Libby received the Nobel Prize for his work in 1960.
The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen.
The Carbon-14 within a living organism is continually decaying, but as the organism is continuously absorbing Carbon-14 throughout its life the ratio of Carbon-14 to Carbon-12 atoms in the organism is the same as the ratio in the atmosphere.
Once an organism dies it stops taking in Carbon in any form.
There's a small amount of radioactive carbon-14 in all living organisms.
When they die no new carbon-14 is taken in by the dead organism.
The resulting radiocarbon combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire 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 older a sample is, the less (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out. The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.The carbon-14 it contained at the time of death decays over a long period of time.By measuring the amount of carbon-14 left in dead organic material the approximate time since it died can be worked out.The age of glaciers, snow fields, and even wines can be estimated by radioisotopic dating.