re: A Meteoric Event
"How big a meteor to kill everyone on this planet from the aftereffects?"
Humans are the most dangerous thing in this solar system,
spooking them can be dangerous.
But a rock about 10 km in diameter is said to have killed the dinosaurs. The same rock shouldn't kill the humans [unless they are spooked- in that case, a 300 meters rock could kill us all]. Probably anything over 100 km would kill everyone- assuming it hit us without us knowing that it was going to hit us.