'Surprising' methane dunes found on Pluto

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Alexander Hayes (Cornell University) wrote in an article on the study that researchers will have to find out "how high the dunes are, when they are most active, whether they change' and whether particles can be swept into dunes without rising into the air".

An worldwide team of researchers reviewed photos of the Tombaugh Regio - dubbed "the heart" - snapped by the New Horizon space probe during its 2015 fly-by of the dwarf planet, and discovered 357 regularly spaced ridges along a bordering mountain range.

"We have been focusing on what's close to us", said Radebaugh, "but there's a wealth of information in the distant reaches of the solar system too".

Yet mild winds blowing across Pluto's surface at speeds of some 19-25 miles (30-40 kilometres) per hour have forged these ripples at the border of an ice plain and mountain range, said the report in the journal Science.

An global science team discovered dunes on Pluto, suggesting that they likely have been formed of methane ice grains released into its rarefied atmosphere.

The research is yet another moment to reflect on just how surprisingly diverse Pluto has been revealed to be.

Launched in 2006, New Horizons was the first spacecraft ever to visit Pluto, passing within 12,500 kilometres. What they got was an icy world with a giant heart-shaped plain and water-ice mountains, and hints of geological activity deep below the surface.

Pluto's surface is mostly nitrogen, which is solid at the average temperature of around -230°C.

Co-author of the study, Jani Radebaugh from the Brigham Young University said in a statement that, "Dunes on Pluto, or any other body, tell us there is a significant enough atmosphere to move materials around, and that there are particles to move-in this case, frozen methane sand". Telfer and his colleagues spotted pits along the edge of the plain, where they suspect nitrogen ice sublimated.

Pluto, smaller than Earth's moon with a diameter of about 1,400 miles (2,380 km), orbits roughly 3.6 billion miles (5.8 billion km) away from the sun, nearly 40 times farther than Earth's orbit, with a surface marked by plains, mountains, craters and valleys. They demonstrate two of the things that are required to make dunes: grains (of sand, or dust or, as in Antarctica, ice) and wind.

Understanding how dunes form on Pluto will help scientists study similar features found elsewhere in the solar system, according to the study. "It turns out that even though there is so little atmosphere, and the surface temperature is around -230 degrees Celsius [-382 degrees Fahrenheit], we still get dunes forming".

The scientists also believe the undisturbed morphology of the dunes and their relationship with the underlying glacial ice suggests the features are likely to have been formed within the last 500,000 years, and possibly much more recently. 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. The probe is now gearing up for a flyby of a small object called 2014 MU69, which lies about 1 billion miles (1.6 billion km) beyond Pluto.