What method has been used to determine the age of the earth and the moon?

The age of the Earth and the Moon has primarily been determined through radiometric dating, particularly using isotopes like uranium-lead and potassium-argon. By analyzing the decay rates of these isotopes in ancient rocks and lunar samples, scientists can calculate the time that has elapsed since the rocks solidified. The oldest known terrestrial rocks are about 4.0 billion years old, while lunar samples brought back by the Apollo missions suggest the Moon formed around 4.5 billion years ago, shortly after the Earth. These methods provide a reliable framework for understanding the age of our planet and its satellite.