What is the approximate age of the Earth based on our understanding of radioactivity?

The approximate age of the Earth is determined through radiometric dating, particularly by measuring the abundances of certain isotopes in rocks and meteorites. The most commonly cited age is about 4.6 billion years, which aligns with the age of the oldest rocks found on Earth and the ages of meteorites that have not undergone significant alteration since the formation of the solar system.

This method of dating relies on the principle of half-lives, where radioactive isotopes decay into stable daughter isotopes at a predictable rate. By examining the ratios of parent to daughter isotopes in ancient materials, scientists can calculate how long these processes have been occurring. The consistency of these findings across various isotopes and rock samples supports the conclusion that the Earth is approximately 4.6 billion years old.

Additionally, the ages derived from lunar rocks collected during the Apollo missions have also supported this timeline, further corroborating the age determined through meteorite analysis and Earth’s oldest minerals. This comprehensive approach to dating has led to a consensus in the scientific community around the 4.6 billion-year estimate.