About Martian Ice News

  • Thread starter lwymarie
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  • #26
DaveC426913
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Apparently not the same page, since you seem to persist in wanting to interpret the visual evidence, absent the additional facts relating to time, and pressure and temperature.
No, I do not. You are misreading me.

I thought that that's what you were doing. I was arguing against that.

Not to mention the gamma ray scattering data that chose this landing zone precisely because it was mid-region to the high hydrogen band scattering readings.

To be specific the melting point of CO2 at about 8 millibars is -125C. The weather at the site on Sol 33 showed a temperature range of -80C to a high of -34C with wind out of the SE at 11 to 14 km/h with atmospheric pressure at about 8.3 millibars. Welcome to the land of rapid boil-off CO2.

Now ice on the other hand at -34C - call it 240K has a vapor pressure of about .33 millibar. With the reported wind conditions contributing to accelerating sublimation and the naturally low percentage of water measured in the Martian atmosphere (low humidity) then the kind of shrinkage observed looks to be consistent with it being H2O.

Hence a visual inspection of two photos, showing sublimation over the time period reported should indeed exclude CO2. So much so are the weather conditions unfavorable that it's not clear to me that from the time the trench was dug by the scoop and retracted out of the way that a picture of solid CO2 could have been made exposed like that.

:grumpy: So, we both agree that CO2 is ruled out, right?
 
  • #27
LowlyPion
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So, we both agree that CO2 is ruled out, right?

Yes I would certainly say that CO2 is ruled out by the combination of factors including the pictures (and perhaps not necessarily by one picture alone) that would give clues about time lapse as well as other observations about temp and pressure.

Let me encourage you to be a little clearer in your qualified statements then because as you can see I am easily thrown off in thinking you were saying that CO2 was not in fact ruled out.

Cheers and good wishes.
 

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