The Kessler Syndrome

The more dependent upon satellites we become (think GPS, think weather, think communications) the more our satellites are threatened by space junkhttp://www.wired.com/magazine/2010/05/ff_space_junk/...

[In 1978, Donald] Kessler painted a nightmare scenario: Spent satellites and other space trash would accumulate until crashes became inevitable. Colliding objects would shatter into countless equally dangerous fragments, setting off a chain reaction of additional crashes. "The result would be an exponential increase in the number of objects with time," he wrote, "creating a belt of debris around the Earth."

Fascinating article.