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These scientists have their own theories about mass mammilian extinctions.
© AMNH, Ross MacPhee |
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Alvarez and his colleagues had calculated that in order to do the job, the asteroid would have to had to have been about 10 km across, which would have produced a crater more than 150 km across. In 1981, scientists took a hard look at a huge crater off Mexico’s Yucatan Peninsula originally thought to have been volcanic in origin. Research shows that it was indeed created by an extra-terrestrial impact around 65 million years ago, at the end of the Cretaceous Period.
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