One of the largest and most amazing creatures that have ever inhabited our planet are undoubtedly dinosaurs. Since the discovery of the early fossils, they have gained the interest and fascination of all, and until the early 1980s, no one knew for sure how, suddenly, they simply disappeared from the face of Earth about 65 million years ago. If today, we can say that the person responsible for the extinction of dinosaurs and most of the species of that time was the impact of a large asteroid, is thanks to a pair of father and son: Luis and Walter Alvarez.
In the month of Asteroid dayWhen we reflect on the impact of asteroids and their consequences on our planet, it is worth remembering this duo that brought us the clear and frightening understanding of that episode that, in a matter of minutes, has forever changed the story of life on Earth.
Luis Alvarez was a brilliant physicist born in 1911 in the United States. He contributed to the radars in World War II, worked on the Manhattan Project and, in 1968, won the Nobel Prize in Physics for his research on subatomic particles. His son Walter, on the other hand, followed a different trail: that of geology. While his father investigated the invisible in the world of particles, his son excavated the layers of the earth’s geological past, trying to understand the succession of events that shaped the planet over billions of years. Two distinct worlds that would come together in one of the most impactful scientific investigations of the twentieth century.
In the 1970s, it was still a mystery which would have caused the extinction of dinosaurs, about 65 million years ago. There were many theories: abrupt climate change, intense volcanic eruptions in India, disease, and even a collective diarrhea… But nothing seemed to accurately explain the sudden mass extinction recorded at the end of the Cretaceous period. It was in this context that Walter Alvarez, studying sedimentary rocks in the Gubbio region of Italy, realized something peculiar: a very thin layer of clay, dated exactly the transition between the geological periods of the Cretaceous and Paleogen, and which had an abnormal concentration of iridium.
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Intrigued by that iridium, Walter took the discovery to his father. It turns out that iridium is a very difficult chemical element to find in the earth’s crust. Being a rare and heavy metal he migrated to the planet’s core at the time of earthly formation. But you know where iridium is more abundant: in meteorites. This led, Luis Alvarez, with his gaze as an experimental physicist, to see an extraordinary hypothesis: What if that iridium had come from space? What if the planet was actually hit by such a gigantic asteroid that it threw a global cloud of dust and metals, capable of blocking the sun, interrupting photosynthesis and triggering a collapse on the basis that sustained life on Earth?
The two began to make calculations. They estimated that an asteroid would be about 10 kilometers to spread the amount of iridium found in that layer all kick. A body of this size, when colliding with the earth, would release energy equivalent to billions of atomic bombs. And so the hypothesis of the great impact was born – a bold idea that united geology, physical and a lot of scientific intuition.
But like every revolutionary idea, theory faced resistance. Many experts considered it absurd to crediting the extinction of dinosaurs to such a sudden and “exotic” event. It seemed more palatable to imagine long periods of change, gradual processes, not a cinematic cataclysm. But over time, evidence began to accumulate.
In the following years, geologists found the same layer rich in iridio in various parts of the world. Then came the shocked quartz deposits – a type of crystal deformed by intense pressures, typical of meteoric impacts. And finally the icing of the cake: the identification of the crater of Chicxulubin the Yucatan Peninsula, Mexico. A structure with more than 180 kilometers in diameter, buried under the geological layers, dated exactly the end of the Cretaceous. An impact of that magnitude would have caused earthquakes capable of triggering, on the other side of the globe, the intense volcanic eruptions in India, as well as megatsunamis and devastating fires, followed by a global winter caused by dust that covered the planet for several years.
With so many pieces fitting into the puzzle, the scientific community gradually accepted the hypothesis. Today, it is widely recognized as the most plausible explanation for downstreaming – and for the rise of mammals, including some that evolved into a species that developed the ability to reflect on the future and seek answers about the past.
But the consequences of this discovery went beyond paleontology. Alvarez theory has changed the way we perceive the very fragility of life on earth. If a single object coming from space was able to trigger such devastation, which prevents us from suffering something similar in the future? This new awareness was fundamental to the emergence of asteroid monitoring programs near Earth, the Neos. Asteroid Day, which we celebrated all June 30, was also born of this scientific awakening.
Something that also reflected in pop culture. Movies such as Armageddon, Deep impactand even the recent Don’t look up They are direct heirs of the theory of impact. Of course Hollywood exaggerates a little… or maybe a lot… But if we understand that cosmic impacts help to model the planet’s geology and biology, it is because Luis and Walter Alvarez have transformed an intriguing mystery into a powerful and fascinating scientific explanation.
Understanding past events is critical to preparing for the future. Therefore, both the Father and the Son are fundamental figures for science and the protection of our planet. Luis and Walter Alvarez saw, in the rigidity of the rock, a precise portrait of the event that changed the story of life on earth. And that is why, unlike dinosaurs, humanity today has the opportunity to avoid a catastrophe like that of 65 million years ago. We need to follow the sky and study the asteroids that surround us, so that even in the distant future, let us be ourselves telling our own history.
