There is a hole in the atmosphere of Mars that spits hydrogen in space

There is a hole in the Martian atmosphere that opens once every two years, releasing the planet 's water reserves into the void and dumping the rest of the water into the water. poles of the planet.

This is the explanation advanced by a team of Russian and German scientists who have studied the strange behavior of water on the red planet. Scientists working on Earth may find that there is a lot of water vapor in the Martian atmosphere and that water is migrating to the poles of the planet. But until now, there was no satisfactory explanation of the functioning of the Martian water cycle or the reason why the once-soggy planet is now a dry shell.

The presence of water vapor above Mars is disconcerting because the red planet has an intermediate layer of atmosphere that seems to have to completely close the cycle of water. [Mars-like Places on Earth]

"The average Martian atmosphere is too cold to maintain water vapor," the researchers wrote in the study published April 16 in the journal Geophysical Research Letters.

So, how does the water cross this mid-layer barrier?

The answer, according to the computer simulations of the present study, concerns two atmospheric processes specific to the red planet.

On Earth, summer in the northern hemisphere and summer in the southern hemisphere are quite similar. But this is not the case on Mars: as the orbit of the planet is much more eccentric than that of the Earth, it is much closer to the sun during its summer (in the southern hemisphere, once all both years). The summers of this part of the planet are therefore much warmer than those of the northern hemisphere.

When this happens, according to the simulations of the researchers, a window opens in the average atmosphere of Mars between 60 and 90 km altitude, allowing the water vapor to cross and to escape in the upper atmosphere. At other times, the lack of sunshine closes almost completely the cycles of the Martian water.

Mars is also different from the Earth in that the red planet is often invaded by gigantic dust storms. These storms cool the surface of the planet by blocking the light. But simulations of scientists have shown that light that does not reach the surface of the planet is blocked in the atmosphere, warming it and creating more favorable conditions for water movement. In dust storm conditions, like the one that covered Mars in 2017, tiny particles of water ice form around the dust particles. These light ice particles float more easily in the upper atmosphere than other forms of water. As a result, during these periods, more and more water is flowing into the upper atmosphere.

Researchers have shown that dust storms can bring even more water into the upper atmosphere than southern summers.

The researchers wrote that once the water had crossed the median line, two things were happening: part of the water was heading north and south, towards the poles, where it ended up to be deposited. But ultraviolet light in the upper atmosphere can also break the links between oxygen and hydrogen in the molecules, causing the leakage of hydrogen into the space, thus leaving the atmosphere untouched. oxygen behind.

This process could be part of the story of how a once flooded Mars eventually became so dry in its present time, the researchers wrote.

Originally published on Science live.