Radiometric dating: This technique measures the decay of radioactive isotopes to determine the age of rocks and minerals. By measuring the ratios of different isotopes, scientists have been able to determine that the oldest rocks on Earth are around 4.4 billion years old.
Meteorites: Meteorites are pieces of rock and metal that originate from outside the Earth. By studying the composition of meteorites, scientists have been able to determine that they are similar in composition to the Earth's mantle, suggesting that they formed at the same time as the Earth.
The Sun's evolution: The Sun is the source of heat and light for the Earth, and its evolution is closely linked to the evolution of the Earth. By studying the Sun's evolution, scientists have been able to determine that it is around 4.6 billion years old.
The Earth's magnetic field: The Earth's magnetic field is generated by the movement of molten iron in the Earth's core. By studying the Earth's magnetic field, scientists have been able to determine that it has been in existence for at least 3.5 billion years.
All of this evidence suggests that the Earth is between 4.5 and 4.6 billion years old. While there is some uncertainty in this estimate, it is the most accurate estimate we have based on the available evidence.
