3QD’s own Ker Than, in LiveScience.com:
The ancient asteroid that slammed into the Gulf of Mexico and purportedly ended the reign of the dinosaurs occurred 300,000 years too early, according to a controversial new analysis of melted rock ejected from the impact site.
The standard theory states that a giant asteroid about 6 miles wide smashed into the Yucatan Peninsula close to the current Mexican town of Chicxulub about 65 million years ago. The impact raised enough dust and debris to blot out the sun for decades or even centuries.
But Markus Harting of the University of Utrecht in the Netherlands and a small group of scientists thinks the Chicxulub impact happened too early to have been the infamous dinosaur-killer.