Don't know how major this is, but if it's innapropriate here I'm sure the mod team will move it: Spirit finds evidence of subsurface water, JPL

The planetary society blog has a nicer (and I hope correct) interpretation.

1 cm square, 25 micron thick, solar sail type spacecraft to monitor solar storms. Acta Astronautica. Prototypes may be ready for test flight this year !

Thats nice and vague thanks! If it's a meteorite crater might the presence of the sulfates in the crater tell us something about the redistribution mechanism? If the sulfates and the crater are related, and its not just a coincidence that one is in the other, then without knowing how else the sulfates might have got there the idea of fumerole seems (to my very limited geology knowledge) to fit. Mods I won't ask any more questions on this subject after this post, I've no wish to derail the thread.

Is Dburt still about? I'd think he would have a comment or two.

Thanks, thats kept my imagination busy for a good while!

Boing? It still might not be strictly speaking a liquid in those lakes- it might be a massive tangle of long chain hydrocarbons with pore spaces that fill up during the wet season and dry out at other times. It could be like a giant rubbery sponge!

EDIT: That wasn't meant in earnest, but this is: What are the odds of the material in ontario lacus haveing non-newtonian properties, like custard? Many polymer solutions do!

I think you're right!

New scientist has confused me. I know I shouldn't put too much faith in what they report these days but they've said:

This is from their report on the Lunar Exploration Analysis Group meeting, so I was hoping for some interesting tidbits, but I'm just confused! Is the water content several percent, or the hydrogen content? Does anyone know of any other reports from the Lunar Exploration Analysis Group?

The universe today article mentions that ejecta from young craters were 'rich' in water and hydroxyl, which might mean that some of it migrates to the subsurface and sticks around. Plus it seems hard to have ultra cold traps at the poles, a continuos (but yes very tenuos) supply of water and hydroxyl, and not have significant amounts of ice to accumulate in the subsurface of said cold traps over geological time (micrometeorite impacts might drive off surface ice faster than it can accumulate). It seems logical that there will be areas with only an atomic icing and areas with relatively large amounts at a certain depth.

The moon does not seem as dead as once thought today, and coupled with the news of very pure ice on mars it's been a good week for finding ice in the inner solar system.

Many thanks! If I could bombard you with questions for a minute...
Which zones of temperature are expected to cold trap which volatiles? For example the press release mentions that the 35K temperature of the permanantly shadowed regions is more than cold enough to trap H2O, so what other things might be trapped?

I have read somwhere that the regolith temperature at 1 meter depth beneath the poles, even where the surface recieves sunlight, is expected to be around 40K. Does this have a bearing on the quantities of volatiles expected to be trapped by the permanantly shadowed regions- ie might subsurface cold trapping get most of the migrating volatiles before they reach the permanantly shadowed polar craters?

I think that begs the same question I asked dvandorn, but on a bigger scale: Why has 3.5 billion years of meteorite and micrometeorite bombardment not been enough to significantly blur those boundaries?

Thank you dvandorn, that pretty much answers my questions!

Re-reading the article I linked in post three; it suggests that enough dust could have accumulated on the LEAM experiment to significantly decrease its reflectivity in just a few hours. If true than thats a significant transport of material, but the temperature dropped again thereafter so perhaps the effect is almost like frost- a thin layer can build relatively quickly, but it is a strictly temporary phenomena. The wikipedea article mentions that the electrostatic charge on the dust causes it to stick to most things though, so I'm a little confused as to how this works.

On a more than academic; level if significant amounts of dust do move about and attach themselves to things this could be a hazard for temperature control future lunar surface missions.

Thanks for the information dvandorn! I imagine that meteorite impacts over billions of years would put quite a bit of dust about, given that they are a sparse but steady phenomena, so I suppose the logical question (and I do realise I'm drifting off my own topic, so I won't pursue this beyond this post) is why are the rocks so clean?

Aye, thats the answer I was expecting.

Reading this NASA article though has made me wonder if we understand this phenomena as well as we think. I'll quote the part that made me curious:

(my bolding)

I expect this material would be orders of magnitude more tenous than the material coming out of a clean car exhaust, but on the moon, and over geological time, it might still add up to relatively large amounts of material moving. I only persist asking because lunar processes take place over billions of years, enough time perhaps for even the puniest forces to make their presence felt.

dvandorn, you mention that the number of dust particles detected was way down in the noise in the apollo experiments, which seems to contradict the quote I have above. Could you point me towards your source?

I read this article on electrostatic transport of dust on the lunar surface a few days ago, and I was wondering if it had ever been discussed as an erosive or constructive force? What effect might it have had on lunar geology?

Myself I'm trying hard not to get too excited before the actual papers come out, as abstracts can be decieving, but it's taken an effort of will....

I'd think so... in fact seeing as how easy it would be to make a lunar cold trap there should be a lot of them in various forms. It'd just be a case of picking the oldest and least disturbed. An ancient cold trap that got hit by a meteorite would probably leave a fingerprint of volatile species in the lunar exosphere.

I can imagine some 1/6 g rock scrambling and bouldering going on there! Looking at such rough terrain makes me wonder if there are any (much) smaller versions of the permanantly shadowed craters at the poles? A crevice or crater in the middle of such an outcrop would be sheltered from sunlight at comparatively low lattitudes I imagine.

The abstracts on lunar surface composition, titan, enceladus, on the recovered Almahata Sitta meteorite, and the detection of surface water ice on asteroid 24 Themis are enough to set me dribbling, and I lost two hours just reading through....I hope there's plenty of coverage from the sessions when they start!

Thanks for all the info mike, is this the kind of article you were thinking of? There's a neat table about halfway down.

Thats well above my level of organic chemistry! But from working on putting down nitride and oxide coatings there will very likely be an intermediate layer between any two grains. In fact it's bloody hard to get rid of, even under high vacuum conditions most things have a layer of oxides that need ion etching off. Depending on the exact conditions on earth it's almost always water plus greater or lesser amounts of what else is in the atmosphere. From there a lot depends on how the surface reacts with water and the atmospheric gasses, so as a total shot in the dark I'd suggest that the free bases have a better affinity for atmospheric water, or more likely something they make as a layer on reacting with air ( oxygen content a likely suspect?) has a better affinity. On titan the grains would (I imagine) be most likely to condense monolayers of simple organics to start with. More wild speculation: Is there any chance polymers could form and each grain could have a tangle of polymers around it, acting like very tiny velcro?

Exploring the exact mechanisms of adhesion at work with titan materials and under titan conditions would be fascinating. On earth most surface properties are actually determined by the layers of surface contaminants, of which water and organics are among the most common. Actuall direct contact between two materials will often result in an instant bond- hence why frictional forces tend to be so much higher in a vacuum. Low temperatures and direct contact will result in instant cold welds between asperities, or can result in much lower adhesion as the cold changes the properties of surface contaminants. So exactly how things work in titans ultra cold, organic-materials-and-cryo-liquids environment is compelling science. The biggest mystery is why things look so much like earth, and if that continues down to the finest scales?

Surface science is important to almost every industry, so we might learn some new tricks from titan?

It's not world changing but it's still a first for comet studies, and exploring whether the glycine was inherited from the solar nebular or generated on the comet should be interesting.