Narrator: This is Science Today. Most people associate a comet or an asteroid hitting Earth with the extinction of the dinosaurs, but they don't think of themselves as a potential target. Greg Aldering, an astrophysicist at the Lawrence Berkeley National Laboratory, says that your chances of getting hit are actually not that trivial.
Aldering: Averaged over the long term of civilization, your risk of dying due to the impact of an asteroid or comet is comparable to your chances of dying flying on a jet airplane.
Narrator: Aldering says that the shockwave from the impact would be similar to a nuclear bomb exploding over a city - a threat significant enough to get the government involved in tracking and predicting asteroid and comet explosions.
Aldering: There's actually a mandate from Congress to try to find all of these objects that threaten Earth. Now there'll be some smaller ones that will take a long time to find because they're very small really. But the larger ones can be found. And it's a waiting game in part, because even those are fairly faint unless they come somewhat near Earth.
Narrator: For Science Today, I'm Larissa Branin.