Popular Science reports:

The reign of the dinosaurs undisputedly came to a dramatic conclusion 66 million years ago, after the six-mile-wide Chicxulub asteroid slammed into what is now Mexico’s Yucatán Peninsula. However, the exact timeline of their extinction remains a matter of debate. Did most of the Earth’s species die a slow death of starvation after a dust-choked atmosphere blocked sunlight and ushered in a prolonged winter? Or did they quickly incinerate from globe-spanning wildfires sparked by falling, superheated space rock debris?

According to new evidence published today in the Journal of Geophysical Research: Biogeosciences, the answer may be the flash-cooked scenario.

“We’re in the realm where we might be essentially killing off everything within that first hour or two,” said Brandon Johnson, a Purdue University planetary scientist and study co-author.

Chicxulub would have immediately wiped out all life within a wide radius of its impact along the Cretaceous–Paleogene boundary, the geological demarcation between the age of the dinosaurs and the Cenozoic era. Traveling at a rate of speed of about 12 miles-per-second, the asteroid struck Earth with the equivalent force of 100 teratons of TNT—more than one billion times the strength of the atomic blasts at Hiroshima and Nagasaki. The blast created a 62-mile-wide, 19-mile-deep cavity while generating two-mile-high tsunamis and 620 mph winds. Around 25 trillion metric tons of debris rocketed into the atmosphere, which then rained down on Earth as fiery missiles called spherules to set forests ablaze. [Continue reading…]