Not a comet made of ice

Asteroid said to have been “dinosaur killer”

An asteroid - not a comet - is thought to be responsible for the Chicxulub event. (AI-generated image)(Bild: zahidcreat0r)

A rocky asteroid hit what is now Mexico 66 million years ago and caused the extinction of the dinosaurs, Austrian impact researcher Christian Köberl and his colleagues have discovered. It was therefore not an ice-rich comet, as previously assumed. 

The scientists were able to prove this using the "geochemical fingerprint" of the impact body in the crater. The study has been published in the journal "Science".

A team led by Mario Fischer-Gödde from the Institute of Geology and Mineralogy at the University of Cologne (Germany) examined the remains of the impact body in the Chicxulub crater in Mexico.

Based on the variants (isotopes) of the element ruthenium, it is "quite clear that the impact body there was a carbonaceous asteroid", the researchers explain. Also on the team: Christian Köberl, Professor at the Department of Lithosphere Research at the University of Vienna.

"Dinosaur killer" formed beyond Jupiter
The asteroid originated from "beyond the orbit of Jupiter", i.e. much further away from the sun than the Earth orbits around it. Asteroids are chunks of rock and metal that move around the sun in regular orbits like planets, but are much smaller. In the rarest of cases, they go astray and hurtle towards the Earth, like the impact body in question 66 million years ago.

Fragments of the asteroid have spread all over the world.(Bild: AFP/Philippe CLAEYS)

There are thousands of them in the solar system. Comets, on the other hand, consist mainly of dust and ice. When they approach the sun, the latter evaporates and becomes visible as a "tail". A meteor stream such as the current Perseids shower, on the other hand, consists of dust grains that burn up when they enter the Earth's atmosphere.