Is There Water Ice on Mars?

[rewebster]

yeah--but those are ave. temps----you'd have to know the temp and pressure (and the atmospheric concentration of co2) where the thing landed (and the temp of the ground a couple inches down)

 

[B. Elliott]

yeah--but those are ave. temps----you'd have to know the temp and pressure (and the atmospheric concentration of co2) where the thing landed (and the temp of the ground a couple inches down)

Well, you do have to consider the average temps as they change seasonally. That, and I doubt there's drastic changes CO2 movement over a period of just a few hours, or even days. It gives the latitude in the link... 47.2 slightly lower than the Phoenix.

 

[Alienjoey]

Ah, this isn't the first time we've found water on Mars!
http://apod.nasa.gov/apod/ap050401.html

This is certainly an interesting discovery, and evidence is pointing to the likelihood that it really is water!

 

[rewebster]

I think there is water on Mars, but I still don't think those white chunks were (are) water.


You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

 

[B. Elliott]

I think there is water on Mars, but I still don't think those white chunks were (are) water. You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

I think that's been one of the theories so far since Mars atmosphere is over 95% CO2. Allow the atmosphere to be saturated with enough CO2, and you'll have CO2 condensation. And if the atmosphere was actually thick enough, you'd have the pressure available for it ran down as a liquid and flow.

 

[rewebster]

I think that's been one of the theories so far since Mars atmosphere is over 95% CO2. Allow the atmosphere to be saturated with enough CO2, and you'll have CO2 condensation. And if the atmosphere was actually thick enough, you'd have the pressure available for it ran down as a liquid and flow.

I hadn't heard of it before--I'll look around- ...or if anyone else can find it first.

 

[B. Elliott]

Excellent article...

http://www.spacedaily.com/news/mars-water-science-00k1.html

 

[rewebster]

Excellent article...

http://www.spacedaily.com/news/mars-water-science-00k1.html

thanks---good theory---a good 'find', there, B. Elliott ---

-he keeps saying that the valleys weren't caused by 'liquid'--however, I think that there will still be a way for liquid CO2 to flow there--maybe still mixed with that h2o that he mentions. Some of those valleys are (seem) just too much like a 'fluid' erosion, and not a "density flow". Maybe a variation of his idea of underground 'pressure'.

"These flows are part of a suite of "Density Flows", so named because they consist of a dense fluidised cloud that flows downhill as if it were a fluid."

http://www.spacedaily.com/news/mars-water-science-00k2.html

 

[Gokul43201]

I think there is water on Mars, but I still don't think those white chunks were (are) water.


You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

I believe thay have ruled out dry ice:

We can easily and confidently rule out that its carbon dioxide ice," said Lemmon. "There are certainly times of the year that there would be CO2 ice at this location but with the temperatures we are measuring there, it would be the equivalent of water ice existing on Earth at 140 degrees. It wouldn't be there very long, and wouldn't be there long enough for us to take its picture, and it wouldn't last the night. We're very confident this is not CO2 ice.

http://www.universetoday.com/2008/0...ference-update-proof-of-water-ice/#more-15217

 

[rewebster]

I think all they have to do is stick a thermometer down into the 'chunks' the next time they make a trench----

betcha it's dry ice (like a dry ice tundra)


I think the 'surface' temps are probably a whole lot different than even just a couple of inches down on Mars at/near the poles (less direct sun, just like here on Earth). E.g.---how far down is 'frozen tundra' on Earth when its 70-80 degrees F on the surface? --and Mars has a whole lot less atmosphere to aid in the warming of the 'dirt', too.


I wonder how warm the core of Mars is?

 

[jqnsmart]

I think we can definitely rule out carbon dioxide. Mars' atmosphere has a pressure of 0.007 times that of Earth, or 0.007 atm or 700 Pa. At this pressure, carbon dioxide could be solid only at extremely low temperature, close to absolute zero. Even if it could survive underground as ice, it would sublimate almost instantly when coming in contact with the Martian atmosphere.

Water, can exist as ice, because its triple point is at 0.006 atm (almost the pressure of Mars' atmosphere) and about 0 degrees Celsius. This would allow water to sublimate if the temperature rose enough.

This is where I got my info on water and carbon dioxide (I got the atmospheric pressure on Mars from a book):

http://www.uiowa.edu/~c004131a/Phase_Diagrams.html

 

[rewebster]

Today:

"After weeks of testing the soil in the Martian arctic, NASA's Phoenix lander has confirmed through chemical analysis the presence of water on another planet, scientists revealed today."


"The fact that it melted at 0 degrees centigrade leaves very little doubt," said Boynton, speaking at a news conference in Tucson"

http://www.latimes.com/news/science/la-sci-phoenix1-2008aug01,0,3012423.story


"Laboratory tests aboard NASA's Phoenix Mars Lander have identified water in a soil sample. The lander's robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples."

http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080731.html

so...it is water

I think we can definitely rule out carbon dioxide. Mars' atmosphere has a pressure of 0.007 times that of Earth, or 0.007 atm or 700 Pa. At this pressure, carbon dioxide could be solid only at extremely low temperature, close to absolute zero. Even if it could survive underground as ice, it would sublimate almost instantly when coming in contact with the Martian atmosphere.

Water, can exist as ice, because its triple point is at 0.006 atm (almost the pressure of Mars' atmosphere) and about 0 degrees Celsius. This would allow water to sublimate if the temperature rose enough.

This is where I got my info on water and carbon dioxide (I got the atmospheric pressure on Mars from a book):

http://www.uiowa.edu/~c004131a/Phase_Diagrams.html

but there are carbon dioxide polar caps not too far away

 

[jqnsmart]

Sorry it has taken me so long to respond, but I had a problem with my internet company that lasted quite some time. I do, however, feel an obligation to respond. Even thought the polar ice caps are nearby, any carbon dioxide exposed would sublimate almost instantly, especially since it was summer then. In fact the ice caps sublimate in the summer and reform in the winter.