8:46pm UK, Monday September 19, 2011
The asteroid believed to have led to the extinction of the dinosaurs may not have been the culprit according to Nasa, the American space organisation.
Nasa believe the Baptistina asteroids did not kill the dinosaurs Picture: Nasa/JPL-Caltech
While scientists are confident a large asteroid did crash into Earth 65 million years ago it now appears likely the original suspect, the Baptistina asteroid, was not to blame.
New research by Nasa’s Wide-field Infrared Survey Explorer (WISE) seems to have ruled Baptistina out.
“As a result of the WISE science team’s investigation, the demise of the dinosaurs remains in the cold case files,” said Nasa scientist Lindley Johnson.
“The original calculations with visible light estimated the size and reflectivity of the Baptistina family members, leading to estimates of their age, but we now know those estimates were off.
With infrared light, WISE was able to get a more accurate estimate, which throws the timing of the Baptistina theory into question.”
WISE surveyed the entire celestial sky twice in infrared light from January 2010 to February 2011.
Infrared light allows more accurate size estimates of asteroids than visible light.
“As a result of the WISE science team’s investigation, the demise of the dinosaurs remains in the cold case files,”
NASA scientist, Lindley Johnson.
Scientists were able to establish that the Baptistina asteroid actually broke up closer to 80 million years ago, half as long as originally proposed.
This result means the remnants had only 15 million years to get flung down to Earth to cause the extinction of the dinosaurs.
Nasa scientist Amy Mainzer said “this process is thought to normally take many tens of millions of years.”
So the asteroid family that produced the dinosaur-killing remnant remains at large.
Evidence that a 10-kilometer asteroid impacted Earth 65 million years ago includes a huge, crater-shaped structure in the Gulf of Mexico and rare minerals in the fossil record, which are common in meteorites but seldom found in the Earth’s crust.
Article source: http://news.sky.com/home/technology/article/16073156Tags: celestial sky, nasa jpl, news editor, 65 million years, accurate estimate, nasa scientist, infrared light <BR/>