If we're going to travel out in the universe, we're going to need a plentiful supply of water, perhaps much more than we can simply carry. Which is why this crater on the moon is so exciting.
Using data from the Lunar Reconnaisance Orbiter's LEND tool, which is able to detect neutrons moving off the lunar surface, researchers were able to get a good idea of hydrogen levels on the moon. But it wasn't the levels themselves that surprised, it was their variation: Slightly higher levels of hydrogen were found in a very specific area, on the slopes of craters in the moon's southern hemisphere facing the south pole.
So just what does that all have to do with our chances of finding water on the moon? Because that hydrogen could be found as either hydroxol (a single atom bound with a single oxygen atom) — or it may be two hydrogen atoms bound with oxygen, better known as water.
When LEND picks up those extra hydrogen atoms in the crater, what it might be sensing is water (solidified into ice). And, if that is indeed what it's seeing, it's actually mirroring a phenomenon that we can see in our own geography too, explains the lead researcher on the project, Timothy McClanahan from NASA Goddard:
Here in the northern hemisphere, if you go outside on a sunny day after a snowfall, you'll notice that there's more snow on north-facing slopes because they lose water at slower rates than the more sunlit south-facing slopes. We think a similar phenomenon is happening with the volatiles on the moon – PFS [Pole-Facing Slopes] don't get as much sunlight as EFS [Equator-Facing Slopes], so this easily vaporized material stays longer and possibly accumulates to a greater extent on PFS.
Of course, it's still possible that the more intense hydrogen concentrations that are being picked up are not water at all, but simply hydrogen in another form. Still, it's one of the best indications we've gotten yet on where we should be looking for water on the moon.
Image: Hayn Crater as shot by the LRO, NASA/GSFC/Arizona State University