saudi arabian dating azdg arab - Dating with radioisotope

PROBLEMS WITH RADIOCARBON DATING During the last 30 years, a new method of determining C14/C12 ratios has been developed.It uses accelerator mass spectrometry to determine the amounts of C14 and C12 in a small sample which is vaporised in the test.

The radioactive carbon has six protons and eight neutrons in its nucleus, giving it a total atomic mass of 14.

This atom is not stable, and will break down, releasing nuclear energy in the process.

Usually a proton is knocked out of the nitrogen atom's nucleus and is replaced with the neutron.

The proton takes an electron with it and becomes an atom of hydrogen.

But in actual practice, we know neither the original ratios nor if the specimen has been contaminated and are forced to make what we hope are reasonable assumptions.

The tiny initial amount of C14, the relatively rapid rate of decay (the half-life of C14 is currently about 5700 years) and the ease with which samples can become contaminated make radiocarbon dating results for samples "older" than about 50,000 years effectively meaningless.

When they strike ordinary atoms in the upper atmosphere, the cosmic rays smash them apart. Some of these neutrons then collide with nitrogen atoms.

This collision is less destructive than the initial collision that produced them.

The carbon dioxide is absorbed by plants, and the plants are eaten by animals, thus contaminating every living thing on earth with radioactive carbon. As time passes, the C14 in its tissues is converted back into nitrogen.

If we know what the original ratios of C14 to C12 were in the organism when it died, and if we know that the sample has not been contaminated by contact with other carbon since its death, we should be able to calculate when it died by its C14 to C12 ratio.

Surely 15,000 years of difference on a single block of soil is indeed a gross discrepancy!

Tags: , ,