What happened?
The fossil record shows that non-bird dinosaurs disappeared about 66 million years ago. Strong evidence points to a huge asteroid impact, with other Earth changes also studied by scientists.
How do we know?
Scientists use fossil patterns, rock layers, and evidence from the extinction boundary. The Natural History Museum source explains the timing and the strong asteroid-impact evidence.
What is still changing?
The broad timing is well supported, but scientists still study how the impact, climate, volcanoes, and changing ecosystems affected different forms of life.
Why it matters
The extinction is not only an ending; it is a turning point we can study from fossils and Earth evidence. It shows learners that life on Earth can change dramatically, and that the world after the extinction was different from the dinosaur world before it.