How do radioactive isotopes help scientists determine the ages of meteorites?

Scientists determine the ages of meteorites using radiometric dating, a method based on the constant rate at which radioactive isotopes (parent atoms) decay into stable daughter products. Because this decay occurs at a known, immutable rate—often expressed as a half-life—measuring the ratio of parent to daughter isotopes allows researchers to calculate the time elapsed since the meteorite formed.1234

For long-lived radionuclides, scientists frequently employ the isochron method. By plotting isotopic ratios from different minerals or rocks that formed at the same time, they create a line (an isochron) where the slope is proportional to the age of the sample.4

Additionally, while short-lived radionuclides have decayed away, their original presence can be inferred by measuring the excess of their daughter isotopes in primitive meteorites. By comparing these abundances, scientists can determine relative ages, which can then be converted into absolute ages if calibrated against long-lived systems. These techniques have allowed researchers to establish that many meteorites are among the oldest objects in the solar system, dating back approximately 4.567 billion years.54