The collision involved an Iridium commercial satellite, which was launched in 1997, and a Russian satellite launched in 1993 and believed to be nonfunctioning. The Russian satellite was out of control, Matney said.
The article goes on to explain that at the beginning of 2009 there were roughly 17,000 pieces of man-made debris orbiting Earth. The items, at least 4 inches in size, are being tracked by the U.S. Space Surveillance Network, which is operated by the military. (Read more about space junk here.)
Want to learn more about space junk? You can play Space Junk - the game!
There's lots of junk floating in orbit about the Earth! 11 examples can be found in this game. See if you can capture them all by clicking on them as they pass by, but be careful not to capture too many things that aren't junk--if you get three strikes, you'll have to start over!
The game uses actual reported junk. For example, in 1984, a screwdriver was dropped during an American spacewalk and it became space junk for a while, until it was burned up in earth's atmosphere!