New Study Reveals Earth’s Role in Moon’s Unexpected Rusting

Recent research has revealed that the moon is experiencing rust formation, a phenomenon previously thought impossible due to its harsh environmental conditions. A new study suggests that the rust, specifically hematite, is primarily formed from particles originating from Earth’s atmosphere during specific periods in the lunar cycle.

Understanding Lunar Rust

The discovery of hematite on the moon dates back to 2020, during India’s Chandrayaan-1 mission. Scientists were initially perplexed, as rust typically requires both oxygen and water for its formation—elements believed to be scarce on the lunar surface. “It’s very puzzling,” stated Shuai Li, a researcher at the University of Hawaii, in a NASA interview that year. “The moon is a terrible environment for hematite to form in.”

However, the recent study, published in the journal Geophysical Research Letters, posits that the oxygen ions from Earth’s magnetosphere, referred to as “Earth wind,” play a pivotal role in this process. During the lunar cycle, there are approximately five days when the Earth blocks solar particles, allowing the moon to be exposed mainly to these Earth-originating charged particles.

The Mechanics of Rust Formation

According to the researchers, when Earth passes between the sun and the moon, it sends ions of nitrogen, hydrogen, and oxygen into space. These ions can embed themselves in the lunar soil, facilitating the chemical reactions required for rust formation. “Earth wind contains ions that can cause the reactions essential for creating rust,” The Independent reported.

Despite these findings, questions remain regarding the source of the water necessary for oxidation. Current knowledge indicates that water on the moon exists primarily as ice at the poles. Researchers theorize that hematite may have formed in these polar regions and subsequently spread across the lunar surface through unknown processes.

Interestingly, while oxygen ions are vital for rust formation, hydrogen ions can reverse this process. The presence of both types of ions in Earth wind complicates the understanding of rust retention on the moon. To investigate this further, scientists conducted experiments where they irradiated hematite with both high-energy and low-energy hydrogen ions, simulating the conditions found in Earth wind and solar interactions, respectively. Their results demonstrated that high-energy hydrogen ions could reduce hematite back to metallic iron, while low-energy ions were largely ineffective.

The research emphasizes that the amount of rust on the moon is influenced by the energy and relative flux ratio of these ions from Earth wind. The study asserts that these findings provide valuable insights into the distribution of lunar hematite and suggest a long-term material exchange between Earth and the moon.

While the evidence strongly supports the Earth wind theory as a catalyst for lunar rusting, researchers acknowledge that laboratory conditions may not fully replicate the moon’s environment. Further investigations, ideally conducted on the lunar surface, are necessary to validate these processes.