In 1949, American chemist Willard Libby, who worked on the development of the atomic bomb, published the first set of radiocarbon dates.

His radiocarbon dating technique is the most important development in absolute dating in archaeology and remains the main tool for dating the past 50,000 years.

The Mayan calendar used 3114 BC as their reference.

Looking at the graph, 100% of radiocarbon in a sample will be reduced to 50% after 5730 years.

In 11,460 years, half of the 50% will remain, or 25%, and so on.

How It Works: Carbon has 3 isotopic forms: Carbon-12, Carbon-13, and Carbon-14.

The numbers refer to the atomic weight, so Carbon-12 has 6 protons and 6 neutrons, Carbon-13 has 6 protons and 7 neutrons, and Carbon-14 has 6 protons and 8 neutrons.

There are two techniques for dating in archaeological sites: relative and absolute dating.

Relative dating stems from the idea that something is younger or older relative to something else.As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.It is good for dating for the last 50,000 years to about 400 years ago and can create chronologies for areas that previously lacked calendars.Absolute dating represents the absolute age of the sample before the present.Historical documents and calendars can be used to find such absolute dates; however, when working in a site without such documents, it is hard for absolute dates to be determined.Rodents, for example, can create havoc in a site by moving items from one context to another.