Forms of radiometric dating
All rocks and minerals contain long-lived radioactive elements that were incorporated into Earth when the Solar System formed.
These radioactive elements constitute independent clocks that allow geologists to determine the age of the rocks in which they occur.
To date an object, scientists measure the quantity of parent and daughter isotope in a sample, and use the atomic decay rate to determine its possible age.
Nevertheless, there is substantial evidence that the Earth and the other bodies of the Solar System are 4.5-4.6 billion years old, and that the Milky Way Galaxy and the Universe are older still.
The principal evidence for the antiquity of Earth and its cosmic surroundings is: Spontaneous breakdown or decay of atomic nuclei, termed radioactive decay, is the basis for all radiometric dating methods.
Any dead material incorporated with sedimentary deposits is a possible candidate for carbon-14 dating.
Radiometric dating has been used to determine the ages of the Earth, Moon, meteorites, ages of fossils, including early man, timing of glaciations, ages of mineral deposits, recurrence rates of earthquakes and volcanic eruptions, the history of reversals of Earth's magnetic field, and many of other geological events and processes.