Roughly how old is the Earth?

Roughly how old is the Earth? The Earth is about 4.5 billion years old. The best current estimate is approximately 4.54 billion years, with an uncertainty of about 50 million years.

Scientists determine this age primarily through radiometric dating, which measures predictable radioactive decay in minerals and meteorites. Because Earth’s earliest rocks were recycled or altered by plate tectonics, meteorites are especially useful: many formed from the same original material as the planets and preserved evidence from the Solar System’s birth.

American geochemist Clair Cameron Patterson calculated a remarkably accurate estimate in 1956 using uranium-lead dating of meteorites, including the Canyon Diablo meteorite. Later measurements of meteorites, lunar samples and ancient Earth minerals have supported the result. The oldest known terrestrial material includes zircon crystals from Western Australia dated to more than 4.4 billion years, while some calcium-aluminium-rich inclusions in meteorites are about 4.567 billion years old. Earth’s age is not the same as the universe’s age, which is about 13.8 billion years.