Russian scientists explain the origin of noctilucent clouds on Mars

They were helped in this by a computer model of cloud formation on the Red Planet.

Mars also has earth-like noctilucent clouds that scientists say look like coffee with cream. This conclusion was reached by MIPT employees who created a digital model of cloud formation on the Red Planet.

Noctilucent clouds on Earth are nocturnal luminous clouds that appear in the mesosphere at an altitude of 76-85 km above the Earth’s surface and are visible at deep twilight.

But while Earth’s atmosphere is dominated by nitrogen and oxygen, on Mars, 95% of the atmosphere is carbon dioxide. Therefore, on Mars, an analogue of our almost 100% ice noctilucent clouds are dust clouds formed as a result of carbon dioxide condensation at altitudes of about 100 km. The size of dust particles in them is about 100 nanometers.

In order to better study the “silvery” clouds of Mars, MIPT scientists and colleagues developed a mathematical model that describes the mechanism of their formation and evolution. They were helped by the fact that the atmospheres of Earth and Mars have a lot in common: identical temperature profiles, the ionosphere, the mesosphere. All this made it possible to adapt to the Martian earth model for research.

As a result, it turned out that noctilucent clouds are formed due to the condensation of vapors of supersaturated carbon dioxide on accumulations of dust “embryos” in the atmosphere of Mars. This data was published in Jetp Letters magazine.

Scientists have also demonstrated the mechanism of cloud formation in the mesosphere of Mars. To do this, they used the Rayleigh-Taylor effect. It can be visualized using the example of coffee with cream, when a denser liquid is poured on top of a less dense liquid. Gradually, the “cream” (the denser, dusty carbon dioxide of the Martian atmosphere) makes its way down, under the lower boundary of the cloud, where a less dense gaseous medium is located. Since the initial arrangement of dust particles is not the same, their different layers absorb different amounts of carbon dioxide, which leads to mixing of the layers with each other, flattening of the initial cloud of nuclei and the formation of a thin layered structure of clouds.

Such modeling of the phenomena of the Martian atmosphere helps to better interpret new data about the planet.