Radiometric dating relies on the constant rate of decay of

31 Dec

After the passage of two half-lives only 0.25 gram will remain, and after 3 half lives only 0.125 will remain etc.

Thus, if we start out with 1 gram of the parent isotope, after the passage of 1 half-life there will be 0.5 gram of the parent isotope left.

When Rutherford announced his findings it soon became clear that Earth is millions of years old.

These scientists and many more after them discovered that atoms of uranium, radium and several other radioactive materials are unstable and disintegrate spontaneously and consistently forming atoms of different elements and emitting radiation, a form of energy in the process.

The slope of the line determines the date, and the closeness of fit is a measure of the statistical reliability of the resulting date.

Technical details on how these dates are calculated are given in Radiometric dating. As with any experimental procedure in any field of science, these measurements are subject to certain "glitches" and "anomalies," as noted in the literature.