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Thread: Mars. Dry after all.

  1. #1 Mars. Dry after all. 
    Forum Radioactive Isotope skeptic's Avatar
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    NASA spacecraft observes further evidence of dry ice gullies on Mars -- ScienceDaily

    It appears that the fresh looking channels and valleys on Mars are caused by seasonal freezing of CO2, not liquid water. Another nail in the idea of finding extra-terrestrial life.


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    Forum Professor Zwirko's Avatar
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    I think the best location to search for life on Mars would be deep underground. The surface, whether dry or intermittently wetted, always seemed to me to be the least likely of places to find Martian biology. As I understand it, there is expected to be a lot of water deep down, in liquid form. I don't know when we will have the resources to drill dozens of 10 km deep holes below the sterile surface; so I see the life on Mars question being with us for centuries to come.

    Regarding, the article: this mechanism doesn't provide an explanation for all water-like features on Mars. The article mentioned gullies and similar features a lot, but not features such a braided channels, deltas etc. Presumably those are far older features?

    I'm sure I've seen recent articles about studies that have seen evidence of recent water-erosion on the surface; I believe they used the same imaging platform as the one in the quoted article. Can't find a useful link right now, however.

    I wouldn't agree that the search for extra-terrestrial life has reached the coffin-building stage just yet. Keep the nails on hold.


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    not ADM!N grmpysmrf's Avatar
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    Quote Originally Posted by skeptic View Post
    NASA spacecraft observes further evidence of dry ice gullies on Mars -- ScienceDaily

    It appears that the fresh looking channels and valleys on Mars are caused by seasonal freezing of CO2, not liquid water. Another nail in the idea of finding extra-terrestrial life.
    unless it's extra terrestrial life that needs CO2 in order to live.
    "Should any political party attempt to abolish social security, unemployment insurance and eliminate labor laws and farm programs, you would not hear of that party again in our political history. There is a tiny splinter group, of course, that believes that you can do these things. Among them are a few Texas oil millionaires, and an occasional politician or businessman from other areas. Their number is negligible and they are stupid."
    President Dwight Eisenhower
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  5. #4  
    Forum Cosmic Wizard
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    Looking at the list of related stories on the page reveals the researchers are enjoying of a lot of confusion about the features they are observing.
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    Forum Freshman jjmckane's Avatar
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    Quote Originally Posted by skeptic View Post
    Another nail in the idea of finding extra-terrestrial life.
    Exaggerated. As terraformer Martyn Fogg has long suggested, underground locations are possible under pressure. It is the pressure that limits liquid water there, not temperature, since ice floats and is an excellent thermal insulator. Temporarily, especially when suddenly exposed in a canyon wall, water would quickly form a heavy ice crust, and that weight would or could provide enough to prevent immediate evaporation. That which did evaporate would decrease the surrounding temperature, causing it to turn to ice. Salt solution would further somewhat the ability, but in secondary fashion, I would think. Think Boyle's/Charles' Laws. Normally ice sublimes directly into gas at 7 mb.

    What they should be doing is looking for rapid geothermal gradient areas on Mars.


    And, yes, they have already found liquid water on Mars, in a way.

    http://24.media.tumblr.com/tumblr_md...tjeso1_500.jpg


    More seriously:

    Ice and Fire Forge A Reservoir for Life on Mars | Astrobiology Magazine
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    Forum Professor pyoko's Avatar
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    Quote Originally Posted by grmpysmrf View Post
    Quote Originally Posted by skeptic View Post
    NASA spacecraft observes further evidence of dry ice gullies on Mars -- ScienceDaily

    It appears that the fresh looking channels and valleys on Mars are caused by seasonal freezing of CO2, not liquid water. Another nail in the idea of finding extra-terrestrial life.
    unless it's extra terrestrial life that needs CO2 in order to live.
    There is plenty of terrestrial life that breathes CO2, let's not forget that.
    It is by will alone I set my mind in motion.
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  8. #7  
    Forum Freshman jjmckane's Avatar
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    Quote Originally Posted by pyoko View Post
    Quote Originally Posted by grmpysmrf View Post
    Quote Originally Posted by skeptic View Post
    NASA spacecraft observes further evidence of dry ice gullies on Mars -- ScienceDaily

    It appears that the fresh looking channels and valleys on Mars are caused by seasonal freezing of CO2, not liquid water. Another nail in the idea of finding extra-terrestrial life.
    unless it's extra terrestrial life that needs CO2 in order to live.
    There is plenty of terrestrial life that breathes CO2, let's not forget that.
    Yes, but C02 is common in the universe at significant pressures. 02 is not, since it quickly oxidizes with a great many objects, including carbon to get C02. This is why a very strong presence of oxygen is tantamount to discovering life at a great distance by exobiologists. The 02 starts to build up unless a trap exists, like iron on Earth or, it is guessed, Mars. But since Mars has no subduction of plate tectonics, the amount of life necessary to develop amounts of detectable 02 would be small due to the lack of serious amounts of 02 needed (the Earth had to unload 02 into the crust for billions of years). So we then focus upon microbes like this one:

    Purple sulfur bacteria - Wikipedia, the free encyclopedia
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  9. #8  
    Forum Professor pyoko's Avatar
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    Quote Originally Posted by jjmckane View Post
    Quote Originally Posted by pyoko View Post
    Quote Originally Posted by grmpysmrf View Post
    Quote Originally Posted by skeptic View Post
    NASA spacecraft observes further evidence of dry ice gullies on Mars -- ScienceDaily

    It appears that the fresh looking channels and valleys on Mars are caused by seasonal freezing of CO2, not liquid water. Another nail in the idea of finding extra-terrestrial life.
    unless it's extra terrestrial life that needs CO2 in order to live.
    There is plenty of terrestrial life that breathes CO2, let's not forget that.
    Yes, but C02 is common in the universe at significant pressures. 02 is not, since it quickly oxidizes with a great many objects, including carbon to get C02. This is why a very strong presence of oxygen is tantamount to discovering life at a great distance by exobiologists. The 02 starts to build up unless a trap exists, like iron on Earth or, it is guessed, Mars. But since Mars has no subduction of plate tectonics, the amount of life necessary to develop amounts of detectable 02 would be small due to the lack of serious amounts of 02 needed (the Earth had to unload 02 into the crust for billions of years). So we then focus upon microbes like this one:

    Purple sulfur bacteria - Wikipedia, the free encyclopedia
    Well, since CO2 is common and so are CO2 breathing life forms (bacteria and plants) then CO2 extrasolar life forms can be quite common. What I said was we don't need to be fixated on O2 breathing life exclusively, nor do we need to turn to terrestrial extremophiles when there is so much very common life that breathes the abundant CO2.
    It is by will alone I set my mind in motion.
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  10. #9  
    Forum Cosmic Wizard
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    Quote Originally Posted by pyoko View Post
    ....
    Well, since CO2 is common and so are CO2 breathing life forms (bacteria and plants) then CO2 extrasolar life forms can be quite common. What I said was we don't need to be fixated on O2 breathing life exclusively, nor do we need to turn to terrestrial extremophiles when there is so much very common life that breathes the abundant CO2.
    I would like to mention the availability of oxygen is not the most critical limit on life. Other elements like potassium and phosphurous are at least as critical.
    Isaac Asimov even went as far as calling phosphorus “life’s bottleneck” when he was writing about it.

    However life as we know it would certainly require liquid water.
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