How does "outer space" affect the human body? Some movies show it as the body exploding, imploding or even freezing solid.
I know space is essentially a vacuum with 0 pressure and the dispersion of energy makes it very cold. So are the predictions above accurate?
There have actually been cases of (accidental!) exposure to near-vacuum conditions. Real life does not conform to what you see in the movies. (Well, it depends on the movie; Dave Bowman's exposure to vacuum in 2001 was pretty accurate.)
Long-term exposure, of course, is deadly, but you could recover from an exposure of, say, 15-30 seconds. You don't explode, and your blood doesn't immediately boil, because the pressure is held in by your skin.
In one case involving a leaking space suit in a vacuum chamber in 1965:
He remained conscious for about 14 seconds, which is about the time it takes for O2 deprived blood to go from the lungs to the brain. The suit probably did not reach a hard vacuum, and we began repressurizing the chamber within 15 seconds. The subject regained consciousness at around 15,000 feet equivalent altitude. The subject later reported that he could feel and hear the air leaking out, and his last conscious memory was of the water on his tongue beginning to boil
(emphasis added)
UPDATE: Here's a YouTube video regarding the incident. It includes video of the actual event, and the test subject's own description of bubbling saliva.
Another incident:
The experiment of exposing an unpressurized hand to near vacuum for a significant time while the pilot went about his business occurred in real life on Aug. 16, 1960. Joe Kittinger, during his ascent to 102,800 ft (19.5 miles) in an open gondola, lost pressurization of his right hand. He decided to continue the mission, and the hand became painful and useless as you would expect. However, once back to lower altitudes following his record-breaking parachute jump, the hand returned to normal.
If you attempt to hold your breath, you could damage your lungs. If you're exposed to sunlight you could get a nasty sunburn, because the solar UV isn't blocked by the atmosphere (assuming the exposure happens in space near a star). You could probably remain conscious for about 15 seconds, and survive for perhaps a minute or two.
The considerations are about the same in interstellar or interplanetary space, or even in low Earth orbit (or a NASA vacuum chamber). The major difference is the effect of sunlight. As far as temperature is concerned -- well, a vacuum has no temperature. There would be thermal effects as your body cools by radiating heat, but over the short time span that you'd be able to survive, even intergalactic space isn't much different from being in shadow in low Earth orbit.
Reference: http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html
You're right that there is almost zero pressure in space. Which means the pressure difference between the inside and outside of a spacesuit or spacecraft is only one atmosphere. The body can cope with much greater pressure changes. You need only think of diving. You will not explode in space. Space is very cold, but again being a vacuum there is nothing to conduct away your body heat other than self-radiation.
Space has no pressure. As the human body is accustomed to atmospheric pressure, once in space, blood vessels would burst and can cause, in some ways, explosion of the body. Then the body would also freeze. All the liquid in your body would turn ice. The next thing is that, if you're far away from the Earth's magnetosphere, the Sun's radiation would kill you causing the same effect a nuclear radiation would.
So, all in all, space may be amazing, but it is a horrible place to be without a suit. :)
