Radio carbon dating is false
Other corrections must be made to account for the proportion of throughout the biosphere (reservoir effects).
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.
An Anglo-American team found large variations in levels of the carbon-14 isotope, used as the basis of carbon dating, preserved in a 19in stalagmite recovered from a submerged cave in the Blue Holes of the Bahamas, limestone caverns created when sea levels were nearly 330ft lower than today.
These findings suggested dramatic changes in the amount of radioactive carbon in Earth's atmosphere during the last Ice Age, much greater than previously thought, probably as a result of changes in the strength of the planet's magnetic field."Beyond about 20,000 years ago there are some dramatic swings in radiocarbon concentration, which means the age offset between the radiocarbon age and true calendar age can be up to 8,000 years," said Dr David Richards of the School of Geographical Sciences, University of Bristol, who made the study with colleagues in Arizona and Minnesota.
Incidentally, lab techs already have to correct for another historical contingency: The fraction of carbon-14 in the atmosphere decreased after the Industrial Revolution with the rise of fossil fuel combustion.