The same kind of catastrophe that is believed to have wiped out the dinosaurs—a giant meteorite or comet’s impact—may have started life on Earth in the first place. And such an impact could happen again. This program explores many fascinating aspects concerning meteors and comets, from the Oort Cloud beyond Pluto where comets are formed to the most recent meteorites recovered for study. The effects of a large impact are seen in a computer simulation and from experiments at the NASA Ames Vertical Gun Range. Research into space debris reaches a new level as NASA scientists land the NEAR satellite on the surface of an asteroid. A Discovery Channel Production. (53 minutes)