A dramatic computer-animated simulation, produced by NHK Japan and the National Film Board of Canada, depicts what would happen if an asteroid measuring 500 kilometers (300 mi) in diameter collided with Earth.
The massive asteroid -- larger than Japan's main island of Honshu -- is traveling at a speed of over 720,000 kilometers per hour (450,000 mph) when it crashes into the Pacific about 1,500 kilometers (1,000 mi) south of Japan. The impact causes the crust of the Earth to peel away like the skin of an orange, in what is called a "crust tsunami." Japan and a large portion of Asia are disintegrated, and chunks of burning rock as large as city blocks are hurled into the atmosphere before raining back down on the planet.
The crater from the impact measures 4,000 kilometers (2,500 mi) across, and the rim stands 7,000 meters (23,000 ft), higher than many mountains on Earth today.
Moments after the impact, a blanket of rock vapor as hot as the sun spreads quickly across the planet, decimating every living thing in its path. The entire planet is covered within one day. The oceans boil under the intense heat, evaporating at a rate of 5 centimeters (2 in) per second until they vanish.
After a year, the rock vapor starts to dissipate and temperatures begin to drop. Within 1,000 years, the evaporated water vapor -- which does not escape into space due to the Earth's size and gravity -- cools, condenses, and falls back as torrential rain. The oceans start to fill, and life begins again.
It is thought that asteroid impacts of this magnitude have happened six times in the past.
This simulation was featured in "Miracle Planet" (Episode 1 - The Violent Past), a five-part documentary about the 4.6-billion-year history of the Earth.