# Year libby discovered radiocarbon dating

Carbon dioxide also permeates the oceans, dissolving in the water.For approximate analysis it is assumed that the cosmic ray flux is constant over long periods of time; thus carbon-14 is produced at a constant rate and the proportion of radioactive to non-radioactive carbon is constant: ca. In 1958 Hessel de Vries showed that the concentration of carbon-14 in the atmosphere varies with time and locality.A quantity is said to be subject to exponential decay if it decreases at a rate proportional to its value.Symbolically, this can be expressed as the following differential equation, where are customarily given in years BP which implies t(BP) = -t because the time arrow for dates runs in reverse direction from the time arrow for the corresponding ages.C-14 decays to non radioactive nitrogen-14 with half life of 5730 years.

Carbon-14 has a half-life of 5730 years, meaning that the amount of carbon-14 in a sample is halved over the course of 5730 years due to radioactive decay.

It is used extensively in archeology for dating artifacts.

It can date carbon artifacts for upto 60,000 years.

Such raw ages can be calibrated to give calendar dates.

uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" (BP), "Present" being defined as AD 1950.