Carbon dating and half life calculations Free web cam no sign up horny
The process of carbon-14 dating was developed by William Libby, and is based on the fact that carbon-14 is constantly being made in the atmosphere.
Radon seeps out of these ores into the atmosphere or into ground water; it can also infiltrate into buildings.
It can be inhaled into the lungs, along with its decay products, where it will reside for a period of time after exposure.
This radiation is much more intense in the upper troposphere (around 10 km in altitude) and is therefore of particular concern for airline crews and frequent passengers, who spend many hours per year in this environment.
An airline crew typically gets an extra dose on the order of 2.2 m Sv (220 mrem) per year.
Put another way, human history is so short in comparison to a half-life of a billion years that the activity of these long-lived isotopes has been effectively constant throughout our time on this planet.