Researchers Challenge Theory That Asteroid Wiped Out Dinosaurs

A team of London scientists Wednesday challenged the popular theory that an asteroid wiped out the dinosaurs 65 million years ago.

The mass extinction had already been under way for several million years when the asteroid smashed into the Earth, delivering what amounted to the “coup de grace,” they wrote in the Journal of the Geological Society.

According to the 22 experts, led by Norman MacLeod of the Natural History Museum, a period of violent volcanic eruptions combined with a big drop in global sea level to weaken the dinosaurs’ dominance.

There is plenty of evidence that an asteroid did smack into the Earth near what is now southern Mexico, sending out huge tidal waves and throwing up a cloud of dust that brought 5,000 years of winter. But that was only one factor contributing to the extinction, the researchers said.