If this assumption is not true, then the method will give incorrect dates. If the production rate of C in a specimen difficult or impossible to accurately determine. Willard Libby, the founder of the carbon-14 dating method, assumed this ratio to be constant.
His reasoning was based on a belief in evolution, which assumes the earth must be billions of years old.
The atomic number corresponds to the number of protons in an atom.
Atomic mass is a combination of the number of protons and neutrons in the nucleus.
So, a carbon atom might have six neutrons, or seven, or possibly eight—but it would always have six protons.
An “isotope” is any of several different forms of an element, each having different numbers of neutrons.
Carbon-14 is mostly used to date once-living things (organic material). Carbon-14 is constantly being added to the atmosphere.It cannot be used directly to date rocks; however, it can potentially be used to put time constraints on some inorganic material such as diamonds (diamonds could contain carbon-14). Cosmic rays from outer space, which contain high levels of energy, bombard the earth’s upper atmosphere.These cosmic rays collide with atoms in the atmosphere and can cause them to come apart.Neutrons that come from these fragmented atoms collide with C to be useful in age estimates.This is a critical assumption in the dating process.
The illustration below shows the three isotopes of carbon.