The artist’s concept of the moon within the magnetic tail of the earth, the part of our magnetosphere that extends outward from our sun. The moon sweeps every month with full moon inside this tail. Image via E. Masongsong / UCLA / EPSS / NASA / GSFC / SVS / Duluth News Tribune.
By Bob King, aka AstroBob. Originally published in the Duluth News Tribune on February 16, 2021. Reprinted here with permission.
Finding water on the arid moon is one of the most remarkable discoveries of the post-Apollo era. Satellite mapping has revealed ice in craters with permanent shadows on the lunar poles and more recently in Clavius, a prominent crater on the moon nearby, which spends two weeks of each month in sunshine. Comets and meteoroids probably produced the water that eventually froze in ice, although water-rich lavas that erupted in the distant past of the moon may also have contributed.
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Orange soil tripped by the Apollo 17 astronauts contained glass droplets sprayed from a volcanic fire fountain 3.64 billion years ago. Later analyzes found that water was trapped in some of the beads. Image via NASA / Duluth News Tribune.
Back on earth, scientists found that water was trapped in volcanic glasses and rocks collected by the Apollo 15 and 17 astronauts. In 2019, NASA’s LADEE mission (Lunar Atmosphere and Dust Environment Explorer) discovered that the constant stream of micrometeorites (small space rocks) that bombard the moon creates a thin, temporary atmosphere of water vapor. When the particles penetrate at least 8 cm into the surface, the shock releases the impact water molecules attached to minerals into deeper soil that is not exposed to direct sunlight.
Just so we are clean, the moon is still not soaking wet for a long time, but it is not the bone-dry place we once thought. By comparison, the driest part of the Sahara Desert has 100 times more wet material than the moon. To fill your 16-ounce water bottle, you need to process about a ton of lunar soil.
The current of protons and electrons driven by the sun, called the solar wind, affects the earth (shown here) and the moon. Protons (hydrogen) in the wind bind with oxygen in lunar soil to make water. Image via NASA / Duluth News Tribune.
The sun also helps to distill droplets and effluent from lunar water when protons fall into the lunar surface in the solar wind and bind with mineral oxygen atoms to form H2O. Protons are basically hydrogen atoms that have lost an electron. This is the ‘H’ in H2O. Incidentally, the same solar wind sometimes shuts down with the Earth’s magnetic field and produces hordes of protons and electrons that ignite the aurora borealis.
In a new study, a group of scientists discovered that an ‘Earth wind’ of ionized atoms blowing out of the polar regions can communicate with lunar soil and rocks to make water molecules. H stands for hydrogen; He for helium, O for oxygen and N2 for nitrogen. The plus sign means that the atoms or molecules have lost an electron and are positively charged. Image via NASA / Bob King / Duluth News Tribune.
A study conducted on February 1, 2021 in the Astrophysical Journal Letters found that the earth can also play a key role in the creation of water. Similar to the sun’s electrified wind of the particle, the earth has its own wind made of ionized hydrogen, helium, oxygen and nitrogen. “Ionized” means that the atoms have lost an electron and are carrying a positive charge.
Driven by interactions with the solar wind, some ionized atoms and molecules in the planet’s polar atmosphere shoot into space where they are trapped by the Earth’s magnetic field, better known as the magnetosphere.
The moon usually sends away from the magnetosphere, which points like a weather vane away from the sun, but for 3-5 days each month it moves through the time of the full moon. The magnetosphere deflects the solar wind, preventing the sun’s protons from pouring fresh water on the lunar surface. While the moon was cut off from its stock, astronomers assumed that lunar water formed by solar bombardment would quickly lice away into space, and that the moon would come drier and drier from its temporary magnetic shelter.
This image of the moon comes from NASA’s Moon Mineralogy Mapper on the Indian Chandrayaan 1 probe. Small amounts of water and hydroxyl (associated with water) are shown in blue. Most of the moon’s water is concentrated in the colder polar regions. Image via ISRO / NASA / JPL-Caltech / Brown University / USGS.
But no! Using data from the Indian Chandrayaan 1 spacecraft, which maps water in the moon’s polar regions, Chinese researchers have made a surprising discovery. Water levels remained almost the same every time the moon left the magnetosphere. Something had to throw protons to our satellite to make the water come. The earth’s polar wind was probably the suspect.
Additional evidence comes from the Japanese Kaguya lunar orbit, which was active in the early 2000s, locating scales of positively charged oxygen atoms at the moon each time it hid in the shadow of the Earth’s magnetic tail. In addition to hydrogen, oxygen can also contribute to the creation of water on the moon. How wonderful to think that ionic breezes from Earth could help cover the lunar surface with life-giving water that is potentially beneficial to future astronauts.
In short: Particles transported from the Earth’s poles via the planet’s magnetosphere can interact with lunar rocks to create small amounts of water on the moon.
Source: Earth wind as a possible exogenous source of lunar surface hydration
Via Duluth News Tribune
