How Carbon-14 Is Formed

 In the course of even one hour, vast numbers of cosmic rays enter the earths atmosphere. So many that every person is hit by about a half 1 million cosmic rays every hour. Some of these cosmic rays will collide with an atom in the atmosphere, the end result is an energetic neutron. If these neutrons collide with an nitrogen 14 atom it will become a carbon-14 atom.

When the nitrogen-14 atom was hit, the energetic neutron became unbalanced (radioactive). The nitrogen-14 atom consisted of 7 protons and 7 neutrons, nice and balanced. After colliding with the energetic neutron the atom is changed, it now consists of 6 protons and 8 neutrons. Because it’s unbalanced, there is a natural process that wants to turn the carbon-14 atoms back into a nitrogen-14 atom. It takes 5730 years for half of the carbon 14 to return to nitrogen 14 (half life), it takes another 5730 years for half of what left of the original 50 to convert leaving 25 percent of the original amount. When you reach around 50,000 years there isn’t enough carbon 14 left to get an accurate measurement

Ingesting Carbon 14

The earth has a lot of carbon in it, 99% of it is carbon-12. About 1% is carbon-13.  A very tiny amount of it is carbon-14, only about 60 metric tons. Compared with the 40 trillion metric tons of carbon 12 it really is quite small. Probably a good thing with it being radioactive and all.  So our newly born carbons 14 atoms float around with the carbon-12 and 13 atoms.  Sooner or later a plant takes in the carbon 14 molecule through the photosynthesis process. This tags virtually every plant with carbon-14 atoms and they stay in the plant. When an animal eats these plants they absorb the carbon 14 atom as well.  The animal continues to gather these carbon-14 atoms while it’s alive. Once the plant or animal dies and is buried, it is no longer receiving carbon-14 and the carbon-14 atoms begin to return to nitrogen 14.

Carbon 14 Dating

Through scientific experimentation they have been able to determine roughly how much decay will happen to a carbon-14 atom over a certain period of time. For example, say while doing an archaeological dig, you find King Tut. Through other historical data we know when King Tut lived, about 3324 years ago.  We analyze one of King Tuts bone and find that there is 66.892% of of the carbon 14 left. From that measurement we can determine the age of the bone.

By doing carbon dating on various artifacts and cross-referencing them,science is been able to determine roughly how long something has been around on artifacts that are not extremely old.