mission shattered that image in a single flyby, revealing a surprisingly active dwarf planet with glaciers, mountains, and a thin atmosphere. But the data from that 2015 encounter continues to yield new discoveries. The latest, published in Icarus, reports the first detection of landslides on Pluto — large-scale mass movements that reshape the dwarf planet's surface even today.

The team, led by researchers analysing New Horizons imagery, examined the walls of three large impact craters on Pluto. They found debris aprons — piles of rock and ice that had slumped down from the crater rims — that could only have formed through landslide processes. The six identified landslides vary in size, but the largest covers an area of roughly 130 square kilometres, comparable to a medium-sized city on Earth. To put that in perspective, the debris from a single landslide on Pluto could bury downtown Manhattan under hundreds of metres of ice and rock.

What makes Pluto's landslides remarkable is their mobility. On Earth, landslides typically travel a distance roughly equal to the height from which they fall. On Pluto, the debris travelled three to four times farther relative to the drop height. This extreme mobility is a product of two factors: Pluto's low surface gravity, which is only 6 percent of Earth's, and the low coefficient of friction of its icy surface. The debris essentially glides across the frozen landscape, slowing only when it runs out of momentum or encounters obstacles.

The mechanism that triggers the landslides appears to be sublimation-driven. Pluto's surface is rich in volatile ices — nitrogen, methane, and carbon monoxide — that can turn directly from solid to gas as the dwarf planet's seasons change. When subsurface nitrogen ice sublimates, it creates voids and cavities beneath the surface. Over time, the overlying terrain becomes unstable and collapses, sending cascades of debris down the crater walls. This is a slow, ongoing process, not a sudden event — the landslides probably take thousands of years to develop. But their existence demonstrates that Pluto is not a static relic of the early solar system. It is an active world, shaped by processes that continue to this day.