Outer space
From Slackerpedia Galactica
Outer space is one of those terms you can use to really make astronomers cringe. It's like scratching nails across a blackboard.
Much like countless other popular misconceptions about astronomy and the universe, the term is not entirely accurate or appropriate as it is typically used.
For example:
1) Outer space is not a perfect vacuum nor full of empty space but is in fact filled with monatomic particles of hydrogen often commonly referred to as the interstellar medium.
2) Outer space has no set boundary. While some might place it at the stratosphere where meteors start to burn up, others might place it at the mesosphere where air really starts to thin out or even at the exosphere which is farther out than space shuttle orbits! Thankfully, some nice French gentlemen from the FAI decided to come in and declare the official border at 100km, now known as the Kármán line, which lies just at the bottom of the thermosphere.
3) Not all outer space is an expanse of stray atoms, kept at near absolute zero, which either float or drift in random directions. Any given location will have different gravitational and temperature characteristics depending on how close it is to the nearest star, planet, or most unfortunate of all, a black hole.
4) Outer space that lies in a solar system will be full of micrometeorites as well as varying degrees of both solar winds and cosmic rays which are both nice technical euphemisms for horribly scarring radiation. If you're a future astronaut on an interplanetary ship, outer space will definitely not be a boring vacuum.
5) Outer space is and probably will be divided into more specific regions of space such as interstellar space which is outer space between stars, the border of a solar system which is called the heliopause and comprises the Oort Cloud, as well as the inner reaches of a solar system which can be divided into inner planets and outer planets, much like ours.
6) The term is also not used much in astronomy as anything an astronomer observes will be in outer space beyond the reaches of Earth and its light pollution.
7) You will not have to worry about "exploding" in outer space if not using a spacesuit or comparable protection. The good news is that you will die of suffocation as droplets of water from your body freeze and condense.
8) Some organisms, such as microbial bacteria, can survive in outer space for years at a time. It is due to this fact that attempts by NASA and the ESA to search for signs of life with probes require the strictest hygienic standards to avoid instrument contamination.
And now you know.
Related Links
FAI explanation of the Kármán line
Straight Dope debunking the myth that you will explode without a spacesuit in outer space
NASA's attempt to answer the same question
Evil microbes in outer space
