"Floating around" isn't accurate. "Screaming around at 8 kilometers per second" is more accurate.

The fact that debris objects swee through an enormous volume of space per year (and are up there for years to centuries) makes it much worse.

https://commons.wikimedia.org/wiki/File:Orbital_Debris_Lifet...

http://www.youtube.com/watch?v=RvZ3Lr-Tj6A