According to a study by the researchers from Harvard University, a conclusion has been made that the Dinosaurs must have been killed by a comet instead of asteroid. A celestial object that has a nucleus of ice and dust is called a comet. Comet is originated from icy objects that are located at the edge of solar system. Asteroid is a piece of rock that orbits around the Sun, and is found mostly in the asteroid belt.
The study done by Harvard researchers states that a piece of comet crashed into the Earth some 66 million years ago with Chicxulub crater which was linked to the cretaceous Paleogene extinction event that totally wiped off the species of dinosaur with some other species of animals too. There is still a debate going on between some researchers that it was asteroid which created the Chicxulub crater, located on the Yucatán Peninsula of modern-day Mexico. Natalie Artemieva, who is a senior scientist at Planetary Science Institute said that if it was a comet that would have killed them all, then it would have too small to make the Crater.
The study suggest that the size of the crates was 4 miles wide, but Natalia Artemieva said that it must at least be of size 7.5 miles wide to make the crator. Natalia Artemieva was not a part of the study and hence his words were not taken into consideration at that time. But David Kring, who is the principal scientist at the lunar and planetary Institute located in Houston, said that the evidence found until now points that it must have been the asteroid that might have killed all of them and is solely responsible for the extinction of dinosaurs. He also said that the there is no evidence that absolutely proves that the model of the study is incorrect.