Updated

Updated · Space.com · Jul 16

Astronomers Find 6 Pluto Landslides, With 1 Debris Apron Spanning 50 Square Miles

Updated

Updated · Space.com · Jul 16

Astronomers Find 6 Pluto Landslides, With 1 Debris Apron Spanning 50 Square Miles

Q: What strange property of Pluto's ice allows massive landslides to slide farther than any on Earth?

Pluto’s landslides appear to travel unusually far because much of the mobile ice there is not hard water ice, but volatile ice such as nitrogen, with methane and carbon monoxide mixed in. At Pluto’s extremely low temperatures, that nitrogen ice is still soft enough to deform and flow, giving it a much lower effective friction than rock or ordinary Earth ice. That matters because low-friction material can keep moving much longer after it breaks loose. Researchers studying the New Horizons images found Pluto’s landslides have longer “runout” distances than comparable slides on Earth, which points to this unusually slippery, mobile behavior. The contrast with Pluto’s water ice is important. On Pluto, water ice is so rigid it acts like bedrock and forms mountains, while nitrogen-rich ice behaves more like a slowly flowing geological material. Scientists say that strange combination helps explain why massive landslides on Pluto can slide farther than any seen on Earth.

3 articles · Updated · Space.com · Jul 16

Six landslides have been identified on Pluto for the first time, all on the inner walls of three craters along the western edge of Sputnik Planitia.
New Horizons images from its 2015 flyby showed debris aprons stretching 6.3 to 9 miles across crater floors, with one slide in Coughlin crater dropping 1.4 miles.
The largest apron covers 50 square miles, and the long runout suggests some of the most mobile landslides in the solar system, aided by Pluto's low gravity and low-friction icy rubble.
One slide may have been triggered by a nearby secondary impact, but the other five have no clear cause; researchers point to thermal stress from Pluto's cyclical sublimation and recondensation of nitrogen, carbon monoxide and methane ice.
The findings, published in Icarus, add evidence that Pluto remains geologically active on long timescales, though limited New Horizons coverage leaves other suspected landslides unconfirmed.