Remember that movie Deep Impact? It's not terrible! But what are the chances of an asteroid actually doing that? You know, colliding with the earth and causing hundreds of millions of people to drown in tidal waves the size of skyscrapers. Some scientists think about the possibility of this happening just about every day of their lives. In this piece, we talked to science's No. 1 booster, Neil deGrasse Tyson, and the kind folks at NEEMO (NASA Extreme Environment Mission Operations) about what it would take to stop an asteroid from hitting earth.