You would explode. Or actually implode. If there was a leak or a hole when your wearing your suit, the pressure would be soo great that you would explode. Basically. You should read bernollis theory. It explains it
2 years ago
Last edited at 10:16PM on 2/19/2012
If you survived the extreme negative difference in pressure which would boil your blood, the extreme cold which would crystallize your flesh, and the unrelenting solar radiation, you would expire from the lack of oxygen.
However, even if you had a steady supply of breathable air, and you didn't quick freeze, the negative pressure would make it impossible to take breaths, your heart would be unable to push your boiling blood in your veins in order to carry the oxygen. Every gaseous molecule in your body would expand. Your soft tissues would swell under the pressure of the expansion. Your brain, spleen, pancreas, kidneys, eyes, tongue, genitalia, lungs and every other soft tissue would rupture like a cooked hotdog.
Without all the instant hazards, the radiation would fill every cell of your body, erasing the bonds of your DNA. You would die of "omni-canser" (a nonexistent term I had to think up to explain how untreatable your condition would be).
And idiots say "the Universe is finely tuned for life"... lol
To adjust the answer of MAMowattJr: just a bit, the universe is finely tuned for life, but does not suffer fools gladly. Stepping into the airless cold void of space is a foolishly suicidal act just as much as jumping out a high window.