Isotopes in carbon dating
So, using carbon dating for fossils older than 60,000 years is unreliable.Carbon dating was developed by American scientist Willard Libby and his team at the University of Chicago.Carbon-14 has a relatively short 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.By about ten half-lives, or 58,000 years, the amount of carbon-14 left in the fossil is very little- about 1/1000 of the original number of carbon-14 atoms in the fossil.
The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 50,000 ft).
Libby calculated the half-life of carbon-14 as 5568, a figure now known as the Libby half-life.
Following a conference at the University of Cambridge in 1962, a more accurate figure of 5730 years was agreed upon and this figure is now known as the Cambridge half-life.
Atoms are arranged as a nucleus surrounded by an electron cloud, with electrons zinging around at different distances from the nucleus.
Chemists conceive of these distances as shells, and define the properties of atoms by what is in each shell, according to the University of California, Davis.