The extinction of the dinosaurs occurred between 65 and 66 million years ago.
The asteroid or comet that hit Earth was estimated to have been between six and nine miles wide. The extinction event that killed the dinosaurs also caused the sudden mass extinction of 75% of all living plant and animal species.
The evidence used to back up the asteroid impact theory is in the Earth’s geological record. The K-Pg boundary, also called the K-T boundary, is a thin layer of sediment found in the geological record. This thin layer contains high levels of the metal iridium, which is rare in the Earth’s crust, but is very common in asteroids.
The Chicxulub crater located underneath Chixulub, Mexico on the coast of the Yucatán Peninsula, is believed to be the impact crater left by the asteroid or comet that caused the extinct of the dinosaurs.
Ultimately, the extinct of the dinosaurs cleared the way for the evolution of mammals and humans. If the dinosaurs didn’t go extinct about 66 million years ago human may never have evolved.