Relative dating wiki
For example, how do we know that the Iceman, whose frozen body was chipped out of glacial ice in 1991, is 5,300 years old?Well, we know this because samples of his bones and hair and even his grass boots and leather belongings were subjected to radiocarbon dating.In fact, this form of dating has been used to date the age of rocks brought back to Earth from the moon.
Carbon-14 combines with oxygen to create carbon dioxide.
With rubidium-strontium dating, we see that rubidium-87 decays into strontium-87 with a half-life of 50 billion years.
By anyone's standards, 50 billion years is a long time.
When the isotope is halfway to that point, it has reached its half-life.
There are different methods of radiometric dating that will vary due to the type of material that is being dated.
So, if you know the radioactive isotope found in a substance and the isotope's half-life, you can calculate the age of the substance. Well, a simple explanation is that it is the time required for a quantity to fall to half of its starting value.