New Discovery on Chicxulub Asteroid Reveals Its Origins and Implications for Earth’s History

This new view of the asteroid (or asteroids) that hit Chicxulub on the territory of the Yucatan Peninsula today in Mexico should provide a better understanding of the history of celestial bodies that hit the Earth.

“We can now say that this asteroid first formed outside of Jupiter,” lead author Mario Fischer-Gödde told AFP study and a geochemist from the University of Cologne.

This is a very interesting result, also because this type of asteroid rarely hits our planet. According to the scientists, this type of information could be useful in assessing threats to the globe in the future or in explaining how water reached the Earth.

This new work is based on the analysis of sediment samples from 66 million years ago that contained particles that were released into the atmosphere after an asteroid impact.

The scientists measured the isotopes (that is, the types of atoms) of the metallic chemical element ruthenium. Earth’s sediments don’t contain ruthenium, so the researchers knew that the ruthenium they measured came “100 percent” from the asteroid.

“Our laboratory in Cologne is one of the few that can perform this type of analysis,” Mario Fischer-Gödde emphasized. And he said this is the first study of an asteroid from Chicxulub or any other significant celestial body that has hit Earth.

Ruthenium isotopes can be used to distinguish between two main groups of asteroids: C-type (carbonaceous) asteroids, which formed in the outer Solar System, and S-type (silicate) asteroids, which were formed in the inner solar system. The study concluded that the asteroid responsible for the extinction of the dinosaurs was a C-type asteroid that formed behind Jupiter.

Previous studies made this assumption two decades ago, but with much less certainty.

This result is surprising because most meteorites, which are fragments of asteroids that hit the Earth, are type S meteorites according to Fischer-Gödde. So does this mean that the devastating asteroid came to right from behind Jupiter? That is not necessary, according to the scientist.

“We cannot be sure where the asteroid was just before it hit the Earth,” he explained. According to him, after it was formed, it could have stopped in the asteroid belt , which is located between Mars and Jupiter and where most meteorites come from.

The study also contradicted the idea that the object that fell to Earth 66 million years ago was a comet (icy rocks growing at the edge of the Solar System). This hypothesis has been widely published explore in 2021, but it was based on statistical simulations.

Analyzes of the samples now show that the object had a very different composition from a special category of meteorites, the carbonaceous chondrites, which are thought to have been comets in the past. According to Mario Fischer-Gödde, it is therefore “unlikely” that the object is a comet.

The geochemist gives two answers to the question of the wider applicability of these results.

First, he believes that a better explanation of the nature of the asteroids that have hit our planet since its inception, around 4.5 billion years ago, could help solve the mystery of the origin of water on Earth. Scientists believe that asteroids may have brought the water to Earth, but it is more likely that they were C-type asteroids, like the ones that hit 66 million years ago, even though they hit as often

According to the researcher, going back in time also makes it possible to prepare for the future. “If we find that other ancient extinctions are also associated with C-type asteroids, we have to be very careful if such an asteroid were to cross Earth’s orbit again one day,” he said. “Because this might be the last we’ll ever see,” he concluded.