Radiocarbon dating world history
Some chemical elements have more than one type of atom. Carbon has two stable, nonradioactive isotopes: carbon-12 (12C), and carbon-13 (13C).
In addition, there are trace amounts of the unstable isotope carbon-14 (14C) on Earth.
However, it is also used to determine ages of rocks, plants, trees, etc. When the sun’s rays reach them, a few of these particles turn into carbon 14 (a radioactive carbon).
The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 50,000 ft).
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Historical documents and calendars can be used to find such absolute dates; however, when working in a site without such documents, it is hard for absolute dates to be determined.
At high geomagnetic latitudes, the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide.
So, scientists can estimate the age of the fossil by looking at the level of decay in its radioactive carbon.
When it comes to dating archaeological samples, several timescale problems arise.
For example, Christian time counts the birth of Christ as the beginning, AD 1 (Anno Domini); everything that occurred before Christ is counted backwards from AD as BC (Before Christ).
Rodents, for example, can create havoc in a site by moving items from one context to another.
Natural disasters like floods can sweep away top layers of sites to other locations.