This article is geek as hell, and I love it. I kept thinking about the flick Armageddon, and whether or not we could actually blow up or guide a massive asteroid (that we knew would hit earth) away from hitting the earth.
Obviously (and unfortunately) it's not really possible.
Asteroid AG3 missed the Earth by more than three million miles (4.9 million km), 12.86 times the distance from Earth to the moon, which may be considered a narrow miss on the cosmic scale, especially given the speed of space rocks.