Half life of radiocarbon dating
The half-life of Carbon $, that is, the time required for half of the Carbon $ in a sample to decay, is variable: not every Carbon $ specimen has exactly the same half life.
Carbon-14 has a half-life of just under 6000 years and would have long ago vanished from Earth were it not for the unremitting cosmic ray impacts on nitrogen in the Earth's atmosphere, which forms more of the isotope.
Recall that atoms are the basic building blocks of matter.
Atoms are made up of much smaller particles called protons, neutrons, and electrons.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.
Many people have been led to believe that radiometric dating methods have proved the earth to be billions of years old.