"The worst day in the history of the Earth" .. What happened 66 million years ago and will be repeated soon?

Introduction to translation

Our planet is like a huge sprawling network of a very fine and very sensitive silk thread. At the points of intersection of that network are living beings, including humans, but what happens if one of the points of that network vibrates violently or is cut off?

Of course this will affect the whole network, which is already happening.

At first glance, these effects seem very simple, but they accumulate to make major changes in our world. We are witnessing massive heat waves, floods and hurricanes that have not occurred before, but the most dangerous of all is that there are some research indications that the extinction of life forms is currently taking place, and researchers compare it to what It happened to the Earth 66 million years ago and it was the worst day in its history, so are we really on the verge of a catastrophe?

translation material

Planet Earth experienced the worst day in its history exactly 66 million years ago.

The story began when an asteroid the size of Manhattan collided with the Mexican Yucatan Peninsula, leaving a crater 30 kilometers deep.

The heat from this impact was so intense that the rocks evaporated, and the impact flew them away until they reached the moon.

The planet was violently shaken by a 12-magnitude earthquake, causing a tsunami to surge across the Gulf of Mexico. Firestorms, while some of the remaining debris remained stuck in space, in turn blocking the sun's rays from the planet, to begin one of the worst stages of Earth's history, which is the cooling of the planet's surface.

By the time the curtain came down on this chapter of the story, about 75% of all living things on the planet's surface had become extinct, including all non-flying dinosaurs. ' or 'KT Extinction'.

When the hypothesis explaining the "Effect of the End-Cretaceous Mass Extinction on Planet Earth" was first proposed in 1980, the day the dinosaurs went extinct acquired great mythological significance, yet this theory still remains a mystery.

For example, one of the most important questions that we may have now: Why did this particular asteroid end the era of the dinosaurs, which lasted about 180 million years, even though no asteroid that hit the Earth before that caused any mass extinction?!

The secret behind the extinction

To answer this question, a new paper published in October 2019 in the Proceedings of the National Academy of Sciences offers an explanation showing that the impact of this collision altered the chemical content of the oceans. On planet Earth, as this has increased the acidity of sea water, making it a completely unsuitable environment for the most important element of the marine food chain, the small plankton (plankton).

In addition to this catastrophe, the planet also fell captive to a sky shrouded in pitch darkness, and the weather tinged with deadly cold.

In the face of this tragedy, most living creatures could not withstand this violent environmental disturbance.

The answer provided by this paper may be somewhat satisfactory, but it is not without ominous omen, because the phenomenon of ocean acidification, the main cause and most famous feature of the previous mass extinction of the Earth, is repeated again today.

So the most important question here remains: How does an asteroid impact on Earth cause an extinction?

“It seems that the asteroid chose the correct site for the impact, the Yucatan Peninsula was an excellent location for it, because the peninsula is basically accumulations of ancient coral reefs buried with dead sea creatures of up to "It's now more than a mile thick, and the moment the asteroid hit the peninsula, countless tons of that ancient organic matter - rich in nitrogen and sulfur - instantly turned into scattered dust into the atmosphere."

Soon this dust came back down again in the form of nitric oxide and sulfuric acid, and about this, says Hal, "the sky was raining with acid and sulfur", as well as the air that smelled of smoky and burning matches.

The tragedy intensified when acid built up in the oceans, eroding the tiny plankton shells that are the basis of the marine food chain.

Within a few centuries of the impact of all these things, the planet has experienced many types of disasters, the most important of which is an increase in the acidity of the oceans to at least 0.3 pH, which is a significant percentage.

In the same context, Hall says: "This rise in ocean acidification may only last for a thousand years or less, but it was of course long enough to wipe out entire ecosystems."

Ocean acidification has exacerbated other sweeping environmental changes caused by the impact of the asteroid impact, such as the darkness in which the planet has been engulfed for years by ash from global wildfires that has blocked out the planet's sunlight.

Ocean acidification... the straw that broke the camel's back

The third extinction, which is considered the worst extinction in the history of the planet, is the “end-Permian mass extinction” that wiped out nearly 85% of all species, and after it brought a curse of barrenness to almost all of the oceans.

New discoveries have shown that the most prominent feature of the three worst mass extinctions on Earth was ocean acidification.

The list of these extinctions included: the Cretaceous Tribal Extinction "KT", and the mass extinction at the end of the Triassic period, when volcanoes in New Jersey wiped out 75% of all living things on the planet.

The third extinction, which is considered the worst extinction in the history of the planet, is the “terrible end-Permian mass extinction” that wiped out nearly 85% of all species, and after it brought a curse of barrenness to almost all of the oceans.

As a result of this tragedy that affected the entire planet, scientists called this event the "Great Death".

The pattern adopted by previous extinctions is worrying, because the same scenario is gradually being repeated today, and the closest evidence for this is the dissolution of carbon dioxide - the main air pollutant and the main cause of global warming - and its melting in the oceans, which resulted in an increase in the acidity of sea water.

Since the late 1980s, ocean acidity has been rising by 0.02 pH every decade, according to a September 2019 report from the Intergovernmental Panel on Climate Change. The report also showed that more than a fifth of modern carbon pollution has already dissolved in oceans.

The degree of acidification today is not what it did during the Tertiary Cretaceous extinction, but it is "moving in that direction," says Hall.

The common factor between the current conditions of our world and this period of extinction is “the possibility of many other environmental disasters interfering with the phenomenon of ocean acidification, resulting in all of this catastrophic disturbance. Therefore, we must think of the phenomenon of ocean acidification as the straw that broke the camel’s back.”

Hal continues: “As if the pitch-black darkness the planet plunged into during this extinction, along with the relentless specter of coldness, were not enough to burden the planet, so the acidification of the oceans came to add to its burden, and turned into the last straw that broke the camel’s back, and folded This era page.

Earth's future

In the same context, Chris Lowery, who is interested in studying oceans in past times at the University of Texas at Austin, believes that this research paper represents a “big step” in our understanding of extinction, saying: “It is true that we have known for some time that there is a degree of ocean acidification resulting from the impact of the asteroid on an island Mexican Chicxulub, where evidence was found from the huge Chixulub crater left by its impact, but this is the first time that scientists have determined the actual amount of ocean acidification.”

Lowry says that the assumptions made by paleontologists to explain how an asteroid impact might have caused the Triassic extinction are only preliminary.

Although the asteroid hit Mexico at the time, the definitive evidence for this study emerged from a cave in the Netherlands that preserves fossils from the oceans from decades or centuries immediately after the impact.

To analyze the chemical fingerprints of these fossils, Michael Heinehan, a scientist at the German Research Center for Geosciences and a researcher in Hull's laboratory, collected and crushed more than 7,000 plankton fossils found in the cave, each about half the size of a grain of sand. After that to analyze their chemical fingerprints.

About this, Hall says: "It was not easy to obtain these measurements, as it required tremendous efforts to obtain them, and we believe that there is one place in the world that preserves these fossils."

Two years ago, another study revealed the first geological evidence to support the hypothesis of global cooling that imposed itself on the planet for many years.

It is worth noting that the results of this study do not support the idea that the environmental impacts of massive volcanic eruptions in India in the area known as the Deccan Traps may have a role in increasing ocean acidification and mass extinction, but this hypothesis is supported by a few scientists Among them is Gerta Keeler, a geologist at Princeton University, who believes that volcanic activity in India's Deccan region was the main reason for the extinction of these species.

Ultimately, Lowry says, "this study shows conclusively that these volcanic eruptions have had no effect on ocean chemistry."

While Gerta Keeler criticized this research paper, saying: "This study does not investigate the accuracy of the date of this asteroid impact on Earth, as the real date of its impact occurred more than 100,000 years ago, that is, before the beginning of the extinction."

In the end, scholars differ between a supporter of this hypothesis and an opponent of it, and each of them clings to its arguments, but it remains a hypothesis worthy of contemplation, as it is terrifying in the extreme.

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Translation: Somaya Zaher

This report has been translated from The Atlantic and does not necessarily reflect the website of Meydan.