The reason we know dinosaurs existed, and were wiped out by an asteroid, is that no matter where you dig in the world, you’ll find a distinct layer of clay. All dinosaur fossils are found below this layer, and never above it! This layer has iridium that is very rare on earth but found in asteroids.
It is called K-T (Short for Cretaceous-Tertiary) boundary
The Dinosaur series on Netflix is one of the best things I’ve watched this year, but also just reminds how temporary our existence is. once Earth decides she’s done with us, we will be dealt with lol