The leading scientific explanation is that a giant asteroid struck Earth about 66 million years ago, near today’s Yucatán Peninsula, triggering the K–Pg mass extinction that wiped out the non-avian dinosaurs. The impact blasted dust and debris into the atmosphere, blocked sunlight, disrupted plant growth, and collapsed food chains.

What happened

  • The asteroid was roughly 10 to 15 kilometers wide and formed the Chicxulub crater.
  • The impact caused massive fires, tsunamis, and a long period of darkness and cooling known as an “impact winter”.
  • About 75% of Earth’s species died out in that event, including all non-avian dinosaurs.

Other factors

Some research suggests volcanic eruptions and longer-term climate shifts may have made things worse, but the asteroid impact is still considered the main cause.

Tiny timeline

  1. Asteroid strikes Earth.
  2. Dust and soot fill the sky.
  3. Sunlight drops sharply.
  4. Plants fail.
  5. Herbivores collapse, then predators follow.

A simple way to picture it: the impact didn’t just hit the dinosaurs directly; it broke the planet’s ability to keep food webs running.