The rate of isotope decay is very consistent, and is not effected by environmental changes like heat, temperature, and pressure. This makes radiometric dating quite reliable. Because carbon-14 decays relatively rapidly compared to other isotopes, it can only be used to date things that are less than 60,000 years old.

Why is radiometric dating a reliable method for determining numerical dates?

18.4 Why is radiometric dating a reliable method of determining numerical dates? Radiometric dating is reliable because the rates of decay for many isotopes have been precisely measured and do not vary under the physical conditions that exist in Earths outer layers.