821-Dinosaur Killing Asteroid

Scientific results are consistent with the hypothesis that the dinosaur killing, K-T layer forming Chicxulub impactor came from well beyond Jupiter while the other 5 impactors in the past 541 million years as well as most meteorites found on Earth came from asteroids formed between Mars and Jupiter. All of this prompts us to marvel that we are here at all and puzzle over how to prepare for what the future might hold. In particular asteroid hunters should take seriously the possibility of an impactor from deep space with our number on it.