Recent studies from a team of NASA scientists have suggested that water can be found on the moon. This discovery could streamline future space exploration and colonization, and also has implications for extraterrestrial life beyond our galaxy.
These recent findings are the culmination of a longer series of prior space exploration.
Space exploration began in the middle of the 21st century, and in 1959, the Soviet-owned Luna 2 became the first spacecraft to impact the moon. As more expeditions were launched, scientists began to detect small amounts of water within lunar samples. However, whether this water was formed on Earth or the moon was uncertain.
Ray Garner, a graduate student in the Case Western Reserve University Department of Astronomy and a Solar System Ambassador at NASA, states that scientists theorized that the transport of lunar samples introduced contamination. Garner said, “When it came to investigating those [lunar] samples for water, [scientists] determined that they were actually contaminated with Earth water, and not lunar water; somewhere along the transport it got contaminated.”
Early results were inconclusive about whether the moon contained water, but early research formed an early hypothesis that the moon may contain water. In 2009 and 2018, large impactors sent to the moon detected patches of ice on the surface of the moon, confirming that the building blocks for water could be found on the moon.
Garner explains that these studies prompted further research to determine if water, in its purest form, was present on the moon. “The problem was that it wasn’t pure water. It was a water mix with hydroxyl compounds, and we didn’t know how much of it was actually H2O,” he said.
Water is a molecule formed from a single oxygen atom bonded with two hydrogen atoms. Although liquid water is overabundant on Earth, liquid water can only form between 32 and 212 degrees Fahrenheit. On the moon, temperatures can exceed 250 degrees Fahrenheit or drop well below minus 200 degrees Fahrenheit. Scientists hypothesized that the extreme conditions of the moon could have formed hydroxyl radicals, which develop from a single oxygen and hydrogen atom. Though hydroxyl and water particles are formed from the same atoms, the configuration and bonds between these species lead to radically different properties.
How did scientists distinguish between hydroxyl compounds and water molecules on the moon? Researchers from NASA used a specialized technique, infrared spectroscopy, to detect the unique chemical signatures from the surface of the moon. Based on their chemical structure, molecules may vibrate at different frequencies, which can be picked up through infrared spectroscopy. To avoid signals from Earth, scientists used NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA). As Garner explained, “This group of scientists used a particular type of spectrograph attached to a [Boeing] 747 that flies at an altitude of between 38 and 45,000 feet. It’s way higher than commercial flights that go maybe 12,000 feet up in the air.” SOFIA uses an infrared technology to detect the signatures from far away planetary bodies. Using SOFIA, scientists isolated a unique chemical signature. It was confirmed. The moon contained water.
At approximately 240,000 miles away, the moon is the closest astronomical body to the Earth. However, the Earth’s mass is greater than the moon’s by a factor of 81. In other words, the atmosphere on the moon is essentially nonexistent, and combined with the frequent exposure to sunlight, all the water vapor would theoretically diffuse into outer space. Still, the evidence was undeniable; water was, in some form, retained on the moon’s surface. So where was the water coming from? How was it present on the moon?
The team of scientists theorize that micrometeorites could be bringing a small, but significant, stream of water to the moon. These meteorites burn up quickly in the atmosphere of the Earth, but the nonexistent atmosphere of the moon allows these meteorites to pass through. Along with them, they can bring other molecules to a planetary body, such as water. When these meteorites crash into the moon’s surface, they can trap water within glass.
As Garner explained, “The immediate impact region will vaporize. The surrounding area will get incredibly hot, and everything will fuse for a split second, forming a glass. Anything that was in the lunar soil in that region will be fused into this glass. So not only can the micrometeorites bring water to the moon, but then they also can freeze it, putting it in a glass.”
So what does this mean for future travels? Garner states that this recent discovery could greatly streamline scientific exploration to the moon by saving potential resources. In space travel, every ounce of extra material could incur expensive costs, and freshwater is no exception. Harvesting water on the moon, as compared to bringing water on spacecraft, could trim extra weight and save potential resources. Unfortunately, as Garner states, “If you take a cubic meter of lunar soil, it might contain about 12 ounces of water. There’s a bottle of water in that one cubic meter. Even then the Sahara Desert has 100 times that much water in its sand.”
These groundbreaking discoveries both answer many questions from prior scientific studies and pose new questions towards understanding the climate of the moon. Where is the most water found? Is there more water beneath the surface? At the moment, though, this discovery makes future human colonization on the moon, and potentially other planets, more feasible than ever.