Uranium-lead dating is a method used to determine the age of rocks and minerals. It relies on the radioactive decay of uranium isotopes into stable lead isotopes over time. By measuring the ratio of uranium to lead in a sample, scientists can calculate how long this decay process has been occurring, providing an estimate of the sample's age. This dating technique is particularly useful for dating ancient geological formations, as it can be applied to materials that are billions of years old. It is one of the most reliable methods for dating the Earth's oldest rocks and has helped scientists understand the history of our planet.