We all know that The Moon and Asteroids are covered in dust, dirt and tiny bits of matter but recently, a new way of explaining how all this dust gets around has been proposed. Research conducted at NASA has shown that dust moves around on the surface of the Moon without the help of any wind, atmosphere, or even air to blow it around. When we look at a full Moon, there aren’t many shadows because the Sun is directly above the surface, resulting in very little shadows on the surface. However, when the Moon appears to us as a crescent or half-Moon there are large portions of the Moon that are covered in a mixture of both shadow and light. It is the interaction between the dust particles in the shadow and the light that makes all of the difference.
When dust is exposed to the direct sunlight of our Sun without the protective effects of Earth’s atmosphere, it gets very hot – up to 253 degrees Fahrenheit. This can cause a change in the electrical charge of the dust, making the dust positively charged. In contrast, the freezing –387 degree Fahrenheit temperatures that are normal for the shaded portions of the Moon the dust has a negative charge associated with it. This causes an electrical imbalance and thus electric fields form on the surface of the Moon connecting the positively charged hot regions of the Moon with the cold, negatively charged regions. While these electrical fields are not extremely intense, it is enough to get some dust moving. The positively charged dust is repelled from the surrounding positively charged dust and is attracted toward the negatively charged dust. While some models predict that the dust could move much further, study has shown that the dust can move anywhere from 1 to 10 meters (3 to 30 feet) due to this type of effect. This photo shown on the left is from the Surveyor-7 mission and it shows white streaks just above the surface of the Moon which seems to slowly move and could possibly be these tiny, localized, electrically charged dust motions.
Since this effect is predicted on the Moon, it is also thought that it might play a role on asteroids as well. This would help explain how minor bodies are able to get dirt and dust so well compacted together as to form the look of a unified body, rather than large amounts of unevenly distributed clumped matter. It could also have an effect on comets, which are known for their long tails of mostly ice and some dust. More study is needed to determine whether one out of a thousand, million, or billion particles can electrostatically move in this fashion. Since most of the Moon is completely covered in this type of dust, this type of motion could be significant in understanding a new type of erosive force that isn’t even acknowledged here on Earth. This type of study could even lead to advances in how to capture dust in sensitive areas or even your house without ever having to break out a dust rag or sponge. (Shown on right - (top) A Moon walk results in a large amount of Moon dust covering the astronaut. (bottom) So much dust that could collect that it could get tracked inside the spacecraft and possibly even end up on the astronauts' skin)