It was a turning point in the history of life on Earth. An asteroid an estimated 10-15 km wide slammed into Mexico's Yucatan Peninsula 66 million years ago, triggering a global cataclysm that eradicated about three-quarters of the world's species and ended the age of dinosaurs.
The impact pulverized the asteroid and spread its debris worldwide, still present in a global layer of clay deposited in the aftermath of that fateful day. A new analysis of this debris has resolved a long debate about the nature of the asteroid, showing that it was a type that originated beyond Jupiter in the outer solar system.
The impactor, based on the debris composition, was a carbonaceous asteroid, or C-type, so named because of a high concentration of carbon. The study ruled out that the impactor was a comet or that the debris layer had been laid down by volcanism, as some had hypothesized.