Carbon-14 has a half-life of about 5730 years, and therefore it is used to date biological samples up to about 60,000 years in the past.
Note that, contrary to a popular misconception, carbon dating is not used to date rocks at millions of years old.
Furthermore, if a sample has been contaminated, scientists will know about it.
Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food.
They have the same ratio of carbon-14 to carbon-12 as the atmosphere, and this same ratio is then carried up the food chain all the way to apex predators, like sharks.
Carbon dating has a certain margin of error, usually depending on the age and material of the sample used.
Many people have been led to believe that radiometric dating methods have proved the earth to be billions of years old.
This has caused many in the church to reevaluate the biblical creation account, specifically the meaning of the word “day” in Genesis 1.
Later called Ötzi the Iceman, small samples from his body were carbon dated by scientists.
The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. It is found in the air in carbon dioxide molecules.
The approximate time since the organism died can be worked out by measuring the amount of carbon-14 left in its remains compared to the amount in living organisms.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.