Earth's atmosphere could be source of some lunar water and ice

A new research by scientists at the University of Alaska Fairbanks Geophysical Institute has found that ions escaping from Earth's upper atmosphere could be one of the sources of the known lunar water and ice.

The research estimates that the moon's polar regions could hold up to 3,500 cubic kilometres - 840 cubic miles - or more of surface permafrost or subsurface liquid water created from hydrogen and oxygen ions that escaped Earth's atmosphere.

UAF Geophysical Institute associate research professor and lead author, Gunther Kletetschka, and his colleagues suggest hydrogen and oxygen ions are driven into the moon when it passes through the tail of the Earth's magnetosphere, which it does on five days of the moon's monthly trip around the planet.

According to the researchers, the moon's presence in the magnetosphere's tail (magnetotail) causes some of Earth's broken magnetic field lines to reconnect with their opposing broken counterparts. During this process, hydrogen and oxygen ions that had escaped Earth rush to those reconnected field lines and are accelerated back toward Earth.

Many of those returning ions hit the passing moon, which then combine to form the lunar permafrost. Some of that is driven below the surface, via geologic and other processes such as asteroid impact, where it can become liquid water.

"As NASA's Artemis team plans to build a base camp on the moon's south pole, the water ions that originated many eons ago on Earth can be used in the astronauts' life support system, said Kletetschka.

The researchers used gravitational data from NASA's Lunar Reconnaissance Orbiter (LEO) to study polar regions along with several major lunar craters. Anomalies in underground measurements at impact craters indicate locations of fractured rock conducive to containing liquid water or ice, the team said.

The study "Distribution of water phase near the poles of the Moon from gravity aspects" is published in the journal Nature. More information can be found here.