On the July 20, in 1969, Neil Armstrong made history for the human race. In one small step, he became the first man to physically cross the threshold between Earth and the cosmos, and step foot on the big white satellite orbiting our world that we call the moon. But although the landing itself was a spectacular exhibition, it really didn’t do too much for our understanding of our orbiting companion. For years, scientists and researchers have analyzed various lunar samples for trace substances that could tell us more about the composition of the moon, as from this we can learn more about its formation, and perhaps, its habitability as another celestial body. On Oct. 26, something huge was announced by the tireless trailblazers working at NASA—the Moon is wet.
Scientists have postulated the existence of water (and more certainly, the existence of ice crystals) on the moon for a long time, but this is the first study to have essentially guaranteed the presence of H2O molecules, as opposed to the very similarly-identified OH molecule (or some other hydroxide molecule). What’s more, the molecules have been spotted on the sunlit surface of the moon, an occurrence previously thought impossible due to the lack of an atmosphere on the moon that would surely cause the excitation and loss of lone H2O molecules to the cosmic void from harsh sunlight.
The lead author of this research expedition Casey Hannibal, using the Stratospheric Observatory For Infrared Astronomy (SOFIA) telescope, accomplished this identification by scanning the moon with infrared light of wavelengths ranging from 5 to 8 µm. Flying high above 99.9% of the Earth’s own hydrated atmosphere, the infrared camera received signals corresponding to a 6 µm spectroscopic emission band coming from the equator of the moon – a wavelength response corresponding specifically to that of H2O.
The existence of water on the sunlit side of the moon suggests that the H2O molecules present must be protected by some sort of other material. NJIT Physics professor, director of the Owens Valley Radio Observatory and Interim Director of Big Bear Solar Observatory, Dr. Dale Gary, asserted that “the supposition that [the water] is within crystalline hydrates is only a guess, although the signal does agree with a similar signal in meteorites contaminated with Earth water.” Hannibal’s team surmised just this conclusion, that the H2O molecules being detected were actually being sheltered from the sunny lunar climate within basalt glass orbs, most likely melted and formed by the impacts of high-speed meteors on the moon.
So yes, there is water on the moon, but it is in very sparse amounts across its surface, and is trapped in glass beads. Dr. Gary commented that “Although [the water] could in principle be collected, it may take too much energy and effort to extract a reasonable amount.” There are more likely sites of water deposits at the moon’s poles, where shadowed ridges have shielded voids in the moon’s soil for centuries upon centuries.
As for the application of this infrared scanning technology on other planets, Dr. Gary said that “The discovery probably does not affect the exploration of most other planets, which have a wide variety of conditions very different from the moon.” Whereas the moon is a fairly unshielded planetoid with not much in its atmosphere and a stagnant surface, gas giants like Saturn or Jupiter have much more interesting and turbulent atmospheres that would likely skew the ability of a SOFIA telescope to accurately scan for water. Not to mention, they are both much farther out of range than the moon, meaning readings from our Earth telescopes will be weaker and more inaccurate. But not all hope is lost, as “Mercury and airless bodies such as asteroids could be studied with the same methods from spacecraft,” meaning that Mars research can likely benefit from these developments as well, if observing spacecrafts bring similarly capable infrared cameras along with them.
Although this discovery is groundbreaking, it raises many more questions than it answers, as any good discovery tends to do. Where did this water come from? Are there more copious amounts beneath the moon’s surface? What does this mean for future lunar explorations? In all of this potential and uncertainty, the main takeaways from this observation may become muddled. Perhaps, only two things can be said for certain about the moon: for one, it bears an irrefutable presence of water, and for another, there is much more work to be done in fully comprehending the origins of our solar system, and the nature of our cosmic neighbors.