Earth is constantly under attack from asteroids - nearly 1 asteroid per week enters the Earth's atmosphere. Thankfully, our protective atmosphere shields us from most of these impacts. According to NASA, asteroids that are smaller than about 1 meter diameter will generally burn up in the atmosphere due to atmospheric heating.

But not all asteroids are this small. There are plenty of massive errant rocks floating through our Solar System.

According to the video description, the simulation below shows an asteroid with a diameter of 500 km impacting the Pacific Ocean. First, the topmost 10 km of Earth's crust would be torn from the planet and ejected into low-Earth orbit. Next, the impact shockwave would travel around the surface of the Earth, obliterating any living thing in it's path. Finally, the debris from the impact would begin to re-enter to the Earth's surface and further encircle the Earth in a cataclysmic firestorm. Within about 1 day of the impact, the Earth becomes uninhabitable.