Some members of the wider scientific community were skeptical of the hypothesis. However, in 1991, scientists found that the Chicxulub crater was the right age to have been formed by a massive asteroid strike coinciding with the demise of the dinosaurs. Over the years, researchers have gathered more and more evidence that the asteroid strike was indeed the impetus for the cataclysmic extinction event.
The asteroid was huge — likely between 6 and 9 miles (9.7 and 14.5 kilometers) in diameter. But its colossal size is why it largely disappeared. The rock, roughly the size of Mount Everest, hurtled toward Earth, traveling 15.5 miles per second (25 kilometers per second), according to NASA
“Basically, all this kinetic energy is converted into heat,” Goderis said. “When the thing hits the target, it will more than explode; it will be vaporized.” The impact created a cloud of dust composed of the asteroid itself and the rock it landed on. The dust spread worldwide, blotting out sunlight and lowering temperatures for years, resulting in mass extinction.
As for the asteroid, “there’s nothing left except for this chemical trace that is deposited all around the globe,” Goderis said. “This forms this tiny clay layer you can recognize everywhere in the world, and it’s basically the same instant in time, 66 million years ago.”
