The reason this age may not be a true age—even though it is commonly called an absolute age—is that it is based on several crucial assumptions.
Most radiometric dating techniques must make three assumptions: The major problem with the first assumption is that there is no way to prove that the decay rate was not different at some point in the past.
Determining the relative age of a rock layer is based on the assumption that you know the ages of the rocks surrounding it.
Most scientists and many Christians believe that the radiometric dating methods prove that the earth is 4.5 billion years old.
The textbooks speak of the radiometric dating techniques, and the dates themselves, as factual information.
The method of calculating radiometric dates is like using an hourglass.
You can use the hourglass to tell time if you know several things: the amount of sand in the top of the hourglass when it started flowing, the rate that the sand flows through the hole in the middle, and that the quantity of sand in each chamber has not been tampered with.