carbon-14 dating

Method of determining the age of once-living material, developed by U.S. physicist Willard Libby in 1947. It depends on the decay of the radioactive isotope carbon-14 (radiocarbon) to nitrogen. All living plants and animals continually take in carbon: green plants absorb it in the form of carbon dioxide from the atmosphere, and it is passed to animals through the food chain. Some of this carbon is radioactive carbon-14, which slowly decays to the stable isotope nitrogen-14. When an organism dies it stops taking in carbon, so the amount of carbon-14 in its tissues steadily decreases. Because carbon-14 decays at a constant rate, the time since an organism died can be estimated by measuring the amount of radiocarbon in its remains. The method is a useful technique for dating fossils and archaeological specimens from 500 to 50,000 years old and is widely used by geologists, anthropologists, and archaeologists.

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Year 14 was a common year starting on Monday (link will display the full calendar) of the Julian calendar.

Events

By place

Roman Empire

• Tacitus reports that the town and port of Nauportus has been plundered by a mutinous Roman legion that was sent there to build roads and bridges.
• Augustus dies and is declared to be a god.
• Tiberius succeeds his stepfather Augustus as Emperor of the Roman Empire.
• Legions on the Rhine revolt after the death of Augustus; Germanicus and Drusus put down the revolt.
• Germanicus is appointed commander of the forces in Germany, beginning a campaign that will end in 16.
• A census indicates that there are 4,973,000 Roman citizens.
• Claudia Marcella marries Sextus Appuleius.
• Sextus Appuleius and Sextus Pompeius serve as Roman consuls.

Asia

• First year of tianfeng era of the Chinese Xin Dynasty.
• Famine hits China. Some citizens turn to cannibalism.

By Topic

Art

• Hellenistic period ends, by some scholars (usual date 31 BC).

Births

• Lucius Caecilius Iucundus, Pompeian banker

Deaths

• August 19 — Roman Emperor Augustus.
• Julia the Elder, daughter of Roman Emperor Augustus.
• Postumus Agrippa, grandson of Roman Emperor Augustus.