Solid methane dunes discovered at bottom of major mountain range on Pluto

International team of scientists analyse images taken by Nasa's New Horizons spacecraft

Dunes made from solid grains of methane have been discovered by scientists at the bottom of a major mountain range on Pluto.

An international team of geographers, physicists and planetary scientists analysed the planet’s surface using detailed images captured in 2015 by Nasa’s New Horizons spacecraft.

Spanning 47 miles across the boundary of an ice plain called Sputnik Panitia, the rippling methane dunes can be seen pushing up against mountains on the freezing planet, which has an average surface temperature of -230C.

Following an analysis of the shape and size of the dunes, and nearby wind streaks on Pluto’s surface, scientists concluded solid nitrogen converting directly into gas, known as sublimation, likely released sand-sized grains of methane directly into the atmosphere.

They were then blown by Pluto’s thermal winds across the ice plane and settled at the bottom of the mountain range.

The researchers concluded the dunes were probably formed in the last 500,000 years, and possibly much more recently, due to the fact they were largely undisturbed.

Matt Telfer, lecturer in physical geography at the University of Plymouth, and the paper's lead author, said: "We knew that every solar system body with an atmosphere and a solid rocky surface has dunes on it, but we didn't know what we'd find on Pluto.

“It turns out that even though there is so little atmosphere, and the surface temperature is around -230C, we still get dunes forming.”

He continued: “It is another piece of the jigsaw in making sense of this diverse and remote body, and gives us a more fundamental understanding of the geological processes which are influencing it."

Dr Jani Radebaugh, associate professor in the department of geological sciences at Brigham Young University, said the discovery of dunes was “really surprising” due to the planet’s weak atmosphere.

“However despite being 30 times further away from the sun as the Earth, it turns out Pluto still has Earth-like characteristics. We have been focusing on what's close to us, but there's a wealth of information in the distant reaches of the solar system too," she added.

The research was led by scientists from the University of Plymouth, University of Cologne in Germany, and Brigham Young University in the US.

It was published in the journal Science.