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The Dry Ice 'Snowflakes' of Mars

Posted by Soulskill on from the requires-advanced-snowman-construction-skills dept.

astroengine writes "After collecting the vast quantities of data gathered by orbiting Mars spacecraft, MIT scientists have uncovered some rather interesting facts about Martian snow. For starters, as the majority of the Mars atmosphere is composed of carbon dioxide, the snowflakes are made from CO2 ice — basically tiny particles of 'dry ice.' Also, the snowflakes are very small — approximately the size of a red blood cell. 'These are very fine particles, not big flakes,' said MIT assistant professor Kerri Cahoy in a press release. If you saw these 'snowflakes' fall, 'you would probably see it as a fog, because they're so small,' she added."

6 of 44 comments (clear)

  1. Aerosol formation by relikx · · Score: 5, Interesting

    I assume even with the smaller size the mechanics for formation are more or less the same as rain and snow here on earth. If so, it could be possible that microorganisms past, present, or imagined would play a part in the process at times to assist in precipitation. Of course for something to live at temps low enough to live through dry ice formation would be nothing like here on earth, but if they are capable of withstanding extreme conditions that could be a place to find them.

    1. Re:Aerosol formation by theshowmecanuck · · Score: 5, Informative

      I lived a while in Manitoba. When it gets anything below say 28 or 29 below, celcius, there is often a haze in the sky formed by tiny ice crystals in the air. It causes an effect known as "Sun Dogs." When you see sun dogs, you know it is at least as cold as I mentioned.

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      -- I ignore anonymous replies to my comments and postings.
    2. Re:Aerosol formation by TapeCutter · · Score: 5, Interesting

      There is a place called the "Dry Valleys" high in the Antartic mountains that is considered the best terrestrial proxy for Martian conditions. There has been no rain or snowfall there for two million years and it can get cold enough for dry ice to form (whether it does or not I don't know). Of course it has a denser and different atmosphere, but like Mars the humidity is for all practical purposes zero.

      From the oblig. WP article: "The unique conditions in the Dry Valleys are caused, in part, by katabatic winds; these occur when cold, dense air is pulled downhill by the force of gravity. The winds can reach speeds of 320 kilometres per hour (200 mph), heating as they descend, and evaporating all water, ice and snow." Note that it states the ice "evaporates", as with Mars, water ice normally sublimates directly into the atmosphere rather than running off as melt water. Despite having similar tempratures and moisture levels to those found on Mars the WP page lists two groups of bacteria that are native to the area. One group lives inside granite the other underneath a glacier that protrudes into one of the valleys.

      Life is incredibly durable, once it takes hold of a planet I find it hard to believe that anything short of a Venutian style "runaway greenhouse" will erase it. If life did once take hold of Mars in the distant past then I think it follows that it is still there,most probably just below the surface.

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      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
  2. Re:Yellow snow! by wierd_w · · Score: 5, Informative

    Personally, I wouldn't try it, but if you like exposing your penis to pressures so low that the blood inside it boils, while also subjecting it to temperatures so low as to cause the urine to flash freeze before it can leave the urethra, be my guest.

    Not exactly what I would call "fun" myself, but I guess everyone has their kink.

  3. Re:Yellow snow! by ldobehardcore · · Score: 5, Informative

    According to Wikipedia fluids inside the human body don't boil when depressurized from 1atm to 0atm, why would penis blood boil on Mars, which has a higher atmospheric pressure than a total vacuum? Granted, if one were to expose only his penis to the low pressure (strategically placed airlock and gasket I guess...) of the Martian atmosphere he would have the most insane erection of his life as all his blood would quickly pool there. Most likely it would freeze in a matter of a second or two, depending on season and time of sol, then rocket off as warm blood would still be trying to depressurize out of his body in an icy spray.

    On second thought, that'd be an interesting, if horrific way to die.

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    Hectice, baby, Mercator says hello to you
  4. Exotic snows of the Solar System by Sussurros · · Score: 5, Informative

    Pluto has nitrogen snow, carbon monoxide snow, and methane snow.
    Mars only has water snow and carbon dioxide snow.
    Venus though is the coolest of them all because it has lead sulfide snow and bismuth sulfide snow - but only in the cool uplands above 2600m.

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    I said - don't look Ethel!..., but it was too late..., she'd already looked.