Water on the Moon

by Laura Gervais

Science & Environment Editor

At the end of October, two new studies were published about the presence of water on the moon. It was discovered by NASA’s SOFIA (Stratospheric Observatory for Infrared Astronomy) that there is more water than originally thought — not only is it frozen in permanently shadowed areas, but also within lunar soil in sunny areas. How were scientists able to discover this, how is water even created on the moon, and what does this discovery mean for future space exploration?

Thanks to SOFIA, we know there is indeed water on the sunny lunar surface. According to NASA’s article “NASA’s SOFIA Discovers Water on Sunlit Surface of Moon,” the jetliner used its FORCAST (Faint Object infraRed CAmera for the SOFIA Telescope) and was “able to pick up the specific wavelength unique to water molecules, at 6.1 microns, and discovered a relatively surprising concentration on sunny Clavius Crater”. So, we know with certainty that our good old friend H2O resides on the moon. Beforehand, experts could not be sure if it was actually water being detected or its close cousin, hydroxyl (OH).

The interesting question about how water forms on the moon now arises. Dr. Casey Honnibal, the lunar scientist who, according to her bio, “originated the project to use SOFIA” to search for water on the moon, remarked: “Something is generating the water, and something must be trapping it there.” There are a couple of interesting theories. One states that when micrometeorites collide with the moon, they release the water that they contain into the lunar soil. Another more complex cause could be that “the Sun’s solar wind delivers hydrogen to the lunar surface and causes a chemical reaction to create hydroxyl, and radiation from the bombardment of micrometeorites could be transforming that hydroxyl into water.” These are two plausible theories, and who knows how many more could emerge.

As for how much water exists on the moon, there is no clear answer. In Sid Perkins’s article “The Moon may hold much more water than we think,” he reports that “each kilogram of lunar soil [studied by Honnibal and her team] contains between 100 milligrams and 400 milligrams of water”. Why is this significant, you may ask? These quantities of H2O (equivalent to about 7 - 27 sips, FYI) would most likely be “trapped in glassy materials, so it would be relatively easy to melt the glassy materials and, in essence, ‘mine’ the water,” said planetary scientist Paul Hayne.

Finally, what does this all mean for the future? There are a multitude of good things to come from the discovery of water on the lunar surface. Firstly, trips to the moon would cost less - the transportation of water is a phenomenal expenditure. Get this: on the International Space Station, a water bottle can cost nearly $10 000 USD. Imagine having to bring water all the way to the moon! Furthermore, more equipment could be hauled to the moon as a result of not having to carry water. Having a significant reserve of drinkable water on the moon increases the likelihood of, in the words of NASA, “establishing a sustainable human presence there by the end of the decade.”

With some questions answered, even more surface. Could there be even more water than we think? What does the water cycle look like on the moon? Could there be some form of life within that water?

Photo via NASA