The object's approximate age can then be figured out using the known rate of decay of the isotope.
For organic materials, the comparison is between the current ratio of a radioactive isotope to a stable isotope of the same element and the known ratio of the two isotopes in living organisms.
As with any experimental procedure in any field of science, these measurements are subject to certain "glitches" and "anomalies," as noted in the literature.
Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.
The latest high-tech equipment permits reliable results to be obtained even with microscopic samples.Radiometric dating is self-checking, because the data (after certain preliminary calculations are made) are fitted to a straight line (an "isochron") by means of standard linear regression methods of statistics.Atoms are made up of much smaller particles called protons, neutrons, and electrons.In the past 150 years they have not found any fossils that Darwin would not have expected.New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.