Current theory suggests an asteroid came from outside the galaxy and got all the way to the third planet from the sun, without getting caught in the galaxy's gravitational field. It is an impossible scenario. If the asteroid came from inside the galaxy, where did it come from? Planets and moons do not supernova. What then did happen to the dinosaurs?

Dinosaurs were big. Food is limited. Is it possible dinosaurs ran out of food? Herbivores went first, as they simultaneously starved and got eaten by carnivores. Then the carnivores ate each other. Maybe some of the smaller dinosaurs changed into birds or something else?