The hunt for the asteroid that wiped out the dinosaurs is back on, after a NASA mission indicated that the current suspected space rock is not the likely culprit.
A study in 2007, which used visible-light data from ground-based telescopes, had suggested that a fragment of a huge ancient asteroid known as Baptistina had been the one to plunge to Earth and annihilate the ancient reptiles. But NASA's Wide-field Infrared Survey Explorer (WISE) has figured out that Baptistina broke up just 80 million years ago, which doesn't give the remnants enough time to make it to Earth and plunge the dinos into extinction 65 million years ago.
"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," said Lindley Johnson, program executive for the Near Earth Object Observation Program at NASA.
Many scientists believe that dinosaurs – which as a group comprised over 1,000 species – were wiped out along with several other species when a massive asteroid hit Earth, throwing dust clouds and smoke from forest fires up into the sky, thereby darkening and cooling the planet. According to this theory, the resulting climate change affected the growth of plants at the bottom of the dinosaurs' food chain, leading to the eventual demise of the monsters.
Evidence to support this claim includes a huge crater in the Gulf of Mexico and layers of rare minerals in the fossil record, which are rare in the Earth's crust but often found in meteorites. ®