The moon is rusting underneath. Oxygen from Earth may be to blame

While no one expected it, scientists at the Hawaiian Institute of Geophysics and Planetology (HIGP) discovered hematite in the moon's polar regions, a kind of rust that no one expected.

There is no oxygen on the moon

Iron reacts very willingly with oxygen - causing the formation of reddish rust, which enthusiasts of Japanese motorization know all too well. The problem, however, is that there is no oxygen on the surface or in the interior of the Moon, so pure iron predominates on the Silver Globe, and oxidized iron was not recorded in the samples imported as part of the Apollo mission. As if that were not enough, hydrogen in the solar wind directly hits the lunar surface, further slowing down the oxidation process. For this reason, the presence of hematite on the moon greatly surprised researchers.

Our hypothesis is that hematite on the moon is formed by the oxidation of surface iron by oxygen from the Earth's upper atmosphere, which is continually blown onto the Moon by the solar wind as the Moon passes through the Earth's magnetogon over the past several billion years.

Says Shuai Li, author of an article published today in Science Advances.

The blue areas in the mosaic composed of measurements from the Chandrayaan-1 spacecraft indicate high water content areas at the Moon's poles. It was there that scientists discovered hematite, a form of rust.

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Analyzing the data from the Chandrayaan-1 probe, the researchers noticed that completely different spectral features are visible near the poles than around the lunar equator or at the Apollo landing sites. After some time, researchers realized that what they were seeing were hematite signatures.

Hematite has been found in places that are strongly associated with the presence of water. Moreover, there is more of it on the side facing Earth than on the side not visible from Earth.

The fact that more hematite is on our side indicates that its presence may be somehow related to the Earth. At one point, I remembered the discovery made by the Japanese Kaguya probe. According to data sent by the probe to Earth, oxygen in the upper atmosphere of the Earth can be blown away in the Moon's dust by the solar wind as the Moon passes through the Earth's magnetogon every month. It may therefore be that it is oxygen from the Earth's atmosphere that oxidizes the iron on the Moon's surface. This discovery is set to revolutionize our understanding of the Moon's circumpolar regions. It turns out that the Earth could have played a much larger role in the evolution of the lunar surface than we thought

Says Li.

Researchers hope that astronauts will bring samples of hematite from the moon to Earth as part of the Artemis mission. The chemical signatures of these samples will eventually confirm the hypothesis that hematite on the moon was oxidized by oxygen from the Earth.

The moon is rusting underneath. Oxygen from Earth may be to blame