All kidding aside, the danger is real. One of those big ones hits Orange County, and no more baseball. Or people.
A former astronaut is helping to build an infra-red telescope that will hopefully be launched in 2018 to track near-Earth asteroids by looking at their heat signatures. The project is privately funded and still needs a lot of money to complete. They figure to map 20,000 asteroids in the first year.
http://www.komonews.com/news/local/Former-astronaut-wants-to-save-the-world-from-asteroids-256273781.html