Absolute ages

The absolute age of an Earth material is a measure of how old it actually is in years. Some scientists prefer to call it calendar age, because the term suggests that the age can be plotted on a calendar. The absolute age of a material is much more desirable when constructing the timeline of our planet because it does not rely on comparisons to other materials. Instead of saying a material is older or younger than something else, scientists can simply report the age in years.