When a celestial body with an estimated diameter of around 14 kilometers fell to Earth 66 million years ago, a huge disaster altered the environment causing the extinction of the great inhabitants of the planet, the dinosaurs. And the consequences marked the development of life in our world. But how did the massive cosmic fireball come from and where? The question about the devastating event that has now taken over the other thesis that saw the end of the giants for an atmosphere devastated by volcanic eruptions, two researchers from the illustrious Center for Astrophysics Harvard-Smithsonian asked themselves, defining the details of a story that has attracted and has been discussed for decades, arriving at the conclusion that it was a comet and not an asteroid that was responsible.
The Chicxulub crater
As is known, the evidence of the tremendous impact was the discovery of the remains of the great Chicxulub crater excavated by the comet and discovered under the Yucatan Peninsula with a diameter of 150 kilometers and a depth of 19. The devastating result was a sudden extinction of mass that led to the disappearance not only of dinosaurs, but even three quarters of the plant and animal species that lived on Earth due to a profound alteration of the atmosphere caused by tons of material thrown into the air and distributed around the globe. In the study published in the Scientific Reports of the British scientific journal Naturethe two scientists Amir Siraj and Avi Loeb elaborate a new theory that reconstructs the dramatic event by pointing the finger, first of all, at Jupiter, the largest planet in the solar system.
The influence of Jupiter
By evaluating the available data with the tools of mathematical analysis and a mountain of numerical simulations, they calculated how many comets disturbed by the strong gravitational action of Jupiter are torn from the Oort Cloud, that is, from the reservoir of relics of the formation of the Solar System that surrounds the planetary procession. «The solar system acts as a sort of pinball machine», explains Siraj, who in his life also cultivates a passion for the piano as well as that of the stars, «and so the stars with their tails come close to the Sun». Destiny is sometimes unhappy on their journey as it happened in July 1994, when comet Shoemaker-Levy crumbled under the effect of the internal tidal effect caused by the action of gravity right in the vicinity of Jupiter, falling like a brutally broken pearl necklace. in the whirlpool of the Jovian atmosphere while the Hubble Space Telescope was filming the exceptional event live.
It was not an asteroid
According to Siraj and Loeb, 20% of comets end up like this and most – they say – have a high probability of falling to Earth as well. Their assessments also coincide with the age of the Chicxulub impact, thus explaining what happened. Furthermore, the evidence gathered in the crater would confirm everything. In fact, here the findings examined are formed by carbonaceous chondrite and this would contrast with the theory that it was an asteroid coming from the asteroid belt between Mars and Jupiter that hit the Yucatan peninsula. “The carbonaceous chondrites”, the scholars specify, “are rare among the asteroids of the main belt, but probably widespread among the long-term comets coming from the Oort Cloud and this provides further element in favor of the type of impact”. Now the hypothesis of Siraj and Loeb is the subject of further investigations especially at the Vera Rubin Observatory in Chile which will go into operation next year, where we will focus in particular on the search for cometary shattering phenomena linked to the stars coming from the Oort Cloud . “It is an important step”, say the two scholars, “to prevent other disastrous events from happening again on our blue globe”.
February 16, 2021 (change February 16, 2021 | 20:05)