Scientists Pinpoint Asteroid Origin That Extinguished Dinosaurs

The infamous asteroid that struck Earth around 66 million years ago, leading to the mass extinction of dinosaurs, is believed to have originated from our solar system, specifically beyond Jupiter. A recent study, published on August 16, supports this claim.

This catastrophic impact left geochemical evidence, including elevated levels of iridium, in a thin rock layer found across various countries worldwide.

Through chemical analysis of these rock sediments, which mark the boundary between the Cretaceous and Paleogene periods (the KPg boundary), scientists are piecing together a forensic profile of the asteroid responsible. The asteroid, which created the Chicxulub crater in present-day Mexico, has been identified as a C-type asteroid.

This new research challenges previous theories that suggested a comet was responsible for the mass extinction event.

Geochemist Mario Fischer-Gödde from the University of Cologne in Germany, along with his team, analyzed five isotopes of ruthenium found in the KPg rock layers, five other impact craters from events that occurred between 36 million and 470 million years ago, and Earth-based platinum ores.

“Our lab in Cologne is one of the few facilities capable of conducting these measurements,” Fischer-Gödde explained, adding that “this was the first time such advanced techniques were used on impact debris layers.”

Ruthenium, like iridium, is part of the platinum group of elements, which are rare in Earth’s crust but more common in asteroids and other space objects. The relative abundance of ruthenium isotopes can vary depending on the origin of the space object.

The team found that the ruthenium signatures in the KPg rocks were distinct and consistent with a single event, confirming the extraterrestrial origin of the material. This evidence suggests that the asteroid impact, not volcanic activity, was the primary cause of the dinosaurs’ extinction.

Most meteorites found on Earth are siliceous or stony and originate from the asteroid belt between Mars and Jupiter. This belt was also the source of the five non-Chicxulub impactors analyzed. However, the Chicxulub impactor was a carbonaceous asteroid, which came from the outer regions of the solar system, an ancient asteroid belt located beyond Jupiter.

“With this new understanding, we can confidently say that this asteroid initially formed beyond Jupiter,” Fischer-Gödde told AFP.