Radiocarbon dating also referred to as carbon dating or carbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon , a radioactive isotope of carbon. The method was developed in the late s at the University of Chicago by Willard Libby , who received the Nobel Prize in Chemistry for his work in It is based on the fact that radiocarbon 14 C is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14 C combines with atmospheric oxygen to form radioactive carbon dioxide , which is incorporated into plants by photosynthesis ; animals then acquire 14 C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of 14 C it contains begins to decrease as the 14 C undergoes radioactive decay. Measuring the amount of 14 C in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died.
The Story of Carbon Dating
Carbon dating accuracy called into question after major flaw discovery
Seventy years ago, American chemist Willard Libby devised an ingenious method for dating organic materials. His technique, known as carbon dating, revolutionized the field of archaeology. Now researchers could accurately calculate the age of any object made of organic materials by observing how much of a certain form of carbon remained, and then calculating backwards to determine when the plant or animal that the material came from had died. An isotope is a form of an element with a certain number of neutrons, which are the subatomic particles found in the nucleus of an atom that have no charge. While the number of protons and electrons in an atom determine what element it is, the number of neutrons can vary widely between different atoms of the same element. Nearly 99 percent of all carbon on Earth is Carbon, meaning each atom has 12 neutrons in its nucleus.
New scientific tests on the Shroud of Turin, which went on display Saturday in a special TV appearance introduced by the Pope, dates the cloth to ancient times, challenging earlier experiments dating it only to the Middle Ages. Pope Francis sent a special video message to the televised event in the Cathedral of Saint John the Baptist in Turin, Italy, which coincided with Holy Saturday, when Catholics mark the period between Christ's crucifixion on Good Friday and his resurrection on Easter Sunday. The Vatican, tiptoeing carefully, has never claimed that the foot linen cloth was, as some believers claim, used to cover Christ after he was taken from the cross 2, years ago. Francis, reflecting that careful Vatican policy, on Saturday called the cloth, which is kept in a climate-controlled case , an "icon" -- not a relic. But Cesare Nosiglia, the Archbishop of Turin and "pontifical custodian of the shroud," said the special display on Holy Saturday "means that it represents a very important testimony to the Passion and the resurrection of the Lord," The Telegraph reported.
Geologists do not use carbon-based radiometric dating to determine the age of rocks. Carbon dating only works for objects that are younger than about 50, years, and most rocks of interest are older than that. Carbon dating is used by archeologists to date trees, plants, and animal remains; as well as human artifacts made from wood and leather; because these items are generally younger than 50, years.