Who uses radiometric dating
By 1950, Willard Libby and his group at the University of Chicago had worked out ways to measure this proportion precisely.Their exquisitely sensitive instrumentation was originally developed for studies in entirely different fields including nuclear physics, biomedicine, and detecting fallout from bomb tests.(1) Much of the initial interest in carbon-14 came from archeology, for the isotope could assign dates to Egyptian mummies and the like.In 1958, Hessel de Vries in the Netherlands showed there were systematic anomalies in the carbon-14 dates of tree rings.His explanation was that the concentration of carbon-14 in the atmosphere had varied over time (by up to one percent).After a creature's death the isotope would slowly decay away over millennia at a fixed rate.Thus the less of it that remained in an object, in proportion to normal carbon, the older the object was.
He was looking for the carbon that human industry had been emitting by burning fossil fuels, in which all the carbon-14 had long since decayed away.
A stronger field would tend to shield the planet from particles from the Sun, diverting them before they could reach the atmosphere to create carbon-14.
and "not very attractive."(8) However, solar specialists knew that the number of particles shot out by the Sun varies with the eleven-year cycle of sunspots.
De Vries thought the variation might be explained by something connected with climate, such as episodes of turnover of ocean waters.(7) Another possible explanation was that, contrary to what everyone assumed, carbon-14 was not created in the atmosphere at a uniform rate.
Some speculated that such irregularities might be caused by variations in the Earth's magnetic field.