There are lots of theories about how the dinosaurs died out, and some evidence to support them. The most popular seems to be that a big meteor hit earth and caused a lot of climate problems – fires, and changed the weather. Some scientists think this was the reason that the dinosaurs died out. Other scientists have suggested that their food died out, that there was some disease and a few other reasons. We have evidence for a large meteor strike on the planet around the time the dinosaurs died out, but we can only speculate about the effects those strikes had.