Non radiometric dating methods
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.
Before the advent of absolute dating methods in the twentieth century, nearly all dating was relative.
The main relative dating method is stratigraphy (pronounced stra-TI-gra-fee), which is the study of layers of rocks or the objects embedded within those layers.
When carbon-14 falls to Earth, it is absorbed by plants.
These plants are eaten by animals who, in turn, are eaten by even larger animals.
The rings form a distinctive pattern, which is the same for all members in a given species and geographical area.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.Dendrochronology: Also known as tree-ring dating, the science concerned with determining the age of trees by examining their growth rings.Half-life: Measurement of the time it takes for one-half of a radioactive substance to decay.