How do scientists estimate the age of the earth?
Primarily a combination of radiometric dating of Earth rocks, moon, rock, meteoritic rock and a plausible model of how the solar system formed.
Radiometric dating of Uranium is particularly useful. Both
One challenge is to find really early rocks near the surface of the earth. The earliest Earth rock dated are some zircon inclusions in rocks found in Australia at about
The moon has not been subject to so much vulcanism, and the oldest moon rock that we have tested has been dated at about
Meteorites have been dated between
From our understanding of how the solar system formed, that results in an estimated