The key is to measure an isotope that has had time to decay a measurable amount, but not so much as to only leave a trace remaining.

Given isotopes are useful for dating over a range from a fraction of their half life to about four or five times their half life.

how old is the earth radiometric dating-10

Symbolically, the process of radioactive decay can be expressed by the following differential equation, where N is the quantity of decaying nuclei and k is a positive number called the exponential decay constant.

The meaning of this equation is that the rate of change of the number of nuclei over time is proportional only to the number of nuclei.

Another limitation is that carbon-14 can only tell you when something was last alive, not when it was used.

Note that although carbon-14 dating receives a lot of attention, since it can give information about the relatively recent past, it is almost never used in geology.

One way Young Earth Creationists and other denialists try to discredit radiometric dating is to cite examples radiometric dating techniques providing inaccurate results. Helens, creationists attempted discredit the discipline through dishonest practices.

This is frequently because the selected technique is used outside of its appropriate range, for example on very recent lavas. The Institute for Creation Research's RATE project aimed to show scientifically that methods of radiometric dating produced wildly inconsistent and incorrect values.

They tie themselves in logical knots trying to reconcile the results of radiometric dating with the unwavering belief that the Earth was created ex nihilo about 6,000 to 10,000 years ago.

Indeed, special creationists have for many years held that where science and their religion conflict, it is a matter of science having to catch up with scripture, not the other way around.

This is consistent with the assumption that each decay event is independent and its chance does not vary over time.

where is the half-life of the element, is the time expired since the sample contained the initial number atoms of the nuclide, and is the remaining amount of the nuclide.

The oldest rock so far dated is a zircon crystal that formed 4.4-billion-years ago, which was only 200 million years or so after the Earth itself formed.