On second thought, the Moon's water may be widespread and immobile

February 23, 2018, NASA's Goddard Space Flight Center
Credit: NASA/JPL/USGS

A new analysis of data from two lunar missions finds evidence that the Moon's water is widely distributed across the surface and is not confined to a particular region or type of terrain. The water appears to be present day and night, though it's not necessarily easily accessible.

The findings could help researchers understand the origin of the Moon's water and how easy it would be to use as a resource. If the Moon has enough water, and if it's reasonably convenient to access, future explorers might be able to use it as drinking water or to convert it into hydrogen and oxygen for rocket fuel or oxygen to breathe.

"We find that it doesn't matter what time of day or which latitude we look at, the signal indicating water always seems to be present," said Joshua Bandfield, a senior research scientist with the Space Science Institute in Boulder, Colorado, and lead author of the new study published in Nature Geoscience. "The presence of water doesn't appear to depend on the composition of the surface, and the water sticks around."

The results contradict some earlier studies, which had suggested that more water was detected at the Moon's polar latitudes and that the strength of the water signal waxes and wanes according to the lunar day (29.5 Earth days). Taking these together, some researchers proposed that water molecules can "hop" across the lunar surface until they enter cold traps in the dark reaches of craters near the north and south poles. In planetary science, a cold trap is a region that's so cold, the water vapor and other volatiles which come into contact with the surface will remain stable for an extended period of time, perhaps up to several billion years.

The debates continue because of the subtleties of how the detection has been achieved so far. The main evidence has come from remote-sensing instruments that measured the strength of sunlight reflected off the lunar surface. When water is present, instruments like these pick up a spectral fingerprint at wavelengths near 3 micrometers, which lies beyond visible light and in the realm of infrared radiation.

But the surface of the Moon also can get hot enough to "glow," or emit its own light, in the infrared region of the spectrum. The challenge is to disentangle this mixture of reflected and emitted light. To tease the two apart, researchers need to have very accurate temperature information.

Bandfield and colleagues came up with a new way to incorporate temperature information, creating a detailed model from measurements made by the Diviner instrument on NASA's Lunar Reconnaissance Orbiter, or LRO. The team applied this temperature model to data gathered earlier by the Moon Mineralogy Mapper, a visible and infrared spectrometer that NASA's Jet Propulsion Laboratory in Pasadena, California, provided for India's Chandrayaan-1 orbiter.

The new finding of widespread and relatively immobile water suggests that it may be present primarily as OH, a more reactive relative of H2O that is made of one oxygen atom and one hydrogen atom. OH, also called hydroxyl, doesn't stay on its own for long, preferring to attack molecules or attach itself chemically to them. Hydroxyl would therefore have to be extracted from minerals in order to be used.

The research also suggests that any H2O present on the Moon isn't loosely attached to the surface.

"By putting some limits on how mobile the water or the OH on the surface is, we can help constrain how much water could reach the cold traps in the polar regions," said Michael Poston of the Southwest Research Institute in San Antonio, Texas.

Sorting out what happens on the Moon could also help researchers understand the sources of water and its long-term storage on other rocky bodies throughout the solar system.

The researchers are still discussing what the findings tell them about the source of the Moon's water. The results point toward OH and/or H2O being created by the solar wind hitting the lunar surface, though the team didn't rule out that OH and/or H2O could come from the Moon itself, slowly released from deep inside minerals where it has been locked since the Moon was formed.

"Some of these scientific problems are very, very difficult, and it's only by drawing on multiple resources from different missions that are we able to hone in on an answer," said LRO project scientist John Keller of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Explore further: Researchers create first global map of water in Moon's soil

More information: Joshua L. Bandfield et al. Widespread distribution of OH/H2O on the lunar surface inferred from spectral data, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0065-0

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rossim22
1 / 5 (7) Feb 23, 2018
So, scientists thought they were measuring an abundance of water, when in reality they may have been observing strictly hydroxyl ions?

Can someone firmly established within academia please apply this realization in cometary systems? Perhaps, the "geysers' of moons across our solar system could benefit from this profound insight and produce models which don't require unobservable gravitational tiding?
jonesdave
3.4 / 5 (5) Feb 23, 2018
So, scientists thought they were measuring an abundance of water, when in reality they may have been observing strictly hydroxyl ions?

Can someone firmly established within academia please apply this realization in cometary systems? Perhaps, the "geysers' of moons across our solar system could benefit from this profound insight and produce models which don't require unobservable gravitational tiding?


I haven't read this paper yet, but observations from Enceladus were of H2O. It is very distinguishable from OH in IR. Different wavelengths, due to the different ro-vibrational states exhibited by water as opposed to OH. Can't remember about Europa, but I'm pretty sure that is definitively H2O as well. In comets it is most definitely H2O. Both in IR and sub-mm. Nothing else it can be. Same with detected ice in the comae and on the surfaces. The first definitive detection of H2O at a comet was in 1985, from the Kuiper Airborne Observatory (a 747), observing Halley.
Caliban
5 / 5 (6) Feb 23, 2018
So, scientists thought they were measuring an abundance of water, when in reality they may have been observing strictly hydroxyl ions?


The article says it could be OH, H2O, or both. Most likely it is both.

Can someone firmly established within academia please apply this realization in cometary systems? Perhaps, the "geysers' of moons across our solar system could benefit from this profound insight and produce models which don't require unobservable gravitational tiding?


Regarding cometary bodies, best evidence is again for both, but mostly H2O.

With regard to geysers, they appear to be occurring on moons that are suspected of having liquid water and/or hydrocarbon inner layers, which are most certainly subject to gravitational tidal forces, just as the Earth's oceans are.

This is all current science, worked out according to the best and most recent observations to date, and don't require any professional interpretation, as they already are.

jonesdave
4 / 5 (8) Feb 23, 2018
.......which don't require unobservable gravitational tiding?


It is observed. Go to your local beach. Go there 6 hours later. What is different? It has also been measured at Io. Some huge amount (> 100m?), but I can't be bothered looking for the paper right now.
jonesdave
3.7 / 5 (6) Feb 23, 2018
Oh yikes, I read the paper. This is stuff I would have to take too long to understand. What they are looking at is absorption spectra from surface materials in which the OH/H2O is included from probable solar wind implantation. It is difficult to distinguish the two evidently. However, I'm sure that when they crashed a probe into a polar crater on the moon some years ago, they definitely saw the signature of H2O. That would have been in emission, I'm guessing. That water is thought to have possibly come from comets, and survived in permanently shadowed areas.
The water at comets, and Enceladus and Europa, is generally detected in gaseous form in IR. Much easier to see in those circumstances. Even the ice on comet surfaces and comae has specific signatures which identify it easily.
5555Volcanoes
5 / 5 (3) Feb 23, 2018
Hopefully the water on the moon,or its substitutes, are easily accessible, that would mean that when we decide we start exploring the cosmos, it will be easy to get water wherever we go, even on those inhospitable places.
rossim22
1.2 / 5 (5) Feb 23, 2018
@jonesdave
I'm not saying water doesn't exist in cometary comas or the plumes we see on Io, etc.
What we have here is a mechanism involving solar wind and the surface of a rocky body which can produce hydroxyl and water. No need to rely on (or assume the presence of) sub-surface ice or water sources.

And gravitational tiding as it relates to the heating of sub-surface bodies of water to produce very confined jets is quite a stretch. Its validity is only established because there were no other sources scientists could point to. Now they have one.
jonesdave
3.7 / 5 (6) Feb 23, 2018
^^^^^Firstly, the process you are talking about cannot produce the volumes of water necessary. I, and a number of people, worked it out for 67P. At the time it was producing 1 l/s, the solar wind 'method' could only produce, at best, 10^-7 that amount. It gets worse as the outgassing rate gets higher. Not least because the solar wind isn't reaching the surface for many months.
Secondly, the subsurface ice is not assumed. One way of seeing if it is there is to smack an impactor into a comet at 10 km/s and see what comes out. Solid ice would be the answer to that. Among other things. Or we could watch cliffs fall down on 67P, and use spectroscopy to see what is revealed. No prizes for guessing.
Again, this method is not explaining anything at Enceladus or Europa. Particularly quantity wise.
You won't see water on Io (I don't think), but you will see volcanism. The gravitational torture that moon is undergoing is more than enough to account for that.
jonesdave
3.9 / 5 (7) Feb 23, 2018
Here is an exercise for anybody who wants to try it:
Comet 67P was outgassing ~ 1 l/s at ~ 3.5 AU.
The number of molecules in 1 l of H2O is ~ 3.3 x 10^25.
The solar wind proton density at that distance = ~ 1 cm^3.
The speed of the solar wind is ~ 400 km/s.
The cross sectional area of 67P can be approximated to ~ 10 km^2.

How many H+ ions will hit 67P per second, and how does that compare to the number of H2O molecules outgassed per second?

It's a moot point really, as at perihelion 67P was outgassing ~ 1000 l/s, and the solar wind was getting nowhere near the comet. This was known to happen from theory, and then from observation at artificial comet experiments in 1984-5, and from comet Halley in 1986. That didn't stop some unscrupulous woo merchants from trying to con their followers years after the events with tales of 'no water, only OH caused by the solar wind.' Some were silly enough to take that as gospel. Hey ho.
eagleon
5 / 5 (1) Feb 23, 2018
"So, scientists thought they were measuring an abundance of water, when in reality they may have been observing strictly hydroxyl ions?"
We've measured the pH (H+ and therefore OH+ or hydroxyl) of water down to 0 celsius - it increases, fwiw - but past that, ice typically excludes ions (H+ and OH-) when it freezes because crystal formation favors that. What I gather the paper is saying (I can only read the abstract :<) is that where ice was ionized, its OH- may have become trapped in crystal defects made by solar wind. The much, much smaller H+ ions that didn't get bound up with another OH- would wiggle out of the crystal eventually.

The spectrometer is measuring OH- in much more places than the previous reflectence map indicated. What that definitely doesn't mean is OH- is just laying around on the surface in ball pits. OH-, like H+, is an ion, and ions are repelled from like charges. If they didn't have a large amount of ice to be trapped in, they'd bug out. So there's ice.
katesisco
1 / 5 (4) Feb 24, 2018
Ah well, another result of this high energy gas cloud the sun's system has traveled into. Wireless energy available for use, fading magnetism, new H2O, perhaps disappearing gravity, and most dangerous of all, smarter people using all their faculties in spite of massive fluoride and chlorine and benzene contamination of water, massive vaccination programs, and constant spinning of media manufactured inanity.
rossim22
1 / 5 (2) Feb 26, 2018
@jonesdave

"Comet 67P was outgassing ~ 1 l/s at ~ 3.5 AU.
The number of molecules in 1 l of H2O is ~ 3.3 x 10^25."

As we see in the article here, "The results point toward OH and/or H2O being created by the solar wind hitting the lunar surface"

So perhaps the 'outgassing' of Comet 67P was not solely H20 as originally inferred, but maybe just -OH or a combination of both.
Then the other issues with your "exercise" would be the fact that cross sectional area does not account for the three-dimensional volume of the coma where the H2O/OH is found and the cometary surface would attract ion bombardment.

All I'm alluding to is that as more objective observations are made, alternatives to the "dirty snowball" model appear less crazy.
jonesdave
2.3 / 5 (3) Feb 27, 2018
So perhaps the 'outgassing' of Comet 67P was not solely H20 as originally inferred, but maybe just -OH or a combination of both.


Ye Gods. Is there anybody associated with Thornhill's mob who actually understand spectroscopy? They detect the H2O in IR. It CANNOT be confused with OH. Totally different wavelengths. H2O is an asymmetric top. OH has just one bond (obviously). Look up ro-vibrational states of water. Secondly, they also detect H2O in sub-mm, at ~557 GHz. That is water. OH is bloody miles away at 1100 or so. Thirdly, the solar wind is getting nowhere near the sodding comet for a long period when outgassing is at its highest. 1500 km Rosetta went to in October '15. SW nowhere to be seen.
You need to forget the lies that Thornhill has been peddling to you lot, and do some bloody research. They have been detecting H2O, definitively, since 1985. There is no chance of confusing it with OH. The only OH knocking around at comets is from the dissociation of H2O.

jonesdave
2.3 / 5 (3) Feb 27, 2018
.....the cometary surface would attract ion bombardment.


What lunacy is this? Why would it 'attract' anything? It isn't charged to any great degree. When the SW has access to the nucleus you will get some charging, as expected for asteroids, and inferred on the moon. It ain't going to attract back all the dissociated products of water that it has already expelled at ~600 m/s! Once they're ionised, they're off mate. Picked up by the solar wind, and off down the tail.
We don't need alternative models for comets. The current one is just fine. Smack it with an impactor, ice comes out. Hang around Hartley 2 and ice is just floating about. Wait for a cliff to fall down on 67P, and see the ice below surface. Et boring cetera.
I realise that Thornhill doesn't tell you this stuff. but Google Scholar is not off limits to EU acolytes.
jonesdave
2.3 / 5 (3) Feb 27, 2018
Then the other issues with your "exercise" would be the fact that cross sectional area does not account for the three-dimensional volume of the coma where the H2O/OH is found....


And the relevance of this is.........? To get into the coma it first has to leave the nucleus. Please don't tell me that this is about Thornhill's idiotic claim that SW H+ is going to hurtle, at ~ 400 km/s into a non-existent O- ion to create OH? Please don't tell me you fell for that crap! It's a fairy story. A scientifically illiterate one, at that. I'll let you into a secret - Wal and Dave believe a load of gubbins as proposed by the loon Velikovsky. They want comets to be the result of his physics defying planetary billiards back in the mesolithic. I'll let you into another secret - it's bull****. That is the only reason the electric comet nonsense exists. It's why they wanted them to be rock - they aren't. And electric woo to explain the jets - it doesn't. It is a risibly bad idea.
rossim22
1 / 5 (1) Feb 27, 2018

That is the only reason the electric comet nonsense exists. It's why they wanted them to be rock - they aren't.


You're right. Pretty much everything the mainstream predicted was spot on.

What the world observed was a dirty snowball, with softened relief. The cometary surface must have been far too soft for those ice screws on Philae to stand a chance. We're just lucky the lander didn't fall right through the surface.

Maybe we both just see what we want to see.
jonesdave
1 / 5 (2) Feb 27, 2018

That is the only reason the electric comet nonsense exists. It's why they wanted them to be rock - they aren't.


You're right. Pretty much everything the mainstream predicted was spot on.

What the world observed was a dirty snowball, with softened relief. The cometary surface must have been far too soft for those ice screws on Philae to stand a chance. We're just lucky the lander didn't fall right through the surface.

Maybe we both just see what we want to see.


No, I can back up what I say with evidence. You can't. Want to know what MUPUS discovered about the strength of that consolidated layer? It wasn't close to that of rock. Other instruments looked at the surface in various ways. None of them see rock. The impact at Tempel1 left a crater too big for rock. Etc, etc. I can produce links to multiple papers for all that. What have you got? Fairy tales from a Velikovskian woo merchant, who couldn't find his own arse with an extra pair of hands.
jonesdave
1 / 5 (2) Feb 27, 2018
What the world observed was a dirty snowball, with softened relief.


What did you think they'd find? Did you not follow previous missions, going all the way back to Halley in '86? What you expected to see was a strawman vision, painted by the aforementioned woo merchant/ con man Thornhill. Hence your disappointment. Not my fault you fell for that garbage. I could (and possibly did) tell you that was wrong, long before the spacecraft got near 67P. Instead of having a go at real science, perhaps you should look elsewhere for the source of your disappointment. We didn't lie to you.
jonesdave
1 / 5 (2) Feb 27, 2018
Here are some questions, Rossim; did you know about the solid ice grains excavated by the impact at Tempel 1? Reported in the literature in 2006/7? Did you ever see Thornhill refer to those papers? On the other hand, did you know about a non-existent pre-impact electrical flash at Tempel 1? Did Thornhill ever refer to that? What about the Chandra and SWIFT x-ray data, that show that it didn't happen? Did he refer to that? Did he tell you that Pete Schultz predated his 'double flash' prediction, and did so in the scientific literature? Did he point out all the ice floating around Hartley 2, and the CO2, non-electrical jets that put it there? What about the first definitive detection of H2O, back in '85 by the KAO? And then Vega in '86? Or was he still flogging the 'they're mistaking OH for H2O' line?
Answer those questions truthfully, and you'll realise that you've been conned. Console yourself with knowing that you weren't the only one.
jonesdave
1 / 5 (2) Feb 27, 2018
[You're right. Pretty much everything the mainstream predicted was spot on.


And here's another thing - predictions. 'Mainstream' doesn't really do them. That is for tabloid psychics, like Thornhill. We 'hope' to see, it'd be 'interesting to see', 'maybe we'll find'.......etc.
Thornhill does predictions. And gets them wrong. Unfailingly. Why do people like you think people like me go into science? To be part of some sort of illuminati worldwide conspiracy to keep the lid on utter idiocy like EU? Which, trust me, most scientists are completely unaware of. I have news for you - EU is, has been and will continue to be a complete and utter irrelevance to real science. There is nobody within that cult capable of overturning a tortoise, let alone well established science. It is a non-event, run by Velikovskian woo merchants with naff all qualifications in the subjects they pronounce upon. Get the hell out of it, Rossim. Try some real science.

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