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. At Plutonian noon, the sunlight is comparable to Earth's dusk.
After an epic trek through the solar system that took almost a decade, New Horizons sped by at a speed of 58,536 km/h, gathering data as it passed. The spacecraft also uncovered Pluto's versions of familiar geography.
Sand dunes rise next to Pluto's mountains.
A new study reveals that there are dunes present on Pluto, but they're not like the ones found on Earth.
Pluto got taken off the list of the solar system's planets a few years ago, but that does not make it any less of an interesting body for astronomers to study.
Before New Horizons, the clearest image of Pluto was only 12-pixels.
The images showed that on the boundary of the Sputnik Planitia ice plain, pushed up against a major mountain range, there is a series of dunes spreading across an area less than 46.6 miles.
Initially, given Pluto's size, exceedingly thin atmosphere, and solid gases, experts weren't expecting to find dunes as you might on Earth.
"When we first saw the New Horizons images, we thought instantly that these were dunes but it was really surprising because we know there is not much of an atmosphere", said co-author Dr. Jani Radebaugh, from the Department of Geological Sciences, College of Physical and Mathematical Sciences at Brigham Young University.
A British-led team announced the findings on Thursday (Friday NZ time) in the journal Science. They were able to detect the dunes using the map of Pluto created by New Horizons and modeling of the surface. "There're a bunch of things out there that are vaguely dunelike", Telfer said. Previously, scientists had spotted them on Mars, Titan, and even on a freaking comet. This implies that the basics of dune formation are tiny bits of grains and a kind of force just like that of the wind.
Though the winds may be relatively slow, the nature of the terrain has contributed to the formation of the dunes, the researchers argue.
With that warming of the ice below the surface, methane crystals should enable nitrogen ice to sublimate - and that would allow the methane crystals to be wafted into the atmosphere. The scientists calculated that the methane grains are probably a hundredth of an inch in diameter.
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Pluto's dunes rise to about 100 feet, roughly as high as the Mesquite Flat Dunes in Death Valley National Park.
These are then transported by Pluto's moderate winds (which can reach between 30 and 40 kmh), with the border of the ice plain and mountain range providing the ideal location for such regular surface formations to appear.
Yet the sand must flow. Winds are relatively slow, at most 25 miles per hour on average. Pluto's are the only ones known to consist of methane.
But those winds are too gentle to kick up methane grains, normally packed close together, from the surface.
A third factor important in the construction of dunes is the ability of the grains to be moved by the wind.
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The study authors suspect a process called sublimation did the trick.
Pluto's existence at the edge of the known solar system led to questions of its composition: there was early recognition that methane was a significant component of Pluto, but was it mainly composed of ice and gas like its nearest neighbour Neptune? "However despite being 30 times further away from the sun as the Earth, it turns out Pluto still has Earth-like characteristics".
Other explanations for the dunes might include increases in atmospheric pressure, William McKinnon, of Washington University in St Louis, told the Post.
Discoveries that remind Radebaugh of home.
It's now heading towards an object in the Kuiper Belt nicknamed Ultima Thule, about 1.6 billion kilometres beyond Pluto, on January 1.