He fact that all radioisotopes of elements such as potassium, thorium, carbon and uranium decay at a constant rate means they behave like clocks. By examining the ratio of uranium-238 to lead-206, which is non-radioactive, in meteorites scientists determined that the Earth and the rest of the planets are some 4.6 billion years old. The half-life of a radioisotope is the period of time it takes for half the nuclei to decay into an isotope of the same or a different element. The half life of U-238 is 4.6 billion years, and because the ratio of U-238 and Pb-206 is 1:1, the age of the Earth is also 4.6 billion years. No rocks that old can be found on the Earth because of plate tectonics and erosion but a few rocks have been found that are nearly 4 billion years old.

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Carbon dating

That isn't a complete question, let alone a thought. The Earth's age is estimated at about 4.6 billion years. This is estimated through radiometric dating (dating of half life of igneous rock formations. We also dated rocks from the moon and various meteorites. we also look at emission evidence from the sun.

That isn't a complete question, let alone a thought. The Earth's age is estimated at about 4.6 billion years. This is estimated through radiometric dating (dating of half life of igneous rock formations. We also dated rocks from the moon and various meteorites. we also look at emission evidence from the sun.