Floating in Space

Ever saw a movie where, for some reason, someone finds himself in space, without any equipment? More often than not, that person freezes almost instantaneously and dies. Turns out that, if you find yourself in outer space, reality will be a bit less eventful.

Your first problem would be the difference in air pressure between your lungs and the emptiness of space. Knowing that you won't be able to breathe, you might be tempted to first take a deep breath first, but that will only rip your lung out. You need to empty your lungs. Also, the pressure of your body fluids and tissues is apparently of no real concern, in the short term.

Second place in your list of problem is lack of air. An average person can hold his breath for about two minutes before starting to lose consciousness, so with empty lungs, let's assume around a minute. That would be your lifespan, within which you'll have to find another source of oxygen.

So when will you freeze? Actually, this is another really good example of the power of Hollywood. While the temperature of outer space is around three Kelvin, it is a near vaccuum - there is not much material to transfer heat! It is exactly the concept behind insulation and thermos - air or nothing (vaccuum) hinders a transfer of heat between the inside and the outside. If you are in the viscinity of a star, you are going to be sunburned to death first, or solar flared to death. Outer space is the perfect insulation, so it would take a very long time before you freeze (assuming, of course, that you can find some oxygen).

Other interresting points to mention:

• There is no air pressure to propagate sound waves - you will hear nothing.
• There is no movement in the air to propagate smells - you will smell nothing.
• You will only feel heat. What you feel on your skin is pressure and temperature. You won't feel cold, and no pressure from an external source. If you're very far from any star, you won't even feel heat.
• Newton's first law of motion makes sure that you won't be able to change direction or speed, unless helped by an external force (eg. rocket booster).

Another thing that surprise everyone: astronauts are in a state of free-fall. If you're in outer space, orbiting a planet or a star, you will feel yourself falling, constantly. This apparently takes a lot of getting used to, and the physics might be better left for another post.