A massive asteroid impact 66 million years ago, combined with volcanic activity, killed the dinosaurs. This is not a mystery anymore — we have the impact crater, the geological evidence, and the mechanism. Here is what actually happened.
66 million years ago, an asteroid roughly 10 kilometers (6 miles) wide struck the Yucatán Peninsula in present-day Mexico. The impact released energy equivalent to billions of nuclear bombs. It vaporized rock, triggered earthquakes, and sent a tsunami across the Gulf of Mexico. The crater from this impact — Chicxulub — is still visible today.
Non-avian dinosaurs went extinct, but birds (which ARE dinosaurs, technically) survived. So did mammals, crocodiles, turtles, and many other species. Why? Smaller body size helped — mammals and early birds needed less food and could shelter in burrows. Some species could survive on insects, carrion, and seeds. Dinosaurs were massive and required enormous amounts of food daily. In a world of darkness and cold, they could not adapt fast enough.
Before the asteroid hit, the Deccan Traps in India were already in the middle of a massive volcanic period that lasted hundreds of thousands of years. Volcanoes released CO₂, causing warming and acid rain. This weakened ecosystems before the asteroid strike, making them more vulnerable to collapse. The combination — volcanic stress + impact — was lethal.
Pro tip: The K-Pg boundary (the geological layer marking the extinction 66 million years ago) contains an unusually high concentration of iridium, an element rare on Earth but common in asteroids. This iridium signature is found in the same layer worldwide, which is how scientists confirmed a single impact event killed the dinosaurs. It is detective work, not speculation.