Asteroid!

"[G]round-based lasers might be used to zap debris."

It's really depressing to me to consider that we're not only trashing our planet, but we're also spreading our garbage out into the atmosphere. And, I'll be honest, it's also a little disappointing to realize those movie photos from Armageddon, Red Planet (no, uh...of course I didn't see this movie...), and the like are apparently inaccurate in their portrayals of the vast untouched universe beyond our Mother Earth.