That is, billion-year half-lives can be measured statistically in just hours of time.
These are rocks which form when hot, molten material cools and solidifies.
Since we did not observe the initial conditions when the hourglass time started, we must make assumptions.
All three of these assumptions can affect our time calculations.
Scientists use observational science to measure the amount of a daughter element within a rock sample and to determine the present observable decay rate of the parent element.
Dating methods must also rely on another kind of science called historical science. Determining the conditions present when a rock first formed can only be studied through historical science.