The probabilities of dying via an asteroid impact are very, very small.
Asteroids that pose an existential risk to life on Earth simplest strike as soon as each 500,000 years or more. Even the 140-meter-huge asteroids that could smash towns and areas rain down dying once each 10,000 years. And the chance of being even injured from a 20-meter object — just like the one which exploded over Chelyabinsk, Russia, in 2013 and harm nearly 1,500 people — is tiny.
But, ok: WHAT IF? If a large asteroid have been to wreck into Earth, what might manifest to us? We