Paper Casts Doubt on Dinosaur Death Theory A group of researchers is challenging the popular theory that the disappearance of dinosaurs on Earth was caused by the planet's collision with a single asteroid 65 million years ago. The scientists say the Yucatan Peninsula's Chicxulub crater -- often thought to be the result of the catastrophic strike -- is too old to have been involved in the creatures' demise. NPR's Richard Harris reports.

Paper Casts Doubt on Dinosaur Death Theory

Researchers Question Single Asteroid Impact Scenario

Paper Casts Doubt on Dinosaur Death Theory

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">

It's thought that 65 million years ago, a large meteor crashed into the Yucatan Peninsula, leading to the death of dinosaurs. But a new paper contends the Chicxulub impact site is too old to be the culprit. Reuters/Corbis hide caption

toggle caption

The blue semi-circle at the center of this three-dimensional map marks the Chicxulub crater, now covered by hundreds of meters of sediment. V. L. Sharpton, Lunar & Planetary Institute hide caption

toggle caption
V. L. Sharpton, Lunar & Planetary Institute

Dinosaurs abruptly disappeared from the Earth about 65 million years ago. In the early 1990s, scientists found what seemed to be the smoking gun for this mass extinction -- a huge crater, created by an extraterrestrial impact, in the Gulf of Mexico.

Now, a group of scientists is challenging the conventional wisdom about the Chicxulub crater in a report published in the current issue of the Proceedings of the National Academy of Sciences. Led by Princeton University's Gerta Keller, the scientists say the crater predates the mass extinction by 300,000 years. Keller suggests that a massive impact elsewhere on the planet is responsible for the final blow to the dinosaurs. But other geologists dispute her findings. NPR's Richard Harris reports on the debate over the Chicxulub crater.