Which allowed scientists to determine that Earth was at least 4.3 billions years old

Scientists determined that Earth is at least 4.3 billion years old through the use of radiometric dating techniques. One of the key methods involves dating the oldest rocks on Earth and meteorites that have fallen to Earth.

The most commonly used isotopes for dating ancient rocks are uranium-lead (U-Pb) dating and rubidium-strontium (Rb-Sr) dating. The U-Pb method, in particular, allows scientists to date zircon crystals found in sedimentary rocks and continental crust, which are some of the oldest materials available for study.

The oldest known minerals on Earth, zircon crystals found in Australia, have been dated to about 4.4 billion years old. In addition, the ages of meteorites, which represent remnants from the early solar system, have been dated to around 4.56 billion years, providing insight into the time when the Earth was forming.

These methods, along with geological and astronomical evidence, collectively support the conclusion that Earth is at least 4.3 billion years old.