What would happen if you were exposed to the vacuum of space in nothing but your birthday suit?
So you find yourself the victim of an unlikely mutiny and now you are about to be spaced out an airlock. How long will it take you to die and what should you prepare yourself for?
Inflation
You’ll live for longer than you might think. First, you’ll inflate up to twice your size as the nitrogen in your blood stream bubbles up, no longer contained by any sort of pressure. The technical term is ebullism. This won’t kill you, but may make you feel pretty fucking miserable.
Much worse than the US dollar
Flash Frozen
Next up is the part where you freeze. At a temperature of -270.5 Celcius (about 4x colder than the coldest temperature ever recorded in Antarctica) you are fucked. However, not as fucked as you might think. You can survive a couple minutes in space at these temperatures. Why? Because in a vacuum there is no convection or conduction of heat. In other words there is no air to siphon away your precious heat. So you are left with simple thermal radiation and because your skin is pretty good at insulation you can survive a couple of minutes in the deathly cold vacuum of space.
Not a pleasant Disney Fairy Tale
Sunburn and cancer
If you somehow were pulled back into the safe confines of your ship, you’d have to deal with intense UV exposure thousands of times greater than anything you would experience on earth. Unprotected by earth’s atmosphere this would cause flash sun burns and very likely instant mutagenic changes and cancer from unfiltered UV radiation. However, you would live!
SPF 10 billion needed
Air and oxygen
This is what will actually kill you and it’ll take about 2 minutes. There’s no air in space and thus no oxygen. Your body is not equipped to deal with this and will continue pretending there is plenty of oxygen to be had. Your blood will cycle past your lungs and up to your brain without oxygen. Within 15 seconds you will lose higher functions such as consciousness and bladder control. Within 2 minutes you will be irretrievably dead from oxygen deprivation. Your body will freeze and then shatter like a balloon full of ice crystals. You might be wondering if you can extend that 15 second window by holding your breath. The answer is no. Never try and hold your breath in a vacuum. If you try and hold your breath your lungs will rupture. You will die even faster.
Oxygen has never looked so sweet
Keeping it simple
So in the event of being jettisoned out an airlock (a common cause of death in the 24th century, I predict) you have two minutes to live and 15 seconds to remain conscious. During that time you will experience agonizing pain as your skin tries to keep your organs from inflating outside your body and you flash freeze to death. Ultimately, simple oxygen deprivation will kill you.