Relative age dating and absolute age dating
Relative age will require the comparison of two or more objects, whereas absolute age does not.
Continue Reading Relative age comes up often in various fields, such as archeology.
Particular isotopes are suitable for different applications due to the type of atoms present in the mineral or other material and its approximate age.
For example, techniques based on isotopes with half lives in the thousands of years, such as Carbon-14, cannot be used to date materials that have ages on the order of billions of years, as the detectable amounts of the radioactive atoms and their decayed daughter isotopes will be too small to measure within the uncertainty of the instruments.
Here's the next step in that journey: the Geologic Time Scales of Earth and the Moon.
In the science of geology, there are two main ways we use to describe how old a thing is or how long ago an event took place. When you say that I am 38 years old or that the dinosaurs died out 65 million years ago, or that the solar system formed 4.6 billion years ago, those are absolute ages.
There are absolute ages and there are relative ages. We use a variety of laboratory techniques to figure out absolute ages of rocks, often having to do with the known rates of decay of radioactive elements into detectable daughter products.
Unfortunately, those methods don't work on all rocks, and they don't work at all if you don't have rocks in the laboratory to age-date. They are descriptions of how one rock or event is older or younger than another.
In historical geology, the primary methods of absolute dating involve using the radioactive decay of elements trapped in rocks or minerals, including isotope systems from very young (radiocarbon dating with Radiometric dating is based on the known and constant rate of decay of radioactive isotopes into their radiogenic daughter isotopes.However, this does not say anything about the absolute age of the layers.That is, scientists cannot tell exactly how old the layers are in years to the present date, only which is older than the other.An absolute age is one determined usually by mass-spectrometry where an isotope is measured and then an age can be calculated (a very very basic explanation).So in the end you can say this fossil is 50 thousand years old (always with an associated uncertainty).
We can absolute date materials but it will always have an uncertainty range, we can never know the age with infinite precision.