But new research by creationists has revealed a large number of problems with radiometric dating.
In some cases such as Carbon-14 dating, radioactive dating actually gives strong evidence for a young Earth.
Radiometric dating is based on the decay rate of these isotopes into stable nonradioactive isotopes.
This method relies on the uptake of a naturally occurring radioactive isotope of carbon, carbon-14 by all living things.
When living things die, they stop taking in carbon-14, and the radioactive clock is "set"!
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.
In addition to the ages of Earth, Moon, and meteorites, radiometric dating has been used to determine 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 the age and duration of a wide variety of other geological events and processes.
Radioactive elements were incorporated into the Earth when the Solar System formed.
All rocks and minerals contain tiny amounts of these radioactive elements.
Radioactive elements are unstable; they breakdown spontaneously into more stable atoms over time, a process known as radioactive decay.
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.
For example, K-Ar dating assumes that there was no argon in the original rock.