There were other estimates but the calculations were hotly disputed because they all were obviously flawed by uncertainties in both the initial assumptions and the data.
There are a number of long-lived radioactive isotopes used in radiometric dating, and a variety of ways they are used to determine the ages of rocks, minerals, and organic materials.
Some of the isotopic parents, end-product daughters, and half-lives involved are listed in Table 1.
Second, the rock or mineral must not lose or gain either potassium or argon from the time of its formation to the time of analysis.
By many experiments over the past three decades, geologists have learned which types of rocks and minerals meet these requirements and which do not.
he question of the ages of the Earth and its rock formations and features has fascinated philosophers, theologians, and scientists for centuries, primarily because the answers put our lives in temporal perspective.
Until the 18th century, this question was principally in the hands of theologians, who based their calculations on biblical chronology.
The main point is that the ages of rock formations are rarely based on a single, isolated age measurement.
On the contrary, radiometric ages are verified whenever possible and practical, and are evaluated by considering other relevant data.
The point is that not all methods are applicable to all rocks of all ages.
One of the primary functions of the dating specialist (sometimes called a geochronologist) is to select the applicable method for the particular problem to be solved, and to design the experiment in such a way that there will be checks on the reliability of the results.
My purpose here is not to review and discuss all of the dating methods in use.