We thank you in advance for partnering with us in this small but significant way. All methods of radioactive dating rely on three assumptions that may not necessarily be true: It is assumed that the rate of decay has remained constant over time.

This assumption is backed by numerous scientific studies and is relatively sound.

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.

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.

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

For teaching and sharing purposes, readers are advised to supplement these historic articles with more up-to-date ones suggested in the Related Articles and Further Reading below.

Before 1955, ages for the Earth based on uranium/thorium/lead ratios were generally about a billion years younger than the currently popular 4.5 billion years. old Earth is reviewed and deficiencies of the uranium/lead method are discussed.

Dating schemes based on rates of radioactivity have been refined and scrutinized for several decades.

The latest high-tech equipment permits reliable results to be obtained even with microscopic samples.

This is an informational tour in which students gain a basic understanding of geologic time, the evidence for events in Earth’s history, relative and absolute dating techniques, and the significance of the Geologic Time Scale.

Because of the distortions and lies spread by fundamentalists about scientific dating there is a need for a centralized source of information on the topic.

The basic theory of radiometric dating is briefly reviewed.