This age is determined using various methods, including:

* Radiometric dating: This technique measures the decay of radioactive isotopes found in rocks and minerals. By comparing the amount of parent isotope to the amount of daughter isotope, scientists can calculate the age of the sample.

* Meteorite dating: Meteorites are believed to have formed at the same time as Earth. By dating meteorites, scientists can infer the age of Earth.

* Lunar samples: Studying samples brought back from the Moon by Apollo astronauts also provides insights into the age of the Earth-Moon system.

These methods consistently point to an age of around 4.54 billion years for Earth.