How would the unprotected human body react to the vacuum of outer space?
imagine.gsfc.nasa.gov
imagine.gsfc.nasa.gov
Edit: Found the scene: http://www.youtube.com/watch?feature=player_detailpage&v=0Nb...
Hah, I thought that was just a tick. You would take a breath before doing any hard physical effort and I'm pretty sure you'd try to do it even in the vacuum of space just because you're used to.
The interesting thing is that Arthur C. Clarke was a very experienced scuba diver and still had a problem with the scene. Ah well.
It's one of my favorite action scenes in any science fiction film. The interesting thing is that the trick just relied on good photography, piano wire and dropping Keir Dullea. It's easy to imagine how a present-day director would mess that scene up with CGI effects, slow-motion, stuntmen, and so on.
That would be awesome.
There are a lot of advantages to this idea, but it is not without tradeoffs. For example, for these sorts of suits to work properly they need to be in contact with all of your body. Any gap, between your toes or your legs... and you will have problems. This can be overcome but you basically end up having to tailor each suit to a particular astronaut. The suits currently used on the ISS are not specially tailored, they basically just have "small/medium/large" (though they have a greater variety of sizes for gloves).
Mechanical compression suits are lighter than pressure suits in the first place (in addition to being less bulky), so having every astronaut bring along their own might not be too unreasonable now that I think about it. More labor with the tailoring bit, but not if you heatshrink them...
Better try it on some sausage or a (dead) chicken first :)
Is it? A naive application of the Stefan–Boltzmann law yields a loss of about 1 kW through heat radiation alone.
http://www.youtube.com/watch?v=8f0iDL3pAhE
(The scene where Cohagen gets exposed to the martian atmosphere and dies).
"THE EFFECT ON THE CHIMPANZEE OF RAPID DECOMPRESSION TO A NEAR VACUUM."
Eight chimpanzees, used in nine separate tests, were
decompressed from 179 mm Hg (100% oxygen) to less than
2mm Hg in 0.8 seconds and remained at this altitude from
5 to 150 seconds.
All subjects showed slight neutrophilia, increased
transaminase, and facial edema which returned to normal
within 72 hours after decompression. All subjects survived
in good health and no lasting effects of rapid decompression
to a near vacuum could be detected.
[1] - http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=ht...
I like this article much better. Covers more topics with more detail.
Can someone explain the boiling water on his tongue?
The main thing stopping the molecules of a liquid boiling away (flying off, out of the container) is the pressure exerted by the gas above or around them.
If you make the liquid molecules move faster (i.e. give them energy, i.e. heat them up), a greater proportion of them will be able to overcome this pressure. So heating increases evaporation and leads to boiling - which we're familiar with.
Alternatively, if you reduce the pressure of the gas pushing the liquid molecules together, you don't need to heat up the liquid as much to get the same evaporation/boiling effect.
Reduce the gas pressure enough and the liquid will boil at a very low temperature.
[1] http://en.wikipedia.org/wiki/Boiling_point
[2] http://en.wikipedia.org/wiki/Heat_of_vaporization
[3] http://en.wikipedia.org/wiki/Vapor_pressure
[4] A solid can "boil" too, but it's called sublimation. http://en.wikipedia.org/wiki/Sublimation_(physics)
[5] http://www.engineeringtoolbox.com/boiling-point-water-d_926....
If you don't hold it in, the air will simply leave your lungs and you have about 12-15 seconds before the remaining oxygen in your blood leaves your body making you unconscious. The lungs, instead of trading CO2 for O2 is now working in reverse in the vacuum, exchanging O2 for... nothing. That amount of time should be enough for you to reattach your O2 hose and open the airlock etc.
I also recall reading somewhere that you may urinate, defecate and projectile vomit simultaneously after a while, however by that time, you may already be unconscious.
The diving comparison comes up a lot with these space exposure questions. Even the article mentions Scuba diving. But diving is applicable in many ways not just in terms of physiology, but behavior and psychology as well.
I remember there was once also an experiment in an undersea lab where a group of people spent time to see what would happen on similar long duration space missions.
1atm->0atm won't do it, but apparently 9atm->1atm can.
Pressure differentials are powerful.
http://www.amazon.com/Moon-Machines-Robert-Seamans/dp/B0026I...
The peak of Mount Everest is about 1/3 atmosphere, and base camp is in about 1/2 atmosphere. This means the partial pressure of oxygen at those locations is about 0.07 and 0.1 atmospheres, respectively. People who have not acclimated to high altitudes (by spending 2 months at base camp) will pass out on the peak (and it still sucks pretty hard even if you're acclimated).
So, it seems like pure oxygen at 0.1 atmosphere should work, although I suspect it'd be hella uncomfortable even without the vacuum, since it'd probably feel like you were trying to blow up the worlds largest balloon while standing on Mount Everest.
But it does let us move on. So you're standing in a vacuum (on the Moon, maybe) sucking on 0.1 atmosphere of pure oxygen. How long can you survive for?
You might need to keep a small amount of lung pressure (say, less than that used to blow up party balloons) to slow the egress of oxygen through the lungs.
The next problem is likely that your lungs catch fire as the O2 concentration builds up in them. One thing at a time though.
Hyperventilating is good for removing CO2 from your blood, which reduces your "I really need to breath" reflex (turns out that is, at least largely, cause by the presence of CO2 rather than the absence of O2). From personal experience I can tell you this can allow you to push yourself further without breathing, but you also run the risk of blacking out because you pushed too far (I don't have experience with that part).