The New Zealand curve is representative for the Southern Hemisphere, the Austrian curve is representative for the Northern Hemisphere. This makes it possible to tell the age of substances that contain carbon. Dates obtained are usually written as before present ('present' is 1950).Atmospheric nuclear weapon tests almost doubled the concentration of Radiocarbon dating, also known as the C14 dating method, is a way of telling how old an object is. Plants take up atmospheric carbon dioxide by photosynthesis, and are eaten by animals, so every living thing is constantly exchanging carbon-14 with its environment as long as it lives. In 1958 Hessel de Vries showed that the concentration of carbon-14 in the atmosphere varies with time and locality.
Note the consequence of the law of large numbers: with more atoms, the overall decay is more regular and more predictable.
Suess said he drew the line showing the wiggles by "cosmic schwung" – freehand, in other words.
It was unclear for some time whether the wiggles were real or not, but they are now well-established.
) is the time required for a quantity to reduce to half its initial value.
The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo, or how long stable atoms survive, radioactive decay.
The term is also used more generally to characterize any type of exponential or non-exponential decay.