what wiped out the dinosaurs

The extinction of the dinosaurs was caused by a catastrophic event that occurred around 66 million years ago. The most widely accepted theory is that a massive asteroid, estimated to be nearly nine miles wide, collided with Earth, causing a global mass extinction that wiped out most dinosaurs and three-quarters of the planets plant and animal species. The impact of the asteroid threw huge amounts of debris into the air, causing massive tidal waves to wash over parts of the American continents and substantial fires. The asteroid impact also generated a massive "megatsunami" with waves more than a mile high. The exact nature of the catastrophic event is still open to scientific debate, but evidence suggests that an asteroid impact was the main culprit. Volcanic eruptions that caused large-scale climate change may also have been involved, together with more gradual changes to Earths climate that happened over millions of years. The extinction of the dinosaurs left gaps in ecosystems around the world, which were subsequently filled by the only dinosaurs to survive - birds - and mammals, both of which went on to evolve rapidly.