Ancient Mars was warm recognized because of the unusual atmosphere.
Interaction, missing in the earth’s atmosphere, but typical for ancient Martian, can give the answer to the question about the mysteriously high temperature on Mars is the past.
Scientists from the US analysed the causes of paradoxically warm climate on ancient Mars in the era of there being open water.
According to their calculations, all previous work did not take into account the importance of the interaction of carbon dioxide and methane between them.
This unaccounted factor in Martian conditions could give a greenhouse effect much greater than previously thought.
The new work also shows that modern ideas about the outer edge of the habitable zone was wrong: the planets with atmospheres of the same type as that ancient Mars may be inhabited, even if according to modern views is impossible. The corresponding article is published in Geophysical Research Letters.
In recent years there is evidence that the ancient Mars had liquid water and perhaps oceans full, even 4 billion years ago, when the Sun was almost 30 percent fainter than today.
Mars then and now gets from the Sun 2.5 times less light than Earth. This means that 4 billion years ago, he received 3.5 times less heat from our sun.
Simple calculations show that if the Earth’s heat is weaker, at least twice, it generally will not be liquid water.
And even if on Mars in ancient times would have been a carbon dioxide atmosphere a hundred times denser than today, it would still be too cold for open water.
The authors of the new work say that this means that all existing models of ancient Mars that radically not considered.
The researchers conducted calculations of how collisions of the molecules of carbon dioxide and methane are changing the probability of absorption of photons.
According to them, was that the probability of blocking of photons in this case is many times higher than in atmospheres consisting of only carbon dioxide or only methane.
Any realistic estimates of the gas envelope of Mars in ancient times based on the atmospheric pressure above 1.5—2 units modern earth. A denser atmosphere with a weak Martian gravity, it would be difficult to keep.
The atmosphere of the two gases retains heat much better than previously thought possible for such a moderate range of pressures.
Up to the present time such a possibility no one considered, simply because in the Earth’s atmosphere and methane and carbon dioxide are contained in very small quantities and interaction between their molecules is unlikely.
Model, where carbon dioxide 90 percent and methane and its degradation products 5 to 10 percent, quickly showed the authors that the greenhouse effect in this scenario is much stronger than previously thought.
He could heat Mars to zero degrees Celsius even though the weak sunlight that fell then on the Red planet.
The researchers note that a similar interaction of carbon dioxide and methane can be heated to the high temperatures of the planet that are now considered outside of the habitable zone. So, today, Mars is at the outer edge of the habitable zone.
But 4 billion years ago, he, apparently, was far beyond its borders. New work shows that the most distant orbits of the inhabited planets can be on a 12-13 percent farther from the sun than previously believed.
Accordingly, many extrasolar planets, today regarded as too cold for life, potentially quite suitable for her — at least for anaerobic.
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