According to the findings of the American planetologists ofColorado University in Boulder, Martian clouds, periodically occurring in the upper atmosphere of Mars, may have an alien origin. Scientists believe that they owe their existence to meteorites, whose burnt remains help water vapor to condense and turn into small pieces of ice. A study of planetologists is reported in a new article in the journal Nature Geoscience.
The Mystery of the Martian Clouds
If you compare the atmosphere of Mars with otherthe planets of the solar system, it will be very pitiful. It is very thin, the density is less than 1 percent of the earth. However, the atmosphere of the Red Planet was not always so weak. Scientists have reason to believe that it was once so dense that it allowed water in liquid form to be on the surface of the planet.
Despite its present state, the atmosphereMars is able to surprise, for example, with the generation of the most powerful dust storms covering the entire planet. One of these storms buried the sunrise of NASA's Opportunity aerospace agency, which ceased to communicate after June 10, 2018. Scientists note that, along with the ability to kill defenseless rovers, the atmosphere of the Red Planet protects the surface from meteorite impacts, and is also capable of forming clouds.
Clouds do not arise by themselves - for themFormation needs something that will help the water to condense. This requires “nuclei” of condensation — particles on which the first water molecules “stick”, which then attract the others to themselves and form a drop. On Earth, microparticles of dust, microbes, or soot particles and soot from emissions of volcanoes and car exhausts can play the role of such embryos. Over the past few decades, physicists have found evidence in favor of this, but they could not explain how clouds appear where there is no dust, cars or volcanoes — over oceans and forests.
Moreover, some scientists have even recently begunsuspect that cosmic rays are directly implicated in the birth of some types of clouds, helping such drops of water to grow. Other condensation nuclei can enter the atmosphere from space, in the form of particles of interstellar dust, or due to a kind of "breathing" of plankton.
How do clouds appear in the atmosphere of Mars?
But how to explain the appearance of clouds over Mars? What process triggers their formation in the middle layers (30-60 kilometers) of the Red Planet, if there is neither water nor life on its surface? The question is complicated by the fact that the air gap of Mars is so rarefied that the water in it can almost always exist only in the form of microscopic ice crystals. So what do they interact with to form clouds?
According to a new study, the answer to thisthe question may lie not on the surface of the planet, but in the interplanetary space. Observations made by the NASA MAVEN spacecraft, which is currently circling over the Red Planet, indicate that between 2 and 3 tons of “space debris” in the form of meteorites pass through the atmosphere of Mars every day. At the same time, probe tools found an extremely unusual set of metal ions in the atmosphere of Mars, which scientists subsequently associated with the combustion of meteorites and the formation of the so-called “meteoric smoke”.
Scientists decided to find out whether the particles areof this “meteoric smoke” by those “germs” of condensation themselves, by analogy with how luminous noctilucent clouds appear in the Earth’s mesosphere. To test their assumptions, scientists used complex computer simulations designed to simulate the dynamic atmospheric processes of Mars. By adding to the simulation data on the amount of meteorite dust recorded by MAVEN, the scientists obtained the desired result. Clouds really formed.
Frame computer simulation showing the clouds at mid-altitude of the atmosphere of the Red Planet
"Our climate models simply could notexplain how they could form at a similar height in the atmosphere of Mars. When we added meteor smoke there, all the problems disappeared and the clouds appeared, ”says Victoria Hartvik of the University of Colorado at Boulder.
What is interesting is the appearance of clouds in the computerMars’s models in a very unusual way influenced the weather and climate of the planet, as well as the behavior of the polar regions of its atmosphere. For example, their disappearance or appearance leads to a decrease or increase in air temperature by ten degrees Celsius or even higher values, and also dramatically changes the height of the air gap of Mars in the vicinity of its poles.
Researchers believe that the conclusions of their workwill shed light on the evolution of the atmosphere of the Red Planet, as well as, in particular, clarify the issue related to how the planet in the past could maintain the presence of water in liquid form on its surface.
“More and more climate models show thatMars could have been warmed up by high-altitude clouds in that epoch when rivers flowed over its surface, and life could exist in their waters. It is likely that our discovery will be one of the parts explaining how Mars has become warm and habitable, ”concludes Brian Thun, a university colleague at Hartwick.
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