New Study Casts Doubt on the Asteroid Strike Theory of Dino Extinction

The enormous meteor that smashed into Mexico's Yucatan peninsula 65 million years ago didn't deal a death blow to the dinosaurs, a new study declares. Based on a close examination of sediment layers from that epoch, a team of researchers led by Gerta Keller has previously argued that the Chicxulub impact happened 300,000 years before the mass extinction known as the Cretaceous-Tertiary extinction event. Now, Keller has found supporting evidence that the impact had little immediate effect on the planet's biome. Says Keller: