Clay is, no life - new Curiosity results
Curiosity has come to its senses for the second week after a radiation strike, but the main thing it managed to do was to send the results of the soil study from the well. There were fears that just at the time of their transfer, he and “hung”, but it cost. Data received, analyzed and made public.
The main news is clay! The same clay, to which the Opportunity went for three years, was looking for half a year, and finding it could not really study. Curiosity found it and studied it for 200 years of its Martian career, simply by drilling the first test well. I thought the intrigue would last for another year, because the nearest clay deposits from the satellite were found 3 km closer to the mountain, but even here NASA did not expect such a gift / trick. A serious trick - there is no life, although there is organic.
The main message of the press conference: “Curiosity has found evidence of favorable conditions for living in the past.”
These conditions are characterized by a moist environment in which there were compounds of sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. But more importantly, this medium was pH neutral. Such favorable conditions are characteristic of one of the most ancient geological periods of Mars - Noisky. It is named after the land of Noah, the area most intensively dug in by craters, i.e. the most ancient. At that time there was pure liquid water, there was a dense atmosphere, there was a magnetic field, i.e. Formally, the planet did not differ in terms of conditions from the Earth. This is the basis of all hopes of finding traces of microbial life on Mars.
Water eroded volcanic rocks and they formed clay deposits — smectites or phyllosilicates (these are synonymous). The pictures of the CheMin X-ray diffractometer show that the volcanic sand from the Rocknest site is very similar to the clay from the John Klein site - this is due to the fact that their mineral base is almost the same - olivine-pyroxene volcanic rocks. The difference is that in John Klein worked pH-neutral water and as a result - 20% of phyllosilicates, noted in the picture.
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Then the era changed, the heaviest asteroids fell on Mars , the core stopped forever, the magnetic field disappeared, and the awakened volcanoes filled the atmosphere with sulfur and chlorine compounds, making the water on the surface acidic and unsuitable for life.
Geological layers, formed with the participation of acidic water, studied the Opportunity on the plateau of Meridiani immediately after landing.
(The color of the pictures is balanced under the terrestrial lighting conditions. )
Their characteristic feature is a brown color from iron oxides. Therefore, when the scientists saw the light gray soil extracted by Curiosity in the place of John Klein, they were surprised, but then they didn’t even think that the new Holy Grail of Mars, the long-awaited clay, would be in their power. Earlier, with the same zeal, they were looking for evidence of water activity on the surface - Opportunity found them. Then they looked for water ice — Phoenix Lander and the MRO and Mars Odyssey satellites found it. NASA tried so hard that, until now, some people are sure that Americans continue to search for water.
Meanwhile, NASA is no longer surprised by water on Mars. The same SAM device isolated it from recruited clay:
More interestingly, this water is lighter than that which was investigated in the ground of the Rocknest site. Let me remind you that in studies conducted 4 months ago, the water found in the sand was five times "heavier" than the water on Earth. “ Heavy ” refers to water in which heavy isotopes of hydrogen — deuterium — prevail among the molecules. In terrestrial oceans, one atom of deuterium accounts for 6,400 atoms of the light isotope of hydrogen — protium. Accordingly, water with a ratio of 1 deuterium atom to 1280 light hydrogen atoms was found in the Martian soil. But in the Martian clay, John Klein allocated water, which turned out to be lighter than in Rocknest. True, how much easier is not specified yet, but the fact itself points to the new method of dating geological layers that has opened.
The difference in the "lightness" of water is due to the fact that as the existence of water on the surface of Mars, under the influence of solar radiation and radiolysis , the atoms of light hydrogen released and left the atmosphere of the planet. Accordingly, Proty flew away, but the deuterium remained, its concentration increased. But water, which turned out to be connected at the molecular level in geological rock, avoided such degradation, therefore now the D / H ratio in minerals will allow relative dating. Perhaps, if scientists can build a chronological scale of the process of hydrogen degradation, a means of absolute dating of the rock will appear, but this is still in the future.
In the meantime, you can say with considerable confidence that Curiosity has drilled into the bottom of the lake, which is about 3.5 billion years old.
High thermal inertia of the rocks (red color on the map) indicates the boundaries of this lake, due to the fact that the bottom rocks are distinguished from the rest by a high percentage of water content. The water has a high heat capacity, so this characteristic of the soil was discovered from the Mars Odyssey satellite. When Curiosity went to explore this place, no one knew what he would find there.
So, there is pure liquid water, there is a nutrient medium ... And there is organic matter!
But too simple to be proof of past life on Mars. Signs of chloromethanes were discovered in Rocknest, but then NASA stated that it did not vouch for the Martian origin of this organic matter. Now there is no doubt - the local hydrocarbon. But its origin is quite possible without the participation of wildlife. It is enough to look into Wikipedia : Dichloromethane - Obtained by direct chlorination of methane with chlorine under conditions of a radical mechanism at 400–500 ° C ... The result is a mixture of all possible chlorides: chloromethane, dichloromethane, chloroform and carbon tetrachloride. Apparently, the necessary conditions and ingredients, in addition to methane, could provide volcanoes. Yes, and with methane is not so simple. Although on Earth its clusters are associated with the activity of the biosphere, a similar mechanism is excluded for the atmospheres of Jupiter or Titan, where methane is much more than on Earth. Where methane on Mars is still an open question, but only big optimists can link its origin to the biosphere.
But NASA does not give up. It intends to carefully study the process of diagenesis - that is, the formation of solid sedimentary rocks from loose sediments. The main question is: what conditions and processes experienced the studied deposits, and could any complex organic compounds be preserved in such processes? That is, now the pursuit of Martian life passes from the hands of the drivers of rovers, into the hands of experimental chemists. Will they be able to simulate such conditions in which the entire Martian life decomposed to chloromethanes and inorganic compounds, or the dream of the Martians can be buried forever? Although, let's not forget that this is only the very first test at the very beginning of a long journey.
Sharpe Mountain is waiting ...
Other panorama sizes: VK. or View on GigaPan .
Those who faithfully keep the hope of the Martian life still have consolation. Curiosity has drilled only 7 centimeters. And although, even at such a depth, the clay has not changed its properties for 3.5 billion years, we still cannot look deeper. Meteorite craters will meet on the way of the rover, there will be a channel similar to a river at the foot of the mountain, filled with the same ancient clay, there will be a mountain canyon but ... 7 centimeters.
In 2016, an InSight mission with a drilling platform is planned, which will go deeper by 6 meters and will study the tectonic structure of Mars. But the search for life in her plans are not yet included.
In 2018, they promise the rover from ESA and Roskosmos - ExoMars .
His main tool is a 2.5 meter drill. And he will fly to search for life regardless of the results of the research in the Gale crater.
In 2020, NASA promises another Curiosity, but what tools and devices will be on its arms and what goals it will pursue on Mars is not yet known.
The main news is clay! The same clay, to which the Opportunity went for three years, was looking for half a year, and finding it could not really study. Curiosity found it and studied it for 200 years of its Martian career, simply by drilling the first test well. I thought the intrigue would last for another year, because the nearest clay deposits from the satellite were found 3 km closer to the mountain, but even here NASA did not expect such a gift / trick. A serious trick - there is no life, although there is organic.
The main message of the press conference: “Curiosity has found evidence of favorable conditions for living in the past.”
These conditions are characterized by a moist environment in which there were compounds of sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. But more importantly, this medium was pH neutral. Such favorable conditions are characteristic of one of the most ancient geological periods of Mars - Noisky. It is named after the land of Noah, the area most intensively dug in by craters, i.e. the most ancient. At that time there was pure liquid water, there was a dense atmosphere, there was a magnetic field, i.e. Formally, the planet did not differ in terms of conditions from the Earth. This is the basis of all hopes of finding traces of microbial life on Mars.
Water eroded volcanic rocks and they formed clay deposits — smectites or phyllosilicates (these are synonymous). The pictures of the CheMin X-ray diffractometer show that the volcanic sand from the Rocknest site is very similar to the clay from the John Klein site - this is due to the fact that their mineral base is almost the same - olivine-pyroxene volcanic rocks. The difference is that in John Klein worked pH-neutral water and as a result - 20% of phyllosilicates, noted in the picture.
')
Then the era changed, the heaviest asteroids fell on Mars , the core stopped forever, the magnetic field disappeared, and the awakened volcanoes filled the atmosphere with sulfur and chlorine compounds, making the water on the surface acidic and unsuitable for life.
Geological layers, formed with the participation of acidic water, studied the Opportunity on the plateau of Meridiani immediately after landing.
(The color of the pictures is balanced under the terrestrial lighting conditions. )
Their characteristic feature is a brown color from iron oxides. Therefore, when the scientists saw the light gray soil extracted by Curiosity in the place of John Klein, they were surprised, but then they didn’t even think that the new Holy Grail of Mars, the long-awaited clay, would be in their power. Earlier, with the same zeal, they were looking for evidence of water activity on the surface - Opportunity found them. Then they looked for water ice — Phoenix Lander and the MRO and Mars Odyssey satellites found it. NASA tried so hard that, until now, some people are sure that Americans continue to search for water.
Meanwhile, NASA is no longer surprised by water on Mars. The same SAM device isolated it from recruited clay:
More interestingly, this water is lighter than that which was investigated in the ground of the Rocknest site. Let me remind you that in studies conducted 4 months ago, the water found in the sand was five times "heavier" than the water on Earth. “ Heavy ” refers to water in which heavy isotopes of hydrogen — deuterium — prevail among the molecules. In terrestrial oceans, one atom of deuterium accounts for 6,400 atoms of the light isotope of hydrogen — protium. Accordingly, water with a ratio of 1 deuterium atom to 1280 light hydrogen atoms was found in the Martian soil. But in the Martian clay, John Klein allocated water, which turned out to be lighter than in Rocknest. True, how much easier is not specified yet, but the fact itself points to the new method of dating geological layers that has opened.
The difference in the "lightness" of water is due to the fact that as the existence of water on the surface of Mars, under the influence of solar radiation and radiolysis , the atoms of light hydrogen released and left the atmosphere of the planet. Accordingly, Proty flew away, but the deuterium remained, its concentration increased. But water, which turned out to be connected at the molecular level in geological rock, avoided such degradation, therefore now the D / H ratio in minerals will allow relative dating. Perhaps, if scientists can build a chronological scale of the process of hydrogen degradation, a means of absolute dating of the rock will appear, but this is still in the future.
In the meantime, you can say with considerable confidence that Curiosity has drilled into the bottom of the lake, which is about 3.5 billion years old.
High thermal inertia of the rocks (red color on the map) indicates the boundaries of this lake, due to the fact that the bottom rocks are distinguished from the rest by a high percentage of water content. The water has a high heat capacity, so this characteristic of the soil was discovered from the Mars Odyssey satellite. When Curiosity went to explore this place, no one knew what he would find there.
So, there is pure liquid water, there is a nutrient medium ... And there is organic matter!
But too simple to be proof of past life on Mars. Signs of chloromethanes were discovered in Rocknest, but then NASA stated that it did not vouch for the Martian origin of this organic matter. Now there is no doubt - the local hydrocarbon. But its origin is quite possible without the participation of wildlife. It is enough to look into Wikipedia : Dichloromethane - Obtained by direct chlorination of methane with chlorine under conditions of a radical mechanism at 400–500 ° C ... The result is a mixture of all possible chlorides: chloromethane, dichloromethane, chloroform and carbon tetrachloride. Apparently, the necessary conditions and ingredients, in addition to methane, could provide volcanoes. Yes, and with methane is not so simple. Although on Earth its clusters are associated with the activity of the biosphere, a similar mechanism is excluded for the atmospheres of Jupiter or Titan, where methane is much more than on Earth. Where methane on Mars is still an open question, but only big optimists can link its origin to the biosphere.
But NASA does not give up. It intends to carefully study the process of diagenesis - that is, the formation of solid sedimentary rocks from loose sediments. The main question is: what conditions and processes experienced the studied deposits, and could any complex organic compounds be preserved in such processes? That is, now the pursuit of Martian life passes from the hands of the drivers of rovers, into the hands of experimental chemists. Will they be able to simulate such conditions in which the entire Martian life decomposed to chloromethanes and inorganic compounds, or the dream of the Martians can be buried forever? Although, let's not forget that this is only the very first test at the very beginning of a long journey.
Sharpe Mountain is waiting ...
Other panorama sizes: VK. or View on GigaPan .
Those who faithfully keep the hope of the Martian life still have consolation. Curiosity has drilled only 7 centimeters. And although, even at such a depth, the clay has not changed its properties for 3.5 billion years, we still cannot look deeper. Meteorite craters will meet on the way of the rover, there will be a channel similar to a river at the foot of the mountain, filled with the same ancient clay, there will be a mountain canyon but ... 7 centimeters.
In 2016, an InSight mission with a drilling platform is planned, which will go deeper by 6 meters and will study the tectonic structure of Mars. But the search for life in her plans are not yet included.
In 2018, they promise the rover from ESA and Roskosmos - ExoMars .
His main tool is a 2.5 meter drill. And he will fly to search for life regardless of the results of the research in the Gale crater.
In 2020, NASA promises another Curiosity, but what tools and devices will be on its arms and what goals it will pursue on Mars is not yet known.
Source: https://habr.com/ru/post/172511/
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