For example, carbon dating took discoveries including counting tree rings to determine a tree's age, the origins of all the radiation on Earth -- spoiler: it was the Earth itself, but also cosmic rays which was the important bit, nuclear half-lives and creating a chart of specifically useful half-lives for historical dating, the discovery of a rare isotope of carbon which can only be made by cosmic rays (carbon-14) as a near perfect clock for human timescales, how to build a sensor that can read faint carbon-14 radioactivity while filtering out all the radioactive noise from the environment, making another chart of expected radioactive readings based on geographical location including the depths of the ocean, and of course not to mention all of the archeological data used to calibrate all of the charts and devices used in the process.