Mountains of ice several kilometers high. Nitrogen glaciers Volcanoes that, instead of magma, could expel water. Since NASA’s New Horizons flew over Pluto, the dwarf planet has impressed astronomers with its geological oddities. Now, to the list, you have to add dunes, made of methane instead of sand.
They have discovered an international research led by the University of Plymouth (United Kingdom), thanks to data sent by New Horizons, which reached Pluto in 2015. It is an amazing find because the thin atmosphere of the dwarf planet, with a density of 100,000 times smaller than Earth, it did not seem capable of generating strong enough winds to form dunes.
“We knew that all bodies in the Solar System whose atmosphere and a solid rocky surface have dunes, but did not know what we would find on Pluto, ” he said in a statement Matt Telfer, a researcher at the University of Plymouth and lead author of the Science in the one that presents the finding. “It turns out that, even with such a tenuous atmosphere and a surface temperature of 230 degrees below zero, we have dunes in formation,” adds the astronomer.
The thin atmosphere of the dwarf planet, with a density 100,000 times smaller than that of Earth, did not seem capable of generating strong enough winds to form dunes
The formation is located in the west of the Sputnik Planitia, which is the western part of the region known as the Heart, the brightest surface of Pluto. It is an area of nitrogen, carbon monoxide and methane, substances that usually gas on Earth but are solid in the small icy star.
The dunes stretch at regular intervals between 400 meters and one kilometer, in a 75-kilometer-diameter area rich in methane. They are in the shadow of the al-Idrisi Mountains, a mountain range of icy water up to five kilometers in altitude.
Researchers have found the dunes in images captured by the LORRI instrument (from the English Long Range Reconnaissance Imager) of the ship New Horizons. To explain their origin, they have developed a mathematical model that has revealed that they are formed by grains of methane sand between 0.2 and 0.3 millimeters – a size similar to that of the Sahara sand – from the al-Idrisi Montes.
To find a planetary body so diverse orographically and endowed with its own meteorology was science fiction, as well as the dunes of methane ice particles that make up vast extensions of its surface “
According to the simulations, the sun’s radiation heats the mountains, which are covered in methane snow and have some nitrogen below the surface. When heated, the nitrogen goes from solid to gas, expands and throws methane grains into the air.
The atmosphere of Pluto is dense enough to generate winds between thirty and forty kilometers per hour, which would be able to drag these methane grains to the Sputnik Planitia. As in the Sahara desert, when the grains impact with the methane in the region’s soil, they, in turn, raise more methane than the air drags into new dunes.
“It’s another piece of the puzzle to make sense of this diverse and remote body and gives us a more fundamental understanding of its geological processes,” says Matt Telfer.
“New Horizons has changed our vision about Pluto,” says Josep Maria Trigo, a researcher at the Institute of Science of the Space (IEEC-CSIC), who has not participated in the research. “Given the distance that separates us from this body of the Kuiper Belt, there was nothing but crude images of albedo achieved with large telescopes,” he adds. But the NASA spacecraft has revealed a very complex world. “To find a planetary body so diverse orographically and endowed with its own meteorology was science fiction, as well as the dunes of methane ice particles that make up vast extensions of its surface”, remarks Josep Maria Trigo.
How was Pluto formed?
Other research from the Southwest Research Institute in San Antonio (United States) has used data collected by New Horizons and the Rosetta spacecraft of the European Space Agency (ESA), which traveled to comet 67P / Churyumov-Gerasimenko, to find out how it was formed, Pluto. According to the authors presented last week in the magazine Icarus, the enormous amount of nitrogen present in the Sputnik Planitia could be explained if the dwarf planet was a kind of giant comet.
“We have found an intriguing consistency between the estimated amount of nitrogen and the amount that would be expected if Pluto were formed by the agglomeration of one billion comets or other similar Kuiper Belt objects in chemical composition at 67P,” he said in a statement. Christopher Glein, lead author of the research.