Homo sapiens appeared about 500,000 years ago. People are the first animal to dominate the earth because of intellect and cooperation. People are bright and formed social units for teamwork. Humanity developed morality which allowed for even greater harmony. All progress made by humanity has been made because morality restrained our savage animal nature to allow cooperation.
Paleontologists estimate the age of fossils using techniques such as carbon dating.
It is known that life forms have the same percentage of the radioactive isotope known as carbon 14 which exists in the atmosphere. The rate of decay of a radioactive isotope is measured by their half-life. The half-life of a radioactive isotope is the time needed for half of the radioactive isotope to decay. The half life for carbon 14 is 5,730 years. Therefore, if the remains of an organism are found which contains one half the amount of carbon 14 that is in a living organism, the remains are 5,730 years old.