By comparing how much carbon-14 there is in the dead organism with the amount in a living one, the age of the dead organism can be estimated.
The half-life of uranium-238 is 4500 million years.
When it decays it forms thorium-234 which is also unstable.
Finally, after a series of radioactive isotopes are formed it becomes lead-206, which is stable.
With our focus on one particular form of radiometric dating—carbon dating—we will see that carbon dating strongly supports a young earth.
When they die, they stop exchanging carbon with the biosphere and their carbon 14 content then starts to decrease at a rate determined by the law of radioactive decay.
You probably have seen or read news stories about fascinating ancient artifacts.
The amount of carbon-14 in the atmosphere has not changed in thousands of years.
Even though it decays into nitrogen, new carbon-14 is always being formed when cosmic rays hit atoms high in the atmosphere.