For billions of years, Earth's magnetic field has guided tiny particles from its atmosphere to the moon, according to new research. This process explains excess volatiles in Apollo mission samples and suggests the lunar surface preserves Earth's atmospheric history. The findings could aid future lunar exploration by highlighting potential resources on the moon.
New research from the University of Rochester reveals that Earth's magnetic field, rather than blocking it, has facilitated the transfer of atmospheric particles to the moon over billions of years. Published in Communications Earth & Environment in 2025, the study challenges earlier assumptions and uses computer simulations to demonstrate how solar wind interacts with Earth's atmosphere.
Moon rocks and soil from the Apollo missions in the 1970s contain volatiles such as water, carbon dioxide, helium, argon, and nitrogen in the regolith. While some originate from the solar wind, the amounts—especially nitrogen—exceed what solar sources alone could provide. In 2005, scientists from the University of Tokyo suggested these came from Earth's early atmosphere, before the magnetic field formed and supposedly prevented escape.
The Rochester team, including graduate student Shubhonkar Paramanick, professor Eric Blackman, professor John Tarduno, and computational scientist Jonathan Carroll-Nellenback, modeled two scenarios: an early Earth without a magnetic field and a stronger solar wind, versus modern Earth with its protective field and weaker solar wind. Their simulations showed particle transfer is more efficient today, as solar wind dislodges charged particles from the upper atmosphere, which then travel along magnetic field lines extending to the moon's orbit.
"By combining data from particles preserved in lunar soil with computational modeling of how solar wind interacts with Earth's atmosphere, we can trace the history of Earth's atmosphere and its magnetic field," says Eric Blackman, a professor in the Department of Physics and Astronomy.
This ongoing exchange implies the moon's soil acts as an archive of Earth's climatic and evolutionary past. It also points to practical benefits: volatiles like water and nitrogen could support astronauts, easing logistics for long-term stays.
"Our study may also have broader implications for understanding early atmospheric escape on planets like Mars," Paramanick adds, noting Mars once had a similar magnetic field and thicker atmosphere.
The work was funded by NASA and the National Science Foundation.