I think that's the first line of The Hitchhiker's Guide to the Galaxy. The book itself, not the book about the book. According to wisegeek.com, the US Space Surveillance Network, which keeps tabs on any object in Earth orbit larger than 10 cm in diameter, is currently tracking about 8,000 man-made objects, 3,000 of which are satellites. Presumably the rest is debris, much of which will eventually burn up in the atmosphere.
NASA just found something big hiding out behind Pluto http://finance.yahoo.com/news/nasa-just-found-something-big-205800491.html
Space stations, shuttles, etc. have to maintain speeds over 17k mph to remain in orbit... So the speed of the flying debris is matched by the astronaut, like jumping on an elevator.
Retrograde orbit is extremely rare and requires a lot of fuel... Debris will always be in prograde orbit.
Retrograde orbit is rare but does happen. But the prograde orbits that are used are in many different elevations, angles and many different kids of orbits including many polar orbits. Orbits cross each other, orbits decay and collisions send material off in strange directions. Not everything out there is all cruising along next to each other.
There is a lot of stuff out there, but there is a lot of space out there too. Low earth orbit is basically from 160KM to 2000KM..that is stuff that orbits, way lower than stationary satellites. The volume of space encompassed by the high and low range of Low earth orbit is about 1000 times the volume of all the oceans on earth. You can put a lot of junk in that volume. Of course, if you are on a spacewalk at the wrong place and the wrong time, that is it.
