10
$\begingroup$

Is there enough information to conclude whether or not the water ice in the permanently shaded craters around the poles likely also contains carbon and nitrogen chemicals? (Or any other potentially useful substances not present or hard to access on the moon?)

$\endgroup$
  • 2
    $\begingroup$ LCROSS ejecta:N 6.6000% CO 5.7000% H2O 5.5000% Zn 3.1000% V 2.4000% Ca 1.6000% Au 1.6000% Mn 1.3000% Hg 1.2000% Co 1.0000% H2S 0.9213% Fe 0.5000% Mg 0.4000% NH3 0.3317% Cl 0.2000% SO2 0.1755% C2H4 0.1716% CO2 0.1194% C 0.0900% Sc 0.0900% CH3OH 0.0853% S 0.0600% B 0.0400% P 0.0400% CH4 0.0366% O 0.0200% Si 0.0200% As 0.0200% Al 0.0090% OH 0.0017% $\endgroup$ – HopDavid Sep 21 '14 at 4:46
  • $\begingroup$ Above numbers from October 2010 Science if memory serves $\endgroup$ – HopDavid Sep 21 '14 at 4:48
  • $\begingroup$ The LEND data don't seem to support the more optimistic estimates of polar water ice. $\endgroup$ – HopDavid Sep 21 '14 at 4:49
  • 1
    $\begingroup$ You didn't want to list that as an answer? That looks like an answer to me. $\endgroup$ – kim holder Sep 21 '14 at 19:48
  • 1
    $\begingroup$ The 600 million cubic meters seems to be indicated by elevated CPR. But the Lunar Exploration Neutron Detector doesn't support that. I hope for the more optimistic estimates but we don't really know. $\endgroup$ – HopDavid Sep 22 '14 at 0:19
4
$\begingroup$

Edit prompted by DougSpace on December 30, 2015. LCROSS numbers may have been over estimated.

Here's a screen capture from the Moon Society's Facebook page:

enter image description here

I hate to break this bad news but it seems the numbers I reported below are optimistic :(.

I don't have access to the 23 Sept. 2011 edition of Science. If anyone can access it and report back, I'd be grateful.


The Oct. 2010 Science Journal looked at Lcross ejecta. Here are some of the percentages:

N 6.6000%

CO 5.7000%

H2O 5.5000%

Zn 3.1000%

V 2.4000%

Ca 1.6000%

Au 1.6000%

Mn 1.3000%

Hg 1.2000%

Co 1.0000%

H2S 0.9213%

NH3 0.3317%

Cl 0.2000%

SO2 0.1755%

C2H4 0.1716%

CO2 0.1194%

C 0.0900%

Sc 0.0900%

CH3OH 0.0853%

CH4 0.0366%

O 0.0200%

OH 0.0017%

$\endgroup$
  • 1
    $\begingroup$ I understand that the percentages of volatiles listed above are in error due to an incorrect calculation. It is very hard to get the corrected percentages as the LCROSS researchers haven't responded to email request. But my understanding is that carbon monoxide is more like 1.3%. $\endgroup$ – DougSpace Dec 29 '15 at 1:12
  • $\begingroup$ @DougSpace A Christopher Carson comment from the Moon Society's Facebook page: "Did anyone else catch the correction published in SCIENCE (23 Sept 2011)? Basically, all the LCROSS numbers except hydrogen have to be revised downward, mostly by a factor of 5.5." $\endgroup$ – HopDavid Dec 31 '15 at 0:51
1
$\begingroup$

I've done an examination of the literature on the subject, and I can't find any mention of any volatiles except for water ice, but there are indicators that there should be others. Let's examine what characteristics of volatiles should be on the Lunar surface.

  1. It would have to be solid in a vacuum at low temperatures, about 100K.
  2. The material should be abundant, rare materials are unlikely to have this performance.
  3. A volatile will vaporize at the temperature of the moon in the daylight. Let's call that about room temperature, 300K. It could also vaporize by the presence of sunlight.

    • Water is an obvious candidate for such, as it is available throughout the solar system, and meets the temperature requirements.
    • Nitrogen wouldn't remain a solid, and thus wouldn't solidify.
    • Carbon Dioxide would probably remain frozen, it will remain solid in the realm of 100 degrees.
    • Carbon Monoxide probably won't remain stable, it doesn't seem to remain solid with an extremely low temperature.

Bottom line, there likely won't be many others, but I suspect Carbon Dioxide would also be at the surface in permanently shadowed craters on the Moon.

$\endgroup$
  • $\begingroup$ What about clathrates? The LCROSS data points to some nitrogen, and carbon monoxide, and that would be an explanation. $\endgroup$ – kim holder Aug 26 '15 at 14:06
  • $\begingroup$ Clathrates are a possibility, and would be more likely at the poles. I'd have to think about that one more than I have time for at the moment, I'll come back to it... $\endgroup$ – PearsonArtPhoto Aug 26 '15 at 14:33
  • $\begingroup$ Why would it have to be solid above 100K? there are lunar cold traps much colder, for example Hermite Crater: lunar.gsfc.nasa.gov/lola/feature20110331.html Hermite is about 24K $\endgroup$ – HopDavid Aug 31 '15 at 6:11
  • $\begingroup$ @HopDavid maybe over longer time scales the Moon's axial tilt may have wobbled enough to bring it into sunlight? $\endgroup$ – kim holder Aug 31 '15 at 13:54
  • $\begingroup$ I believe PearsonArtPhoto's model is incorrect. But am waiting for him to explain his 100K number. He linked to a pdf behind a paywall. If the site of the LCROSS impact recently reached 100K, there woudn't be nearly 7% nitrogen. Only a small fraction of the volatile gases from cometary impacts would find their way to the cold traps. It would take eons to build up 7% nitrogen deposits. As well as the other volatile deposits. $\endgroup$ – HopDavid Aug 31 '15 at 14:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.