Why Is NASA Crashing A Spacecraft Into An Asteroid?

GUEST: Dr. Sarah Rugheimer (Allan I. Carswell Chair for the Public Understanding of Astronomy in the Faculty of Science at York University, author of "Searching for Extraterrestrial Life")
GUEST: Dr. Sarah Rugheimer (Allan I. Carswell Chair for the Public Understanding of Astronomy in the Faculty of Science at York University, author of "Searching for Extraterrestrial Life")