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Mars Space Science

The Dry Ice 'Snowflakes' of Mars 44

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."
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The Dry Ice 'Snowflakes' of Mars

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  • by Anonymous Coward

    "Holy fuck we're suddenly on Mars!"

  • Aerosol formation (Score:5, Interesting)

    by relikx ( 1266746 ) on Wednesday June 20, 2012 @12:34AM (#40380927)
    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.
    • Re:Aerosol formation (Score:5, Informative)

      by theshowmecanuck ( 703852 ) on Wednesday June 20, 2012 @01:45AM (#40381327) Journal
      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." [wikipedia.org] When you see sun dogs, you know it is at least as cold as I mentioned.
      • Re:Aerosol formation (Score:5, Informative)

        by Jane Q. Public ( 1010737 ) on Wednesday June 20, 2012 @04:27AM (#40382109)
        Sun Dogs are a form of halo [wikipedia.org], as are rainbows.

        The main difference is, rainbows (and possibly Sun Dogs) are caused by lower-atmosphere particles (or droplets, what have you) while other halos tend to designate upper-atmospheric conditions.

        The higher-atmospheric conditions are well-known and form halos at distinctive angles (i.e., a "10-degree" halo), while lower-atmospheric halos are far more variable.
      • by dtmos ( 447842 ) * on Wednesday June 20, 2012 @06:04AM (#40382661)

        The most useful, entertaining, and educational source, IMHO, for all things optical and atmospheric is the Atmospheric Optics site [atoptics.co.uk] of Les Cowley. Originally built to support HaloSim [atoptics.co.uk] halo simulation software (developed in collaboration with Michael Schroeder), the site now includes photos and physical explanations of everything from green flashes and other refractive phenomena to glories, ice halos (including the types that may form on other planets [atoptics.co.uk]), and rainbows.

        It's the kind of site that nearly everyone finds interesting and, if they're not careful, learns something from.

    • Re:Aerosol formation (Score:5, Interesting)

      by TapeCutter ( 624760 ) on Wednesday June 20, 2012 @05:07AM (#40382305) Journal
      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.
      • This is also where Wolf Vishniac [wikipedia.org] tested the "Wolf Trap" that was to go to Mars on the Viking I lander. The sad tale of it's removal from the flight and his untimely death was chronicled by Carl Sagan in Cosmos [wikipedia.org].

      • Re: (Score:3, Insightful)

        by GloomE ( 695185 )

        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.

        You assume that a "runaway greenhouse" is enough.
        That'd have to be a pretty fast change for life not to keep up.
        Nuke the site from orbit, it's the only way to be sure.

        • Nah, even a good old fashioned global thermonuclear saturation-bombing would only kill the surface life, and if Earth is any indication the vast bulk of the biosphere is actually bacterial chemovores living deep within the planet's crust, possibly even within the mantle. It seems like such life would be extraordinarily difficult to wipe out so long as the planet's core continued to give off heat, and would likely re-colonize the surface in short order unless it was completely inhospitable. Of course photo

  • because no one was there to hear it. *sad face*

  • by Anonymous Coward
    It would be fun to write your name in that snow, as it were.
    • Re:Yellow snow! (Score:5, Informative)

      by wierd_w ( 1375923 ) on Wednesday June 20, 2012 @12:59AM (#40381101)

      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.

      • With very little atmosphere the only significant heat loss would be through radiation. Water requires the loss of a significant amount of energy to freeze.
        As for your blood boiling, it depends if your penis skin can handle the pressure...
      • Re:Yellow snow! (Score:5, Informative)

        by ldobehardcore ( 1738858 ) <steven.dubois@gmai[ ]om ['l.c' in gap]> on Wednesday June 20, 2012 @01:15AM (#40381187)

        According to Wikipedia [wikipedia.org] 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.

      • 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.

        Hey man, don't judge until you try it.

      • Re: (Score:3, Insightful)

        by Anonymous Coward

        Actually, you would be able to pee on mars easily, without very much damage. If you only exposed that single part of your body somehow, and the rest of your body could breath and was at a somewhat normal pressure.

        It would take some time to freeze. The pressure would cause some bruising and an erection (like a hardcore penis pump.)

        Flash freezing requires extremely fast heat exchange. The low pressure and light atmosphere would not do this at all. Humans can survive total vacuum for 30 seconds to a minute eas

        • I was considering more the following, given the mental image:

          AC unzips the space suit, and whips out his johnson.

          Pressurized air from the space suit is forcibly blown out of the opening in the suit, whiping and swirling around said penis, and falling off in pressure as it does so. This is similar to venting compressed gas, such as a compressed air duster. It rapidly chills any surface that the venting gas cloud comes into contact with. Thermal exchange is with this "higher" pressure gas leaving the suit.


        • by mbone ( 558574 )

          From an article in Aviation Week: "The experiment of exposing an unpressurized hand to near vacuum for a significant time while the pilot went about his business occurred in real life on Aug. 16, 1960. Joe Kittinger, during his ascent to 102,800 ft (19.5 miles) in an open gondola, lost pressurization of his right hand. He decided to continue the mission, and the hand became painful and useless as you would expect. However, once back to lower altitudes following his record-breaking parachute jump, the hand returned to normal."

          Note that pressure at 102,000 feet is comparable to that at the lowest places on Mars (i.e., the Hellas Basin).

  • by PPH ( 736903 ) on Wednesday June 20, 2012 @01:30AM (#40381265)

    ... how it would be to ski on.

    • The lubrication in skiing comes from a thin layer of the snow beneath the ski melting, it's the water lubricating you. Im going to assume that thise CO2 is still subliming on mars since liquid CO2 requires atleast 5atm of pressure. Therefore no lubrication even if liquid CO2 acts as a lubricant (does it?). At very low temperatures snow actually becomes incredibly hard to ski on because that thin layer no longer melts
      • That's ice skating you are thinking of. In skiing and snowboarding you actually push the snow to the side (or cut it if you are carving). Thats why you can ski on sand. To state the obvious, you can't ice skate on sand.

        I want to snowboard on Mars! With 0.3g the jumps will be amazing! Also, they have higher mountains.

        • Well obviously - you can't ice skate on snow either. What you need to do is find yourself a nice smooth "frozen lake" of obsidian and some "glass-skates" with heated blades since pressure alone won't be enough to form the molten layer, but then you can knock yourself out with all the melted-and-refrozen sand-skating you want.

      • Not true, actually. While it is true that ice melts under pressure, it does so quite slowly. The mechanisms by which the surface layer of (frozen) water molecules break off and form an extremely slippery lubricating layer between skates and ice is quite fascinating. Not to mention just about impossible to simulate, last I heard.
        So, you can't ski on CO2 because it does not, so far as I know, have any similar surface lubricating properties.

  • by Sussurros ( 2457406 ) on Wednesday June 20, 2012 @02:34AM (#40381545)
    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.
  • What it needs, is a (more energetic?) form of life to turn that CO2, along with other elements, into more organic compounds. This might require energy gathering from more than just photosynthesis.

    I would far rather support genetic engineering in an effort to terraform Mars, than support sterile monocultures with royalty payments by Earthling large, greedy corporations.

    I could go on, but I think I will stop at that.
    • Should have read "... into more organic compounds AND free oxygen".

      After all, that's what Earth plants do. But they have more energy input. So it might have to be some kind of chemical reaction, supplying thermal energy, to allow a catalysis to take place.

      This is not beyond the reach of current technology.
  • And on Earth? (Score:4, Informative)

    by mbone ( 558574 ) on Wednesday June 20, 2012 @09:24AM (#40384127)

    Coldest temperature ever recorded : -89.2 C, in Antarctica

    Sublimation temperature of Dry ice (solid CO2) : -78.5 C (-109.3 F) at atmospheric pressure.

    So, there are places on the Earth where occasionally the temperature gets low enough to precipitate out CO2. I have always wondered if anyone has ever thought to look for it.

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