New Theory on Dinokiller Impact

Now for a little science post, from National Geographic.

The dinosaur killing meteorite that hit the Yucatan penninsula 65 million years ago might have been the result of an cosmic event from far earlier - a collision far out beyond Mars between two enormous asteroids. This family of asteroids, the Baptistina (who knew asteroids had families?) family caused by this collision spewed fragments throughout the solar system, one of which might have been the K-T impactor, which is the reference used to identify the impact event dividing the Cretaceous and Tertiary geologic periods on Earth thought to have ended the Age of Reptiles.

"The new discovery was an accident, said study leader William Bottke of the Southwest Research Institute in Boulder, Colorado. "We didn't actually set about to track down the K-T impactor," Bottke said. Rather, his team of U.S. and Czech scientists stumbled onto the find while studying a group of asteroids called the Baptistina family. By studying the Baptistina asteroids' orbits, Bottke's team concluded that the group was formed in a collision about 160 million years ago."

The collison that caused these fragments is thought to have occurred between two space rocks, one around 100 miles in diameter, the other about 40 miles, and resulted in the creation of approximately 300 fragments greater in size than 6 miles, the estimated size of the K-T impactor. Another of these Baptistina fragments may have also impacted Earth's moon, resulting in the famous Tycho crater on Earth's satellite, 110 million years ago, and may be the cause of as much as 20% of the near Earth asteroids found today.

Very interesting how the orbital data from today can allow us to examine the very distant past.