A research team led by a planetary scientist at the University of Hawaii (UH) at Manoa found that high-energy electrons in the Earth’s plasma layer contributed to weathering processes on the Moon’s surface and, more importantly, the electrons may have contributed to the formation of the Earth. Water formation on the lunar surface. The study was published on: Nature Astronomy.

Understanding the concentration and distribution of water on the Moon is critical to understanding its formation and evolution, as well as providing water resources for future human exploration. The new discovery may also help explain the origin of water ice previously found in permanently shadowed regions of the moon.

Due to the Earth’s magnetism, there is a force field around the planet called the magnetosphere, which protects the Earth from cosmic weather and harmful radiation from the Sun. The solar wind pushes and changes the magnetosphere, creating a long tail on the night side. The plasma layer in this magnetotail is a region of high-energy electrons and ions that may come from Earth and the solar wind.

Previously, scientists focused mainly on the role of high-energy ions in the erosion of the Moon and other airless bodies in space. The solar wind, composed of high-energy particles such as protons, bombards the lunar surface and is thought to be one of the main ways water forms on the moon.

Shuai Li, a research assistant professor in the UH Mānoa School of Ocean and Earth Science and Technology (SOEST), was interested in investigating changes in surface weather conditions based on his previous work showing that oxygen in the Earth’s magnetotail erodes iron in the moon’s polar regions. When the Moon passes through the Earth’s magnetotail, this is a region that almost completely shields the Moon from the solar wind but not from the Sun’s photons of light.

“This creates a natural laboratory for studying water formation processes on the lunar surface,” Lee said. “When the Moon is outside the magnetotail, the lunar surface is bombarded by solar winds. “There are almost no solar wind protons inside the magneto tail, and water formation is expected to drop to almost zero.”

Lee and colleagues analyzed remote sensing data collected by the Mineralogy Mapper instrument on India’s Chandrayaan 1 mission between 2008 and 2009. Specifically, they evaluated changes in water formation as the Moon passes through the Earth’s magnetotail, which includes the plasma layer. .

“To my surprise, remote sensing observations showed that the formation of water in the Earth’s magnetotail is almost the same as when the Moon is outside the Earth’s magnetotail,” Lee said. “This suggests that there may be additional formation processes or new sources of water in the magnetotail that are not directly related to the implantation of solar wind protons. In particular, the emission of high-energy electrons shows similar effects to protons in the solar wind.”

“Overall, this finding and my previous findings on rusty lunar poles suggest that Mother Earth is strongly connected to its moon in many unknown ways,” Lee said.

In future research, Li plans to work on a lunar mission using NASA’s Artemis programs to monitor the plasma environment and water content on the Moon’s polar surface as the Moon is in different phases as it passes through Earth’s magnetotail.