A recent study of data from two lunar missions reveals proof that the water on the Moon’s surface is widely dispersed and not restricted to any one area or kind of terrain. The water doesn’t necessarily have easy access, but it seems to be there day and night.
The results might make it easier for scientists to comprehend where the water on the Moon comes from and how simple it would be to utilize it as a resource. Future explorers could be able to use the Moon’s water as drinking water or to transform it into hydrogen and oxygen for rocket fuel or oxygen to breathe if it is abundant there and reasonably easy to reach.
“We find that it doesn’t matter what time of day or which latitude we look at, the signal indicating water always seems to be present,” said Joshua Bandfield, a senior research scientist with the Space Science Institute in Boulder, Colorado, and lead author of the new study published in Nature Geoscience. “The presence of water doesn’t appear to depend on the composition of the surface, and the water sticks around.”
The findings go against some past research that claimed the strength of the water signal waxes and wanes throughout the lunar day and that more water was identified near the Moon’s polar latitudes (29.5 Earth days). Combining these ideas, some scientists hypothesized that water molecules may “hop” over the lunar surface and eventually end up in frigid traps in the deepest parts of craters near the north and south poles.
A cold trap is an area in planetary science that is so cold that water vapor and other volatiles that come into touch with the surface will remain stable for a long time, possibly up to several billion years.
The complexities of how the detection has been made thus far have led to ongoing disagreements. The primary supporting data came from remote-sensing devices that assessed how strongly sunlight was reflected off the lunar surface.
These sensors detect a spectral imprint of water at wavelengths of approximately 3 micrometers, which is beyond visible light and in the infrared region of the electromagnetic spectrum.
However, the Moon’s surface can also become hot enough to “glow,” or emit its own light, in the infrared spectrum. It is difficult to separate this concoction of reflected and emanate light. Researchers need to have very precise temperature data in order to distinguish between the two.
We find that it doesn’t matter what time of day or which latitude we look at, the signal indicating water always seems to be present. The presence of water doesn’t appear to depend on the composition of the surface, and the water sticks around.
Joshua Bandfield
By using observations from the Diviner instrument on NASA’s Lunar Reconnaissance Orbiter, or LRO, Bandfield and colleagues developed a novel technique to include temperature data.
The researchers used the Moon Mineralogy Mapper, a visible and infrared spectrometer supplied by NASA’s Jet Propulsion Laboratory in Pasadena, California for India’s Chandrayaan-1 spacecraft, to collect data earlier.
Given the surprising discovery of widespread and largely stationary water, it is possible that OH, a more reactive relative of H2O, which is composed of one oxygen atom and one hydrogen atom, makes up the majority of its presence. OH, commonly known as hydroxyl, is a short-lived substance that prefers to attack molecules or chemically bond to them.
Therefore, in order to be used, hydroxyl would need to be extracted from minerals. The discovery also indicates that any water on the Moon isn’t just clinging to the surface loosely.
“By putting some limits on how mobile the water or the OH on the surface is, we can help constrain how much water could reach the cold traps in the polar regions,” said Michael Poston of the Southwest Research Institute in San Antonio, Texas.
Researchers may be able to better understand the origins of water and its long-term storage on other stony surfaces around the solar system by sorting out what occurs on the Moon. What the data reveal about the origin of the water on the Moon is still a topic of discussion among researchers.
The team didn’t completely rule out the possibility that OH and/or H2O could come from the Moon itself, slowly released from deep inside minerals where it has been held since the Moon was formed, but the data indicate toward OH and/or H2O being made by the solar wind striking the lunar surface.
“Some of these scientific problems are very, very difficult, and it’s only by drawing on multiple resources from different missions that are we able to hone in on an answer,” said LRO project scientist John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
LRO is run by the Science Mission Directorate at NASA Headquarters in Washington, D.C.’s Goddard Space Flight Center in Greenbelt, Maryland. The Diviner instrument is created, maintained, and operated by JPL.
