There has been a great deal of speculation over the years and substantial evidence that an asteroid is likely what extinguished all dinosaur life. Science could never prove what asteroid may have triggered the extinction. One of the most likely candidates, the 9-mile-wide asteroid that impacted Chicxulub, Mexico, was believed to have occurred 300,000 years prior to the extinction.
Now, however, European and American scientists have re-tested debris from Chicxulub using state-of-the-art equipment and narrowed the asteroid impact down to a period of 11,000 years, between 66.03 and 66.04 million years ago — almost simultaneous with the Cretaceous-Paleogene extinction.
The collision, which left behind a 180-kilometer (110-mile) crater, released 420 zettajoules of energy — 100 teratonnes of TNT. The impact created a huge dust cloud that blocked out the Sun, starting the extinction ball rolling by killing off much of the world’s plants, and thus the herbivores soon after. Due to high levels of oxygen in the Cretaceous atmosphere, the impact may also have caused intense, global firestorms that killed off many other species. Because the asteroid landed in the ocean, megatsunamis would’ve swept the world’s coasts, too.