A Heterogenous Moon

Since the end of the Apollo program, and the analysis of all the samples returned from those expeditions, the orthodox view of the moon has been one of dreary, dusty, homogeneity. Oh, there were things like Mascons, and your occasional magnetic anomaly to spicen things up somewhat, but the Moon was thought to be for the most part bone dry, boring, and overall pretty much the same wherever you went (with only minor difference for highlands vs. maria). Over the last several years, new data and new theories are starting to question that orthodoxy, painting the picture of a Moon that is potentially far more interesting than had been previously thought–both scientifically and economically.

Lunar Polar Deposits
The first major crack in the orthodox view of the moon came with the detection by both the Lunar Prospector and Clementine orbiters of potential hydrogen concentrations in the lunar polar regions. It had long been speculated by some scientists that the polar regions could possibly serve as a “cold-trap” that could keep volatiles from escaping back into space, however here was some hard evidence that that might very well be the case. Now this data is not without controversy. Recent data from the Arecibo radio telescope try to call the original data into question, however there are possible good explanations for that contradictory evidence, and the idea of lunar polar concentrations of volatiles has gains considerable traction recently. We don’t know a whole lot (yet) about the form of these volatiles (it could be water ice, hydrogen molecules trapped by the regolith, or maybe something else entirely), and are not entirely sure of their origin (cometary impacts, solar wind implantation, etc), but the general scientific consensus appears to support the idea that there is at least something interesting going on.

Ni-Fe Meteorites
Another recent attempt at challenging the orthodox view of the moon has come from research done by a good friend of mine, Dennis Wingo. In his book, Moonrush, Wingo makes the case based on recent research for the possibility of intact platinum-group-metal-bearing nickel-iron meteorite impacts on the moon. Wingo’s case was based on models that predict the impact velocity distribution of objects striking the moon, computer models that predict the effect of impacts on the impacting body, and data on the number and distribution of Ni-Fe asteroids in the solar system and impact craters on the Moon. If he’s right, there’s a very strong possibility that there are economically interesting concentrations of nickel, iron, and platinum group metals on the moon.

Now, while the idea of lunar polar volatiles has gained considerable respect within the scientific community, Wingo’s hypothesis hasn’t gained anywhere near as much traction yet. As Wendell Mendell likes reminding Dennis at various conferences, there’s very little evidence from the Apollo lunar samples of his hypothesis. Fortunately, Dennis provided several methods in his book for trying to falsify his hypothesis.

Transient Lunar Phenomena
The most recent challenge to the homogeneous Moon orthodoxy comes in the form of some papers recently published in the journal Icarus regarding Transient Lunar Phenomena. A much simplified overview was provided by Space.com. The work, carried out by Crotts and Hummel of Columbia University in New York, is a rather fascinating read (though very, very complicated–I’m not sure I understood more than 25% of the details). Their main conclusions were that there’s good reason to believe that TLPs are real, they appear to be strongly correlated with specific geographic regions, and they appear strongly correlated to lunar outgassing. This outgassing might possibly lead to discoveries of gas pockets below the lunar surface in several locations, which depending on their makeup could be extremely useful for future lunar development. On a substantially more controversial note, Paper II by Crotts and Hummels postulates a mechanism that could lead to substantial subsurface ice deposits in the regions where TLPs are occurring (particularly in the region of Aristarchus crater). While these ice deposits would have been small enough that the resolution of previous neutron spectrometers and such might very well have missed them, this hypothesis is a long way from proven. If the existence of substantial subsurface gas and ice deposits do prove out though, it could have some very important scientific and economic ramifications. Crotts discusses some methods that they are currently using and some future methods for trying to validate or falsify their hypotheses, including using automated telescopes with computer algorithms watching for TLP events. The hope is that by detecting an event early, additional telescopes and sensors can be brought to bear, possibly providing a lot more useful information about what is going on. With several orbiters planned for the near future, the potential for getting close-up data on these events is even more intriguing. It should be a fun topic to watch.

While many of these hypotheses still have a long way to go before they’ve been proven out, it’s interesting to see that the orthodox view of the moon as being boring from both a scientific and economic perspective begin to change. We’ve got a long way to go yet, and some of these ideas might not pan out, or might end up not being as economically interesting as hoped. However, it’s really starting to look like the Moon may very well be a far more interesting place than anyone imagined.

[Note: this post is part of the 14th weekly Carnival of Space being held at Universe Today. Check out some of the other posts if you have the time]

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
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5 Responses to A Heterogenous Moon

  1. John says:

    Spelling correction: “Aricebo” should be “Arecibo”. Thanks!

  2. murphydyne says:

    Hey Jon! Great post! A couple things:
    -actual hydrogen concentrations, potential water.
    -I’m guessing that at least some of the hydrogen is in the form of methane (CH4), which would lend credence to the hypothesis that the cow did in fact jump over the Moon.
    -SWIEs are unlikely to be the source of the everdark hydrogen concentrations, unless you ascribe to the transport theory, whereby comet remains of non-polar impacts slowly migrate by jumps to the poles. Beattie is strongly against this idea, while others have argued for it. It seems a bit implausible to me, but I’m not a scientist.
    -SWIEs are thought to be found in higher densities at the poles versus other areas of the Moon. I don’t entirely get this one either, but it apparently has something to do with the low angle of incidence.
    -The prevailing theory is that the thick accumulations of lava flows (drawing up heavier materials from the interior) are sufficient to explain the orbital anomalies, but the theory still has some unexplained areas.
    -If Mr. Wingo is correct, and the components of interest remain relatively intact as a potential ore, then I’m guessing that wouldn’t leave much to show up in the Apollo samples.
    -reports of TLPs go back to around 577, when Gregory of Tours saw a light on the Moon, though it wasn’t until the late 1700s that things start picking up. It’s about time that the scientific community starts paying some attention to this. Of course its the amateur Moongazers who keep the march of progress going in Lunar studies.
    -Science fiction has speculated that cometary impacts during the Lunar night could be buried by ejecta blankets from co- or succeeding impactors (think Shoemaker/Levy-9). It’s a compelling idea.

    When I gave a talk last month on ‘The New Moon’ at the Texas Astronautical Society meeting, I covered a lot of the stuff we blog about here. So many people came up afterwards and said that they had no idea about any of this stuff. One high schooler said he was amazed by how much he hadn’t learned in school, but was fascinated by things like EML1 and orbital navigation. [ed: Boo-Yah! That’s what I’m talking about!] I was told that the chapter was mesmerized.

    The Moon! The most exciting destination in space within half a million miles!

  3. Danny says:

    Hey John,

    For the nickel-iron impact craters, that really does make perfect sense. It ranks pretty high on the ridiculous scale that one of our largest nickel mines in the world (Sudbury Basin in Canada) is at the site of an asteroid impact, yet there would be nothing similar on the moon. However, if it’s no better than anything on the surface of the earth, its only economic benefit is that it’s sitting in a much smaller gravity well, if you plan on shipping it somewhere.

  4. Jon Goff says:

    Danny,
    AIUI, The PGM deposits at the Sudbury “astrobleme” are still relatively diffuse, they’re just in a higher concentration than most places on earth. Basically, the impactor that created the astrobleme was probably traveling fast enough that most of the impactor was vaporized and spread over a large area. Due to the moon having a much shallower gravity well, it might be possible for impactors to remain more intact, which might yield higher concentrations…

    Dennis Wingo could correct me if I’m explaining his theory wrong. But basically the idea is that there’s a non-zero chance that the concentrations could be much better than found at terrestrial sources, and also could potentially be much more substantial (ie more of it, and in more concentrated form)…

    but all of that’s academic if we don’t figure out how to get there more efficiently.

    ~Jon

  5. gaetano marano says:

    .

    hi Jon

    I’ve redesigned my ghostNASA blog and changed its purpose from a “virtual Space Agency” to a place where publish my opinions about Space

    http://www.ghostnasa.com/

    do you want to exchange a blog roll’s link with my blog?

    gaetano marano

    .

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