Finally NASA Scientists have claimed that they have found water on moon. We were promised an “exciting new discovery about the Moon” and this time NASA has not disappointed: not only have we just unequivocally discovered water (H2O) on the surface of the Moon, but we have identified areas of the satellite capable of catch it stably . These are two separate discoveries, but they link perfectly in order to think very well about how we face the next missions (which, as we well know , are already being prepared).
Water on the Moon!
But didn’t we already know that there was water on the Moon? Yes it’s correct. What happens is that, until now, the investigations that had found signs of water were based on a specific spectral shape (at 3 µm) that cannot reliably discriminate water from other compounds of the hydroxyl group.
What have they done now? In a first article, Casey Honniball and his team used the Stratospheric Observatory for Infrared Astronomy (SOFIA) to observe the Moon at 6 µm. At this wavelength, a spectral signature of H2O that is not compatible with other compounds can be detected. What’s more, the team found that in the high latitudes of the southern hemisphere there is plenty of water – between 100 and 400 parts per million. According to these authors, it is likely that the detected water is stored in structures that protect it from the harsh environment.
As a curiosity, the SOFIA is a very particular instrument: it is a modified Boeing 747 with a hole to which the largest reflector telescope that we have ever put on an airplane is attached . That avoids up to 99% of atmospheric distortion and allows for much more accurate observations.
Where does the water hide to resist up there? Paul Hayne and his colleagues try to answer that question . This research team tried to prove the existence of what we call a “cold trap” on the Moon. The concept, proposed by K. Watson, BC Murray, and H. Brown in 1961 , suggested that there could be craters located near the lunar poles where it could be kept in virtually perpetual darkness. That could make them retain “any volatile elements that […] have fallen into the area. And especially water, “the most frequent volatile element in the Solar System.”
The authors looked at a very specific type of “cold traps”: one centimeter in diameter. And they found that these “microtraps” are hundreds or thousands of times more numerous than the largest cold traps (and can be found at both poles). To put it in numbers: the authors suggest that approximately 40,000 km2 of the lunar surface has the capacity to trap water .
And now that? Now we have to understand in detail how water arises and accumulates on our satellite. Thanks to this we can begin to think about how to adapt our missions to a huge amount of water that can change everything. Astronomically speaking.