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# Interesting Physics Question

Discussion in 'The Okie Corral' started by Mabo, Jan 19, 2010.

1. ### MaboWant a beer?

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Hey everyone, I have a physics question that I'm wondering if someone could help me guesstimate the answer to. This isn't a homework problem or anything, just something I'm curious about.

Ok, we all know outer space is very cold, approximately 2.7 degrees K (-270C or -455F). We also know that outer space is very empty, containing only a few hydrogen atoms per cubic meter (while the air we breath contains about 10^25 molecules per cubic meter).

I know that if I were to stand outside in 20F air that I would get cold fairly quickly. If you were to put me in 20F water it would draw heat away from my body about 25 times faster than being in the air alone. So even though space is very cold, it doesn't have many molecules with which to draw the heat from my body. So here is my question...

Assuming I were to leave my space shuttle in deep space and were completely naked how long would it take for me to freeze to death? Lets assume that somehow the lack of oxygen and any pressure affects were the least of my concerns. All I'm interested in is how long would it take for me to freeze to death. Extra points if anyone can put it in the form of being in a similar temperature on earth. For example... Being in outer space would be equivalent to being in -200F air here on earth. I have a feeling there is some sort of formula you can use to solve this problem, I just don't know it. Thanks for indulging my curiosity.

2. ### HerrGlockScouts OutCLM

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You wouldn't. Your blood would boil out of your eyes, ears and nose and you'd bleed to death first. You'd never have a chance to become a corpsecickle until after you were dead.

3. ### Atlastransmogrifier

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Is it cold in outer space?
You must mean deep space, away from the Sun or any other star...

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The plane would take off regardless of the treadmill.

5. ### Atlastransmogrifier

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I think he's saying "just s'pose...", suppose lack of atmosphere were not a problem. In other words, you have a space-suit with air, but it has no insulation value and no heat.

6. ### MaboWant a beer?

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Like I said in my post "Lets assume that somehow the lack of oxygen and any pressure affects were the least of my concerns. All I'm interested in is how long would it take for me to freeze to death. "

7. ### CritiasFreelancerCLM

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A nice cardboard box would protect you.

8. ### Atlastransmogrifier

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Not in a vacuum it wouldn't.

9. ### HerrGlockScouts OutCLM

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Your question has too many variable. Okay, assume all of these people were still alive:

Karen Carpenter would freeze to death long before Isabelle Turell. Devine would live for roughly six weeks before freezing to death, though.

10. ### Atomic Punk

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some good questions. for heat transfer you need something for it to transfer with. and while very cold i imagine it would not be as quick as most would imagine. all the molecules that are there, at least while in shadow ( in light you would get warm real quick) so to freeze you would have to encounter enough 2.7 K molecules to bring you down below 32 F.

so how long? i have no idea, but i hope somebody has a way of finding out, should be really cool

11. ### MaboWant a beer?

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Yes Atlas, I was assuming deep space away from the sun. They say the space around Pluto is 35-40k as opposed to deep space with its 2.7k temperature.

12. ### Atlastransmogrifier

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"I bought a high-end spaceship and it came in a lousy cardboard box" ?

13. ### Atlastransmogrifier

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Edited:
FillYerHands explained it much better.

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Last edited: Jan 19, 2010
14. ### FillYerHandsyou son of a

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Air taking away the heat is just one mode of heat transfer, called Convection. There are 2 more modes, Conduction (where the heat is drawn away through direct contact - think about sitting on ice) and Radiation, where heat goes away in the form of photons. While Radiation is by far the least efficient of the three, given the driving force of over 300 Kelvins (your body temp of 37C (310K) minus deep space) it will happen pretty fast. The rate of heat transfer by Radiation is a function of the temperature to the fourth power (T^4) so the rate won't drop significantly as you cool.

It's a differential equation to work out exactly how long it would take for your body temp to drop from 37 to zero, and I have slept about 10,000 times since I had to do the math. So I leave it to the student to work it out.

15. ### Captain America

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I really miss Karen Carpenter. Richard, not so much.

16. ### Atlastransmogrifier

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17. ### G30Jack.88 Magnum

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How long can a human live unprotected in space?

If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury. Holding your breath is likely to damage your lungs, something scuba divers have to watch out for when ascending, and you'll have eardrum trouble if your Eustachian tubes are badly plugged up, but theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.

Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.

From NASA.gov.

18. ### inthefreyMoved on...

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Heat travels to cold...Cold does not "draw" heat.

19. ### HerrGlockScouts OutCLM

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Your eyeballs and all the liquid in your nose and throat do boil, though, according to the Russian ship that got a leak in it and all three died on the way back.

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