Magnetic Anomalies Shield The Moon

Scientists have discovered a new type of solar wind interaction with airless bodies in our solar system.

Magnetised regions called magnetic anomalies, mostly on the far side of the Moon, were found to strongly deflect the solar wind, shielding the Moon's surface.

This will help understand the solar wind behaviour near the lunar surface and how water may be generated in its upper layer.

Observational evidence for these findings will be presented by Dr. Yoshifumi Futaana and Dr. Martin Wieser at the European Planetary Science Congress in Rome, on Friday 24th September.

Atmosphere-less bodies interact with the solar wind quite differently than the Earth. Their surfaces are exposed without any shielding by a dense atmosphere or magnetosphere. This causes them to be heavily weathered by meteoroids or the solar wind, forming a very rough and chaotic surface called regolith.

Previously, the solar wind was thought to be completely absorbed by the regolith. However, recent explorations of the Earth's moon by the Chang'E-1, Kaguya and Chandrayaan-1 spacecrafts have revealed that this interaction is not that simple.

A significant flux of high energy particles was found to originate from the lunar surface, most probably due to the solar wind directly reflected off the Moon's regolith.

"These results may change dramatically the way we understood the solar wind-regolith interaction so far," says Dr. Futaana of the Swedish Institute of Space Physics.