A researcher who uses carbon dating on ancient times
As you learned in the previous page, carbon dating uses the half-life of Carbon-14 to find the approximate age of certain objects that are 40,000 years old or younger.In the following section we are going to go more in-depth about carbon dating in order to help you get a better understanding of how it works.
Radiocarbon dating has transformed our understanding of the past 50,000 years.After a creature's death the isotope would slowly decay away over millennia at a fixed rate.Thus the less of it that remained in an object, in proportion to normal carbon, the older the object was.Isotopes of a particular element have the same number of protons in their nucleus, but different numbers of neutrons.This means that although they are very similar chemically, they have different masses.Age determinations can also be obtained from carbonate deposits such as calcite, dissolved carbon dioxide, and carbonates in ocean, lake, and groundwater sources.
Cosmic rays enter the earth's atmosphere in large numbers every day and when one collides with an atom in the atmosphere, it can create a secondary cosmic ray in the form of an energetic neutron.
When these energetic neutrons collide with a nitrogen-14 (seven protons, seven neutrons) atom it turns into a carbon-14 atom (six protons, eight neutrons) and a hydrogen atom (one proton, zero neutrons).
Since Nitrogen gas makes up about 78 percent of the Earth's air, by volume, a considerable amount of Carbon-14 is produced.
The equipment required to do this is extremely large and costly.
Now, Paolo de Natale and colleagues of the National Institute of Optics and the European Laboratory for Non-Linear Spectroscopy, both in Florence, Italy, have developed a much cheaper alternative that they say is almost as sensitive.
An example of the ingenious technical work and hard-fought debates underlying the main story is the use of radioactive carbon-14 to assign dates to the distant past.