September 13, 2012 – Dinosaur Killing Asteroid Suspect Cleared of Any Wrong Doing: Observations from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope, indicate the family of asteroids, some believed was responsible for the demise of the dinosaurs, is not likely the culprit, keeping open the case on one of Earth’s greatest mysteries.
While scientists are confident a large asteroid crashed into Earth approximately 65 million years ago, leading to the extinction of dinosaurs, they do not know exactly where the asteroid came from or how it made its way to Earth. A 2007 study, using visible-light data from ground-based telescopes, first suggested the remnant of a huge asteroid, known as Baptistina, as a possible suspect.
According to that theory, Baptistina crashed into another asteroid in the main belt between Mars and Jupiter about 160 million years ago (pictured above). The collision sent shattered pieces as big as mountains flying. One of those pieces was believed to have impacted Earth, causing the dinosaurs’ extinction.
Since this scenario was first proposed, evidence developed that the so-called Baptistina family of asteroids was not the responsible party. With the new infrared observations from WISE, astronomers say Baptistina is now finally be ruled out. As a result of the WISE science team’s investigation, the demise of the dinosaurs remains in the cold case files.
WISE surveyed the entire celestial sky twice, in infrared light, from January 2010 to February 2011. The asteroid-hunting portion of the mission, called NEOWISE, used the data to catalogue 157,000 asteroids in the main belt and discovered 33,000 new ones.
Visible light reflects off an asteroid. Without knowing how reflective the surface of the asteroid is, it’s hard to accurately establish the size. Infrared observations allow a more accurate size estimate. They detect infrared light coming from the asteroid itself, which is related to the body’s temperature and size. Once the size is known, the object’s reflectivity can be re-calculated by combining infrared with visible-light data.
The NEOWISE team measured the reflectivity and the size of about 120,000 asteroids in the main belt, including 1,056 members of the Baptistina family. The scientists calculated the original parent Baptistina asteroid actually broke up closer to 80 million years ago, half as long as originally proposed.
This means that the asteroid family that produced the dinosaur-killing asteroid remains at large. Evidence that a 10-kilometer (about 6.2-mile) 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 Earth’s crust.
NASA scientists continue to search for the culprit. Let’s hope it doesn’t come back for a rerun!
The Master of Disaster