Bishop James Ussher, a 17th-century Irish cleric, for example, calculated that creation occurred in 4004 B. There were many other such estimates, but they invariably resulted in an Earth only a few thousand years old.
By the late 18th century, some naturalists had begun to look closely at the ancient rocks of the Earth.
As a result, there is a changing ratio of carbon-14 to the more atomically stable carbon-12 involves actually counting individual carbon-14 atoms.
This allows the dating of much older and smaller samples but at a far higher cost.
decay or the rate of other cumulative changes in atoms resulting from radioactivity. The various isotopes of the same element differ in terms of atomic mass but have the same atomic number..
One half-life is the amount of time required for of the original atoms in a sample to decay.
Can we rely on the radiometric dates alone...no, we can't.
Geologists know that the dates are not perfect, that's why you will see research articles trying to determine the age of a rock, and there will be ten, twenty, or more samples that were dated.I can look in my scientific journals and see apparent discrepancies in dating techniques.Some may be discrepancies…some may just need a bit further explanation.Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.