Could it really have been mud seen earlier by Spirit?

exoscientist · Feb 19, 2005

Yen A. S. * Ming D. W. Gellert R. Clark B. C. Morris R. V. Rodionov D. Schröder C. Klingelhöfer G. Subsurface Weathering of Rocks and Soils at Gusev Crater [#1571]. "Data collected from Spirit at Gusev Crater suggest that enhanced weathering of rocks and soils occurs beneath the immediate surface. We believe that this alteration is a result of diurnal condensation of thin-films of water on subsurface materials." http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1571.pdf This abstract to the upcoming 36th Lunar and Planetary Science Conference argues that thin liquid water films are currently forming subsurface in Gusev. Then perhaps the overlying cover could have reduced evaporation to allow mud to form. cf., Newsgroups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.geology, sci.geo.meteorology From: "Robert Clark" <rgregorycl /> Date: 25 Dec 2004 12:58:34 -0800 Local: Sat, Dec 25 2004 12:58 pm Subject: More on "Frost on the rover solar panels". http://groups-beta.google.com/group/sci.astro/msg/fdf0cd29a02007bb Bob Clark <div class="Discussion_UserSignature"> </div>

8774 · Feb 19, 2005

of what liquid?

rlb2 · Feb 19, 2005

If it looks like muck, if it feels like muck and has the consistency of muck it is muck. Something similar to that was quoted by a scientist after first viewing the Spirit Landers airbag retraction area. Here is a image I colorized of the muck at the Spirit landing sight. I reduced the size so I don't ****** up your thread. <div class="Discussion_UserSignature"> Ron Bennett </div>

centsworth_II · Feb 20, 2005

"If it looks like muck, if it feels like muck and has the consistency of muck..." Using the MERs: Looks can be deceiving. We cannot feel anything. Consistency is at best inferred. Granted, clouds and frost have been seen by the rovers. But the first article refers to "...transient, multiple-monolayer films of water that behave as a liquid." This is "liquid" water seen -- or inferred -- at a molecular level. Hardly the stuff of muck. The other paper talks of water vapor, ice and hydrates. No mention of liquid water. Now, liquid water in the form of brine, in an amount that would actually be detectable by human senses and seen in an image would be an exciting find. But just as those who see bones in the rocks mock the search for life, those who see puddles of water in every dust pocket and mud in every dark patch of sand cheapen the true hunt for liquid water. <div class="Discussion_UserSignature"> </div>

rlb2 · Feb 20, 2005

This is "liquid" water seen -- or inferred -- at a molecular level. Hardly the stuff of muck. Did I say what that muck was made out of??? What do you mean by molecular level???? Go out to the beach and half burry yourself in the sand and feel the pressure of the sand on your body...... the top layers of regolith has pressure....... Don't leave out ammonia. Mars has about 2.7 percent nitrogen in its atmosphere, where did that come from? If Mars cant hold onto oxygen and other lighter gasses then how can it hold onto Nitrogen??????????. Now, liquid water in the form of brine, in an amount that would actually be detectable by human senses and seen in an image would be an exciting find. Would you know what it is if you saw it..... What’s this??? <div class="Discussion_UserSignature"> Ron Bennett </div>

centsworth_II · Feb 20, 2005

"What do you mean by molecular level????" I mean that the paper refers to monolayers of water acting as a liquid. I take this to mean that the layer of water is on the order of one molecule thick. Which would not exactly render the surface it was on noticeably wet. I don't know what they mean by "mutiple monolayers", two or three molecules thick? Still not the makings of "muck". "...brine...Would you know what it is if you saw it..... " No one would. It would take the right instruments at the right place and the right time. The MERs do not have the right instruments. <div class="Discussion_UserSignature"> </div>

centsworth_II · Feb 20, 2005

"...never venturing away from the herd mentality - and throwing rocks at those who do." It's fun to speculate. My problem is not with those who theorize about conditions under which mud may exist on the surface of Mars, but with those who say this is mud on the surface of Mars. <div class="Discussion_UserSignature"> </div>

centsworth_II · Feb 20, 2005

"What’s this???" I think it's one of those dust puddles I referred to in my earlier post. <div class="Discussion_UserSignature"> </div>

exoscientist · Feb 20, 2005

Or hundreds of "monolayers" over several diurnal cycles. Bob Clark <div class="Discussion_UserSignature"> </div>

alpha_taur1 · Feb 20, 2005

" It would take the right instruments at the right place and the right time. The MERs do not have the right instruments." Hold that thought. Tell me why you think the miniTES can't detect brine. If you mean brine at depth, I concur. The most likely form of water at these latitudes is hydrated salts. Kieserite (MgSO4.H2O) has been detected on Mars. This would absorb water from the vapour phase to form higher hydrated products such as epsomite, somewhat in the manner of a laboratory vacuum dessicator.. So are you saying that there is some interference at the 1640 cm-1 region?

alpha_taur1 · Feb 20, 2005

"Now, liquid water in the form of brine, in an amount that would actually be detectable by human senses and seen in an image would be an exciting find. But just as those who see bones in the rocks mock the search for life, those who see puddles of water in every dust pocket and mud in every dark patch of sand cheapen the true hunt for liquid water." My sentiments exactly. The main problem is that water is at best a very volatile liquid on the surface of Mars. It just isn't stable. "....liquid water in contact with the current Martian atmosphere is unconditionally unstable as the water vapour partial pressure is always orders of magnitude lower than the triple point of water." (1) Unfortunately certain ex NASA personnel have given rise to the urban legend that the atmospheric pressure is the relevant criterion here. (1) Richardson, Mark; Mischna, Michael, December 2004 The Long-Term Evolution of Transient Liquid Water on Mars Also in that paper is an interesting conclusion regarding the precession of the orbital parameters of Mars (particularly the argument of perihelion.) Currently the arg of perihelion is such that the aphelion coincides closely with the southern winter soltice. If the arg of perihelion varied by 180 degrees such that the Northn Winter coincided with the aphelion, then the Northern polar cap would be considerably more extensive as a result. Some of the long term features that we are seeing are consistent with these obliquity effects.

silylene old · Feb 20, 2005

the paper refers to monolayers of water acting as a liquid After looking at dozens of MI photos which seem to show unusual "filament or thread" patterns in the grains of the surface soils, I suspect that water (ice, to be exact) played a role in arranging these patterns. I posted this hypothesis in a long thread, before the forum wipe. I do think this hypothesis needs to be re-visited, in view of the much more extensive information we have subsequently learned about water modification on the surface, and the confirming observation of surface frosts in the Martian winter. In many cases, these "filaments" or "threads" did not seem to be artifacts of the compression algorithm, because the same observation repeated across multiple images, and sometimes slightly different angles. Yes, they often were near the resolution limit of the MI, which causes ambiguity of interpretation or even certainty of existance. The human eye is uncanningly good at finding patterns, even where they might not exist. I have carried out simple experiments over months in my freezer. I have very lightly dusted different squares of my freezer tray with dusts (fine sand, talc, house dust, natural carbonate rime) and observed them through several cycles of frost collection (pull the tray out for a moment to collect frost from the air) and slow sublimation in my freezer. The dusts are pulled by frost formation to the edges of the individual ice crystals and interfaces between crystals. This process aligns the dust particles into some very fine linear orientations. When the ice frost fully sublimes, what is left is a "imprint" of the missing ice crystals as a pattern in the dusts. I think is it possible (likely?) that the dust patterns actually seed the locations of the centers of the ice crystals in the next cycle of frost formation/sublimation. This might exaggerate the "thread" formation. But it is hard to <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

exoscientist · Feb 20, 2005

I'm not sure which side you're arguing in your post in regard to liquid water's stability, Alpha. Are you saying the total atmospheric pressure is the important factor or the water vapor pressure? Bob Clark <div class="Discussion_UserSignature"> </div>

alpha_taur1 · Feb 20, 2005

What I'm saying is that water is inherently unstable on the surface of Mars, except for ephemeral films, and even they are only stable for about 60 sols a day at selected locations, and only for about an hour per sol at best.

alpha_taur1 · Feb 20, 2005

On another forum a long time ago, I argued the same point. A major component of these dusts is soluble salts such as calcium and mag chlorides and sulfates. I have also seen filaments using these chlorides as dessicants in a laboratory dessicator. That gets pretty close to Martian conditions. The freeze drying process produces almost radial effects as an alkaline earth salt is evaporated rapidly. The other factor is water of crystallisation. As hydrated mineral salts lose or gain their water of crystallisation, there have to be metastable regions where ephemeral water films may exist for a fleeting moment. As far as mud is concerned, we are not obviously not seeing mud. A simple consideration of temperature and pressure should convince us of that. The articulation device temperatures for the first 90 sols are a rough approximation of surface temperature, although that will vary according to thermal inertia. Slightly below the surface, away from direct solar radiation, the temperature does not get high enough for brines to melt. There might be some elusive pockets of geothermal energy on Mars which maintain higher temperatures at depth, but so far we have only seen hints of this. The thermal anomalies at Hellas could equally be due to the evaporation of local ice deposits. Sorry about the rambling post.

exoscientist · Feb 20, 2005

<blockquote>In reply to:<hr />As far as mud is concerned, we are not obviously not seeing mud. A simple consideration of temperature and pressure should convince us of that. The articulation device temperatures for the first 90 sols are a rough approximation of surface temperature, although that will vary according to thermal inertia.<hr /></blockquote> You mentioned the possibility of brines. These can remain liquid well below 0 C and the triple point for pressure is also reduced. Then it could be a briny mud. Bob Clark <div class="Discussion_UserSignature"> </div>

alpha_taur1 · Feb 20, 2005

Bob, As I said before this paper is worth a read. It's a 10.4Mb download: Richardson, Mark; Mischna, Michael, December 2004 The Long-Term Evolution of Transient Liquid Water on Mars http://www.agu.org/pubs/pip/2004JE002367.pdf It's one of the best papers I've come across on the varying conditions on Mars over time, and the effect on the potential for surface liquid films. One of the points that it makes is that brines don't make a great deal of difference over water. "The maximum temperatures fall below the melting point of all but the strongest plausible brines" The best potential for liquid brine is within any area that is at least partially sealed in some way from the atmosphere, so that an equilibrium is set up between liquid and vapour phases. If we can get such a situation where the temperature exceeds 220 K (-53 degrees C), it is possible that calcium chloride brines can exist in liquid form. The main difficulty is that for such a perfect eutectic mix, there needs to be recharged by 'fresh water' or water with lower ionic strength. There are phase diagrams available that illustrate the point that a saturated brine doesn't achieve the best freezing point depression. Getting back to our surface 'muck', the main reason that it can't be mud is that the mini TES would have detected this, and free liquid brine on the surface would be _big_ news. There are mini TES reports publically available for the first 90 Sols at least if you want to check this data. One of the things I'd expect to see in the event of free surface water, including brines, muds etc, would be a fog of microscopic ice crystals drifting in the wind. The temperature differential between surface and atmosphere is quite considerable, as I'm sure you are aware. - Jim You might know me as Aldebaran f

alpha_taur1 · Feb 21, 2005

Another factor to consider is what would happen if we placed a container of brine on the surface of Mars. If the ambient temperature was around 293K during a summer day, the brine would start to boil until it lost so much heat that the temperature dropped as low as its boiling point, which we'll say for the exercise is around 0 degrees C. Any free liquid would produce a thermal anomaly for this reason. It's similar to ether evaporating on Earth. It feels cold because it absorbs heat from its surroundings.

exoscientist · Feb 21, 2005

<blockquote>In reply to:<hr />"The maximum temperatures fall below the melting point of all but the strongest plausible brines"<hr /></blockquote> You have to explain the context where they make this statement. It is well known that maximum temperatures can exceed 300 K, 27 C, or 80F near the equator on Mars. Also the mini-TES DID detect water. The problem is it can't differentiate between free water and water contained within other compounds. Bob Clark <div class="Discussion_UserSignature"> </div>

centsworth_II · Feb 21, 2005

"Tell me why you think the miniTES can't detect brine."-- Alpha_Tauri My concern was that with all the "sightings" of mud and frozen water in rover tracks, I've seen no definative statement from NASA that yes, miniTES would see it if it was there, and "yes it is" or "no it isn't". Maybe I missed it. Maybe NASA doesn't think it's worth commenting on, being a preposterous premise. My general feeling is summed up by this quote from one of your posts (thanks by the way for such helpful posts): "...the main reason that it can't be mud is that the mini TES would have detected this, and free liquid brine on the surface would be _big_ news." -- Alpha_Tauri <div class="Discussion_UserSignature"> </div>

centsworth_II · Feb 21, 2005

"Sometimes the simplest explanations are the best." I'll agree that the cause of dark vs, light soils is a legitimate scientific concern. And considering the possibility that water -- in some form -- plays a role is also valid. But saying that what is being seen is "mud" is simple in the worst sense of the word. And the simple explanation for images of "muddy puddles", is collected dust or fine sand with grain size below the resolving capability of the cameras. <div class="Discussion_UserSignature"> </div>

alpha_taur1 · Feb 21, 2005

Well I Guess NASA has not stated the obvious. You're talking about surface brine- in other words flows of brine on the surface. If there was surface brine, we would expect to see water permeating through the dirt, and this would show up at 1640cm-1. Hydrated minerals generally result in peaks in the near IR, and there are also a few at the other end of the spectrum, which are probably more important in this case. Yes, there is a difference in detection between hydrated minerals and brine/ice. I've worked with IR Spectroscopy in the past, so I know its capabilities. There are others on this forum who have also had experience with it, and hopefully we may get some comments. Arizona State University is responsible for the miniTES, and it's probably worth hearing what thay have to say on the subject. On another forum, there was a response from a researcher from ASU. If you doubt his credentials, do a basic web search. Surface frost can be detected by TES. He showed more discretion than I have in not being led by the 'water flow features' discussion. http://www.markcarey.com/mars/discuss-23169-could-the-human-eye-compete-with-the-minites.html See reply 5. For frosts, the same thing applies to brines, frozen or otherwise. Another thing to discuss is the viscosity of calcium chloride brines at low temperature, and their behaviour in the presence of enormous quantities of dry salts on the surface. You can accuse me of not backing up my statements with experimental evidence all you like, but at least I have worked brines at low temperature, albeit in a different context. Brines are used extensively in the oil industry. I have also worked with calcium and magnesium chlorides in a laboratory environment, so my posts are not idle speculation. Fine powder can be

alpha_taur1 · Feb 21, 2005

"How does all of this "watery" material (and more) combine with the fine dusts, the soils, and the salts we see? " Well the frost itself has only been seen on the solar panels of Opportunity, although it could exist on areas of low thermal inertia. I know that it was considerably more evident at the Viking II site on Planitia Utopia. The frost has only been seen briefly during winter mornings at incredibly low temperatures. It sublimates extremely quickly. Getting back to your question, water vapour can be absorbed directly from the vapour phase by partially hydrated or anhydrous salts such as Magnesium sulfate, which make up a significant proportion of the Martian regolith. The recently discovered frozen 'sea' is an interesting find. It seems to indicate that there is permafrost below the surface. This seems reasonable, since temperatures a few centimetres from the surface never get high enough for even brine ice to melt. It's held in a cold trap so to speak. This material could be preserved by a layer of dust, even on the Martian equator. The fact that it exists to this day (subject to confirmation) suggests that this is the case.

alpha_taur1 · Feb 21, 2005

If we look at temperatures during a Martian summer day, they vary enormously from early morning through to the maximum just after mid-sol. There is a graph of atmospheric temperatures at the Athena site : (top right corner of the text) http://athena.cornell.edu/the_mission/ins_minites.html Ok, I know that surface temperatures are higher, but the diurnal range is about the same. The night-time temperatures are much lower. If we take the mean diurnal surface temperature, then this roughly represents the temperature a few centimetres below the surface. It's a little bit like the temperature variation of a shaded pool on Earth. It never reaches the daily maximum, and never reaches the minimum nightly temperature either.

jindivik · Feb 21, 2005

im sorry, this has nothing constructive but its cracking me up seeing "mud" all over the thread...sounds so scientific! hehehe

Could it really have been mud seen earlier by Spirit?

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