Outer Space

A quick note about something that has come to be very annoying to me about science fiction and a common misconception about outer space.

Space is not cold. Okay it kinda is. Here's the thing. Temperature is a measure of average number of particle collisions per unit volume per unit time. That's the proper definition of temperature. In space there are no particles. So therefor logically there are no collisions and so by definition the temperature is zero. It should be zero, but space isn't a perfect vacuum.

You change temperature as the particles in you collide with particles around you. If you are warmer your particles are moving faster. They collide with slower moving bits of your surroundings and both move away at the average speed. Yours slow down, the surroundings speed up. You lose heat, your environment gains some. You cool down.

In space there aren't any particles. Your particles never collide with the surrounding ones. Because there aren't any surrounding particles. Things never average out. You never cool down. Now because space isn't a perfect vacuum this isn't completely true. The average particle speed in space is in fact insanely fast so we can actually assume if it were purely particle collisions you would warm up the longer you drifted freely in the cosmos. You do however lose heat by radiation. You are an infra-red light bulb and that burns energy. Thus as time goes by you would slowly begin to cool down. Slowly, like tea in the greatest thermos it is possible to ever build slowly. On the order of, it would become uncomfortably cold after the first few dozen years, slowly.