How paleontologists estimate geologic time through radiometric dating List of 100 free adult chatlines
While the oldest known rocks on Earth are about 3.5 billion years old, researchers have found zircon crystals that are 4.3 billion years old [source: USGS].
This is what archaeologists use to determine the age of human-made artifacts. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old.The methods work because radioactive elements are unstable, and they are always trying to move to a more stable state. This process by which an unstable atomic nucleus loses energy by releasing radiation is called radioactive decay.The thing that makes this decay process so valuable for determining the age of an object is that each radioactive isotope decays at its own fixed rate, which is expressed in terms of its half-life.You can learn more about fossils, dinosaurs, radiometric dating and related topics by reading through the links below.
Radiometric dating isn't the only method of determining the age of rocks.
Each of them typically exists in igneous rock, or rock made from cooled magma.