What's cooler than being cool?


#1

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#2

Still not as cool as Lemmy…


#3

dang. that’s even cooler than ice cold.


#4

If you had asked me where I thought the coldest surface temperature was on Earth, I probably would have guessed a valley in Antarctica, but I wouldn’t have guessed that it was cold enough to freeze CO2 out of the air.


#5

It’s colder than dry ice cold! (-109F)


#6

hivemind


#7

Ahh, but its not cold enough to freeze it out of the air :slight_smile:

The everyday example:
Water boils at 212f, but condenses out of outside air at 50-80f (depending on humidity).


#8

Wouldn’t that be sweet - dry ice in Antarctica. Trouble is the -109 F sublimation temperature is for pure CO2 at 1 ATM. The partial pressure of CO2 in our atmosphere however is 0.0003 ATM. That puts the deposition temperature far lower than -109 F. Maybe some smart chemist reader could calculate and post the temperature at which sublimation and deposition rates would be equal.


#9

There you go, spoiling facts with science again…


#11

Dang. Having superfine dry ice snow would have been awesome too.

I guess all you can say is you could store Dry Ice in there uncovered without losing too much for part of the year.


#12

You just gotta know that these vallies are full of Things from another age that we’re better off not knowing about.


#13

You can extend that thought to one of the more odd propositions for stopping global warming: build gigantic refridgerators in Antarctica and freeze all the CO2 out of the atmosphere .


#14

So bring an extra sweater, I guess.


#15

At -136, it is somewhere around 1000 ppm http://en.wikipedia.org/wiki/Carbon_dioxide_data

So, not actually too far off


#16

Damnit, you beat me to it!


#17

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#19

The rare Antarctic Valley Hare – the only creature capable of surviving there:


#20

I wasn’t able to find a phase diagram that went cold enough for the given partial pressure, but I think we can interpolate from the graph on this page that it would be about -140 to -150 C (-220 F to - 240 F). So can we get CO2 snow on Earth? Well, the -136 F was at the surface, so it is not entirely conclusive that temps can’t get lower as you go up into the atmosphere. Anyone who has watched it snow when the surface air temp is above freezing knows how this works.


#21

It’s probably a pretty narrow band where it gets that cold. It’s the atmosphere that is shaded from the sun by the nearby mountains for an extended period of time.