There have been many mass extinctions throughout the history of the Earth. Probably the most famous is the extinction that finally saw the end of the dinosaurs reign on the Earth, 65 million years ago. It wasn't just the dinosaurs that died out in this extinction. Whatever caused the death of the dinosaurs also caused the death of around 70% of all of the species on the Earth. Although the dinosaurs had been in a period of decline, it is thought that some sort of catastrophic event prevented their recovery. There are many theories about why the dinosaurs finally became extinct, some of which are more than a little outlandish. According to one theory, the impact of asteroid or comet caused massive destruction of the environment, leading to the extinction of the dinosaurs. Evidence to support this theory includes the discovery of a buried impact crater (conjectured to be the result of a large comet striking the earth) that is 124 miles in diameter in the Yucatan Peninsula of Mexico, and a recently recovered deep-sea core contains convincing new evidence of an asteroid impact 65 million years ago, when dinosaurs went extinct.
This deep-sea core provides convincing support to the hypothesis that an asteroid collision devastated ter