Science

Pluto is covered with icy methane dunes

Pluto is covered with icy methane dunes

Launched in 2006, New Horizons was the first spacecraft ever to visit Pluto, passing within 12,500 kilometres.

Meanwhile, British researcher Matt Telfer from the University of Plymouth has published a paper about what appear to be dunes on a plain on Pluto called Sputnik Planitia. Thought to be relatively recent, the parallel rows of dunes are located in Pluto's heart-shaped region at the base of mountains as tall as the Alps and formed from giant blocks of ice with frosty methane snowcaps.

These plains in the left lobe of Pluto's "heart" are known as Sputnik Planitia.

They suggest nitrogen ice coating the surface of Sputnik Planitia transformed into gas that lifted methane particles into the air. Research shows that the dunes are spread across an area that is less than around 45 miles (75 kilometers) across.

"We understand now that this celestial body on the outskirts of the Solar system is not a frozen planetoid - actually is a dynamic world that is constantly changing and to this day", says Telfer.

To Telfer and other planetary scientists, those ripples looked like windswept sand - a bit of a puzzle, because scientists weren't sure whether Pluto's thin atmosphere could muster enough wind for sweeping.

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Combining an analysis of wind streak and dune-like features with spectral and numerical modeling, the scientists determined what might be the underlying architect of dunes on Pluto.

"I can drive down to the sand dunes at Little Sahara and be driving around on something that's nearly exactly the same as the surface of Pluto", Radebaugh said. Alternatively, the methane may come directly from the bottom of the nearby mountain range, getting swept up in the winds that flow down the mountainous slopes at roughly 22 miles per hour (35 kilometers per hour).

The dunes have reportedly formed in the last 500,000 years.

"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". Jani Radebaughis, the co-author of the study and an associate professor of the geological sciences department at the Brigham Young University. They now plan to carry on investigating the dunes through computer simulations, which will in turn further enlighten them about how Pluto's winds shaped its geography.

Dr. Eric Parteli of the University of Cologne explains that Pluto's low gravity and atmospheric pressure means that the wind strength necessary for sediment transport can be 100,000 times lower than on Earth.

"It's an exciting discovery, I'll say that for sure", said Ryan Ewing, a geologist at Texas A&M University who was not involved with this report. The temperature gradients in the granular ice layer, caused by solar radiation, also play an important role in the onset of the saltation process [movement of particles over an uneven surface]. There was some doubt about whether Pluto's extremely thin atmosphere, mainly nitrogen with minor amounts of methane and carbon monoxide, could muster the wind needed to form such features. An astronomer unrelated to the study told Gizmodo that there needs to be higher-resolution images of the structures to determine whether or not they may be dunes.