Answer:
The decay of potassium to argon, uranium to lead, and one isotope of lead to another are some common yardsticks used to date very old rocks. These dating methods allow scientists to put real ages on rocks with astonishing accuracy.
Explanation:
The best estimate for Earth's age is based on radiometric dating of fragments from the Canyon Diablo iron meteorite. From the fragments, scientists calculated the relative abundances of elements that formed as radioactive uranium decayed over billions of years.
