Water on Mars - Page 11

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Barsoomer


Posts: 344

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PostPosted: February 29, 2012 11:17 PM 

The relevant factor is the vapor pressure. Salts like calcium chloride result in a very low vapor pressure, which may be lower than that of the atmosphere.

> Spirit showed that the atmosphere is the dessicant as salts lost moisture once the protective regolith was breached.

Even if the soil vapor pressure is higher with one salt in one location at one time, that does not imply the same is true for all salts at all times in all localities. In fact, Gusev is thought to be drier than Meridiani; for example, frost was never seen at Gusev.

> We have seen no indication whatsoever of moisture at Meridiniani

We have seen dark-toned patches in the midst of light-toned soil. We have seen rover tracks in which the churned soil has a "splattered" appearance. We have seen dark areas emanating from crevices on the rover deck.


Barsoomer


Posts: 344

Reply: 202



PostPosted: February 29, 2012 11:24 PM 

Spirit showed that the atmosphere is the dessicant as salts lost moisture once the protective regolith was breached.

By the way, that shows the salts had moisture to lose. Where do you think that moisture came from?

LWS


Posts: 3062

Reply: 203



PostPosted: March 1, 2012 12:35 AM 

Barsoomer; It not only showed that salts, or the area immediately below the surprisingly springy soil surface, had moisture but that the major point that Serpens and some others use to deny the presence of water at both gusev and meridiani is moot.

That is that all the water in the soil suggested by the orbital remote readings over Mars (up to 15%) is bound in immovable hydroxyl ions. Not true, the gusev discovery of salts almost at the surface and their quick loss of water to the atmosphere showed clearly that there is an exchange of water between the atmosphere and the Martian surface and ALL the visual clues pointed to that from the very beginning of the Spirit and Oppy campaigns.

Once again, there are geologists who have accepted the myth that Mars' surface and near surface is completely devoid of water and they selectively exclude any evidence to the contrary from their and, by ridicule, from anyone else's consideration.

To add insult to injury, Serpens in his inimitable style, goes the extra mile to declare ad nauseum that everything about mars and water has been discovered already and that no new findings are possible. Anything that points to those muddy spots being indeed mud is swept aside or ridiculed while any obscure model that hints that mars surface has been bone dry for billions of years is accepted with open arms as the best science.

Any winding of water bands by the APXS is interpreted as hydroxyl ions. There is a strong possibility that much of the apxs results have been showing water, in for instance the rat scrapings and the exposed surfaces of the evaporite rocks, but that wouldn't fit the paradigm, so it is ignored or explained away.

Winston

John Henry Dough


Posts: xxx

Reply: 204



PostPosted: March 1, 2012 1:55 AM 

Winston,,Your comments are well and easily understood,and enjoyed.Ignoring the serpens data,,,I also
have come to believe my eyes.I add that
MPJ,,,posting that link is the most exciting thing I have seen here in many moons.
Yes.

Now,,Sir,,how about some more pretty pictures?
Seems you are currently the MRB photographer?
Respectfully,
John
btw:I could be wrong but I don't' think anyone is watching the server.

Serpens


Posts: xxx

Reply: 205



PostPosted: March 1, 2012 2:06 AM 

Barsoomer. At Gusev the regolith cover which has a high thermal inertia resulted in a stable environment under the surface. Perhaps you may like to read up on hydration states and associated stabilities. Such protection occurs on Earth with change once exposed to the atmosphere. Blood Falls at Taylor glacier (dry valleyss) is one example as is the kieserite found in German salt beds.

At Meridiani there is kieserite at the surface and this means no moisture. Keiserite is a dessicant of choice and if there was any moisture then it could not exist.

"Intuitive Observations" - observations based on what one feels to be true even without conscious reasoning. This non scientific approach is what got Levin into trouble with his interpretation of water pools at Endurance. Dark patches in tracks attributed to water (that doesn't sublimate with time) rather than material differences in the regolith sediment. Mud in tracks. The identical intuitive reasoning as that behind the ludicrous conspiracy theories that man never landed on the moon because the footprints are so clear, which means that they were made in damp soil. Yeah...sure.

Don't be ridiculous Winston. I have never indicated oin any way that all to be found on Mars has been discovered. But I have said that there has been no indication of water or life at Gusev or Meridiani.

MPJ


Posts: 250

Reply: 206



PostPosted: March 1, 2012 4:36 AM 

"But I have said that there has been no indication of water or life at Gusev or Meridiani."

Interesting (unsupported?)thesis based on robotic exploration incapable of directly detecting life nor water!
Has anybody seriously looked for both yet by squeezing out relevant data besides the geology centered approach?
What will happen if an expert team of astrobiologists would deeply analyze the MER data in the course of a good funded study? But would you allow that or would you ridicule any such afford in the first place? Smile

Serpens


Posts: xxx

Reply: 207



PostPosted: March 1, 2012 5:57 AM 

MPJ. Interesting argument there. After a number of extremely successful NASA landers the result is nil indication of life or water. Not unsupported, just a basic statement of fact. But a wealth of scientific information has been gained and this is a good return for resources expended.

Satellites cannot detect life but can detect water. Result nil - including in areas of slope streaks. NASA keeps astrobiologists on staff and as you are aware funds many of the extreme environment studies. Mission data available has been available to the astrobiologists on the payroll and your allegation that the information had not been deeply analysed is really silly. On a purely economic basis, return on the not insignificant funding allocated to astrobiology - nil.

I do not in any way begrudge the funding allocated to astrobiology, any advance in scientific knowledge has value, but please do not try and pretend that the nil result is just because no-one investigated. Nor do I subscribe to the conspiracy theories espoused on this site that NASA covers up evidence of life on Mars. But when push comes to shove with respect to allocation of the severely reduced funding available to space - I would rather see astrobiology rather than hard science cut.

MPJ


Posts: 250

Reply: 208



PostPosted: March 1, 2012 6:51 AM 

Serpens, ok at the above. We all know that science is not and should not be a democratic process based on consensus but i really would like the goals of scientific exploration being decided by a more democratic process and a broader audience.
Today i see a dramatic domination of the NASA (unfortunatly the only agency which is or was able to conduct deep space planetary missions) Mars program by planetary geologists mostly excluding other fields of study like chemistry and of course life sciences / astrobiology. Nasa astrobiologists - as you stated - are grounded to Earth researching extreme life which i dont agree with as the extreme life research is mostly done by "ordinary" microbiology scientists at their specific fields. Astrobiologists should get the opportunity to mount their instruments to deep space exploration and shouldnt be left out like it was the case with all past Mars missions after Viking.

Regarding water on Mars (topic here) i see a shift now in the Nasa community advertising a sterile Mars to move away from the statement "life is not possible on Mars" to "there is no current water on Mars" - interesting isnt it? Smile

Barsoomer


Posts: 344

Reply: 209



PostPosted: March 1, 2012 11:25 AM 

The Gusev finding shows that there is moisture that could be mobilized by life just under the surface.

Also, it seems unlikely that a "regolith cover which has a high thermal inertia" would be enough to protect a cache of moisture for 3 billion years. That implies a recharge mechanism within relatively recent times. Indeed, the MER team concluded as much in their analysis of salts in Scamander crater.

LWS


Posts: 3062

Reply: 210



PostPosted: March 1, 2012 12:55 PM 

Here's extracts from the summary of Spirit's operations at Scamander crater

Spirit Mars Rover Mission: Overview and selected results from the northern Home Plate Winter Haven to the side of Scamander crater

This paper summarizes Spirit Rover operations in the Columbia Hills, Gusev crater, from sol 1410 (start of the third winter campaign) to sol 2169 and provides an overview of key scientific results............ Silica-rich nodular rocks were discovered in the valley to the north of Home Plate. The inoperative right front wheel drive actuator made climbing soil-covered slopes problematical and led to high slip conditions and extensive excavation of subsurface soils. ....... Examination of the materials exposed during embedding showed that Spirit broke through a thin sulfate-rich soil crust and became embedded in an underlying mix of sulfate and basaltic sands.

The nature of the crust is consistent with dissolution and precipitation in the presence of soil water within a few centimeters of the surface.

The observation that sulfate-rich deposits in Troy and elsewhere in the Columbia Hills are just beneath the surface implies that these processes have operated on a continuing basis on Mars as landforms have been shaped by erosion and deposition.

No similar set of circumstances have so far occurred with Spirit. Therefore for Serpens to appear to conclude that a similar situation with sulphates might not exist at meridiani is disingenuous at the least.

Winston

LWS


Posts: 3062

Reply: 211



PostPosted: March 1, 2012 1:00 PM 

Oops! That should have been

No similar set of circumstances have so far occurred with Opportunity.

Winston

LWS


Posts: 3062

Reply: 212



PostPosted: March 1, 2012 8:46 PM 

Anybody remembers the microcraters and the puddled looking depressions seen quite often on Oppy's intercrater runs. They might have been examples of salty soils that had captured the sparse atmospheric water.

Winston

Serpens


Posts: xxx

Reply: 213



PostPosted: March 1, 2012 8:55 PM 

Barsoomer. The ferric sulphates uncovered at Tyrone would have been formed by evaporative or diagenetic processes and, with a host of other indicators, prove the presence of early water around home plate. One important aspect of ferric sulphates is that they are hygroscopic, although most hydration phases are stable in Martian conditions.

The most likely ferric sulfate for Tyrone is ferricopiapite which can dehydrate at temperatures close to zero celcius. The dehydration occurred once the surface was breached so prior to that the sulphate was protected.

Winston. Magnesium sulphate also has complex hydration/dehydration processes. But kieserite is a very clear indicator that there is no water.

Barsoomer


Posts: 344

Reply: 214



PostPosted: March 26, 2012 3:43 PM 

http://io9.com/5896293/evidence-is-piling-up-for-water-flowing-on-the-surface-mars

The title says it all. Flowing water is still the best explanation for Transient Slope Lineae.

Barsoomer


Posts: 344

Reply: 215



PostPosted: March 26, 2012 4:09 PM 

link

Also

http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1856.pdf
http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2072.pdf
http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1787.pdf

Ben


Posts: 2270

Reply: 216



PostPosted: March 27, 2012 12:41 AM 

Barsoomer; One aspect that none of the researchers considered is that these slopes are composed of a layer of porous, granular material that remains because the current slope does not exceed the angle of repose.
Being such, it is unlikely that liquid would ever reach the surface of the slope and would instead move downward, below the surface, on the first impermeable layer.
Second, if somehow, a fluid did get to the surface it would soon be absorbed by the porous surface and would not remain on the surface to flow down slope.

Dust on the other hand would not be affected nor would some heavy gaseous compounds.

Barsoomer


Posts: 344

Reply: 217



PostPosted: March 27, 2012 1:10 AM 

Ben, you are positing a theoretical chain of causal mechanisms to reach a conclusion. This kind of reasoning is inherently fragile: it is easy to overlook contravening mechanisms (capillary action, perhaps?).

In situations where the causal mechanisms are not entirely clear, observational evidence must take precedence. The seasonal change aspect is intriguing. Ultimately, spectrographic evidence may provide a definitive answer.

Serpens


Posts: xxx

Reply: 218



PostPosted: March 27, 2012 4:41 AM 

Ben, Right on! The other rather inconvenient facts are the lack of any hydrogen abundance in the streaks which shoudl ecoist regardless of the 'brininess'
and the fact that some originate from the top of sand dunes. of course true believcers will overlook such inconveniences.

Barsoomer


Posts: 344

Reply: 219



PostPosted: March 27, 2012 10:54 AM 

We don't have any orbital instruments with sufficient resolution to measure the hydrogen abundance in the relatively tiny streaks.

Ben


Posts: 2270

Reply: 220



PostPosted: March 27, 2012 1:04 PM 

Barsoomer; These are not theoretical .
They are based on actual field observations I have made at many terrestrial locations.

I have never seen water seeping from the surface of a slope covered by unconsolidated porous material.

I have seen annual seeps from exposed rock cliffs and slopes.
These are related to seasonal precipitation and recharge at a topographically higher surface.
This provides the necessary hydrostatic head to expell the water outward along an impermeable, subsurface barrier that intersects the slope or cliff face.

I don't consider these observations casual and could not be more clear. Shocked

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