Scientific definition of radioactive dating

09 Dec

Because geochronologists want to measure isotopes with different masses, a mass spectrometer works really well for dating things.I do think that radiometric dating is an accurate way to date the earth, although I am a geochronologist so I have my biases.We have also obtained a very similar age by measuring Pb isotopes in materials from earth.

We know it is accurate because radiometric dating is based on the radioactive decay of unstable isotopes.

Hope that helps, and please ask if you'd like more details! I think that I will start by answering the second part of your question, just because I think that will make the answer to the first question clearer.

Radiometric dating is the use of radioactive and radiogenic (those formed from the decay of radioactive parents) isotopes (isotopes are atoms of the same element that have different numbers of neutrons in their nuclei) to determine the age of something.

This is why crystals are good for radiometric dating: the atoms in a crystal are extremely efficiently packed, and it's very difficult to get anything into a crystal such as a contaminant by any means short of destroying the crystal and re-growing it anew.

The oldest crystals on Earth that were formed on Earth are zircon crystals, and are approximately 4.1 billion years old.