so, that asteriod that'll end life on earth was we know it? we won't see it coming.
"Asteroids are tracked by telescope, as they are too far away to be detected by radar. Because of this, they are observable only when illuminated by the sun against a dark background. If they are small and dark-colored, they are far more difficult to observe. In the case of the Russian asteroid, it approached Earth with the sun behind it.
"The reason it wasn’t detected by telescopes on Earth is because it literally came out of the daylight sky and, as you know, telescopes can’t see things in the daytime,” [NASA Scientist Bill] Cooke said."