For decades,scientists have puzzled over the presence of gases like water and carbon dioxide within the Moon’s soil,or regolith. New research published in Communications Earth & Habitat suggests these compounds aren’t remnants of the Moon’s formation or the early solar system, but are continuously delivered by Earth itself. Utilizing computer simulations and data from Apollo missions, researchers at the University of Rochester have found that Earth’s magnetic field actively channels atmospheric molecules stripped by the solar wind toward the Moon, a process with potential implications for future lunar resource utilization.
For billions of years, the solar wind has been stripping molecules from Earth’s atmosphere and depositing them on the Moon, where they’ve become embedded in the lunar soil, or regolith. A new study, detailed by CNN, suggests this process is ongoing and could explain long-standing mysteries about the Moon’s composition.
The research, utilizing computer simulations, aims to resolve a decades-old puzzle stemming from the presence of water, carbon dioxide, helium, and nitrogen atoms in lunar regolith samples returned by the Apollo missions. Previous theories pointed to the Sun as the source, or to Earth’s ancient atmosphere before it developed a global magnetic field.
However, Shubhonkar Paramanick of the University of Rochester and his colleagues propose that Earth’s magnetic field doesn’t *prevent* atmospheric molecules from reaching the Moon – it actually *facilitates* their journey. “This means that Earth has been continuously supplying the lunar regolith with volatile gases, including oxygen and nitrogen,” explained Eric Blackman, an astrophysicist at the University of Rochester and a co-author of the research published in Communications Earth & Environment in December.
Artistic illustration of the solar wind carrying Earth’s atmospheric molecules to the Moon.
Photo:
Shubhonkar Paramanick
The Moon formed approximately 4.5 billion years ago from debris created when a Mars-sized object, dubbed Theia, collided with the early Earth. This impact is believed to have left behind mysterious structures within Earth’s mantle, as reported previously. The collision also transferred some of Earth’s volatile materials to the Moon. “Our results suggest that the sharing of volatile materials has continued for billions of years,” Blackman added.
The process is particularly efficient when the Moon passes through a region called a magnetotail during its orbit. “When the Moon is in the magnetotail, the magnetic field opens up a channel that allows atmospheric material stripped from Earth by the solar wind to reach the Moon more directly,” Blackman said. The researchers validated their simulations using samples of lunar regolith collected during the Apollo 14 and Apollo 17 missions.
The presence of Earth-derived molecules on the Moon could have implications for future lunar missions. “There’s already been work on how to process water found in lunar regolith and break it down into hydrogen and oxygen for fuel,” Blackman noted, suggesting that innovative approaches could unlock resources delivered to the Moon by the solar wind. This research highlights the interconnectedness of Earth and its satellite and could inform strategies for resource utilization in future space exploration.
