# Carbon dating fossil

With time, the carbon ratio falls; the lower the ratio, the older the remains.

Trouble is, humans have surprising power over the relative amount of carbon-14 and carbon-13 in the world.

Archaeologists use the exponential, radioactive decay of carbon 14 to estimate the death dates of organic material.

The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into nitrogen 14 and other particles.

When an organism dies it ceases to replenish carbon in its tissues and the decay of carbon 14 to nitrogen 14 changes the ratio of carbon 12 to carbon 14.

Experts can compare the ratio of carbon 12 to carbon 14 in dead material to the ratio when the organism was alive to estimate the date of its death.

The new study suggests that some of these current uses will be affected over this century, depending on how much fossil fuel emissions increase or decrease.

"If we reduced fossil fuel emissions, it would be good news for radiocarbon dating," said the study's author, Dr Heather Graven from the Department of Physics and the Grantham Institute - Climate Change and Environment at Imperial College London.

If the fossil has 35% of its carbon 14 still, then we can substitute values into our equation.After 5,730 years, the amount of carbon 14 left in the body is half of the original amount.If the amount of carbon 14 is halved every 5,730 years, it will not take very long to reach an amount that is too small to analyze.Radiocarbon dating can be used on samples of bone, cloth, wood and plant fibers.The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay.