In The Cosmic Story of Carbon-14 Ethan Siegel writes: The only major fluctuation [in carbon-14] we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th Century.
If you ever wondered why nuclear tests are now performed underground, this is why.
Radiocarbon dating uses isotopes of the element carbon. Cosmic rays – high energy particles from beyond the solar system – bombard Earth’s upper atmosphere continually, in the process creating the unstable carbon-14. Because it’s unstable, carbon-14 will eventually decay back to carbon-12 isotopes.
Because the cosmic ray bombardment is fairly constant, there’s a near-constant level of carbon-14 to carbon-12 ratio in Earth’s atmosphere.
is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.
It can be used on objects as old as about 62,000 years.
Bottom line: is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.
Follow the links in this post to learn more about radiocarbon dating.Radon and its isotopes, parent radionuclides, and decay products all contribute to an average inhaled dose of 1.26 m Sv/a.Radon is unevenly distributed and variable with weather, such that much higher doses occur in certain areas of the world.In Europe, the average natural background exposure by country ranges from under 2 m Sv annually in the United Kingdom to more than 7 m Sv annually in Finland, as shown in.The biggest source of natural background radiation is airborne radon, a radioactive gas that emanates from the ground.Organisms at the base of the food chain that photosynthesize – for example, plants and algae – use the carbon in Earth’s atmosphere.