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| The south pole region of the Moon. The actual pole is just to the left of the crater marked "A", named Shackleton, and the crater marked "B" is Shoemaker, where the Lunar Prospector spacecraft crashed in 1999. |
Well, this is a bummer.
Scientists at Cornell have just announced that there is no ice on the Moon.
It sounds goofy to think there may be water (really, ice) on the Moon, but it’s actually near fetched (the opposite, you see, of far fetched). Comets and other icy bodies hit the Moon. When they do, the ice in them is distributed across the surface. The lunar day is 29 Earth days long, so probably within a week or two the raw sunlight hitting the ice particles will vaporize them.
However, at the lunar poles, especially the south pole, there are very deep craters. The Sun is always low to the horizon as seen from the poles, and with a deep crater the floor of the crater may never be kissed by the Sun. In such a crater, it’s always dark and cold, so any ice landing there would stay.
So it’s possible, but that doesn’t mean it’s actually there. But if it were there, it would be detectable using radar.
So people did that, and Lo! It looked like there was in fact ice in the lunar Antarctic. Then the US Clementine mission also searched for signs of ice, and also found them. It was looking good. People were planning on building lunar bases near the south pole, to tap into all that ice.
But now these guys at Cornell are, uh, throwing cold water on the whole thing. They used higher resolution radar, and they say they do in fact see that signal, but they see it not only in deep, dark craters, but also in places that do get hit by sunlight. They then conclude that what they are seeing cannot be from ice. It may be from rocks or some other substance, but ice it ain’t. The earlier, lower resolution surveys were seeing both the dark and the lit craters at the same time, and couldn’t differentiate them.
So this is too bad. Dreams of a lunar base at the south pole may have just evaporated along with the purported ice.
October 18th, 2006 at 6:11 pm
Well that just ruined my whole day.
All of that hydrogen and oxygen (i.e. rocket fuel) was the perfect reason to go back to the moon and start a colony as a logical jumping off point for expeditions.
Dang…
- Jack
October 18th, 2006 at 6:27 pm
Shouldn’t this be a double DAGNABBIT!? No breaks for the weary traveler.
Dang is right.
October 18th, 2006 at 8:37 pm
Yeah, dang. Dang it all to heck.
(Mind you, what I really said aloud was substantially more, ah, colorful.)
October 18th, 2006 at 8:56 pm
You know, I wrote this in a hurry and made light of it, but in fact a lot of people have been touting the ice at the lunar south pole as a real reason for going there. I suspect a lot of people are pretty fracking unhappy about this result right now. I also bet a lot of strategizing is going on as well.
October 18th, 2006 at 9:27 pm
Um, hasn’t the Cornell study merely proved that high circular polarization ratios are not necessarily an indicator of water ice, but that the hydrogen so detected can be in other forms? As far as I can tell, all that they have proven is that their previous radar technique cannot tell whether water is present or not.
I’ve never trusted the Arecibo radar data as an indicator of water ice anyhow; it simply cannot look inside the craters of interest, not at their permanently-shaded bottoms anyhow. The angle of incidence of the radar is basically the same as the angle of incidence of sunlight.
October 18th, 2006 at 10:06 pm
Ed, you beat me to it, though far more eloquently. I still say all is not lost, as you have indicated the radar signal has not been able to reach the shadowed region of the polar craters, therefore there can never be a return, at least not until we have a signal that can reach vertically into that crater, with respect to the floor of said crater.
This could be achieved by:-
(1)- having a Lunar fly-by of a suitable radar or other sensor that could read “ice”;
(2)- a great big lunar reflector that would enable the original Earth-bound radar signal to bounce off and penetrate the shadowed area - the return signal following the same path back to the receiver here on earth;
(3)- or, of course the deployment of a lunar polar orbitting satellite with the radar gear to achieve a flyover, or even a “stationary” satellite parked over the south pole at a much higher altitude.
There, I’ve solved your problems. Go do it.
And …ah..I’ll have mine shaken not stirred.
Ivan.
October 19th, 2006 at 1:08 am
Hmm… is the lunar regolith useful for anything?
If not, a moon base will end up being a purely research station, not one where things like building a Mars ship happen.
Of course, a moon base would still be awesome.
October 19th, 2006 at 2:16 am
Keeping in mind that I’m judging only from your blog rather than actual sources; high resolution radar detects the same signal in lunar sunlit areas as in dark shadowy areas. This now indicates that the signature interpreted as ice is not ice. But could it not also simply mean that the signature interpreted as ice is irrelevant to the actual ice that might still be unseen in the crater shadows? In other words, the phenomenon that is presumed to allow for ice to exist at the lunar poles could be in effect but detection is blurred by a another sunlit phenomenon that mimics the same indication.
Would a future moon base, (if we ever decided to build one,) be totally dependent on ice having to be on the moon, or would it mean we’d have to send water or ice there ahead of construction?
Let’s also keep in mind that even if the moon is devoid of ice, there is plenty of ice in the solar system with more distant objects apparently being mostly dirty ice.
October 19th, 2006 at 7:26 am
This conversation (a topic which has always been of great interest to me) needs more links than just the Cornell press release.
Here’s a short summary from Nature.
Here’s the Campbell et al paper.
October 19th, 2006 at 8:10 am
Actually, the investigation for the reasons of the absence ice at the lunar poles would be just as fascinating
But don’t worry folks. This is just a paper.
Hold on until next one comes up claiming there is ice in the deep craters indeed.
And so on and so forth until we go there and sample the real thing
October 19th, 2006 at 8:59 am
From BBC News
http://news.bbc.co.uk/1/hi/sci/tech/6061984.stm
Dr Spudis, from the Johns Hopkins Applied Physics Laboratory in Maryland, added: “When I look at their paper, I see them setting up a straw man, which they demolish. But it’s a straw man of their own devising. The title of their paper is ‘No evidence of thick deposits of ice at the lunar south pole’. No one ever claimed that there was.
October 19th, 2006 at 9:31 am
H2 and O2 are chemically reactive molecules and as such will be present in some combination, whether as water ice or in some other form. The entire idea of ice at the lunar poles is merely one wherein we can get the H2 and O2 we need for sustaining a lunar base as cheaply as possible. I expect there is H2O somewhere on Luna, though it may well be buried in the regolith. Doesn’t matter though as the essential elements will be found and can be extracted, though it may require a more energy intensive effort, ie, by “cooking” the regolith to extract the relavent materials. We need to start some kind of construction on this large resource(the moon) in order to begin building solar power sats. Eventually we will build space colonies, but that will only come from a logical investment protocol. I.E., if there’s no possible payoff, there ain’t no good reason to go there. The profit motive(selling power to an energy dependant earth) is one of the best ways of keeping score, knowing whether what we’re doing is worth the effort.
Gary 7
October 19th, 2006 at 10:54 am
Well, Gary, we know for certain that there is Oxygen on the moon, locked up in the regolith. And now that the high CPR indicates that the Hydrogen is present in areas outside the permanently-shaded polar craters… sounds to me like there is plenty of both of these elements available.
October 19th, 2006 at 11:33 am
OK, this is getting interesting. I may have been too hasty– but I haven’t read the paper, and cannot access it online. We get Nature here at work, so I’ll see what the article says and post a follow-up when I can.
October 19th, 2006 at 12:59 pm
I wonder what this implies for Mercury. Similar radar data was what let to the original announcement of possible water ice at it’s pole (even before the lunar data, if I remember correctly). So, are we going to lose the Mercurian icecaps too?
October 19th, 2006 at 9:07 pm
Actually there’s still the prospect of building a lunar base at one of the poles — for the almost constant solar energy it would be able to tap into, not to mention being an ideal site for a moon-based observatory.
October 20th, 2006 at 10:29 am
I’m not the sharpest tool in the shed, but how could one mistake rocks for ice?
October 20th, 2006 at 9:36 pm
they didn’t mistake rocks for ice omni, what they had said previously was that ice could exist, albeit in small amounts in those asteroid impacts. [think of it as a bunch of dirt with a little ice in it, not mistaking rock for ice] the neutrons say this place has hydrogen, not neccessarily water- just atoms of hydrogen in some sort of form. water was a good guess as hydrogen could reduce oxides in the regolith or water from the impact its self. although this new development is as Ed Minchau put it so: “the Cornell study merely proved that high circular polarization ratios are not necessarily an indicator of water ice, but that the hydrogen so detected can be in other forms” there is also the fact that the crater “B” is only partially shaded- all this actually means is that theres no water in that particular crater where that particular probe crashed. there’s about 50 million kilometers^2 left to go- [although only a small amount of that is worth looking for water] hope isn’t lost yet. we could just shuttle hydrogen to the moon, its a lot cheaper than hauling big giganic tanks of water- just use it to reduce the carbon dioxide made from reducing Iron oxides with carbon monoxide that we use to mine and voila! water and some nice Iron with it to build a spiffy base.
CO2+H2+heatCO+H2O, 3CO+Fe2O3=>2Fe+3CO2 or 4CO+Fe3O4=>3Fe+4CO2
October 21st, 2006 at 5:24 am
Ah ha! Gotcha bud! Thanks. Cause I sure as hell hate rocks with my Tang.
October 22nd, 2006 at 3:37 pm
So piffle- we truck in ice from elsewhere in the system (keep miners happy) and dump it in the dark craters. No biggie….
Jess Tauber