If you go to the Gulf of Mexico, you can see there is a big hole. It is called Chicxulub Crater. Some people believe it was because of a huge asteroid(小行星) hitting this place, and the hit made dinosaurs die out millions of years ago.
This idea was first suggested in 1980. Later, scientists used special tools to find out what would happen if it was true. It showed that the asteroid could hit Earth at 40,000 miles per hour, leading to a big hole, a great tsunami(海啸), earthquakes, and the melting(融化) of tons of rock. The hit took away millions of lives around the Chicxulub Crater.
The terrible story didn't stop there. Minutes later, hot rock started to rain down, and there was deadly dirt everywhere on the ground. More animals were burnt to death. After several hours, a super- hot wind knocked down anything still standing.
In weeks, the sky was full of ash. Days became nights. This covered the sunlight for months or even years. Many plants died first. Then lots of animals died too because of food shortage, including almost all dinosaurs.
Although this idea sounds possible, the question of how dinosaurs died out remains unsolved scientifically. But as scientists discover more dinosaur fossils, we may know the truth one day.