What Killed the Dinosaurs? The Chicxulub Impact

66 million years ago, an asteroid approximately 10 km in diameter struck what is now the Yucatan Peninsula in Mexico, creating the 180 km Chicxulub crater. The impact released energy equivalent to 100 million megatons of TNT, about a billion times the Hiroshima bomb. Immediate effects included massive tsunamis, global wildfires, and an earthquake estimated at magnitude 11-12.

Long-term, dust and sulfate aerosols blocked sunlight for years, collapsing food chains. About 75% of all species went extinct, including all non-avian dinosaurs. The extinction opened ecological niches that allowed mammals to diversify and eventually produce humans..