???? Some 66 million years ago, the Earth was populated by majestic and imposing creatures that dominated continents and oceans. Dinosaurs, giant reptiles whose diversity and power continued to grow over the millennia, seemed invincible in their domination of the world. For more than 160 million years, these fascinating creatures evolved, thrived and adapted to diverse environments, from vast arid plains to dense tropical forests. However, this golden age of prehistoric megafauna was to come to an abrupt and mysterious end. The sudden disappearance of the dinosaurs, which marked the transition from the Cretaceous to the Paleogene, is one of the most enigmatic and studied events in Earth's history. The extinction of the dinosaurs, which also took with it almost 75% of all living species of the time, remains a subject of fascination and debate among scientists. There are many hypotheses to explain this cataclysm, and while some have been consolidated over the years, they continue to be refined as new discoveries are made. The most widely accepted theory, supported by a large body of evidence, is that of an asteroid impact. This dramatic scenario proposes that a celestial body, about 10 kilometres in diameter, struck the Earth with unprecedented force, triggering a series of events that radically transformed the global environment. Traces of this impact can be seen in the Chicxulub crater on Mexico's Yucatan peninsula. This crater, about 180 kilometres in diameter, is a vestige of the titanic collision that is believed to have released energy equivalent to billions of atomic bombs. The impact would have thrown immense quantities of debris into the atmosphere, forming a cloud of dust and aerosols that would have obscured sunlight for years, even decades. This “impact winter” would have caused a drastic global cooling, altering climate cycles, reducing photosynthesis and causing food chains to collapse. Marine ecosystems would not have been spared. Ocean acidification due to lower temperatures and chemical changes caused by the impact would have had devastating consequences for marine life. Coral reefs, home to a wide variety of life, would have collapsed, and many species of plankton, the base of the marine food chain, would have disappeared. Without enough sunlight, land and marine plants would have declined, depriving herbivores of food and, consequently, carnivores of the prey they needed to survive. However, although the impact theory is compelling, it alone is not enough to explain the mass extinction of the dinosaurs. Other environmental factors probably contributed to this catastrophe. At the same time, the Earth was experiencing intense volcanic activity, especially in what is now India. Eruptions of the Deccan Traps, a vast region of lava flows, are believed to have released huge amounts of carbon dioxide and other greenhouse gases into the atmosphere, exacerbating climate change. These eruptions are also believed to have released sulphur aerosols, further darkening the atmosphere and cooling the planet. The combination of these events – an asteroid impact, volcanic eruptions and global climate change – is believed to have created unbearable conditions for the survival of the dinosaurs. Within a few years, these creatures, once the undisputed masters of the Earth, were gone. But the extinction of the dinosaurs also ushered in a new era, that of mammals, which allowed them to diversify and colonise ecological niches that had been left vacant. These included primates, whose distant descendants would end up dominating the world in turn. Research into the extinction of the dinosaurs is constantly evolving. Each new discovery, whether a preserved fossil, geochemical traces or climate simulations, adds new elements to this complex puzzle. Other hypotheses have been proposed, from the multiplication of epidemics to variations in the sea, but none has as much support as the impact theory. However, this scientific debate is far from over, and discussions continue around the scale of the respective contributions of these different factors. ???? As a reminder, videos are published on SUNDAYS at 9:00 p.m. This channel is an official affiliate of the ORBINEA STUDIO network.