About 66 million years ago, the Earth was populated by majestic, imposing creatures that dominated continents and oceans. The dinosaurs, giant reptiles whose diversity and power increased over the millennia, seemed invincible in their dominion over the world. For more than 160 million years, these fascinating creatures evolved, thrived and adapted to a wide variety of habitats, from vast arid plains to dense rainforests. However, this golden age of prehistoric megafauna came to an abrupt and mysterious end. The sudden disappearance of the dinosaurs, which marks the transition from the Cretaceous to the Paleogene, is one of the most enigmatic and well-studied events in Earth's history. The extinction of the dinosaurs, which also took with it almost 75% of all species living at that time, remains a subject that fascinates scientists and inspires debate. There are many hypotheses to explain this catastrophic event, and although some have become established over the years, they continue to be refined with new discoveries. The most widely accepted theory, supported by a wealth of evidence, is that of an asteroid impact. This dramatic scenario states that a celestial body about 10 kilometers in diameter hit the Earth with unprecedented force, triggering a series of events that radically changed the global environment. Traces of this impact can be seen in the Chicxulub crater on Mexico's Yucatán Peninsula. With a diameter of about 180 kilometers, this crater is a remnant of the gigantic collision that released energy equivalent to billions of atomic bombs. The impact would have hurled huge amounts of debris into the atmosphere, creating a cloud of dust and aerosols that would have obscured sunlight for years, even decades. This "impact winter" would have caused drastic global cooling, disrupting climate cycles, reducing photosynthesis, and leading to the collapse of food chains. Marine ecosystems would not have been spared either. Ocean acidification due to falling temperatures and chemical changes caused by the impact would have had devastating consequences for marine life. Coral reefs, home to a rich diversity of life, would have collapsed, and many species of plankton that form the basis of the marine food chain would have disappeared. Without sufficient sunlight, land and marine plants would have died, leaving herbivores without food and, consequently, carnivores without the prey they needed to survive. The impact theory, while convincing, is not sufficient on its own to explain the mass extinction of the dinosaurs. Other environmental factors probably contributed to the catastrophe. At the same time, the Earth was experiencing intense volcanic activity, particularly in what is now India. Eruptions in the Deccan Traps, a vast region of lava flows, would have released huge amounts of carbon dioxide and other greenhouse gases into the atmosphere, exacerbating climate change. These eruptions would also have released sulfur aerosols, further contributing to atmospheric darkening and global cooling. The combination of these events—asteroid impact, volcanic eruptions, and global climate change—would have created untenable conditions for the dinosaurs. Within a few years, these creatures, once the undisputed rulers of the Earth, were gone. But the extinction of the dinosaurs also ushered in a new era, that of mammals, allowing them to diversify and colonize vacant ecological niches. Among them were the primates, whose distant descendants would eventually rule the world in their turn. Research into the extinction of the dinosaurs is constantly evolving. Each new discovery, whether it is a preserved fossil, geochemical traces, or climate simulations, adds more pieces to this complex puzzle. Additional hypotheses have been put forward, ranging from the proliferation of epidemics to sea level fluctuations, but none has as much support as the impact theory. However, this scientific debate is far from over and there is ongoing debate about the extent of the respective contributions of these various factors. 🔥 As a reminder, the videos are published SUNDAYS at 9:00 p.m. This channel is an official affiliate of the ORBINEA STUDIO network