[ad_1]
Oceans buried like the one who thought to slip under the icy surface of dwarf planet Pluto can be incredibly common across the cosmos.
A new study indicates that the gaseous insulation layer probably prevents Pluto water from freezing in the liquid water of the ocean. And something similar could happen under the surface of icy worlds in other solar systems The members of the study team also said.
"It could mean that there are more oceans in the universe than previously thought, making the existence of extraterrestrial life more plausible," wrote the author. Principal author Shunichi Kamata, from Hokkaido University in Japan. said in a statement.
Related: Photos of Pluto and its moons
The bright "heart" of Pluto is located near the equator. Its left half is a big basin called Sputnik Planitia.
(Image: © Figures created with the help of images from NASA / Applied Physics Laboratory of Johns Hopkins University / Southwest Research Institute.)
The "heart" of Pluto hints at the buried ocean
The proposed interior structure of Pluto. A thin layer of clathrate hydrate (gas) serves as a thermal insulator between the ocean underwater and the ice shell, preventing the ocean from freezing.
(Image: © Kamata S. et al., The Pluto Ocean is covered and isolated by gas hydrates.) Nature Geosciences, May 20, 2019.)
The case of an underground ocean at Pluto is reinforced by the location of Sputnik Planitia, a plain of 600 km wide (1,000 km) nitrogen ice that forms the left lobe of the famous "heart" of the dwarf planet.
NASA's observations New Horizons probe showed that Sputnik Planitia is aligned with the tide axis of Pluto – the line along which the gravitational pull of Charon, the largest moon on the dwarf planet, is the most powerful. Scientists believe that Pluto has entered this orientation because of the extra mass concentrated at the surface and near the surface in the Sputnik region Planitia.
This additional mass probably comes from the nitrogen ice that accumulated in the plain, as well as from the buried ocean water, which was released to go back deep underground after the impact of the comet that formed Sputnik Planitia broke the crust at this place. previous research suggests.
But how could a buried ocean be frozen on Pluto during the 4.6 billion years of the solar system's history? After all, the dwarf planet does not surround a gas giant, so its entrails are not shaken and heated by the tidal forces as dramatically as the interior of Jupiter's moon, Europa, and Saturn's satellite, Enceladus, also harboring underground oceans.
The new study offers a possible explanation. Kamata and his colleagues hypothesized that an insulating layer of "gas hydrates" – ice-like solids composed of gases trapped in "cages" of water molecular – under the ice shell of Pluto could be responsible for it, and then carried out computer simulations to test the idea.
In simulations performed without gas hydrates, the Pluto Ocean froze hundreds of millions of years ago. But with the insulating layer, the ocean still persists today, researchers discovered. Gas hydrates also act as an insulator in the opposite direction, helping to keep the Pluto surface cold enough to withstand the observed variations in the thickness of the ice shell, the researchers said.
It is not known what the gas inside the water cages could be (if such a layer actually exists). But the study team thinks that methane is a good candidate, partly because Pluto's sneaky atmosphere lacks a lot of substance.
The new study was published online today (May 20) in the newspaper Nature Geoscience.
Mike Wall's book on the search for extraterrestrial life, "Over there"(Grand Central Publishing, 2018, illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on twitter @Spacedotcom or Facebook.
[ad_2]
Source link