Why is Space a Vacuum

[Fyron]

Geo... your skin will also rupture with many tiny holes as the molecules inside your body attempt to diffuse from areas of very high concentration to areas of 0 concentration. Skin is a very weak barrier. It is, at best, no better than going from high pressure to low pressure. Of course, it is exactly the same as divers coming up from high pressure to low pressure...

[Fyron]

Originally posted by narf poit chez BOOM:
in one of the short stories i read, people evacuated from one ship in space to another after expelling air from their lungs. no-one was in space more than 30 seconds. feasible?

No. 0 pressure environment is entirely different from high pressure environment. High pressure environment pushes things into the system, low pressure environment pulls things out of it.

[geoschmo]

Originally posted by Imperator Fyron:
Geo... your skin will also rupture with many tiny holes as the molecules inside your body attempt to diffuse from areas of very high concentration to areas of 0 concentration. Skin is a very weak barrier. It is, at best, no better than going from high pressure to low pressure. Of course, it is exactly the same as divers coming up from high pressure to low pressure...

So you say, but you are contradicting everything I can find from people that are supposed to know this stuff. If you can post something to support your assertion, fine. Otherwise, I am content with what I have found on the subject.

[narf poit chez BOOM]

I did it once and was able to extend my ability to hold my breath to somewhere around a full minute, perhaps even longer.

well, that explains something. i only took two or three breaths.

[Phoenix-D]

The reason the damage isn't as extreme as in going from depth is that the pressure difference as said isn't that big. Go down 38 feet into water..congradulations, you've just doubled the pressure. Going from here to the surface is very similar to going from the surface to space.

It's not going to be a pleasurable experience, but Fyron is exaggerating.

"If you don't try to hold your breath, exposure to space for half a minute or so is unlikely to produce permanent injury."

This is confirmed with experimental animals.

http://imagine.gsfc.nasa.gov/docs/as...rs/970603.html

[geoschmo]

Some more literature to edify you...

http://space.about.com/cs/basics/a/bodyvacuum1.htm

The human body is amazingly resilient. The worst problem would be lack of oxygen, not lack of pressure in the vacuum. If returned to a normal atmosphere fairly quickly, you would survive with few if any irreversible injuries.

There have actually been cases of parts of astronauts bodies being exposed to vacuum, when suits were damaged. The results were negligible.

And some more of the same:

http://www.urbanlegends.com/death/bo..._in_space.html
http://www.badastronomy.com/mad/1999/space_feel.html

Nothing I have found talks about anything seeping through your skin. Long term a body in a vacuum would be desicated, that's why food is often vacuum packed. But it doesn't happen that fast, certainly not as fast as you are going to asphyxiate anyway.

[geoschmo]

Originally posted by narf poit chez BOOM:
in one of the short stories i read, people evacuated from one ship in space to another after expelling air from their lungs. no-one was in space more than 30 seconds. feasible?

side note: the book mentioned a technique where you breath heavily a few times then expell the air from your lungs. i tried this and was able to hold my breath for 20 seconds at the start and after some practice, 35 seconds. it really is easier, despite sounding counter-productive.

Basically this is feasible, as long as someone is there to pull in the unconcious people. The technique divers use doesn't really help in vacuum. A diver will expell all the air they can, but there will still be enough oxygen there to keep you concious. And as you surface the lower pressure causes the air in your lungs to expand, which satisfys your instinct to inhale. If you don't expell the air in your lungs it will still expand, but cause damage. That's why you can't hold your breath in vaccum too, cause the air will expand and damage your lungs. The difference is expelling your lungs in a vacuum leaves you without enough oxygen to keep you concious for more then a few seconds.

So 30 seconds wont kill you or cause any permenant damage. But it will incapacitate you. You'll need someone there to pull you in.