Free live couple webcams no sign up - Calibrated age dating
This represents the ideal date for the amount of 14C measured for the sample.
However, as the quantity of 14 absorbed by all life fluctuates from year to year, the figure must be calibrated based on known fluctuation.
At the same time, atmospheric nuclear testing, which throws huge amounts of carbon into our atmosphere, was begun in the 1940's.
Radiocarbon dates after 1950 are virtually useless unless and until we can figure out a way to calibrate for the excessive amount of carbon still being deposited in our atmosphere.
That methodology has been refined and improved several times over the last few years.