Most carbon atoms have six protons and six neutrons in their nuclei and are called carbon 12. But a tiny percentage of carbon is made of carbon 14, or radiocarbon, which has six protons and eight neutrons and is not stable: half of any sample of it decays into other atoms after 5,700 years.Carbon 14 is continually being created in the Earth's atmosphere by the interaction of nitrogen and gamma rays from outer space.Argon is an inert, colorless and odorless element — one of the Noble gases.
Argon led to other eureka moments for Ramsey, as well.
Since atmospheric carbon 14 arises at about the same rate that the atom decays, the Earth's levels of carbon 14 have remained constant.
In living organisms, which are always taking in carbon, the levels of carbon 14 likewise stay constant.
Argon makes up about one percent of the atmosphere.
It is used in electric light bulbs, fluorescent tubes, and radio vacuum tubes.