Sixty-six million years ago, a massive celestial eruption struck off the coast of modern-day Mexico, triggering a catastrophic “winter impact” that wiped out three-quarters of life on Earth, including dinosaurs .
A pair of astronauts at Harvard say they have now solved long-standing mysteries about the nature and origin of the “Chicxulub winner.”
Their analysis reveals that it was a comet that originated in an area of frozen debris on the edge of the solar system, on which Jupiter was responsible for the matter entering our planet, and that we can expect similar effects every 250 million to 750 million years.
The duo ‘s paper, published in the journal Scientific Reports this week, pushes back against an older theory that a fragment of an asteroid originated from the Main Belt of our solar system that was in the object.
“Jupiter is so important because it is the largest planet in our solar system,” lead author Amir Siraj told AFP.
Jupiter ends up as a kind of “pinball machine” that “kicks these long-distance comets into orbits that bring them very close to the sun. ”
The so-called “long-lived comets” come from the Oort cloud, which is thought of as a large spherical shell around the solar system like a bubble made of frozen pieces of mountain size or larger.
The comets take about 200 years to orbit the sun and are also called sungrazers because of their proximity.
Because they come from the deep freezing of the outer solar system, comets are superior to asteroids, and are known for the amazing gas and dust passages they make during melting.
However, Siraj said, the warming effects of solar heat on sungrazers are nothing compared to the massive tidal forces they receive when one side confronts our star.
“As a result, these comets experience such a tidal force that the largest of them would shake into about a thousand fragments, each of these fragments large. enough for a Chicxulub-sized machine gun, or a dinosaur-killing event on Earth. ”
Siraj and co-author Avi Loeb, a professor of science, developed a statistical model that showed the likelihood of long-term comets hitting Earth that is consistent with the age of Chicxulub and other known influencers.
The previous theory about the object being an asteroid yields an expected rate of such events that went off by a factor of about 10 compared to what was observed, Loeb told AFP.
‘Beautiful view’
Another line of evidence favoring the origin of the comet is the composition of Chicxulub – only about a tenth of asteroids from the Main Belt, which lies between Mars and Jupiter, are composed of carbonaceous chondrite, while as it is with most comets.
Evidence shows that the Chicxulub crater and other similar craters, such as the Vredefort crater in South Africa that was wrecked about two billion years ago, and the million-year-old Zhamanshin crater in Kazakhstan, were all air carbonaceous chondrite.
The hypothesis can be verified by further study of these cavities, those on the moon, or even by the deployment of space probes to extract samples from comets.
“It must have been a beautiful sight to see this rock come close to 66 million years ago, it was bigger than the length of Manhattan Island,” Loeb said. we prefer to learn to keep track of such things and devise ways to remove them, if necessary. ”
Loeb said he was excited about the prospect of the Vera Rubin Observatory in Chile operating next year.
The telescope may see a tidal wave of long-running comets “and will be crucial in making predictions for the next 100 years, to see if anything bad could happen to us , “he said.
While Siraj and Loeb ‘s measurement of Chicxulub – like effects would occur once every few hundred million years, “it’ s a statistical thing,” Loeb said. “You say ‘average; It so often,’ but you don’t know when the next one will come.”
“The best way to find out is to study the skies,” he concluded.