¡Û (Dendrochronology) During severe weather, the tree rings are thin, during lush and profitable weather, the rings are thicker. These are then compared with live tree samples to predict climate conditions of the time.

¡Û (Thermoluminescence) Given the proportions of light to heat, the date of creation of an archaeological artefact can be determined. Thermo means heat and luminescence translates to light.

¡Û Another method is Carbon 14 dating which measures proportions (of C") in the atmosphere. It has one definitive characteristic of decaying in a specific rate. All living things including plants, animals and humans take in C14. After death, the amount of C14 in the body decays at a graphable rate.

¡Û By C14 dating, the year may be estimated with plus or minus a couple of years. The larger the number of,,b years, the longer ago in time it was.

¡Û More than 7,500 year old fossils - C14 is not...