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."
Re:Yellow snow! (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.
Re:Yellow snow! (Score:5, Informative)
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.
Re:Aerosol formation (Score:5, Informative)
Exotic snows of the Solar System (Score:5, Informative)
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.
Re:Aerosol formation (Score:5, Informative)
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.
Atmospheric optics info source (Score:5, Informative)
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.
And on Earth? (Score:4, Informative)
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.