New research suggests that the Moon has water because it is taken up from Earth’s magnetosphere via hydrogen and oxygen ions escaping from Earth’s upper atmosphere: they form lunar permafrost which then turns into liquid water.
In 2020, NASA confirmed that the Moon has large reserves of ice, not only in the craters of the polar regions, where it had been discovered in the late 1990s, but also in deeper depressions that would have retained ice for years. thousands or millions of years.
In general, it is believed that most of the lunar water was deposited by asteroids and comets that collided with the moon. Most were during a period known as the Late Heavy Bombardment.
In that period, about 3.5 billion years ago, when the solar system was about 1 billion years old, Earth’s early inner planets and Moon suffered an unusually strong impact from asteroids.
A iResearch from the University of California at Los Angeles (UCLA), published last year, pointed to another possible explanation: the magnetic field that surrounds the Earth or magnetosphere is capable of “seeding & rdquor; water on the Moon by means of ions that travel in the so-called “terrestrial wind”.
The observations made in this study detected high concentrations of oxygen isotopes, products of leaks from the Earth’s ozone layer, which became embedded in the lunar soil.
new explanation
According to new research by scientists at the University of Alaska Fairbanks Geophysical Institute, hydrogen and oxygen ions escaping from Earth’s upper atmosphere combine on the Moon and would have created up to 3,500 cubic kilometers of surface permafrost or liquid groundwater, a volume comparable to North America’s Lake Huron, the eighth largest lake in the world.
The researchers based that total on the lowest volume model calculation: considering that only 1% of Earth’s atmospheric exhaust reaches the Moon.
These authors suggest that hydrogen and oxygen ions enter the Moon, not directly through the solar wind, but when our satellite passes through the Moon. tail of the magnetosphere from Earth, which occurs during the five days of the Moon’s monthly trip around the planet.
Due to the solar wind, which drags the Earth’s magnetic field forming a vast tail, some of the Earth’s magnetic field lines are broken: they are only attached to the planet at one end.
moon shower
And when the Moon interferes with the tail of the magnetosphere, some of these broken connections are repaired, leading hydrogen and oxygen ions, which had previously escaped from Earth’s atmosphere, to suddenly return to Earth.
“It is as if the Moon were in the shower: a rain of water ions that return to Earth, fall on the surface of the moon & rdquor ;, explains Kletetschka in a statement. And since the Moon has no magnetosphere of its own to repel them, the ions combine to form the lunar permafrost.
Some of that permafrost, through geological and other processes such as asteroid impacts, settles below the surface, where it can turn into liquid water.
Recent measurements from multiple space agencies have confirmed significant amounts of water-forming ions present during the Moon’s transit through this part of the magnetosphere, reinforcing this hypothesis.
In any case, the authors consider that their suggestion of how water has reached the Moon should not be the only one, but that this process is surely due to several sources.
Reference
Distribution of water phase near the poles of the Moon from gravity aspects. Gunther Kletetschka et al. Scientific Reports volume 12, Article number: 4501 (2022). DOI:https://doi.org/10.1038/s41598-022-08305-x