Unusual Origin Found for Asteroid That Killed the Dinosaurs
New York TimesAug 15
Study Links Dinosaur Extinction to Carbon-Rich Asteroid
Image copyright: Historical/Contributor/Corbis Historical via Getty Images
The Facts
Researchers from Germany's University of Cologne have found evidence that the rock that hit Earth 66M years ago, causing the extinction of the dinosaurs, was a carbon-rich "C-type" asteroid that formed beyond Jupiter's orbit around the same time as the Solar System.
By analyzing the remains of the crater where the asteroid hit Earth in what is now Mexico, called the Chicxulub impact, the scientists discovered the isotope ruthenium, which is commonly found in asteroids but not in the Earth's crust.
The Spin
Narrative A
The comet theory was understandable given the prevalence of carbonaceous chondrites in long-period comets, but the discovery of ruthenium proves it was more likely to have been an outer Solar System asteroid. The rocks from the impact site were from C-type asteroids, while most of the others were S-type, which are from the inner Solar System.
Narrative B
While scientists appear to have finally found the cause of the dinosaur's abrupt extinction, the species was likely on its way out — albeit at a slower rate — without the help of a celestial attack. At the time, the Earth was cooling, thus turning widespread tropical climates into a less vegetative climate. Dinosaurs, like most species throughout Earth's history, were slowly losing their food source.