American scientists have discovered hundreds of crescent-shaped depressions on the surface of Mars, the so-called ghost dunes. These geological formations were left behind by the disappearance of high sandy hills, in which primitive life forms could escape from the effects of radiation. Russian experts stressed the importance of researching their overseas colleagues, at the same time noting that it is extremely difficult to explore the ghost dunes due to the features of the relief.
Much of the surface of Mars is covered with dunes. These sandy hills are formed and disappear by the wind. However, if lava flows are frozen at their foot or sedimentary rocks are present, then after the destruction of the dunes, depressions form in their place. Such geological formations are called "ghost dunes" because in satellite photographs they look like the shadows of the majestic mountains.
A place to live
In a new study, scientists from the University of Washington (USA) have identified nearly 800 ghostly dunes in satellite images of the surface of Mars. Of these, 480 were found in the Labyrinth of Night - a complex of intersecting canyons - and 300 in the Hellas Plain, a lowland that appeared on the site of an impact crater. The depressions are crescent-shaped. Usually the edges of the dunes are parallel to the direction of the prevailing winds, but the "horns" of the Martian dunes are directed against the wind.
“In the direction of the elongated edges of the ghostly dunes, we were able to learn that in the distant past, when the sand hills were just forming, the Martian winds were blowing in the opposite direction. This indicates that the climate on Mars is not static and has changed over the past several billion years,”said study author Day Mackenzie.
Mars / Reuters / NASA.
According to American scientists, billions of years ago on the site of the "ghost dunes" there were sand mounds, the height of which reached 75 m. And inside these mounds, ancient microorganisms could hide from the effects of radiation.
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Scientists believe that ghost dune areas may contain sand that has been isolated from the external environment for a long time. Since it was possible to detect microorganisms in the dunes existing on Earth, the researchers believe that an attempt to find traces of microbial life on the Red Planet could also be crowned with success.
Hope for the future
According to Russian experts, it is necessary to check any assumptions about the existence of life on the surface of the Red Planet, including in the areas of ghostly dunes.
“Once upon a time, conditions for the existence of microorganisms on Mars were favorable. The planet was full of water and probably life. However, so far no evidence of the existence of primitive life forms has been found. Therefore, any clue, for example, a satellite image, will help to find regions with favorable conditions for searching for traces of microorganisms, Mikhail Kuznetsov, an employee of the Moscow State University GAISh, told RT.
However, the scientist emphasized that it is quite difficult to explore the ghost dunes, since the relief form on the Red Planet is extremely diverse. So, according to the expert, there are caves and many other formations on the surface of Mars, which theoretically would allow primitive life forms to hide from unfavorable environmental conditions. However, to test these theories, it is necessary to send "field" expeditions to Mars.
“Of course, during the next missions it is worth studying the places where liquid water existed. Now in such places rovers are working, although recently, due to the onset of a dust storm, their work had to be suspended. Also, the process of such research is complicated by the fact that the relief of Mars is constantly changing, - said Kuznetsov.
According to the interlocutor RT, to test new theories, it is worth sending manned expeditions to Mars, since a person will be able to work more efficiently than rovers.
“No matter how dangerous the manned expeditions are, it is necessary to send a man to Mars in order to achieve a scientific breakthrough in the search for traces of ancient life,” Kuznetsov concluded.
Victor Mironov