How you know that dinosaurs exists on earth?

Answer 1

Scientists know that dinosaurs existed back then because all of the fossils that they found and tested dated back between 64 and 65 millon years ago. They also have a theory that a massive asteroid hit the earth and that is what they think killed all of the dinosaurs but nobody knows for definite.

Answer 2

There is a very large impact crater in Mexico's Yucatan Peninsula that has been dated to 65 million years ago. Also, rock strata from 65 million years ago consistently show an unusually high amount of iridium, a metal that is rare on earth but common in asteroids.

Answer 3

Paleontologists don't know all about dinosaurs - there are many things we don't yet understand about these extinct animals, and new facts are coming in all the time. For example, up until fairly recently, we didn't know that many theropod dinosaurs were feathered, until better preserved fossils were uncovered. Furthermore, there are many debates about the particulars of dinosaur Biology and behavior, for example, the infamous debate over whether T.Rex was an exclusive scavenger, a predator, or some combination of the two, or the ongoing debate over whether or not certain dromeosaurs (raptors) hunted in packs. However, it is pretty amazing that we have so much information about dinosaurs to begin with, since they lived and died millions of years before humans appeared on this planet! Most of the information that we do have stems from fossil evidence (dinosaur bones, trackways, nesting sites etc.) and the study of the closest living relatives of dinosaurs - the birds (which are now known to be dinosaurs as well), crocodilians and other reptiles, as well as general traits exhibited by animals that occupy certain niches and environments. This data is interpreted in a variety of ways, and new technologies, such as advanced computers, have greatly improved our ability to analyze the evidence. For example, bio-mechanical studies can help us virtually put flesh on long dead dinosaur bones, helping us understand how they moved and what their physical abilities were like, and CT scans of dinosaur skulls can tell us about their brain structures, e.g. which areas of the brain were more or less developed, which indicates how a given species of dinosaur might have lived. Certainly, much more remains to be discovered - we have only found the fossils belonging to a fraction of dinosaur species that are thought to have existed during the Mesozoic!

Answer 4

Dinosaurs don't exist on earth today. We know they once existed because of their fossil bones.