Two methods of absolute dating
If certain things are known, it is possible to calculate the amount of time since the parent isotope began to decay.For example, if you began with 1 gram of carbon-14, after 5,730 years you would be left with 0.50 g and only 0.25 g after 11,460 years.Uniformitarian geologists use so-called dating methods to determine the ages of the surrounding rocks.Certain types of rocks, especially those that form from magma (igneous), contain radioactive isotopes of different elements.A fear of God and reverence for His Word is the beginning of wisdom.
The textbooks focus on relative dating, based on the layering of the rocks, and radiometric dating.
The claimed “fact” that decay rates have always been constant is actually an inference based on a uniformitarian assumption.
It is true that radioisotope decay rates are stable today and are not largely affected by external conditions like change in temperature and pressure, but that does not mean that the rate has always been constant.
Recent research by a team of creation scientists known as the RATE (arth) group has demonstrated the unreliability of radiometric dating techniques.
Even the use of isochron dating, which is supposed to eliminate some initial condition assumptions, produces dates that are not reliable.