Scientists have traced the origin of dust around the moon

Scientists have traced the origin of dust around the moon

It turned out that it is caused by impacts of meteoroids of small dimensions.

Scientists from the higher school of Economics, space research Institute Russian Academy of Sciences, MIPT and the University of Colorado found out the origin of a plasma-dust cloud surrounding the moon, and extending to several hundred kilometers above it. With high probability it forms the substance ejected from the moon’s surface after falling meteoroids. Relevant article presented in Journal of Physics: Conference Series.

Almost all of the interplanetary space of the Solar system is filled with dust particles. They are in plasma ionosphere and magnetospheres of the planets in the surrounding space bodies, not having an atmosphere.

No dust, only in the Sun and in the immediate vicinity — because of the high temperatures.

In the 1960s, during the first missions to the moon the American spacecraft and manned spacecraft revealed that the solar light is scattered in the field terminator of the moon (the boundary between its day and night sides). This leads to the formation of the lunar dawn and streamers (threads) above the surface, despite the absence of appreciable atmosphere. Scattering most likely occurs on electrically charged dust particles originate from the surface of the moon. Indirect evidence of the existence of lunar plasma and dust cloud were obtained during the expeditions of the Soviet Luna 19 and Luna 22.

In the new work, the authors consider the possibility of formation of plasma-dust clouds over the Moon by impacts of meteoroids on the lunar surface. Obtained by modeling the parameters of such clouds correspond to the results of experimental studies carried out in the framework of the American mission LADEE (Lunar Atmosphere and Dust Environment Explorer). Around the moon in a radius of several hundred kilometers there is a cloud of submicron (particles with a diameter less than one micron) dust. Measuring the characteristics of this dust was carried out using an impact ionization sensor dust LDEX. The purpose of the experiment was to determine the distribution of dust particles for heights above the surface of the moon, and to classify them according to the sizes and concentrations on various portions of the lunar surface.

As the researchers note, the concentration of particles in plasma-dust cloud obtained by calculation, does not contradict the experimental data.

On the lunar surface are bombarded by a continuous stream of meteoroids, micron and millimeter sizes.

Therefore, the surface actually continuously ejected substance, while part of it is in the molten state. Rising over the lunar surface, the liquid drops of the melt solidify. Due to the interaction with electrons and ions of the solar wind, and solar radiation, they acquire electric charges. The particulate matter from the blows received speed exceeding the escape velocity for the moon to leave its neighborhood and fly away into deep space. Well, and the remaining particles that do not have enough speed, just forming around the moon a plasma-dust cloud, generating the lunar dawns.

During the experiments, LADEE was discovered an abrupt increase in dust concentration in the interaction of some annual meteor showers with the Moon. Especially this effect is manifested during high-speed meteor shower Geminids. All this confirms the relationship between the processes of formation of dust clouds and by collisions of meteoroids with the lunar surface.

There are alternative theories that attempt to explain the formation of lunar dawn through dust particles rising above the surface of the moon by electrostatic processes — for example, the so-called fountain model. However, in their framework, yet failed to explain the facts of lift dust to high altitudes (up to hundreds of kilometers) and, consequently, the formation of the observed in the experiment, the LADEE plasma-dust cloud.