I'm taking this one on separately, as I don't know if it belongs in a religion thread.
No one claims, with absolute certainty, that a single asteroid destroyed the dinosaurs. In fact, there are still dinosaurs alive today. Alligators and crocodiles, as well as sharks and some other sea creatures, are virtually unchanged from 100 million years ago.
But there is evidence to suggest that the asteroid which struck the Yucatan Peninsula 65 million years ago caused such a disruption in the Earth's climate that the large dinosaurs, the "thunder lizards" died out. There is ample evidence to show that an asteroid did, indeed, strike the Earth at that time. There are calculations which show that it would have had to be of a certain mass striking at a certain speed in order to have covered the globe with the debris layer which scientists have found. And to date there is no evidence to show that any large populations of dinosaurs (other than those few which I mentioned) survived past that impact period.
I don't claim to have the type of education which would allow me to interpret the kinds of data that is being discussed here, but I know that there are many scientists who do have that education and who do agree with the interpretation.And there are many who do not agree. By studying both sides of the issue I have come to the conclusion that this particular asteroid strike was most likely responsible for the ultimate extinction of most of the Earth's species. The arguments in favor make more sense to me than those against.
That does not mean that this is a fact! It's just a theory, and evidence could turn up tomorrow which will overturn it. That's the beauty of science. We are always learning new things, and sometimes the old things are tossed out like old garbage. They don't fit anymore.