Water tucked away deep in the interior of the moon may have been deposited there by asteroid impacts in the distant past, a new study concludes. This contradicts previous ideas that the material came to reside there following comet impacts.
The moon was once thought to be a completely parched, bone-dry world. This idea was reinforced by analysis of the samples returned by the Apollo astronauts more than 40 years ago. Now, astronomers know of ice deposits trapped in the eternally-dark craters found at the poles of the moon, as well as under the surface.
The moon was likely created during the collision of the Earth with a body the size of Mars, in the early age of the solar system. During this tumultuous period, our natural satellite may have been bombarded by water-rich asteroids known as Carbonaceous chondrites. This process may have gone on for tens of millions of years before the downfall subsided. Water deposits found on the moon match the composition of these water-rich asteroids, as opposed to comets, leading to the conclusion of the new study.
Water under the lunar surface would not be liquid, but large quantities of ice — as much as 1,100 tons of the material, may be found at the polar regions of the natural satellite. Much of the water could also be in the form of hydroxyl molecules, containing one molecule each of hydrogen and oxygen.
These treasure troves of these two gases could provide a valuable resource for future space travelers living on the moon, or stopping there on the way to Mars or beyond. Hydrogen can be used, along with an oxidizer, to power machinery or spacecraft. Supplies of oxygen would be utilized for breathing, or for farming.
"This may seem like science fiction. But it is one of the reasons several space agencies — including the European Space Agency and NASA — are currently developing robotic missions to explore new regions to better estimate the quantity of ice," Roman Tartese of the National Museum for Natural History in France said.
Examination of the ancient impacts on the lunar surface might also reveal new information about the development of our own planet as well, researchers contend. Erosion on our world has erased most of the geological record from that distant era. However, the moon preserves such evidence in nearly pristine condition.
Analysis of the ultimate origins of water on the moon was published in the journal Nature Communications.