>And even if NASA was on track to meet that goal, they still would have missed 2016 QA2, which is only about 50-100 feet. Asteroids of this size are so small that there's almost nothing we can do to detect them. And they can still cause a lot of damage. The Chelyabinsk asteroid, which exploded over Russia in 2013, damaged multiple buildings and injured over 1500 people. That asteroid was only about 55 feet wide.<p>So it was a city destroyer at best, let me know when it's a continent/planet killer.