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Exposure to the vacuum of space: How long would you remain conscious? Or alive?


Souper

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You would theoretically be able to be revived until about 90 seconds. 90 seconds is the cutoff point.

That really depends on a number of factors, some of which are age, physical fitness, body mass, speed of pressure loss, temperature of the body, ...

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you would survive, yes. but naturally you would hold your breath in reflex, and that would damage your lungs.

so if you are ever in space and take a hitchhiker with you, just close your eyes and breathe out before opening the door to let him in :D

I'll....keep that in mind. :P

Why would you freeze? Your body has lots of heat inside and it takes some time before that heat is removed in sufficient quantities so that your temperature drops below the freezing point of intercellular fluid which is somewhat below 0°C.

The moisture on your eyes would evaporate rather quickly in the first minute, later the capillaries would lose their elasticity and burst, spilling foamy flood below and on conjuctiva and making your eyes look something like this.

http://upload.wikimedia.org/wikipedia/commons/2/2c/Human_eye_showing_subconjunctival_hemorrhage.jpg

Again, the speed of pressure loss is critical when discussing this. Explosive decompression yields more damage. After you die, the ice would slowly sublimate and cause shrinkage of soft tissues until you look like a fresh mummy, desiccated. Your eyeballs would sink in like a dried up jellyfish after a week or so.

Yes, Stone could've survived that, but it wouldn't look so peaceful (it hurts), and there'd be more fog than it was shown in the scene.

I don't know why you would freeze, i just heard it somewhere. I never put any thought to it until now. Now that i think about it, i think i heard it on a CSI or something like that where a guy got shot in some station in space and they threw him out the airlock. (they were suborbital, so the guys body actually hit the ground in a city, not that that is realiztic at all, just in this show) and i just remember them explaining what would've happened. Guess i learned my lesson about trusting daytime television. :P Thank you for your explanation.

In regards to the loss of heat, it is really slow, since there are virtually no particles to exchange energy with. You would mainly lose heat through radiation (all matter emit some radiation depending on its temperature, making it lose heat), but it is a slow process.

Yeah i thought about that after posting it, since in my Earth/space science lesson they said that the top portion of the thermosphere is at 3,600 degrees farenheight, but it would still feel cold because the heat couldn't be transfered because there are virtually no particles.

Quite the opposite - I expect you'd boil, just at a much lower temperature than expected. The only thing that would keep it from happening as rapidly is that your own body is an imperfectly pressurized container.

yeah some other people on here were talking about blood foaming up and stuff.

EDIT: I feel so special. 4 people responded to my one post. :D

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Yeah i thought about that after posting it, since in my Earth/space science lesson they said that the top portion of the thermosphere is at 3,600 degrees farenheight, but it would still feel cold because the heat couldn't be transfered because there are virtually no particles.

According to [1], it sounds about right (the ionosphere seems to go as high as 4000K).

[1] https://upload.wikimedia.org/wikipedia/commons/8/8b/Nomenclature_of_Thermosphere.jpg

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I'd like to reply to this particular bit, as the answers I've read here (most people say about 90 secons) is in the same order of magnitude of what I've heard.

People keep saying its only one atmosphere of difference, might be worth noting that the "one atmosphere" is the most important one, the difference between negative and positive pressure is quite big. in fact there isn't a pump on earth that can produce a perfect vacuum in fact even existence of a perfect vacuum is questionable.

In most conditions, outer space included, there is no such thing as negative (absolute) pressure.

While you are right in saying there is not a pump on earth that can produce actual vacuum, there are many pumps on earth that can produce a better vaccum than space. Source: my old physics professor.

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in my Earth/space science lesson they said that the top portion of the thermosphere is at 3,600 degrees farenheight, but it would still feel cold because the heat couldn't be transfered because there are virtually no particles.

Think about that statement for a moment - then ask yourself how the Sun transmits heat across 150 million kilometers of "virtually no particles" if that's true.

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Anyone here ever see Outland?

It was a fairly realistic space movie (set on a mining base on Io) except for the fact that it seemed to be in love with the idea that the human body would completely explode into a bloody paste if exposed to vacuum for even a second.

It was completely ludicrous but it happened to a ton of characters in the movie.

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Think about that statement for a moment - then ask yourself how the Sun transmits heat across 150 million kilometers of "virtually no particles" if that's true.

Thats because radiation (light) carries the heat from the sun, not particles.

He's right about the temperature. Air molecules in the thermosphere do move at very high velocities (they're basically on sub-orbital trajectories). Therefore, each individual particle would be extremely "hot" but due to the low low density the thermosphere wouldn't transfer much thermal energy to an object at that altitude.

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I'd like to reply to this particular bit, as the answers I've read here (most people say about 90 secons) is in the same order of magnitude of what I've heard.

In most conditions, outer space included, there is no such thing as negative (absolute) pressure.

While you are right in saying there is not a pump on earth that can produce actual vacuum, there are many pumps on earth that can produce a better vaccum than space. Source: my old physics professor.

Indeed you are correct, which verifies my point that the difference between 0 atm and 1 atm is far greater than 1 atm to 2 atm :D

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In most conditions, outer space included, there is no such thing as negative (absolute) pressure.

I think what confuses people is that it's conventional for pressure to be expressed as gauge pressure, rather than absolute.

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Thats because radiation (light) carries the heat from the sun, not particles.

He's right about the temperature. Air molecules in the thermosphere do move at very high velocities (they're basically on sub-orbital trajectories). Therefore, each individual particle would be extremely "hot" but due to the low low density the thermosphere wouldn't transfer much thermal energy to an object at that altitude.

That's why you can comfortably sit in a sauna at 90C but not a jacuzzi at the same temperature.

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I don't know why you would freeze, i just heard it somewhere. I never put any thought to it until now. Now that i think about it, i think i heard it on a CSI or something like that where a guy got shot in some station in space and they threw him out the airlock. (they were suborbital, so the guys body actually hit the ground in a city, not that that is realiztic at all, just in this show) and i just remember them explaining what would've happened. Guess i learned my lesson about trusting daytime television. :P

Then the body most likely froze in the upper atmosphere where pressure is high enough to transfer thermal energy and the air is way below zero degrees.

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Then the body most likely froze in the upper atmosphere where pressure is high enough to transfer thermal energy and the air is way below zero degrees.

That makes so much sense. they probably weren't actually all the way in space, since they were on a (i think) suborbital test plane or something.

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Then the body most likely froze in the upper atmosphere where pressure is high enough to transfer thermal energy and the air is way below zero degrees.

That makes so much sense. they probably weren't actually all the way in space, since they were on a (i think) suborbital test plane or something.

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This sounds kind of like some old red cross book I read about drowning from the 50s. Lots of conjecture, and even some valid points based on data, but considering I had 60 years on whoever came up with that book (and a ridiculous amount of studies have been done since then, especially recently), so I knew very precisely what happens when you drown and the book almost seemed laughable.

I say that to point out that we just don't know how exactly our bodies will react to space, because it doesn't happen often enough to gather any meaningful data points or track someone's condition as it progresses. And we don't really have a line forming of volunteers to test this.

As far as drowning goes, sometimes people go in the water and come out dead, sometimes dive teams pull kids out of the lake after 30 minutes and they get revived. There's just so many variables as far as the human body is concerned that trying to predict exactly how long it'll take someone to die, and exactly how they'll die, is statistically impossible, and in fact the only reason we even have a general idea as to what goes on during the drowning process is due to decades of research studying however many drowning cases there are per year.

Now, move to space, where we only have a handful of people at any given time, and they are all trained in ways to avoid the effects of depressurization, anyway. I don't know, but off the top of my head I'd say the number of people who died due to exposure to space is 0. So we have no idea what will actually happen, because it's never happened. (Or I'm wrong and its happened a few times, but my point still stands).

We can come up with good guesses as to what might happen, and who knows, maybe we could even be right. But I think that, because both space and the human body are such complex, chaotic systems, we could predict until we're blue in the face and not be right.

I think that, in general, the human body tends to be more durable than we predict rather than less, so I'd probably agree more with people saying it's survivable for longer vs shorter periods of time. But that's just me.

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This sounds kind of like some old red cross book I read about drowning from the 50s. Lots of conjecture, and even some valid points based on data, but considering I had 60 years on whoever came up with that book (and a ridiculous amount of studies have been done since then, especially recently), so I knew very precisely what happens when you drown and the book almost seemed laughable.

I say that to point out that we just don't know how exactly our bodies will react to space, because it doesn't happen often enough to gather any meaningful data points or track someone's condition as it progresses. And we don't really have a line forming of volunteers to test this.

As far as drowning goes, sometimes people go in the water and come out dead, sometimes dive teams pull kids out of the lake after 30 minutes and they get revived. There's just so many variables as far as the human body is concerned that trying to predict exactly how long it'll take someone to die, and exactly how they'll die, is statistically impossible, and in fact the only reason we even have a general idea as to what goes on during the drowning process is due to decades of research studying however many drowning cases there are per year.

Now, move to space, where we only have a handful of people at any given time, and they are all trained in ways to avoid the effects of depressurization, anyway. I don't know, but off the top of my head I'd say the number of people who died due to exposure to space is 0. So we have no idea what will actually happen, because it's never happened. (Or I'm wrong and its happened a few times, but my point still stands).

We can come up with good guesses as to what might happen, and who knows, maybe we could even be right. But I think that, because both space and the human body are such complex, chaotic systems, we could predict until we're blue in the face and not be right.

I think that, in general, the human body tends to be more durable than we predict rather than less, so I'd probably agree more with people saying it's survivable for longer vs shorter periods of time. But that's just me.

We do know plenty about it, and it didn't include volunteers. There were accidents (Soyuz 11, Volkov, Dobrovolski and Patsayev died because of depressurization) and there were tortures, specifically war crimes in World War Two. Germans and the Japanese did horrific experiments on people which included exposing live, conscious prisoners to very low atmospheres, just to mention those particular cases.

Kids can be revived after drowning because it's ice cold water. Most of such cases will not be successful. You won't be resuscitating anyone drowned in higher temperatures after half an hour.

Drowning in fluid at 1 atm and suffocating in vacuum are unrelated. Injuries are different and outcomes can not be compared.

Edited by lajoswinkler
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