Dinosaurs may have been killed by comet, new extinction study reveals

Harvard researchers speculated that a piece of a comet crashed into Earth over 66 million years ago to create the Chicxulub crater, according to a study published Monday in Scientific Reports.

The Chicxulub Crater is located on the Yucatán Peninsula in modern Mexico and stretches for approximately 110 miles. The impact that created the crater is linked to the Cretaceous-Paleogene extinction event, which killed dinosaurs and many other species, according to the study.

Loeb theorizes that a piece of a comet was the culprit for the mass extinction event, not an asteroid as many scientists have assumed. The comet originated from the Oort Cloud, a group of icy objects located on the edge of the solar system, he said.

A comet is a piece of space debris made up mostly of frozen gas, while an asteroid is a piece of rock most commonly found in the asteroid belt, a collection of asteroids between Mars and Jupiter, according to the weather correspondent of CNN Chad Myers.

According to the study, the probability that an asteroid with a diameter of at least 6.2 miles will cause an impact on Chicxulub is one in 350 million years. Long-period comets – comets with an orbit of more than 200 years – that are capable of the Chicxulub event are significantly rarer, with one occurring every 3.8 to 11 billion years, according to the study. .

The potential path of the comet

The researchers come up with a scenario on how the comet could have beaten these odds from afar.

As the comet made its way to the center of the solar system from the Oort Cloud, Jupiter’s gravitational force could have given it a boost so that it had enough speed to reach the sun, according to Loeb.

“Jupiter acts like a pinball machine,” Loeb said. “When something approaches it, it can kick it.”

Upon reaching the sun, the sun’s gravitational force could have shattered the comet into several pieces, he said. With more comet pieces, it’s 10 times more likely the comet will hit Earth when the pieces move away from the sun, according to Loeb.

Other researchers disagree

Other researchers disagreed with the results of the new study and still claim that there are several clues that indicate that an asteroid created the Chicxulub crater.

On the one hand, Iridium – along with a handful of other chemical elements – was found scattered around the world after the impact, said David Kring, senior scientist at the Lunar and Planetary Institute in Houston, who was not not involved in the study of comets.

Kring said the proportions of these elements are the same as seen in meteorite samples from asteroids.

The piece of comet would also have been too small to form a crater of this size, said Natalia Artemieva, a senior scientist at the Institute of Planetary Sciences, who also was not involved in the study.

The study estimated that the size of the comet piece was around 4 miles wide, and Artemieva argued that the comet would need at least 7.5 miles wide to form a crater the size of Chicxulub. With the little piece of comet, she said, “that’s absolutely impossible,” and the size of the impact crater would be at least half the size.

Kring also noted that the frequency with which an asteroid or comet hits Earth to create such an impact is statistically insignificant.

It doesn’t matter if it’s about “once every 350 million years and we had an event 66 million years ago” because statistically that would be the only event in a 350 million year period. , did he declare.

Researchers also have a plethora of asteroid samples to study compared to comets, Kring said.

“There is absolutely no evidence to prove their model is incorrect, but on the other hand, there is a lot of evidence that still points to an asteroid being the most likely impact,” Kring said.

Loeb said he wanted to look for the remaining comet pieces from the rupture to verify his theory.