Researchers scratch their heads.
The Rover Curiosity has been within the Gale crater since the beginning of its Martian mission, i.e. since 2012. It is a crater measuring 154 kilometers in diameter, which was created by the meteor about 3.8 billion years ago. For three Martian years (over five earthly) Curiosity analyzes the composition of the atmosphere in this region. These studies have even confirmed that the Martian atmosphere is 95% carbon dioxide.
Curiosity's analysis has also shown that the composition of the Martian atmosphere varies slightly depending on the season. In winter, carbon dioxide near the poles freezes, causing the pressure in the entire atmosphere to drop, and in the summer it turns back to gas again, so that the pressure rises again. The concentration of argon and nitrogen varies depending on how much carbon dioxide there is in the atmosphere.
What is strange about seasonal changes in the concentration of individual gases in the atmosphere of Mars is the preservation of oxygen. Its concentration increases in spring and summer much stronger than expected by scientists should – even 30% above its base level. In turn, in winter, it falls below the expected level.
Changes in oxygen concentration occurring in the atmosphere of Mars during the Martian year. | Source: NASA
"We have a problem explaining this phenomenon.", said Melissa Trainer, lead author scientific work, which describes the issue of changes in the Martian atmosphere over the years. "The fact that the annual behavior of oxygen is not perfectly repeatable means that we think that it is not a problem associated with the dynamics of the atmosphere. Oxygen must have its own chemical source. Something must also consume him. "
Perhaps the mysterious increases and decreases in the concentration of oxygen in the atmosphere of Mars are related to the concentration of methane. As the Curiosta rover study has shown, sometimes the methane concentration increases by up to 60% in summer, after which at completely random moments, for unknown reasons, it falls.
"We are beginning to see the confusing correlation between methane and oxygen that manifests itself during most of the Martian year.", said Sushil Atreya, a professor of climate and space sciences and engineering from the University of Michigan at Ann Arbor. "I think there is something to it. However, I don't have any answers yet. "
Who knows, maybe in the future it will be possible to solve the mystery of methane and oxygen in the atmosphere of Mars. Both gases may have biological sources (such as microbes) or geological sources, although there is a greater chance that the geological sources are responsible for the mysterious changes in concentration. That said, for now researchers have no idea what exactly these sources can be.