A groundbreaking study has revealed that the asteroid responsible for the mass extinction event 66 million years ago, which wiped out about three-quarters of Earth’s species including the dinosaurs, likely originated from beyond Jupiter in the outer solar system.
This asteroid, estimated to be 6-9 miles wide, struck the Yucatan Peninsula in Mexico, creating the massive Chicxulub crater. The impact triggered a global catastrophe, and debris from the asteroid has since been found in a worldwide layer of clay. Recent analysis of this debris has confirmed that the asteroid was a carbonaceous, or C-type, asteroid—rich in carbon and among the oldest and most common types in our solar system.
The study, published in the journal Science, was led by geochemist Mario Fischer-Gödde of the University of Cologne in Germany. It dispels previous theories that the impactor might have been a comet or related to volcanic activity.
The researchers specifically examined the isotope ratios of ruthenium, a metal found in the clay layer left by the impact. These ratios matched those of known C-type asteroids, reinforcing the conclusion that the asteroid originated in the outer solar system. The study suggests that after forming far from the sun, the asteroid likely migrated inward to the main asteroid belt between Mars and Jupiter before being deflected towards Earth.
This rare cosmic event not only ended the reign of the dinosaurs but also paved the way for mammals, and eventually humans, to become the dominant species on Earth. As Fischer-Gödde noted, without this asteroid impact, life on Earth might have followed a vastly different path.