Russian Meteorite explains mystery behind dinosaur extinction

Washington: A new study on Russian Chelyabinsk meteorite has shed a light on the long-standing debate about the source of the asteroid that impacted the Earth and caused the extinction of the dinosaurs.

Astronomers have debated whether the dinosaur killer was linked to the breakup of a large asteroid forming the Baptistina Asteroid Family (BAF) beyond Mars, some of which ended up on Earth-crossing orbits. The asteroid impacting Earth is thought to have been dark and carbonaceous. The BAF hypothesis was bolstered by them being dark and with a spectral shape similar to carbonaceous meteorites. Analysis of the Chelyabinsk meteorite shows that shock produced during catastrophic disruption of a large asteroid can darken otherwise bright silicate material. Shock darkening was first reported by Dan Britt (now at the University of Central Florida) in the early 1990s. Vishnu Reddy, Planetary Science Institute Research Scientist and lead author of "Chelyabinsk meteorite explains unusual spectral properties of Baptistina Asteroid Family", said that the Chelyabinsk meteorite has both bright unshocked and dark shocked material, however, the details of the spectra of the dark Chelyabinsk material closely reproduces spectral signatures seen with members of the Baptistina Asteroid Family. He further explained that not all dark asteroids are rich in carbon as once thought, so the latest measurements rule out the possibility for the Baptistina family being the source of the K/T impactor. The new finding has implications for hazards from Near-Earth Objects and for mining asteroids for space-based resources and a potential target identified as primitive and rich in volatiles/organics and carbon based on its spectral colors could in fact be just shocked material with entirely different composition. The study is published in the journal Icarus shows.