Scientists have warned about the danger of dust clouds flying above the Moon's surface.

In the 1960s, the Surveyor series spacecraft repeatedly transmitted images from the Moon, clearly showing a thin line of light above the dark lunar horizon about fifteen minutes after sunset. This phenomenon was aptly named the lunar horizon glow. It has been established that this effect is due to dust suspended above the surface, largely influenced by an electric field.

In 1972, during the Apollo 17 mission's orbit around the Moon, the crew reported not only horizontal bands but also rising columns of light similar to the so-called crepuscular rays that occasionally break through clouds at sunset on Earth. These appeared only for a few seconds before dawn or after sunset, and they could not be captured on film, prompting astronaut Eugene Cernan to at least sketch what he saw.

On the lunar surface, Apollo 17 deployed a special instrument to observe lunar dust kicked up by micrometeoroid impacts. Due to this very dust, it had to be periodically turned off to prevent overheating: it is suspected that the dust adhered to the instrument's casing due to electrostatics, thereby darkening it — lunar dust is electrically charged.

Recently, scientists from the Institute of Space Research of the Austrian Academy of Sciences summarized all that is known about the various appearances of dense dust accumulations above the Moon, noting that these phenomena were observed long before the space age began.

For example, there is a photograph from 1944 taken at the moment Jupiter set behind the lunar horizon, showing a dark band directly above the horizon line on the planet's disk. Additionally, reports of a light line above the dark edge of the Moon date back to the 18th century. Furthermore, as researchers state, this glow sometimes appeared to extend the "horns" of the lunar crescent to the point of creating an effect reminiscent of a "ringed Moon."

All of this was discussed by the researchers in an article available on the Cornell University preprint server (USA). They consider the data from the LADEE (Lunar Atmosphere and Dust Environment Explorer) mission particularly significant. Between 2013 and 2014, it orbited the Moon at altitudes of 235-250 kilometers and detected five dust clouds approximately 75 kilometers above the surface. These clouds were found roughly along the so-called terminator line — the boundary between light and darkness on the surface.

Overall, the comparison of all information over the years revealed several intriguing trends. Firstly, statistics indicate that signs of abundant dust floating above the Moon are more frequently noted during intense meteor showers. This suggests that the dust is being lifted as a result of meteoroid bombardment of the lunar surface.

Secondly, an analysis of solar activity during these phenomena showed that, for some reason, dust clouds tend to form more often during periods of low, quiet solar activity. It is hypothesized that during peak solar activity, the high-speed stream of charged particles known as solar wind "blows away" lunar dust and disperses clouds. This is quite surprising for scientists, as they previously believed that solar charged particles would instead compact these clouds.

Additionally, researchers have been able to roughly identify two areas where dust above the horizon is most frequently observed: the vicinity of the Sea of Serenity (strangely enough, on the western edge of the near side) and the Sea of Tranquility on the opposite side, that is, to the right.

However, the main conclusion drawn by the scientists is that lunar dust clouds can be dense enough to pose a serious threat to spacecraft: the friction of the spacecraft's body against these particles would "slow down" the vehicle's movement and could even lead to its destruction. According to scientists, the failures of the "Vikram" and "Beresheet" landers in 2019 could very well have been caused by lunar dust interfering with their descent process.