The Moon Is Rusting: Earth’s Surprising Role In Lunar Hematite Formation

Researchers have recently uncovered a fascinating phenomenon: the moon is rusting! Surprisingly, this process is partially driven by the Earth itself. According to a new study analyzing data from the Indian Space Research Organisation's Chandrayaan-1 orbiter, the lunar poles exhibit a notably different composition compared to the moon's equatorial regions.

This groundbreaking research reveals that hematite, a common form of iron oxide or rust, has been detected on the moon's surface. Typically, rust formation necessitates the presence of oxygen. However, the moon is known for lacking a significant atmosphere, raising questions about how this rust could form in such an inhospitable environment.

Shuai Li from the University of Hawaii, who led the study, expressed his astonishment, stating, “It’s very puzzling. The moon is a terrible environment for hematite to form in.” To unravel this mystery, Li collaborated with scientists from NASA's Jet Propulsion Laboratory, who also expressed skepticism about the findings, given the prevailing lunar conditions.

One of the key aspects of this investigation was the role of water on the moon. Since the discovery of water ice in lunar craters, theories have emerged suggesting that water may react with lunar rocks to produce a wider variety of minerals than previously understood. The presence of trace amounts of oxygen, carried to the moon by Earth's magnetic field, could also contribute to the rusting process.

Through careful analysis, the study identified three primary mechanisms that could account for the formation of rust on the moon. Despite its lack of atmosphere, the moon possesses minute traces of oxygen thanks to Earth's magnetic influence. This oxygen can travel the vast distance of 385,000 kilometers from Earth to the moon.

Additionally, researchers found that the side of the moon facing Earth has a higher concentration of hematite compared to its far side. This suggests that the Earth's magnetic field plays a crucial role in this phenomenon. The study also points to the historical proximity of the moon to Earth, which may have allowed for greater oxygen transfer in the past.

Another factor contributing to lunar rust formation is hydrogen, which is carried by solar winds from the Sun and bombards both the moon and Earth. On the moon, hydrogen acts as a reducer, adding electrons to materials and facilitating the oxidation process. The moon lacks the protective magnetic field that Earth enjoys, making it susceptible to these solar winds.

Interestingly, the research indicates that during the lunar cycle, specifically when the moon is full, Earth's magnetotail may block much of the solar wind activity, providing a unique opportunity for rust formation. Moreover, the presence of water ice in the moon's far side craters could interact with dust particles, potentially liberating water molecules that mix with iron and accelerate rusting.

In conclusion, this research not only enhances our understanding of the moon's geology but also challenges our perceptions of its environment. As scientists continue to explore these findings, they may shed light on similar processes occurring on other airless celestial bodies, such as asteroids. This exciting new frontier in lunar research will be published in Science Advances.