"Although there isn't a currently known asteroid that's on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there..." by Chris Lefcow via phys.org In the 1998 Hollywood blockbuster Armageddon, Bruce Willis and Ben Affleck race to save the Earth from being pulverized by an asteroid. While the Earth faces no such immediate danger, NASA plans to crash a spacecraft traveling at a speed of 15,000 miles per hour (24,000 kph) into an asteroid next year in a test of "planetary defense." The Double Asteroid Redirection Test (DART) is to determine whether this is an effective way to deflect the course of an asteroid should one threaten the Earth in the future. NASA provided details of the DART mission, which carries a price tag of $330 million, in a briefing for reporters on Thursday. Lindley Johnson, NASA's Planetary Defense Officer, said: "Although there isn't a currently known asteroid that's on an impact course with the Earth, we do