The mysteries of the crater Chicxulub, the Mexican site where scientists think the end of the dinosaurs began



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In the mid-1980s, when a group of American archaeologists examined satellite images showing the Yucatan Peninsula in Mexico, they did not know how to interpret an image that deciphered them completely: an almost perfect ring, about 200 km wide

The cenotes, this reservoir of blue spring water, is a fundamental part of the Yucatan Tourist Brochures and they are repeated in this arid landscape that crosses the vast plains of Yucatan, a dry and low forest state in the far east of Mexico.

Archaeologists have discovered these deep holes that surrounded the Yucatan capital, Merida, and the port cities of Sisal and Progreso, almost casually, while trying to understand what had happened to the city. Mayan civilization which once ruled the peninsula.

The Mayans used the cenotes as a means of supplying drinking water, but the strange circular arrangement of the holes that could be seen in the satellite images made their professional colleagues puzzled at the Selper conference, held in Acapulco (Mexico) in 1988.

An unexpected hypothesis

For a scientist who was in the audience, Adriana OcampoNASA's young planetary geologist, the circular formation seemed to be the signal that indicated the line of research to which he had devoted much of his career.

"As soon as I saw the slides, I said to myself:" Ah ah, it's an amazing thing! I was very excited, but I stayed silent because, from Obviously, you do not know until you have more evidence. "

As he approached the scientists, beating heart, Ocampo asked if they had considered an asteroid impact, a giant and violent enough to have marked the planet with forms that unfold 66 million years later.

"They did not even know what he was talking about!" He laughs while remembering three decades later.

This informal discussion between Ocampo and scientists during this conference was the beginning of a scientific correspondence that would lay the groundwork for what most scientists already believe to be true today: this ring corresponds to the edge of the crater that caused an asteroid 12 km wide who struck Yucatan and exploded with unimaginable force that turned the earth into water.

Since the early 1990s, teams of scientists from the Americas, Europe and Asia have been working to complete research on outstanding issues.

Now, they believe that the impact caused a Crater 30 km deep almost instantly, coming to create for a moment a mountain twice as high as Mount Everest.

In the years following the impact, the world would have changed drastically, with a huge cloud of ash blocking the sky and creating a perpetual night for a little over a year, bringing the temperatures back to minus zero and killing about 75% of living things on the surface of the Earth, including dinosaurs.

The deadliest place on earth

Today, the central point of impact, where the mountain once stood, is a small town called Chicxulub Puerto.

During my visit to this city of a few thousand residents, I found that it consisted of low houses painted in yellow, white, orange and ocher, surrounding a modest urban square common to many other Yucatan cities.

The city has almost no advertising, so often the few dinosaur lovers attempting to make a pilgrimage on the long and winding roads of this Mexican state are lost in another nearby town called Chicxulub Pueblo, a half-hour drive away.

But even if they reach the right town, located 7 kilometers east of the white sand coast of the famous seaside resort of Progreso, nothing indicates that it was the scene of one of the most disastrous moments of the last 100 million years..

If you cross the main square, you will see dinosaur paintings drawn by children of the city. But the only monument that refers to its prehistoric past is a kind of kid-like dinosaur bone and concrete that is placed on an altar where dinosaur species are represented.

Until the publication of Ocampo's findings in 1991, this region of Yucatan had attracted little international interest. Today, a museum was inaugurated in September 2018 between Chicxulub Puerto and the capital of Yucatán, Mérida, 45 km to the south.

"The Chicxulub Puerto and its surroundings deserve to be better known around the world," said Ocampo, born in Colombia but who moved to Argentina as a child and arrived in the United States at the Age 15 years old.

The asteroid, although it has devastated the regions, he benefited from a kind above all others: humans, millions of years later, as they evolved through the destruction of the world's greatest predators.

Without this impact, humanity could hardly have existed.

"It gave us the advantage of being able to compete and thrive, as we finally did," says the scientist.

A key lesson

The discovery of Ocampo came after more than a decade of research on the impact of asteroids, but the key to understanding what these holes could mean on Earth was his work with a legendary figure of the space science, Eugene Shoemaker.

Shoemaker, the American pioneer geologist known as one of the founders of the field of planetary science, remains, 21 years after his death, the only character whose ashes are buried in the moon.

It was he who had indicated to Ocampo that it was unlikely that nearly perfect circles were the result of land forces other than asteroids and that this hypothesis could provide clues to the geological development of the Earth.

The idea that a giant asteroid destroyed the dinosaurs was proposed by Californians Luis and Walter Alvarez, father and son in the early 80s of the last century. "But at the time, it was extremely controversial," says Ocampo.

But he managed to place one of the last pieces of the puzzle that started to link scattered ideas that there were among the different scientists who worked independently with information.

The first person to connect the Yucatan Ring to Álvarez's Asteroid Theory was a Texas reporter, Carlos Byars, who had written an article for the Houston Chronicle in 1981, asking if the two phenomena could be related.

Later, Byars shared his theory with Alan Hildebrand, a student, who then approached Penfield after examining rocks in Haiti. They are the ones who determined that the crater It was not a volcano, but an asteroidal impact.

"[Byars] He has the merit of being the first to assemble the pieces, a reporter! ", Exclaims Ocampo." It's an incredible story when all the pieces are together. "

The lessons learned in the Mexican crater provided very valuable information to NASA's Curiosity spacecraft, which landed on Mars in 2012 and has spent the last six years studying the Martian environment and geology.

Debris discovered from the impacts of asteroids on Mars Compared to those found in Chicxulub, they show similarities that indicate that Mars must have a much thicker atmosphere than today, closer to Earth today and allowing life on our planet.

"It's important for us to know what has happened in the past to be prepared for the future," Ocampo said. "This gives us a very good idea of ​​what happened in the geological evolution of Mars."

Ignorance of a single phenomenon

Much of the mystery of the crater Chicxulub remains buried and its authenticity is unknown to its inhabitants or those who visit the city, despite the opening of the museum.

Mexico asked that the crater be recognized by Unesco. There is very little that visitors can see because the impact took place a long time ago.

Tourists who visit one of the few remaining vestiges, the impressive cenotes, where you can swim among the fish and the hanging roots of the trees, they will ignore that these geological features only exist because the soft limestone of which they are composed was forced to the surface of the subsoil because of the impact of a gigantic asteroid.

"They [la gente y las autoridades locales] try to get people to have a more knowledge about this phenomenonoronly meno", thinks Ocampo, who is also an advocate for the teaching of planetary sciences in Latin America.

"It's a unique place on our planet, it is and should be kept as a World Heritage Site."


This article was originally published in English for BBC Future and you can read it here.


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