Effective range of radiocarbon dating
Various geologic, atmospheric and solar processes can influence atmospheric carbon-14 levels.Since the 1960s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings.For an example, when they tried to get the carbon dating for presence of Aboriginal people in Australia they get to the number 40,000. Why is that 40,000 years limit for carbon dating methods?Carbon-14 makes up about 1 part per trillion of the carbon atoms around us, and this proportion remains roughly constant due to continual production of carbon-14 from cosmic rays.The half life of carbon-14 is about 5,700 years, so if we measure the proportion of C-14 in a sample and discover it's half a part per trillion, i.e.half the original level, we know the sample is around one half life or 5,700 years old.
Historians can tell what cultures thrived in different regions and when they disintegrated.
Studying the material remains of past human life and activities may not seem important or exciting to the average Joe unlike the biological sciences.
But archaeology’s aim to understand mankind is a noble endeavor that goes beyond uncovering buried treasures, gathering information, and dating events.
Archaeology has undoubtedly enriched mankind’s history like no other science.
There is a greater part of man’s unwritten past that archaeology has managed to unravel.