The Extinction of Dinosaurs For Kids. Around 65 million years ago the dinosaurs and many other species, became extinct. The mystery gave rise to countless theories on why. But in 1981 an outlandish proposal was put forward, that a huge meteor smashed into Earth obliterating life. What started off as a crazy idea has now grown into the best explanation of how and why the dinosaurs became extinct. In this episode, you will learn about the KT Extinction Event. The other explanations put forward by