Mountains of Pluto there are snow caps that may have formed from top to bottom, as opposed to bottom to top, the opposite of how snow caps form on Earth, a new study finds
When NASA New horizons a spacecraft flew from Pluto in 2015, he revealed surprisingly complex and diverse landscape in the distant world. Pluto’s frozen surface varies considerably, including regions dominated by different types of ice cream, from frozen methane to frozen nitrogen and even water ice.
“Pluto’s base is made of water ice, but it’s so cold that the ice is harder than rock,” study lead author Tangi Bertrand, a planetary scientist at NASA’s Ames Research Center in Moffett, California, told Space.com. . “The mountains of Pluto are composed of this cold ice with hard water. “
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In the mountain ranges of Pigafeta Montes and Elkano Montes in Pluto’s dark equatorial region of Cthulhu, scientists found frozen peaks, “strikingly resembling snow-capped mountain ranges observed on Earth,” Bertrand said. “Such a landscape has never been observed anywhere else in the solar system.”
For example, the peaks of Pigafeta Montes, which can rise about 3.5 km above their bases, have brightly reflecting caps at altitudes above about 1 mile (1.5 km). Similar frosts have been observed on the rims and walls of craters in the Cthulhu region.
The exact composition of this frost on Pluto was unclear. While the researchers identified methane, it was not known whether it was pure frozen methane, frozen methane diluted with frozen nitrogen, or a mixture of both. Uncertainty about the composition of the frost made it unclear how it may have formed.
To help solve these mysteries, scientists in this new study examined high-resolution data from New Horizons, focusing on the composition of high-altitude freezing. This new analysis revealed that the freezing of the snow cover “is almost pure methane ice with traces of nitrogen ice,” Bertrand said.
Researchers have also developed computer simulations of Pluto’s high-resolution climate. They focused on how methane circulates around the dwarf planet.
On Earth, mountain snow caps form when humid winds rise and cool as temperatures fall with increasing altitude. The rising humidity condenses when it gets colder, forming snow on the mountain tops.
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“Methane is a trace gas of Plutobecause the water vapor is on Earth, so it initially seemed logical for the high frosts observed on Pluto to form as on Earth, “Bertrand said.
“But the opposite is happening on Pluto,” Bertrand said. “We have discovered that a new and unique atmospheric process forms these snow-capped mountains of Pluto. It is remarkable to see that two very similar landscapes of Earth and Pluto can be created by two very different processes.”
New simulations have revealed that Pluto’s atmospheric circulation can concentrate methane gas a few miles above the planes of the dwarf planet. This in turn can lead to condensation of methane as freezing on mountain peaks.
Pluto’s thin atmosphere is heated by the sun and actually warms with increasing altitude, while its surface temperature remains evenly cold, Bertrand explained. “Pluto’s atmosphere there is more gaseous methane at its warmer, higher altitudes, which allows this gas to saturate and freeze directly on mountain peaks high enough to reach the enriched area. cannot condense. “
Such activity could also help explain how other methane tanks formed on Pluto, the researchers said.
“This discovery teaches us that there are still many physical and dynamic processes in space that we do not know about, and that the climate can be very different from that of Earth, although it forms similar landscapes,” Bertrand said. “It is important to study Pluto and other planetary bodies because they are natural laboratories for research and study of the variety of possible climatic conditions, which gives us a greater perspective on our own climate.”
In addition, this work “also teaches us what is common and what is unique about the planetary climate and helps to understand where the climate of Pluto, the climate of the dwarf planet, fits into the other climates we know in the solar system – Earth, Mars, Venus “Titan, Triton,” Bertrand said.
Scientists in detail their findings in an article published Oct. 13 in the journal Nature Communications.
Follow Charles K. Choi on Twitter @cqchoi. Follow us on Twitter @Spacedotcom and on Facebook.