12/28/2025
🌖 💧The Moon’s water might have come from a surprising source: Earth itself.
While asteroid and comet impacts are known to have delivered some water to the Moon, a new study reveals an unexpected source: Earth’s own atmosphere.
Scientists propose that hydrogen and oxygen ions escaping from Earth, especially as the Moon passes through Earth's magnetosphere tail each month, could have steadily deposited water onto the lunar surface over billions of years.
When solar winds stretch Earth's magnetic field, broken field lines allow atmospheric ions to escape. As the Moon crosses this tail, it triggers the return of these ions, creating a "shower" that implants hydrogen and oxygen onto the Moon’s surface, forming permafrost and, potentially, subsurface liquid water.
Researchers analyzed gravitational data from NASA’s Lunar Reconnaissance Orbiter and identified crater fractures that could trap and preserve this water. They estimate that up to 3,500 cubic kilometers (enough to fill Lake Huron) could have accumulated over 3.5 billion years.
This discovery holds major implications for future lunar exploration. NASA’s Artemis program aims to establish a base camp at the Moon’s south pole, and knowing that ancient Earth-sourced water could be trapped there offers valuable guidance for choosing station locations and securing vital life support resources.
The findings are published in Scientific Reports.
Image by Miguel Claro Astrophotography
RESEARCH PAPER 📄
Gunther Kletetschka, "Distribution of water phase near the poles of the Moon from gravity aspects," Scientific Reports (2022)