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The study of a new water cycle in Martian summer helps to understand why Mars is a barren and dusty land.
Once upon a time, billions of years ago, Mars was a waterlogged world, rich in rivers and oceans. But all this water has been lost and today still, the planet lets escape hydrogen in the space. It is estimated that Mars has lost at least 80% of its original water, as ultraviolet radiation emitted by the Sun has broken down the water molecules of the upper atmosphere into hydrogen and hydroxyl radicals, and the water has been destroyed. Hydrogen gas has escaped irreversibly.
But the mystery lies in the way water has been channeled to that point. Like the Earth's tropopause, Mars has a medium-sized atmospheric layer that should hold up gas, causing it to turn to ice and return to the surface of the planet.
Billions of years ago, Mars could have looked like this with an ocean covering part of its surface. (Credit: NASA / GSFC)
NASA / GSFC
Scientists have now identified a water cycle that could provide clues to Mars' loss of water and why the Earth manages to conserve its reserves.
Every two terrestrial years, summer on the southern hemisphere of Mars, water vapor rises effectively from the lower atmosphere to the upper atmosphere. From there, the winds carry most of the rare gas to the North Pole, where it falls again, but a portion of it breaks down in space.
Computer simulations performed by scientists from the Moscow Institute of Physics and Technology and the Max Planck Institute for Solar System Research (MPS) in Germany revealed a mechanism so far unknown allowing to drill a hole in this protective layer.
The Martian orbit of the Sun is much more elliptical than ours and during the summer in the southern hemisphere, the planet is closer to its star. That means it's a lot warmer than a summer in the northern hemisphere.
"In summer, in the southern hemisphere, at certain times of the day, water vapor can rise locally with warmer air masses and reach the upper atmosphere," says Dr. Paul Hartogh of the Moscow Institute of Physics and Technology (MPS). in a report.
The huge dust storms that afflict Mars every few years compound the problem. Since dust particles can absorb sunlight and thus heat up, they increase up to 30 degrees the temperature in the entire atmosphere.
"Our model shows with unprecedented precision how the dust in the atmosphere affects the microphysical processes involved in the transformation of ice into water vapor," says Dmitry Shaposhnikov of MPS, first author of the new study .
L & # 39; study has been published in Geophysical Research Letters.
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The study of a new water cycle in Martian summer helps to understand why Mars is a barren and dusty land.
Once upon a time, billions of years ago, Mars was a waterlogged world, rich in rivers and oceans. But all this water has been lost and today still, the planet lets escape hydrogen in the space. It is estimated that Mars has lost at least 80% of its original water, as ultraviolet radiation emitted by the Sun has broken down the water molecules of the upper atmosphere into hydrogen and hydroxyl radicals, and the water has been destroyed. Hydrogen gas has escaped irreversibly.
But the mystery lies in the way water has been channeled to that point. Like the Earth's tropopause, Mars has a medium-sized atmospheric layer that should hold up gas, causing it to turn to ice and return to the surface of the planet.
Billions of years ago, Mars could have looked like this with an ocean covering part of its surface. (Credit: NASA / GSFC)
NASA / GSFC
Scientists have now identified a water cycle that could provide clues to Mars' loss of water and why the Earth manages to conserve its reserves.
Every two terrestrial years, summer on the southern hemisphere of Mars, water vapor rises effectively from the lower atmosphere to the upper atmosphere. From there, the winds carry most of the rare gas to the North Pole, where it falls again, but a portion of it breaks down in space.
Computer simulations performed by scientists from the Moscow Institute of Physics and Technology and the Max Planck Institute for Solar System Research (MPS) in Germany revealed a mechanism so far unknown allowing to drill a hole in this protective layer.
The Martian orbit of the Sun is much more elliptical than ours and during the summer in the southern hemisphere, the planet is closer to its star. That means it's a lot warmer than a summer in the northern hemisphere.
"In the summer, in the southern hemisphere, water vapor can rise locally with warmer air masses and reach the upper atmosphere," says Dr. Paul Hartogh of the Institute. of Physics and Technology of Moscow (MPS) in a statement. .
The huge dust storms that afflict Mars every few years compound the problem. Since dust particles can absorb sunlight and thus heat up, they increase up to 30 degrees the temperature in the entire atmosphere.
"Our model shows with unprecedented precision how the dust in the atmosphere affects the microphysical processes involved in the transformation of ice into water vapor," says Dmitry Shaposhnikov of MPS, first author of the new study .
The study was published in Geophysical Research Letters.