Then, copy and paste the text into your bibliography or works cited list.
Scientists who study the ancient Earth have been working for hundreds of years to build an accurate timeline of the formation of the planet and the evolution of all life. In order to build and improve this timeline, scientists must have several types of accurate methods they can use to determine the ages of materials.
There are two main categories by which they do this: relative age dating and absolute age dating.
A range of methods for determining the absolute age of an object or material, for example using radiometric dating which measures the decay product produced by radioactive decay in minerals, or via dendrochronology.
Imagine braving the desert heat for days or even weeks as you dig for dinosaur bones.
, in which figures in solar years (often with some necessary margin of error) can be applied to a particular event.
Unless tied to historical records, dating by archaeological methods can only be relative -- such as stratigraphy, typology, , fluorine and nitrogen test, and radiometric assay.
This method is a bit vague, which is why modern scientists have developed many methods by which to determine the absolute age of Earth materials.
The absolute age of an Earth material is a measure of how old it actually is in years.
Instead of saying a material is older or younger than something else, scientists can simply report the age in years.