Radiocarbon Dating of the Shroud of Turin (Also called carbon 14 dating)
Radiocarbon dating is an accurate method for determining the age of material that has a biological origin. This includes bones, natural fiber cloth, artifacts made of wood and charcoal.
All animals and plants are composed of chemicals that contain three types of carbon isotopes. The most common isotope is carbon 12. It accounts for approximately roughly 99% of all the carbon atoms found in a plant or animal. Another isotope is carbon 13 that comprises about 1% of the total. The third isotope is carbon 14. Carbon 14 is found in only tiny amounts compared to carbon 12. In a living plant or animal there is only about one carbon 14 atom for every trillion carbon 12 atoms.
Carbon (C12, C13 and C14) is acquired by plants from carbon dioxide (CO2) in the atmosphere. Animals get carbon by breathing in carbon dioxide and by ingesting plants and other animals. The result is that all living things have a specific ratio of carbon 12 and carbon 14 isotopes. Generally speaking, it is the same ratio found in the atmosphere. The ratio begins to change when a plant or animal dies and it is no longer taking on carbon from nature.
Carbon 14, unlike carbon 12 and carbon 13, is radioactive. This means that over time the carbon 14 atoms will decay. When the isotope carbon 14 decays it gives off a beta particle and in doing so becomes nitrogen 14. The amount of carbon 12 and carbon 13, however, remains constant.
The half-life of different isotopes range from fractions of a second to millions of years. The half-life of carbon 14 is 5730 years. This means that in 5730 years, half of the carbon 14 atoms will have become nitrogen 14. In the next 5730 years, half of the remaining carbon 14 will have decayed.
Thus, if we are able to measure the percentage of carbon 14 that remains in a sample, we can determine its age. The sample may be from a human bone, an animal antler, a piece of linen made from flax fibers, a wooden tool or charcoal from an ancient fire. All of these things were once part of something that was alive.
