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elakdawalla
I figured it was time for a new thread, since we finally seem to be getting some science results out of Phoenix. The press release should be out shortly.

First numerical result I've heard was given by Peter Smith at today's press briefing at AGU: TEGA found that the soil is composed of 5% calcium carbonate, which is a significant result.

Hopefully more will hit the Web soon -- post here when the links go up!

--Emily
alan
Some AGU related images at the Phoenix site
http://phoenix.lpl.arizona.edu/images.php?gID=0&cID=381
alan
Phoenix Site on Mars May Be in Dry Climate Cycle Phase

QUOTE
PASADENA, Calif. -- The Martian arctic soil that NASA's Phoenix Mars Lander dug into this year is very cold and very dry. However, when long-term climate cycles make the site warmer, the soil may get moist enough to modify the chemistry, producing effects that persist through the colder times.

Phoenix found clues increasing scientists' confidence in predictive models about water vapor moving through the soil between the atmosphere and subsurface water-ice. The models predict the vapor flow can wet the soil when the tilt of Mars' axis, the obliquity, is greater than it is now.
...
Cloddy texture of soil scooped up by Phoenix is one clue to effects of water. The mission's microscopic examination of the soil shows individual particles characteristic of windblown dust and sand, but clods of the soil hold together more cohesively than expected for unaltered dust and sand. Arvidson said, "It's not strongly cemented. It would break up in your hand, but the cloddiness tells us that something is taking the windblown material and mildly cementing it."

That cementing effect could result from water molecules adhering to the surfaces of soil particles. Or it could be from water mobilizing and redepositing salts that Phoenix identified in the soil, such as magnesium perchlorate and calcium carbonate.

The Thermal and Electrical Conductivity Probe on Phoenix detected electrical-property changes consistent with accumulation of water molecules on surfaces of soil grains during daily cycles of water vapor moving through the soil, reported Aaron Zent of NASA Ames Research Center, Moffett Field, Calif., lead scientist for that probe.

"There's exchange between the atmosphere and the subsurface ice," Zent said. "A film of water molecules accumulates on the surfaces of mineral particles. It's not enough right now to transform the chemistry, but the measurements are providing verification that these molecular films are occurring when you would expect them to, and this gives us more confidence in predicting the way they would behave in other parts of the obliquity cycles."
http://www.nasa.gov/mission_pages/phoenix/...x-20081215.html
marsbug
QUOTE
The Thermal and Electrical Conductivity Probe on Phoenix detected electrical-property changes consistent with accumulation of water molecules on surfaces of soil grains during daily cycles of water vapor moving through the soil, reported Aaron Zent of NASA Ames Research Center, Moffett Field, Calif., lead scientist for that probe.


Is this a complete turnaround from previous reports, or did I miss something?
djellison
I think it's consistent. They saw vapour, they saw films, but they didn't see liquid - I think is the main story.

Doug
marsophile
From http://planetary.org/blog/ referring to TEGA results from Phoenix:

"For example, they saw a low-temperature release of carbon dioxide (CO2). This could be a number of things: iron or magnesium carbonates; adsorbed carbon dioxide; or potentially most exciting, combusted organics."

"...if there were organics present, they could have been destroyed by the perchlorate during heating before TEGA had a chance to detect them. Unfortunate --..."

Why cannot the calorimeter distinguish between these possibilities? Wouldn't combusted organics be signalled by an exothermic process? Whereas the others would be endothermic, right?
djellison
QUOTE (marsophile @ Dec 16 2008, 11:57 PM) *
Why cannot the calorimeter distinguish between these possibilities?


Who said it can't? The science team have said they're still working the data.
marsbug
QUOTE (djellison @ Dec 16 2008, 11:15 AM) *
I think it's consistent. They saw vapour, they saw films, but they didn't see liquid - I think is the main story.

Doug


I'm going to be hopelessly pedantic here Doug: the report describes that
QUOTE
"A film of water molecules accumulates on the surfaces of mineral particles. It's not enough right now to transform the chemistry, but the measurements are providing verification that these molecular films are occurring when you would expect them to, and this gives us more confidence in predicting the way they would behave in other parts of the obliquity cycles."


However the preliminary results, described in this article were that:
QUOTE
"There are no indications of thin films of moisture, and this is puzzling.....the probe can detect films of water barely more than one molecule thick."


If the films were around the one molecule thick mark, or the electrical characteristics of the soil were different than expected, or any one of a zillion things, I totally get that the readings might have needed carefully examining before the evidence was apparent. I'm just wondering how exactly they got from 'the soil is puzzlingly free of water', to 'the soil has some thin films of water molecules'.

Sorry for the pedantry, I'm just being greedy for details really.....
fredk
I agree, Marsbug - I also noticed that change in the interpretation of the results and I'm curious about the details too.

If you haven't noticed it, a plot of "simplified" data from TECP was presented yesterday. Perhaps this gives us a clue. To my eye there's no clear anticorrelation between the atmospheric and soil measurements - there are peaks in the soil measurement during the day. Perhaps a sign that there's some non-trivial dynamics going on here - more than just a simple "soil at night" and "air during the day" cycle?

I wouldn't describe it as "hopelessly pedantic", just being curious about the scientific process...
Doc
Wow, thanks for the cool graph fredk; I am sure my temporal insomnia and headache last night was because of this subject (to detect or not to detect water film, that *was* the bloody question!). The graph clearly shows that the ice is literally breathing. smile.gif Cool.
marsbug
QUOTE (fredk @ Dec 17 2008, 03:09 PM) *
If you haven't noticed it, a plot of "simplified" data from TECP was presented yesterday. Perhaps this gives us a clue. To my eye there's no clear anticorrelation between the atmospheric and soil measurements - there are peaks in the soil measurement during the day. Perhaps a sign that there's some non-trivial dynamics going on here - more than just a simple "soil at night" and "air during the day" cycle?


Well we have a layer of ice, lying below a fairly complex regolith mixture containing water absorbing salts, as well as grains for water molecules to adhere to, and probably a small amount of ice in some form, topped by water/CO2 frosts and snow coming from an atmosphere that supports water ice clouds. So there's a lot of sinks and sources of water, which means complex behavoir for water in the soils is pretty inevitable.

On the subject of the films, the impression I get on re-reading the release and the articles is that the team are probably being a little cagey because there's still a lot of analysis ahead.
My hunch is that the films are probably averaging less than one molecule thick throughout most of the soil, and hence form as a series of patchy 'islands' around favourable spots for water molecules to deposit. That would make them much harder to 'see' as a continous electrical path through the soil wouldn't be there. So when the team digs into the data they may find evidence for these islands of water activity, but hesitate to describe them as films, because....er.... well they aren't they're little islands of H2O clustered together!
ngunn
That makes a lot of sense marsbug - I like your hunch.
marsbug
Thanks! I've had a quick look, but I've not found anything relating to the growth of thin water films under matian pressures and temperatures, although this and this might have some interest for anyone with access to springer link.
I think it's an experiment someone will be doing at some point in the near future though!
climber
marsbug,

Who's Albert Einstien?
marsbug
It's a little known fact that there were three brothers, Ienstein, Einstien, and Einstein. Albert was actually their family name (the family had Asian roots). The first two shared the limelight, taking alternate holidays, to preserve some privacy for the family. Albert Ienstein is a character best left unremarked upon.... rolleyes.gif biggrin.gif cool.gif

Or maybe I just made a spelling mistake.... laugh.gif laugh.gif laugh.gif
dvandorn
I've always been amused that the American comedian and actor, Albert Brooks, had to change his real name. He just couldn't see himself using his real name -- Albert Einstein. (His brother, who played the idiot character Super Dave back in the 80s, kept his real name, performing under the name Bob Einstein.)

-the other Doug
marsbug
There's some more on it over on the planetary society blog. Thanks Emily! The description of how water adsorption works is excellent, it really clarifies the difference between thin films of water and thin films of liquid water.
Phil Stooke
This LPSC abstract contains a full list of samples collected by Phoenix - might be useful!

Phil

http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1067.pdf
marsophile
Interesting (LPSC abstract #2196) that the lack of detection of chlorine in TEGA was likely due to a reaction with the nickel in the TEGA ovens.
ustrax
Looks like there is someone defending that the droplets seen on Phoenix's legs are made out of...liquid water... rolleyes.gif
"Nilton Renno from the University of Michigan and Phoenix team member, thinks it could be. "According to my calculations, you can have liquid saline solutions just below the surface almost anywhere on Mars," he said."
Story at Universetoday.

Made a crude animated gif out of the image in the article, although I'm almost sure someone here did one before with higher quality... wink.gif
http://www.gifninja.com/Workspace/a68a18ab...c630/output.gif
fredk
There's an article on New Scientist about this:

http://www.newscientist.com/article/dn16620

In that article there's a link to this conference abstract:

http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1440.pdf
HughFromAlice
QUOTE (fredk @ Feb 19 2009, 03:18 AM) *
conference abstract:


Very interesting abstract. I'm hanging out to hear the full exposition at the conference. This is an important topic with wide implications. Well, they say they have a smoking gun, and let's hope it doesn't turn out to be the smoky sublimation from an ice pistol (sorry I couldn't resist!).

This is basically the story of the photos of two spheroids on the legs of Phoenix. From these photos it looks like a smaller spheroid could have merged with a larger one just below it. For a really good enhanced photo - by HortonHeardAWho - of Phoenix leg and spheroids go to http://www.flickr.com/photos/hortonheardaw...392520/sizes/o/

From my amateur level of understanding the key underpinning general points are that: -
a. The index of refraction of liquid water is larger than that of water ice. [Thus - in these photos - a darker spheroid is likely to be liquid.]
b. If the spheroids were made up of supersaturated aqueous solutions they would grow due to attracting atmospheric water vapour hygroscopically (deliquescence).
c. If they were made up of ice, they would sublimate and so would shrink. [Counter argument: Alternative explanation for growth - water vapour from ice below Phoenix could have sublimated and recondensed on ice spheroids on the relatively cold (in shadow) legs faster than the spheroids were sublimating].

However, the spheroids are highly like to be liquid as: -
1. The fact that shapes observed were spheroidal suggests the presence of the liquid phase. (They could have gone through a number of freeze/thaw cycles).
2. The small upper spheroid darkened between photos. This suggests it changed phase from ice to liquid.
3. The spheroids look as if they joined between photos with the upper spheroid reduced in size afterwards (actual joining not observed). Thus they moved. Therefore they were liquid. [Counter argument - changing light between photos only gives the illusion of movement.]
4. Growth is suppressed in the smaller upper spheroid left behind.......suggesting that when it moved most of its salts were carried with it. [Implication - as a less concentrated solution it froze. This runs against the counter argument in a. above which indicates it should have grown].

Any experts out there, please feel free to correct me!
Juramike
QUOTE (HughFromAlice @ Feb 21 2009, 04:44 AM) *
4. Growth is suppressed in the smaller upper spheroid left behind.......suggesting that when it moved most of its salts were carried with it.


The growth rate suppression is the part I don't quite get.

In the scenario where the two spheroids merged, as the two spheroids joined, the capillary action should have sucked the bulk of the initial upper drop into the lower drop. The uppermost part of the drop would have clung (hanging on for dear life) to the surface of the strut.

The initial upper drop salt concentration should have been uniform across the drop. So when it got ripped apart, the salt concentration in the remaining part of the upper drop should have been the exact same as the part of the upper drop that joined the lower drop.

I *think* that assuming an equilibrium, the salt concentrations of all the drops should all be the same. So the size of the drop should only be dependent on the amount of initial salt that nucleated the deliquesence.

So after the merge/ripping apart, the small remaining upper drop will have a smaller absolute quantity of salt than the big lower merged drop. (The concentration of the two drops should be the same).

If at the time of merge/ripping apart all the drops were close to the maximal final concentration, then the growth rates for all the drops would be pretty small.

So after the merge, did all the drops grow faster than the remainder upper drop? Or were all the growth rates similar (if at all, the merge could have happened close to maximal drop size)

-Mike

[EDIT: Using the images in the abstract, it looks most of the neighbor drops increased ca. 10% from Sol 31 to Sol 44, but the remainder drop didn't appear to increase. I'm baffled.]
Juramike
Oh wait! I get it! Here's a possible mechanism for shrinkage of the remainder:

If the drop was cooling before it merged, then ice would have been crystallizing out of the solution! (refer to simplified phase diagram Fig 1 in abstract)

The drop would thus be non-uniform, a mixture of solid precipitated ice and salts in solution. I'd assume that the ice crystals would nucleate and form at the surface imperfection of the lander strut. So at the time of merge, the salt solution would be pulled over to the big drop, but most of the ice crystals would stay behind with the remainder.

So at the instant of the merge, the salt concentrations of the remainder and merged drops would be the same.

But after warming, and melting of the upper remainder's ice crystals, the salt concentration would be too dilute! Thus water could evaporate off the upper remainder drop until the preferred equilibrium concentration was reached. The remainder drop would shrink!

-Mike

[Now if I understand this right, it should also be possible to imagine a scenario/conditions where salts would have been precipitating at the time of merge. This would cause a remaining drop to grow faster than expected.]

tfisher
If this really is liquid water, it would be a tremendous discovery. It seems a pretty hard conclusion to draw from three* monochrome and fairly low resolution images, with theorizing alone to back up the interpretation. I would really like to see laboratory replication of all of the lines of evidence that it is suggested that we observe in these images. For starters, what should be a pretty easy experiment: prepare a candidate perchlorate brine solution and a controlled experiment box which can replicate the temperature and pressure of the martian pole. Spray the brine on a metal pipe and take photographs under various lighting conditions. Compare with the images from Phoenix. Can you make spherules which look the same? Show clearly how to distinguish between lighting changes and motion and growth/shrinkage of droplets. Try doing the same thing with frozen droplets. Is there something that distinguishes the liquid from the frozen droplets in a still photograph? For a more advanced test, try to demonstrate the effects claimed as "smoking gun" signs in Renno et. al.'s abstract: if temperature, pressure, and humidity are varied over a cycle consistent what was observed by Phoenix, droplet growth is suppressed on material left behind by a droplet that merges with a neighbor; droplets grow selectively where the pipe is splashed with perchlorate salts; and their sizes and growth is proportional to their volume.

I'm really excited about the possibility of liquid water on mars today, but extraordinary claims require extraordinary evidence. So far this looks more at the level of (highly educated) speculation than an airtight demonstration of fact.

(*can any of the image guru's tell me if there really are only 3 images of that strut? Or are there more that just weren't selected for the comparison, because lighting conditions differ or something?)
serpens
A couple of very good points were made over on the baut forum, Phoenix Mars Results thread that warrant repeating here.

In the few seconds of the landing cycle the environment under the lander was high temperature (1200k) and high pressure Ammonia/Nitrogen from the exhaust. This temperature would have broken down perchlorates and vaporised part of the ice layer. Water vapour and dust mixed with the extremely hydroscopic ammonia provides for some interesting products. We can have no certainty over what the the deposits on the strut are made up of, but a possible ammonia water solution, concentration unknown makes for some interesting possibilities.

But the key point made is that the deposits are an exotic phenomenon attributable to the lander - not the Martian environment, and have no relevance to the Martian environment..

(cr Vincent Chevrier, BrianC and Nilrem on baut)
HughFromAlice
QUOTE (serpens @ Feb 27 2009, 11:20 AM) *
A couple of very good points were made over on the baut forum, Phoenix Mars Results (cr Vincent Chevrier, BrianC and Nilrem on baut)


Welcome!!! Thanks for posting. Baut comments are v interesting.

There is a similar interesting discussion on space.com forum. http://www.space.com/common/community/foru...ryCurrentPage=0


Upcoming Lunar and Planetary Science Conference abstracts can be sourced from here http://www.lpi.usra.edu/meetings/lpsc2009/pdf/program.pdf - Interesting looking papers - March 23 Phoenix: Exploration of the Martian Arctic - also - Phoenix: Soil, Chemistry and Habitability. Lots of poster sessions on Mars and other interesting stuff. Is any of this going to be put out as a webcast?
djellison
What has irked me is that the media, and even specialist (should-know-better) media have been pushing this as 'liquid water found on Mars'.

No it wasn't.

It was found on Phoenix. Several hundred pounds of metal and wires that expended most of its energy budget keeping itself warm, having blasted the surface with >1kdegC thruster exhausts. Those droplets tell us very very little about Mars. They tell us about Phoenix.


Doug
Juramike
Well...it does tell us quite a bit about Mars, actually.

It shows that at least under special surface conditions, atmospheric water can condense (deliquese) onto exposed residual salts.

Can those special conditions also exist naturally on Mars?
How abundant? (thermal inertia of substrata?, regional salt types with similar chemical properties?)
How often? (seasonal?, certain times of day?)
Fran Ontanaya
The most similar natural phenomenon to the landing could be the small meteor impacts.
imipak
Getting irked at mass media representation of a specialist area where one is better informed than the hacks churning the stuff out is a short-cut to a broken liver!
nprev
Today's lead story on Spaceflight Now; major paper re liquid water forthcoming? Presented a bit sensationally though, I'm afraid.
imipak
It's that man again (Craig Covault), and that image looks strangely familiar too...

Edit: nprev - the major paper is "PHYSICAL AND THERMODYNAMICAL EVIDENCE FOR LIQUID WATER ON MARS?" - abstract (which is a paper in itself) is here (and was linked above ;p ) coming at LPSC 2009.
Greg Watson
Salty Tears

So it was water on the landing legs................

Greg
ConyHigh
QUOTE (Greg Watson @ Mar 19 2009, 02:50 PM) *
Salty Tears

So it was water on the landing legs................

Greg


Nilton Renno is likely in the minority, despite the fact that a number of the Phoenix Science Team, including the PI, signed on to the paper. Next week's discussion should be interesting.
nprev
Thanks for the link!

The article reminded me of the atomic force microscope as well. Have there been any summaries published yet concerning the AFM's findings & performance? What little I've seen to date has been fascinating, but haven't seen any definitive science results from it yet. (Been assuming that the AFM was primarily intended as a tech demo, anyhow.)
Zvezdichko
Dear friends,

I'm sorry if my question comes off-topic, but I don't know about a better place to ask. My question is - are there any copyright issues if I decide to use graphics and charts publishes on the website of NASA in my own scientific articles in a peer-reviewed journal?

Thank you in advance...
Deimos
QUOTE (Zvezdichko @ Mar 20 2009, 01:58 PM) *
My question is - are there any copyright issues if I decide to use graphics and charts publishes on the website of NASA in my own scientific articles in a peer-reviewed journal?

Usually, the materials presented on the NASA and phoenix.lpl.arizona.edu public sites are copyright-free. Other sites, maybe, maybe not. They usually have a credit associated with them that must be passed on (essentially, part of the proper citation). You cannot transfer copyright to any journal--which may be a stumbling block--since you do not have copyright. Look for any license info at the sites; the best option is to get things through planetary photojournal, so you know they are "released" products.

That said, it's risky. You generally don't know what was done to make the chart, what simplifications were done for public accessibility or to make a specific point that was important at the time but is now irrelevant. Things that were not the emphasized result may be less accurately portrayed. You don't know where PIO simplified or changed something to make it "better" if less accurate. Even with images, significant processing may have been done (or conversely, may be appropriate but not done) and you may not know what that was. Depending on the point being made, that may or may not be important. [I recently tried using the released uncalibrated RAC images of the struts to look at the so-called "droplets"--they are useless and misleading compared to the PDS images.]

It is especially risky using this info for a major point. Obviously publishing your discovery of perchlorate based on the charts would be bad. But even where you are firmer moral ground (ie, showing charts as evidence of the NASA discovery) you are on shaky scientific ground. Little or nothing on those sites has been peer-reviewed. Peer-review is happening. Some results may be reversed (note--this is not deliberate foreshadowing, just a general statement of the process). Most editors and many reviewers will be aware of these risks. Frankly, you should be sure they are if you do such a thing, so that they go into it with their eyes open.

There is a further reputation risk--people who prepared a chart will justly feel a certain sense of entitlement to publish the information in it, and to draw any conclusions that may be drawn from it. Once they have published, you may find their analysis incomplete and build upon it. But, for instance, to discuss implications of the pH measurement, or the TECP measurements, or many other things, you would be directly competing with the papers now being written by those who made the measurements, who may have the same ideas--or better ones--even if they didn't say them in a press release.

The best path is to wait for publications. 4 papers have been submitted to Science and several are about to start the long journey through JGR. Sorry if this seems overly pedantic or over-the-top compared to your intended use. But many of us recall that the first peer-reviewed publication of hematite concretions on Mars was not by a MER team member, it was based on press conferences. This caused some reluctance to release certain details of Phoenix discoveries; further incidents could restrict the information flow from this kind of mission.
Zvezdichko
Thank you for your long answer!

I won't publish an article if there are problems of this type. I don't like taking risks. Anyway, I never intended to claim that I made a discovery they actually made (for example, perchlorates)... I intended to make my own conclusions that are unique. I will wait, as you suggested.

I am aware that some agencies allow using their data for scientific research. For example:

http://wms.selene.jaxa.jp/selene_viewer/terms_of_use_e.html

... but obviously you have to contact the agency and claim the following: "This research made use of the lunar orbiter SELENE (KAGUYA) data of JAXA/SELENE.”

So you have my promise - I won't publish any data for the moment.
Paolo
The traditional Science issue presenting preliminary results from Phoenix will be out tomorrow Friday 3 July.
Watch this space!
Phil Stooke
Some nice new images from these papers on the Phoenix image gallery site, especially panoramas of the trench area.

Phil
HughFromAlice
Has anyone read the Phoenix papers published by Peter Smith et al. - in this current issue of Science?

The Abstract: "H2O at the Phoenix Landing Site - The Phoenix mission investigated patterned ground and weather in the northern arctic region of Mars for 5 months starting 25 May 2008 (solar longitude between 76.5° and 148°). A shallow ice table was uncovered by the robotic arm in the center and edge of a nearby polygon at depths of 5 to 18 centimeters. In late summer, snowfall and frost blanketed the surface at night; H2O ice and vapor constantly interacted with the soil. The soil was alkaline (pH = 7.7) and contained CaCO3, aqueous minerals, and salts up to several weight percent in the indurated surface soil. Their formation likely required the presence of water".

Snowfall blanketed the surface at night!!!?

There's a nonsensational well written article in The Arizona Republic that's worth a quick read on where the Phoenix team are up to - http://www.azcentral.com/arizonarepublic/n...3.html#comments "One lingering question Smith hopes to solve with more study of the data is whether carbon-based organic molecules, the chemical building blocks of life, are present in the soil". But the mission is out of money and they will have to get grants to do this. Very worth keeping an eye on.
HughFromAlice
I've just seen that NASA have published a good summary at http://www.jpl.nasa.gov/news/news.cfm?release=2009-106

It opens with "Favorable chemistry and episodes with thin films of liquid water during ongoing, long-term climate cycles may sometimes make the area where NASA's Phoenix Mars mission landed last year a favorable environment for microbes".

I thought the following was particularly interesting "snow (was detected) falling from clouds...............(they reported that) further into winter than Phoenix operated, this precipitation would result in a seasonal buildup of water ice on and in the ground". Not just virga!
HughFromAlice
I reckon that Phoenix was a second hand mission that produced first class results!

I haven't got to the Science articles but this was an informative popular media article from CBC (Candian Broadcasting Corporation) http://www.cbc.ca/technology/story/2009/07...way-clouds.html

'A few times, around 5 a.m., streaks indicating precipitation appeared in the signals. In one case, the snow fell to the lowest level detectable by the instrument — about 50 metres above the surface.......would have continued to descend through the saturated air to reach the surface.........."It would look like frost," he* said.' *Jim Whiteway from York Uni, team leader.

To me, this is an amazing discovery. I start thinking about when the obliquity of Mars was different....thinking and thinking!!!!!!!!
Gsnorgathon
And for those of us in the hoi polloi without Science subscriptions, the JPL press release.
Phil Stooke
Slightly off topic here, but I was looking through the Analyst's Notebook for Phoenix on PDS... I'm sure there used to be a section giving the names of rocks etc. with a reference image. I was trying to assemble a map of the site with all the named rocks etc. I'm not talking about the rocks right in the sample field, but out beyond that. Now I can't find that section. Does anyone know if there is any information out there that I'm missing?

Phil
Phil Stooke
OK folks, answering my own question here...

The names can be found in the Sol Summaries area of the Analyst's Notebook. Select any sol to get started, then in the Report window, choose 'Features and Targets'. You get a list of feature names which links to identifying pictures and other information. It just needs to be combined with a panorama to make a map with placenames. It's a future goal of mine, it won't be done soon. (but feel free to do it for me!)

Try, for instance, the rock Midgard and the polygon trough Land of Oz. They are clear enough, some others are not.

Phil
Den
QUOTE (Greg Watson @ Mar 19 2009, 11:50 PM) *
Salty Tears

So it was water on the landing legs................

Greg


Temperature range measured during Phoenix mission is -19.6 ... -97.7 C.

How these supposedly liquid droplets acquired so much salt to not freeze at such temperatures? Soil doesn't seem to have that much salt there, right? It's about 1% salt, not 100% salt. And even if it would be 100% salt, how salt was supposed to get on the leg, and stay there? Rocket exhaust tend to blast things away, not deposit dirt on things.

We have winter now in Northern hemisphere on Earth, and today I have about -10 C where I live. It is balmy by martian standards, yet I definitely see no liquid water anywhere outside - only ice and snow. Phoenix was colder that this, most of the time MUCH colder.

I saw such spherical droplets before. I even remember where: in the old fridge of my parents. It was before the era of self-defrosting fridges.

They were made of ice, and despite this, they were slowly changing their shapes over days/weeks.

My theory:

Landing of Phoenix exposed some ice. Also, it was the mid-summer. At this time of year, the near-surface dirt should be releasing water ice adsorbed during a long, dark, *COLD* polar night. So the air is relatively water vapor rich. This water, apparently, was condensing on the legs, and at times (-19.6 C) again sublimating - migrating.
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