The Muslims count the Prophet’s departure from Mecca, or the Hegira, as their beginning at AD 662.The Mayan calendar used 3114 BC as their reference.

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).

The Greeks consider the first Olympic Games as the beginning or 776 BC.

Half-lives vary according to the isotope, for example, Uranium-238 has a half-life of 4500 million years where as Nitrogen-17 has a half-life of 4.173 seconds!

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

AND IF I WASREALLY PREGNANT, "DON'T YOU THINK I WOULD'VETAGGED YOU IN THE FACEBOOK POST?

AND I WAS LIKE, "MOM, I'M NOT REALLY PREGNANT, OKAY?

Historical documents and calendars can be used to find such absolute dates; however, when working in a site without such documents, it is hard for absolute dates to be determined.

As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.

Natural disasters like floods can sweep away top layers of sites to other locations.

Absolute dating represents the absolute age of the sample before the present.

Although relative dating can work well in certain areas, several problems arise.