Archaeological findings may have to be dated again A complete rewrite of the history of modern humans could be needed after a breakthrough in archaeological dating techniques.

British and American scientists have found radio carbon dating, used to give a rough guide to the age of an object, can be wrong by thousands of years.

It means humans may have been on earth for a lot longer than previously thought and accepted versions of early history could need a radical rethink.

Experts have known for years that carbon dating is inexact but until researchers from Bristol and Harvard completed their study no one knew by how much.

Study method

The scientists calculated the age of ancient limestone formations in caves using carbon dating.

The results were checked using a newer, more accurate method known as uranium dating.

They found that the carbon dates were wrong by thousands of years and that the further back in time they went, the more out-of-date they were.

The reason is that carbon dating measures radioactive carbon and there may have been much more of it in the distant past than previously thought.