During its existence, mankind has studied the Moon quite well. We know that there is practically no air on it, there is water ice, but there is no liquid water. The more was the surprise of scientists when they found traces of hematite on our satellite. It is an iron oxide that normally requires both air and water to form.
Hematite was discovered by the Indian orbiter Chandrayan-1. The main question that now interests physicists is how did hematite end up there?
At the moment, scientists have the following evidence. Hematite deposits correlate with previously discovered traces of water that hit the moon as a result of collisions with meteorites. In all likelihood, water ice particles can mix with the lunar regolith and melt at the moments of strong impacts. Another piece of evidence is that most of the hematite found on the Moon is on the side of the satellite closest to Earth. This indicates that the mineral is likely to have something to do with our planet.
The last conjecture is very similar to the truth. The fact is that during a full moon, the Moon is in the Earth’s magnetic tail – a part of the planet’s magnetosphere that is most distant from the Sun. At these times, the solar wind can carry Earth’s oxygen from the upper atmosphere to the lunar surface. This phenomenon was recorded during the Japanese Kaguya space mission. Thus, oxygen from the Earth can act as an oxidizing agent in the formation of lunar hematite.
By combining these factors – traces of water on the surface of the satellite and Earth’s oxygen – and multiplying them by billions of years, you can get hematite deposits on the Moon. However, the mystery of the lunar mineral has not yet been fully solved. For example, small amounts of hematite were also found on the far side of the Moon, where terrestrial oxygen could not reach in principle. The issue requires further study and new space missions.