Differences between lunar dust and terrestrial dust
Dust on the moon is very different from dust on Earth. It is not compressed and remains loose.
Any activity on the surface, such as rock friction, can cause dust to be stirred up, but even without people or modules moving, dust particles and clouds can be seen floating a few centimetres to metres above the surface. This happens even without wind or water, which usually move dust on Earth.
Scientists believe that electrical forces, such as electrostatic charges, help dust particles to spread over long distances.
The influence of the sun
The way dust moves and looks varies depending on its location on the moon and the position of the sun. The part of the moon facing the sun receives constant radiation from the sun.
This solar radiation causes the surface to emit electrons, giving the dust a slight positive charge (a reduction in negative charge leads to more positive charge). This electrical charge causes the dust to stick to the surface, similar to static electricity on Earth.
On the shadow side, however, the dust is negatively charged because charged particles cause interactions there.
In the area between sun and shadow (called ‘the terminator’), a strong electric field is created by the rapid change between positive and negative charge. This can cause dust particles to float and move horizontally. As a result, dust is driven from the dark, shady area to the sunny area, causing a net deposition of dust on the sunny surface.
In short, electric charges and fields play a major role in how dust moves and spreads on the moon, even without wind or water.
