Scientists Identify Dinosaur-Killing Asteroid as Rare CO Chondrite from Outer Solar System
A team of scientists has identified the asteroid that wiped out the dinosaurs 66 million years ago as a rare CO chondrite originating from the outer reaches of the solar system. This finding, which comes from analysis of the Chicxulub impact crater and related geological evidence, suggests the impactor belonged to a class of asteroids that make up less than 5% of near-Earth asteroids.
The research challenges previous assumptions about what made the impact so devastating. Instead of sulfur-rich material—which had been hypothesized as the primary cause of climate cooling—the team's evidence points to planet-cooling dust and debris ejected into the atmosphere as the main culprit behind the mass extinction event.
The unusual chemistry of this asteroid type suggests it contained materials that, when pulverized upon impact, could have created a global dust veil capable of blocking sunlight and disrupting ecosystems for an extended period. This new understanding helps explain the severity of the extinction event that eliminated approximately 75% of all species on Earth.