Using the earth for radiometric dating Nasty girlschat free trial
The Greeks consider the first Olympic Games as the beginning or 776 BC.
The Muslims count the Prophet’s departure from Mecca, or the Hegira, as their beginning at AD 662.
There are two techniques for dating in archaeological sites: relative and absolute dating.
Relative dating stems from the idea that something is younger or older relative to something else.
Usually, atoms have an equal number of protons and neutrons.
If there are too many or too few neutrons, the atom is unstable, and it sheds particles until its nucleus reaches a stable state.
The Mayan calendar used 3114 BC as their reference.
By 1904 physicist Ernest Rutherford showed how this decay process could act as a clock for dating old rocks.
How do scientists know the bones are really 68 million years old?
Today's knowledge of fossil ages comes primarily from radiometric dating, also known as radioactive dating.
Dinosaur bones, on the other hand, are millions of years old -- some fossils are billions of years old.
To determine the ages of these specimens, scientists need an isotope with a very long half-life.
Each of them typically exists in igneous rock, or rock made from cooled magma.