Research has been ongoing since the 1960s to determine what the proportion of in the atmosphere has been over the past fifty thousand years.

The resulting data, in the form of a calibration curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.

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 idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained.

Carbon dating has given archeologists a more accurate method by which they can determine the age of ancient artifacts.

Libby invented carbon dating for which he received the Nobel Prize in chemistry in 1960.

the average or expected time a given atom will survive before undergoing radioactive decay. The calculations involve several steps and include an intermediate value called the "radiocarbon age", which is the age in "radiocarbon years" of the sample: an age quoted in radiocarbon years means that no calibration curve has been used − the calculations for radiocarbon years assume that the , which for more than a decade after Libby's initial work was thought to be 5,568 years.

The ratio of λ is a constant that depends on the particular isotope; for a given isotope it is equal to the reciprocal of the mean-life – i.e.Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages.For example, two samples taken from the tombs of two Egyptian kings, Zoser and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is taken up by plants via photosynthesis.However, the principle of carbon-14 dating applies to other isotopes as well.Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.

The ratio of λ is a constant that depends on the particular isotope; for a given isotope it is equal to the reciprocal of the mean-life – i.e.

Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages.

For example, two samples taken from the tombs of two Egyptian kings, Zoser and Sneferu, independently dated to 2625 BC plus or minus 75 years, were dated by radiocarbon measurement to an average of 2800 BC plus or minus 250 years. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is taken up by plants via photosynthesis.

However, the principle of carbon-14 dating applies to other isotopes as well.

Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.

Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).