The whodunit tale of the extinction of the dinosaurs is pretty much considered to have been a case of death by asteroid. About 65 million years ago one of the millions of space rocks collided with earth and immediately killed millions of the creatures that that roamed the planet. The subsequent climate change caused by debris blasted into the atmosphere resulted in a slow death by starvation of the surviving dinosaurs as the food chain was broken. Smaller mammals became dominant.
Asteroids Belong to Families
Children learn early in school that many millions of asteroids exist in the solar system, and most of them orbit the sun between Mars and Jupiter. What is not generally known is that asteroids often belong to groups composed of thousands of members known as families with similar orbital elements and composition.
The families are thought to result from collisions many millions of years ago. Two asteroids smashing into each other will create large numbers of smaller rocks of various sizes. Some will be hurled into unique orbits, but others will move together for billions of years. About 25 asteroid families are known.
Some Scientists Believe the Smoking Gun has been Found
In 2007 a team of U.S. and Czechoslovakian scientists announced that evidence of a detailed study of asteroid orbits pointed to a little-known asteroid named Baptistina as a relative of the villain. Baptistina is now about 15 to 20 miles in diameter, and resulted from a collision between two larger asteroids tens of millions of years ago. The original asteroid from which Baptistina came was perhaps 100 miles across when it collided with a 35 mile asteroid.
According to the team, the collision occurred 150 million years ago and created the Baptistina family. The related asteroids are still orbiting the sun in the main asteroid belt. Tens of thousands of smaller asteroids were hurled into orbits into altered orbits and many impacted the earth over time. One — six miles in diameter — impacted the earth creating the Chicxulub crater near the present Yucatan Peninsula. The dinosaurs were done for.
New Evidence Casts Doubt on Baptistina as he Dinosaur Killer
NASA’s Wide-field Infrared Survey Explorer mission — WISE — studied over 100,000 asteroids, including over 1,000 members of the Baptistina family. According to their calculations the original asteroids involved in the collision occurred only about 80 million years ago. This would not allow enough time for the suspect to position itself for the extinction impact 65 million years ago.
The process of acquiring a new orbit requires more than making a simple bee-line to earth. Complex interactions with the gravitational field of primarily Mars and Jupiter are involved.The guilty asteroid family is still at large and the search goes on.
Families of asteroids orbit the sun in the main belt between Mars and Jupiter. Czechoslovakian and American scientists announced in 2007 that an analysis of the Baptistina family indicated that one was a six-mile sized chunk that did-in the dinosaurs. Now NASA’s WISE mission has performed a more thorough analysis of over 100,000 asteroids. Their results seem to remove guilt from the Baptistina family.
Sources:
"Origin of Dinosaur-Killing Asteroid Remains a Mystery," nasa.gov. (Accessed September 20, 2011)
Harvey Craft - I am a retired educator with diverse experience. I read anything science, education, and history. I write to share what I learn.
