Dinosaurs are extinct now. Scientists are always wondering about the cause of their extinction. This proves to be difficult, but scientists are still working on it.
It is reported that there is a huge hole on the Yucatan Peninsula in eastern Mexico which was believed to be caused by a large object that fell form space sixty-five million years ago. At about the same time, dinosaurs living on the ground became xetinct.So it is thought that the large object may be the cause of the extinction of dinosaurs. Though it is proved that the large object had a close relation with the death of dinosaurs and other animals,scientists have different opinions upon how the large object led to the death of the ancient animals.
Twenty years ago, scientists disovered that a large cloud of dust was created by the crash of the large object.They concluded that lignt from the sun was stopped from reaching the earth by the cloud. As a result, the weather became greatly cooled. The cold weather and less sunlight killed many plants which were the food of dinosaurs and other animals. Because of no food, the animals soon died.
About ten years ago scientists from the United States and Mexico found that the large object caused a huge hole in Mexico. Some scientists thought that the object was not big enough to create a deadly cloud of dust, but it hit with great force so that poisonous chemicals were given out. Dinosaurs and other ancient animals were poisoned by the chemicals and then died.
Which of the two views is more reasonable, the first or the second? Maybe both. In order to test their discoveries,scientists are preparing to make a study of the rocks that remain after the large object hit. They hope that in the future we will have a better understanding about any chemical reactions which have influenced the environment.