July 26, 2021

They clarify the mystery of the clouds of dust on the Moon

They clarify the mystery of the clouds of dust on the Moon

Physicists have identified a mechanism that explains the appearance of two dusty plasma clouds resulting from a meteoroid that impacted the surface of the Moon.

The collision of a meteoroid with the surface of the Moon greatly changes the properties of the surrounding dusty plasma system a large amount of regolith residue from the lunar soil – dust particles measuring between 10 and 100 microns – in the exosphere, otherwise, relatively clean, reports Europa Press.

In 2015, the astronomers of the Garden Observatory in Gordola (Switzerland) observed a similar phenomenon when they recorded an optical flash resulting from a meteoroid that impacted the Moon. An international group of scientists who used data from astronomical observations concluded that a fairly large and rapidly moving meteoroid had impacted the Moon, raising two clouds of unknown composition.

Russian researchers from the Higher School of Economics, the Institute of Space Research (IKI), the Institute of Physics and Technology of Moscow, the Sternberg Astronomical Institute and the Far Eastern Federal University have now determined that the collision of a meteoroid with the surface of the Moon produces a shock wave that scatters fragments of regolith and drops of molten material into the surrounding free space. The study was published in JETP Letters.

Those fragments and hardened molten droplets rise above the Surface of the Moon, they interact with the electrons of the solar wind and the solar radiation and acquire an electric charge. As a result, two dusty plasma clouds are formed: one composed of regolith fragments and a second one of hardened droplets of molten material. The different characteristics of the two clouds allow observing them separately.

Scientists have calculated the main characteristics of the clouds: the speed at which they expand, the size, the numerical density and the electrical charge of the particles in each, and so on. The calculations and observational data coincide. It was found that a cloud formed by hardened droplets of molten material expands significantly faster than a cloud formed by regolith fragments.

«Moon dust is a major risk factor for spacecraft, the equipment and the health of the astronauts, "explained the co-author of the study, the professor of the Faculty of Physics HSE and the head of the laboratory of the Space Research Institute Sergey Popel.

«Equipment covered with dust may malfunction. Astronauts carry dust in their spacesuits to the lunar module, where they suspend themselves without weight in the air, which causes them to inhale the particles during their entire trip back to Earth – he explained in a statement. Therefore, understanding the mechanism by which dusty plasma clouds form is important to ensure the safety of space flights to the Moon. " EP


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