bTeam Researchers at the University of Hawai’i have made a groundbreaking discovery regarding the interaction between Earth and the Moon. They found that electrons within Earth’s plasma sheet have a significant impact on the Moon’s weathering processes and could have played a role in the formation of water on its surface. This revelation deepens our comprehension of the intricate relationship between Earth and the Moon, offering potential prospects for future exploration.
A team of scientists, spearheaded by a planetary scientist from the University of Hawai’i at Mānoa, uncovered the influence of high-energy electrons from Earth’s plasma sheet on lunar weathering mechanisms. This discovery, published on September 14 in the journal Nature Astronomy, holds paramount importance as it sheds light on the concentration and distribution of water on the Moon. Understanding these factors is crucial for unraveling the Moon’s origin and evolution and for identifying water resources that could support future human missions.
Earth’s magnetosphere, a protective force field generated by its magnetic field, shields the planet from space weathering and harmful solar radiation. As the solar wind pushes against Earth’s magnetosphere, it extends into a lengthy tail on the night side, forming what is known as the magnetotail. This region includes the plasma sheet, comprised of high-energy electrons and ions derived from Earth and the solar wind.
Previously, scientific investigations primarily focused on the role of high-energy ions in space weathering, particularly on airless celestial bodies like the Moon. Solar wind, composed of energetic particles such as protons, bombards the lunar surface and is believed to be a primary factor in the formation of lunar water.
Building upon prior research that revealed oxygen from Earth’s magnetotail rusts iron on the Moon’s polar regions, Shuai Li, an assistant researcher at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), delved into the transformations occurring in surface weathering as the Moon traverses through Earth’s magnetotail. This region effectively shields the Moon from solar wind but not from solar photons.
Li explained, “This provides a natural laboratory for studying the formation processes of lunar surface water. When the Moon is outside of the magnetotail, the lunar surface is bombarded with solar wind. Inside the magnetotail, there are almost no solar wind protons, and water formation was expected to drop to nearly zero.”
To investigate this phenomenon, Li and his team analyzed remote sensing data collected by the Moon Mineralogy Mapper instrument during India’s Chandrayaan 1 mission between 2008 and 2009. Specifically, they examined alterations in water formation as the Moon passed through Earth’s magnetotail, including the plasma sheet.
Li expressed his surprise at the findings, stating, “To my surprise, the remote sensing observations showed that the water formation in Earth’s magnetotail is almost identical to the time when the Moon was outside of Earth’s magnetotail. This indicates that, in the magnetotail, there may be additional formation processes or new sources of water not directly associated with the implantation of solar wind protons. In particular, radiation by high-energy electrons exhibits similar effects as the solar wind protons.”
In summary, this discovery, along with previous research on rusty lunar poles, underscores the profound connection between Earth and its Moon in various unexplored aspects, according to Li.
Looking ahead, Shuai Li plans to engage in lunar missions as part of NASA’s Artemis program, focusing on monitoring the plasma environment and water content on the lunar polar surface during different phases of its journey through Earth’s magnetotail.
