Oxygen in the Martian air changes in such a way that at present it is impossible to explain by known chemical processes.
This is a requirement of scientists working on the mission of the Curiosity rover, who take gas measurements.
They found that the amount of oxygen in Martian "air" increased by 30% in spring and summer.
The pattern remains a mystery, but researchers are starting to narrow down the possibilities.
Although the changes are likely to be geological in nature, planetary scientists cannot completely exclude an explanation related to microbial life.
The results are derived from data from nearly six Earth years (three Martian years) from the Mars Sample Analysis Tool (Sam), a portable chemistry lab in the stomach of the Curiosity rover.
Scientists measured the seasonal changes in gases that fill the air directly above the surface of Gale Crater on Mars, where Curiosity landed. They published their findings in the journal JGR-Planets.
The Martian atmosphere overwhelmingly consists of carbon dioxide (CO2) with fewer other gases, such as molecular nitrogen (N2), argon (Ar), molecular oxygen (O2) and methane (CH4).
Nitrogen and argon followed a predictable seasonal model that varies depending on how much CO2 was in the air (which in turn is associated with changes in air pressure). They expected oxygen to follow this pattern, but it is not.
Oxygen increased during each spring in the northern hemisphere, and then fell in the fall. They considered the possibility that molecules of CO2 or water (H2O) release oxygen when they decompose in the atmosphere, resulting in short-term growth. But it would take five times more water than actually to produce additional oxygen, and CO2 decays too slowly to generate it for such a short time.
“We know that oxygen is created and destroyed on Mars by the energy released by sunlight, which destroys the CO2 and H2O that are observed in the atmosphere of Mars. What does not make sense is the size of the change - it is not. doesn’t match what we expect to see, ”Dr. Manish Patel of Open University, who did not participate in the study, told BBC News.
“Given that Curiosity is taking measurements on the surface of Mars, it is tempting to think that it comes from the surface - but we have no evidence of this. Geologically speaking, this seems unlikely - I can't think of a process that will fit. "
Dr. Timothy McConnoche of the University of Maryland at College Park, who is one of the authors of the JGR-Planets article. “You can measure the water vapor molecules in the atmosphere of Mars, and you can measure the change in oxygen ... There are simply not enough water molecules.
"Mars as a whole contains a rather small amount of water vapor, and several times more mysterious atoms of the oxygen atom than in water vapor on the entire planet."
They also examined why oxygen dropped to the level predicted by famous chemistry in the fall. One idea was that solar radiation could break oxygen molecules into two atoms, which then went into space. But after counting the numbers, the scientists came to the conclusion that it would take at least 10 years for oxygen to disappear in this way.
In addition, seasonal increases are not entirely repeatable; the amount of oxygen varies between years. The results imply that something produces gas and then takes it.
Dr. McConnochie believes the evidence suggests a source of oxygen on the surface “I think this indicates a reservoir (of oxygen) in the soil that interacts with the atmosphere,” he said.
“To exchange (with the atmosphere) fairly quickly on a seasonal time scale, it must be close to the surface. If it is deeper, any process will be slower, ”he said.
Some supporting evidence comes from NASA Viking ships that landed on the Red Planet in the 1970s. The results of the Viking Gas Exchange (GEX) experiment showed that when humidity increased in a chamber containing a sample of Martian soil, this resulted in oxygen evolution.
However, says Dr. McConnocky, the temperature in the chamber of the Viking spacecraft was much higher than on the street, even in spring and summer. This complicates any attempt to apply the results to the Martian environment: “This is a tempting clue, but it does not help us solve the problem directly,” he explained.
Mars becomes wetter in spring and summer. Water ice is deposited on poles in winter. Then, throughout the summer, water vapor is released in the polar regions.
At this time, there may be a connection between the hydration of the entire planet and the release of oxygen.
Interestingly, changes in oxygen are similar to those observed for methane, which in summer increases by about 60% in weight for unexplained reasons. It is not clear if there is any connection though.
This is a requirement of scientists working on the mission of the Curiosity rover, who take gas measurements.
They found that the amount of oxygen in Martian "air" increased by 30% in spring and summer.
The pattern remains a mystery, but researchers are starting to narrow down the possibilities.
Although the changes are likely to be geological in nature, planetary scientists cannot completely exclude an explanation related to microbial life.
The results are derived from data from nearly six Earth years (three Martian years) from the Mars Sample Analysis Tool (Sam), a portable chemistry lab in the stomach of the Curiosity rover.
Scientists measured the seasonal changes in gases that fill the air directly above the surface of Gale Crater on Mars, where Curiosity landed. They published their findings in the journal JGR-Planets.
The Martian atmosphere overwhelmingly consists of carbon dioxide (CO2) with fewer other gases, such as molecular nitrogen (N2), argon (Ar), molecular oxygen (O2) and methane (CH4).
Nitrogen and argon followed a predictable seasonal model that varies depending on how much CO2 was in the air (which in turn is associated with changes in air pressure). They expected oxygen to follow this pattern, but it is not.
Oxygen increased during each spring in the northern hemisphere, and then fell in the fall. They considered the possibility that molecules of CO2 or water (H2O) release oxygen when they decompose in the atmosphere, resulting in short-term growth. But it would take five times more water than actually to produce additional oxygen, and CO2 decays too slowly to generate it for such a short time.
“We know that oxygen is created and destroyed on Mars by the energy released by sunlight, which destroys the CO2 and H2O that are observed in the atmosphere of Mars. What does not make sense is the size of the change - it is not. doesn’t match what we expect to see, ”Dr. Manish Patel of Open University, who did not participate in the study, told BBC News.
“Given that Curiosity is taking measurements on the surface of Mars, it is tempting to think that it comes from the surface - but we have no evidence of this. Geologically speaking, this seems unlikely - I can't think of a process that will fit. "
Dr. Timothy McConnoche of the University of Maryland at College Park, who is one of the authors of the JGR-Planets article. “You can measure the water vapor molecules in the atmosphere of Mars, and you can measure the change in oxygen ... There are simply not enough water molecules.
"Mars as a whole contains a rather small amount of water vapor, and several times more mysterious atoms of the oxygen atom than in water vapor on the entire planet."
They also examined why oxygen dropped to the level predicted by famous chemistry in the fall. One idea was that solar radiation could break oxygen molecules into two atoms, which then went into space. But after counting the numbers, the scientists came to the conclusion that it would take at least 10 years for oxygen to disappear in this way.
In addition, seasonal increases are not entirely repeatable; the amount of oxygen varies between years. The results imply that something produces gas and then takes it.
Dr. McConnochie believes the evidence suggests a source of oxygen on the surface “I think this indicates a reservoir (of oxygen) in the soil that interacts with the atmosphere,” he said.
“To exchange (with the atmosphere) fairly quickly on a seasonal time scale, it must be close to the surface. If it is deeper, any process will be slower, ”he said.
Some supporting evidence comes from NASA Viking ships that landed on the Red Planet in the 1970s. The results of the Viking Gas Exchange (GEX) experiment showed that when humidity increased in a chamber containing a sample of Martian soil, this resulted in oxygen evolution.
However, says Dr. McConnocky, the temperature in the chamber of the Viking spacecraft was much higher than on the street, even in spring and summer. This complicates any attempt to apply the results to the Martian environment: “This is a tempting clue, but it does not help us solve the problem directly,” he explained.
Mars becomes wetter in spring and summer. Water ice is deposited on poles in winter. Then, throughout the summer, water vapor is released in the polar regions.
At this time, there may be a connection between the hydration of the entire planet and the release of oxygen.
Interestingly, changes in oxygen are similar to those observed for methane, which in summer increases by about 60% in weight for unexplained reasons. It is not clear if there is any connection though.
0 Comments