Controversy about carbon dating
Some of the first radiocarbon dates produced showed that the Scottish tombs were thousands of years older than those in Greece.
The barbarians of the north were capable of designing complex structures similar to those in the classical world.
If 1% of the carbon in a 50,000 year old sample is from a modern contaminant, the sample will be dated to around 40,000 years.
Because of this, radiocarbon chemists are continually developing new methods to more effectively clean materials.
With the development of a new method of cleaning charcoal called ABOx-SC, Michael Bird helped to push back the date of arrival of the first humans in Australia by more than 10,000 years.
The total mass of the isotope is indicated by the numerical superscript.
While the lighter isotopes C has decayed that what remains can no longer be measured. In 5,730 years half of the C in the atmosphere, and therefore in plants and animals, has not always been constant.
In addition, samples need to be thoroughly cleaned to remove carbon contamination from glues and soil before dating.
This is particularly important for very old samples.