Stephen Hawking thought an asteroid impact posed the greatest threat to life on Earth. Thanks to Kiwico for sponsoring this video. For 50% off your first month of any crate, go to kiwico.com/veritasium50
For other potential world ending catastrophes, check out Domain of Science: ve42.co/DoS

Special thanks to:
Prof. Dave Jewitt from UCLA Earth, Planetary, and Space Sciences
Prof. Mark Boslough from Sandia National Labs
Scott Manley: www.youtube.com/user/szyzyg
Ryan Wyatt at Morrison Planetarium
Prof. Amy Mainzer
Alexandr Ivanov for the opening shot of Chelyabinsk Meteor

Maps of Asteroid Impacts —https://ve42.co/Map

Time passing animation from Universe Sandbox — universesandbox.com/

Opposition Effect — ve42.co/Belskaya2000
Belskaya, I. N.,