I am not sure of the reason, but it is a great evidence that the Earth cannot be more than around 6,000 years old. Think about it logically, if you go back in time it gets closer and closer. Going back only a few million years puts it practically touching the surface of the earth. What would that do to gravity, the tides, etc. That is one of hundreds, if not thousands of scientifically empirical evidences for a young earth.