Magnetic anomalies on the moon have been a mystery since the Apollo-era missions, and their origin is still being debated to this day.
One of the most important missions to the Moon, other of course than Apollo, is the Chang-e 5 mission by the Chinese Space Agency, as part of the Chinese lunar Exploration Program. This was the fifth exploration mission by China and the first to return samples from the Moon’s surface to Earth. The material brought back for study on Earth has helped us greatly improve our understanding of the Moon and even solve a few mysteries. Like, for example, the lunar magnetic anomalies. Now, a microanalysis of iron sulfide samples returned from the Moon by China’s Chang’E-5 mission has confirmed, for the first time, the presence of impact-induced submicroscopic magnetite.
In planetary science, magnetite is key in answering questions relating to ancient magnetic fields and life indicators. A traditional concept of the Moon is that it is extremely reduced. This indicates that metallic iron rather than iron oxides formed on the lunar surface due to its oxidation state.
Although some studies predicted widespread magnetite crystals in lunar soils during the Apollo era, no other in-situ evidence for magnetite crystals in lunar soils was found. In lunar soil, native magnetite might be widely distributed based on this first discovery of impact-induced sub-microscopic magnetite. Moreover, the origin of lunar magnetic anomalies is still a mystery and has been since the Apollo era. It was only previously established that large impact ejecta and magnetic anomalies are related, but not how the material is transformed during impact. The study was published in Nature Communications.