Video: We asked a NASA scientist: What if an asteroid were going to hit Earth?

There are no known threats to Earth, but NASA asteroid expert Dr. Kelly Fast says it's important to find the asteroids before they find us. That's why NASA's Planetary Defense Coordination Office keeps its eyes on the skies.

This November, we're launching the Double Asteroid Redirection Test, or DART. The test mission will attempt to change the course of an asteroid that is currently no threat to our planet. Get more info at nasa.gov/PlanetaryDefense.