Doomed to be a desert planet? – Mars probably tends towards hostility to life
Earth is probably stabilizing to life-friendly conditions, but Mars is different. This is indicated by simulations and findings from a Mars rover.
The Red Planet from Curiosity's perspective
(Image: NASA/JPL-Caltech/MSSS)
Just as conditions on Earth are constantly returning to life-friendly conditions in the long term, Mars could be condemned to remain a desert planet in the long term. This is suggested by an analysis that planetologist Edwin Kite from the University of Chicago has now published. He and his team want to use it to explain why, although there are traces of sometimes rich water deposits on Mars, the planet may have lost life-friendly conditions again and again. Periods of life-friendliness would therefore be the exception on Mars and ultimately the Red Planet would always regulate itself into the life-hostile state that we know.
Stable life-friendly vs. stable hostile to life
While Mars and Earth are almost identical in structure, they look enormously different today and an explanation is still being sought, the team writes. It is already known about Earth that there is a finely balanced system for the exchange of carbon dioxide between the atmosphere and the rock. If an increasing COâ‚‚ content in the air causes the atmosphere to warm up, the reactions that create the greenhouse gas in the rock also take place more quickly. At some point, this halts the rise in temperature and, over hundreds of millions of years, this has ensured that conditions on Earth have remained fairly stable and life-friendly.
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However, the research team now believes that this does not work on Mars. For example, as soon as increasing solar activity causes it to become warmer and water to become liquid, this water ensures that the COâ‚‚ accumulates in the rocks faster than on Earth. As a result, the planet cools down again immediately and the deserts take over once more. Extensive simulations have shown that the periods in which there was liquid water on the surface of Mars were always quite short and were followed by 100-million-year-long "desert periods". These are very difficult conditions for the development of life.
The research work is based on the discoveries made by NASA's Mars rover Curiosity. It searched for traces of carbon dioxide in a layer of rock that could confirm the theory. Because if Mars tends to deposit COâ‚‚ in the rock, it should also be detectable there in large quantities. To really confirm the explanation, however, it would now have to be shown that these carbonates are actually as widespread across the planet as predicted. The research work is now being presented in the scientific journal Nature and could represent another piece of the puzzle in the exploration of the history of Mars.
(mho)
