Equipment for operation on Mars is being tested in the harshest places on Earth - the Atacama and Ross deserts. For a long time it was believed that they were lifeless. However, thanks to new methods, traces of microorganisms were found there. This forced scientists to reconsider their views on the conditions under which life is possible.
Lost city
At the end of 2000, an American expedition using underwater vehicles discovered buildings at the bottom of the Atlantic Ocean. Giant white towers, 60 meters high, towered over the mountain range near the Mid-Atlantic Ridge. The amazing place was named the Lost city - Lost city.
Its towers are composed of carbonate minerals from hot brines circulating in the mantle. Through deep faults in the ocean floor, these brines are thrown up into the water, together with gases, admixtures of minerals, organic compounds and acids, methane, and a large amount of hydrogen. The temperature of the fluids is approaching one hundred degrees Celsius.
Scientists have calculated that the Lost City has been active for the last thirty thousand years, and in total it is 120 thousand years old. Despite the extreme conditions, microorganisms and even some species of deep-sea invertebrates live in hot springs (hydrothermal waters) at a kilometer depth in complete darkness.
Perhaps something similar is on the moon of Saturn, Enceladus. The orbiter "Cassini" photographed fountains on its surface, breaking through the ice shell. In addition to ice particles, the instruments recorded the presence of nanosized quartz crystals. Modeling showed that they formed in salt water at a temperature of at least 90 degrees - this corresponds to not the hottest hydrothermal waters on Earth, which includes the Lost City.
In addition to silicon, emissions from Enceladus contained ammonia, carbon dioxide and methane, as well as a lot of molecular hydrogen - just like in fluids.
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Enceladus is covered in a 40-kilometer-long shell of ice that does not penetrate sunlight. But, if there is a liquid ocean with hot springs under it, there may be microorganisms that extract energy from the oxidation of inorganics, and not through photosynthesis.
Lost City - hydrothermal structures of carbonates at the bottom of the Atlantic Ocean. Scientists suggest the existence of something similar on Enceladus under the ice shell.
South Maria Elena
The driest region of the planet is located along the western coast of South America - the Atacama Desert. For a long time, Yungai was considered the harshest place here, where NASA is testing equipment and rovers for future Martian missions. In 2014, a team led by NASA-based astrobiologist Armando Azua-Bustos from Chile, who worked with NASA, accurately calculated all regions of the Atacama according to three parameters: the regular absence of rain and fog, the presence of strong winds. It turned out that there is an even drier place - in the south of the Chilean city of Maria Elena (MEY). MEY is located at an altitude of three thousand meters above sea level. It hasn't rained there for the last four hundred years. On the surface during the day, the temperature rises to sixty degrees. The average atmospheric humidity is 17.3 percent. For comparison, on Jungai - 28.8 percent. At 1 meter depth, the MEY is even drier:the average atmospheric humidity is only 14 percent. There, scientists have also found traces of DNA from five species of microorganisms, including Actinobacteria, Geodermatophilus (it lives in the most extreme conditions) and Firmicutes (it was found in the Nike cave in Mexico, famous for huge gypsum crystals). The set of microorganisms from MEU soils is typical for the hottest and driest places on the planet: the McMurdo valleys in Antarctica, the Gobi and Taklamakan deserts. As the authors of the work believe, the MEU is the closest analogue of Mars. Until now, this planet was considered too dry for life, but perhaps future discoveries in the Atacama will change this view. Geodermatophilus (it lives in the most extreme conditions) and Firmicutes (it was found in the Nike cave in Mexico, famous for its huge gypsum crystals). The set of microorganisms from MEU soils is typical for the hottest and driest places on the planet: the McMurdo valleys in Antarctica, the Gobi and Taklamakan deserts. As the authors of the work believe, the MEU is the closest analogue of Mars. Until now, this planet was considered too dry for life, but perhaps future discoveries in the Atacama will change this view. Geodermatophilus (it lives in the most extreme conditions) and Firmicutes (it was found in the Nike cave in Mexico, famous for its huge gypsum crystals). The set of microorganisms from MEU soils is typical for the hottest and driest places on the planet: the McMurdo valleys in Antarctica, the Gobi and Taklamakan deserts. As the authors of the work believe, the MEU is the closest analogue of Mars. Until now, this planet was considered too dry for life, but perhaps future discoveries in the Atacama will change this view.future discoveries at the Atacama will change this view.future discoveries at the Atacama will change this view.
Dark lines on a steep slope in the Acheron furrow on Mars. According to one version, these are moist soils where living organisms can hide.
McMurdo Dry Valleys
In Antarctica, there is also a place that is very close in some conditions to the cold Martian regoliths - these are the dry McMurdo valleys at the southern tip of the continent. It was not for nothing that NASA tested the Vikings descent vehicles for the Mars mission there in the Ross Desert. The Antarctic dry valleys see little wet precipitation, and ice and snow are blown away from there by the strongest winds, so that the land is always bare, in some areas saline. The flux of solar radiation is very large here, and the biomass is minimal. Nevertheless, scientists have found microorganisms in seasonal streams of water slurry flowing down from the slopes. These streams of water reminded scientists of the dark, linear structures visible in images of the Martian surface. Many are inclined to believe that these are sand taluses, but there is a version that these are traces of liquid brines circulating in the Martian soil. The conditions for the preservation of life there are more favorable than in the dry areas of the Red Planet.
Microorganisms have been found in the soils of the dry McMurdo valleys in Antarctica. The closest analogue of - dark streaks on Mars.
Hokkaido hot springs
Of all the planets of the solar system, Venus is the closest to Earth in physical parameters. However, this is the last place that can be considered for the search for life. On its surface, five hundred degrees Celsius, the pressure of ninety atmospheres - as at the bottom of the ocean. In addition, the gas envelope consists almost entirely of carbon dioxide.
Scientists believe that Venus and Earth were formed almost identical and, possibly, life originated on both planets. Then Venus lost all water and became uninhabitable, but especially persistent microorganisms could take refuge in clouds of water vapor saturated with sulfuric acid at an altitude of fifty kilometers. The temperature there ranges from minus 20 to plus 65 degrees Celsius, and the pH value is extremely low.
In such conditions, for example, acid-loving and thermophilic archaea Picrophilus can live. They are found in hot springs on the island of Hokkaido in Japan.
Infernal Valley at Noboribetsu on Hokkaido Island in Japan. The most persistent archaea and bacteria are found in hot brines. Only they are able to survive in the clouds of sulfuric acid on Venus.
Tatiana Pichugina