By measuring the amount of original and transformed atoms in an object, scientists can determine the age of that object.
Cosmic rays: Invisible, high-energy particles that constantly bombard Earth from all directions in space.
This method is based on the assumption (which nearly always holds true) that deeper layers of rock were deposited earlier in Earth's history, and thus are older than more shallow layers.
The successive layers of rock represent successive intervals of time.
These plants are eaten by animals who, in turn, are eaten by even larger animals.The older the pottery, the brighter the light that will be emitted.Using thermoluminescence, pottery pieces as old as 100,000 years can be dated with precision. Known as dendrochronology (pronounced den-dro-crow-NOL-o-gee), tree-ring dating is based on the fact that trees produce one growth ring each year.By measuring the amount of carbon-14 remaining, scientists can pinpoint the exact date of the organism's death.The range of conventional radiocarbon dating is 30,000 to 40,000 years.The nucleus of every radioactive element (such as radium and uranium) spontaneously disintegrates over time, transforming itself into the nucleus of an atom of a different element.