I'll buy the education, and maybe the birth, but the "multi-million year Mammalian evolution" is a bit much. Future humans raised on Mars will/would have just as "instinctual" a knowledge of how Martian surface materials behave as we Earthlings do about the way materials behave on Earth. It's just a matter of repeatedly observing conditions. I'm sure that some people who move from the tropics to a temperate zone are shocked to discover that water falls from the sky as frozen crystals at some times of the year, but they are not evolutionarily conditioned to be unable to learn how snow and ice behave. Human minds are very capable of adapting to circumstances.

Adapting to the near vacuum of Mars would certainly take a few repeating observations!

Drag a fifty pound wheel across your hand slowly, the heating can be more.
In any case assuming salts, daytime temperatures and pressures could already be within the range for liquid water.


Bob Clark

In discussions on the internet one should always endeavor to maintain civility in your discussions.
But I have to say: they HAVE been detected from orbit.
In the thread to the sci.astro post I linked to above I discussed this further. To summarize, the Mars Odyssey GRS spectrometer team found seasonal variations in the amount of water close to the surface. They concluded this is due to ice or frost deposition including at near equatorial latitudes.
And both MGS and Mars Express found seasonal variations in the infrared spectral signature of water including at near equatorial latitudes. The MGS team concluded this is due to seasonal variations in the bound water content. I argue this overwhelming implies there are seasonal variations in the liquid water content at the surface to form the seasonal variations in these hydrated minerals.
The Mars Express team argued as did the Mars Odyssey GRS team that the seasonal variations are due to frost/ice deposition. But this deposition occurs even during the seasonal periods the daytime temperature would be within the range for liquid water.

I discuss this here:

From: Robert Clark
Date: Sat, Feb 11 2006 9:32 pm
Email: "Robert Clark" <rgregorycl...@yahoo.com>
Groups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.mineralogy
Subject: Re: Could We Make A "Solar Still" On Mars?
http://groups.google.com/group/sci.astro/m...5e5bae350f8c285

I must say I find this to be of bombshell importance. I'm quite surprised there was no discussion of this on the online discussions of the 2006 Lunar and Planetary Science Conference results.


Bob Clark

Under 1/3rdG , we're talking less than 10kg per wheel, spread over something like 50-100 sqcm. Take a 10kg weight, drag it thru sand, very very slowly, and the net result is NOTHING. If there's any heating at all, I'd be astonished if it was more than a single degree. To suggest that the friction of wheel drag would cause heating to generate liquid state water is just silly. Consider the daily temperature swing, it's already 50 degrees+, and if you include the fact that we're approaching winter - then we'd have had much warmer temperature in the last 300 sols than anything the frankly laughable concept of wheel drag temperature increases.

If one or two degrees now can liberate liquid water onto the surface - then Gusev would have been a muddy bog for the past 300 sols.

You're just grabbing at straws.

Doug

On Mars, given the reduced gravity, I believe there is far less than 50 pounds per square unit (use which ever you prefer) exerted on the surface. I Did the rough math once but don't have it handy.


In any case the surface of Mars is routinely heated above 32ºF by solar heating, I would assume this heat would easily transmit through the upper few inches of soil, and any water would volatilize.

I believe any water this close to the surface, as seen in data from orbiting spacecraft exists only hydrated minerals, that is to say water molecules bonded to and trapped in mineral structures.

I could be dead wrong on any or all of this, so take it for what is.

46 images down from spirit, I guess this means that Odyssey is back.

Or they just did a 4 hr DTE HGA pass and her battery's now flat

The same site at which you can get UHF session data, also has uplink data for Odyssey. It's not up to date yet, but this is what was done last time Odyssey safed.


Doug

Well I don't agree with you on the effect of this pressure and dragging. Keep in mind we're not talking about inch thick ice here. We considering interstitial ice layers that may be on the order of 10's to 100's of microns thick. This is on the range of the thickness of a snowflake.
Also remember the wheels are black so will absorb more heat. And the rims at least are metal which will also cause more heat to be absorbed. Now imagine these twenty pound wheels, warmer than surrounding temperatures, scraping across snowflakes on the ground.


Bob Clark

I had suggested that one method to observe indications of moisture by the rovers would be to cover an area at night (to preserve deposited frost/ice) and uncover it in the morning:

From: Robert Clark
Date: Thurs, Jan 19 2006 12:15 pm
Email: "Robert Clark" <rgregorycl...@yahoo.com>
Groups: sci.astro, alt.sci.planetary, sci.physics
Subject: Re: Could We Make A "Solar Still" On Mars?
http://groups.google.com/group/sci.astro/m...45193664ad43276

I was wondering if this is what happened with this material revealed in the trench dug by the stuck wheel.
Is there a way to check these data streams to see at what time the wheels were left in place and what time they were moved?




Bob Clark

Let's go totally and utterly nuts - let's say the temperature increase is as much as 5 degrees ( I doubt it would be 1/10th of that)

You're only raising things to a temperature they would have exceeded, regularly, for prolonged periods, all summer. If you're suggestion is that wheel friction is causing an increase in temperature of a few degrees, thus melting ice content of the soil, then that same ice would have been melted just by the warmer temperature of the summer, for hundreds of sols, across the whole planets equatorial regions.

Doug

I agree, Doug.

In fact, they've been incidentally doing that for some time by leaving the instruments in contact with the soil for overnight measurements.
This image from SOL 65, a day which Spirit spent "analyzing soil targets with the alpha particle x-ray spectrometer, Mössbauer spectrometer and microscopic imager," suggests that some interesting surface changes took place.

Whether that smooth white surface is due to mere compaction by pressure or to water vapor or chemical transport I leave to people who got further along in chemistry than I ever did. I presume the Mössbauer and APXS results from SOL 65 are available by now for those who are interested.

Moving a wheel through talcum powder (which has probably far larger grains compared to this stuff) is not going to get you any heat worth talking about.

Theoretically, yes: The grains collide, so frictional heat must be generated. Theoretically yes: there's interstitial water in the salts, so this can be liberated by this "destruction".

Practically, no: I bet we're talking several molecules here. Not an amount that is detectable at all !

Besides, the only situation that (to my opinion) can generate heat with respect to the stalled wheel is when scrapping it along bedrock. Very localized for a very short period of time....

At this point, I don't believe the presence of the ice/frost is theoretical anymore. All the current landers and orbiters confirm it is there.
We can debate about the accuracy of the model. In any case I believe that daytime temperatures alone with the presence of salts are sufficient to melt this ice seasonally.


Bob Clark