Carbon dating years
They found large variations in the radiocarbon 'dates' of objects of known age sent to 38 radiocarbon 'dating' laboratories around the world.
Thirty-one of the labs gave results that the British group called unsatisfactory.
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.
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.
It uses accelerator mass spectrometry to determine the amounts of C14 and C12 in a small sample which is vaporised in the test.
BASIS OF RADIOCARBON DATING Radiocarbon dating compares the amount of normal carbon with the amount of radioactive carbon in a sample.
What effect would the declining strength of the earth's magnetic field and a catastrophic worldwide flood have on radiocarbon dates?
The ions produced are forced into a magnetic field where the different mass of the carbon isotopes causes a different deflection, allowing the quantity of each isotope to be measured.
This method is claimed to be more accurate than the older and slower method of counting the number of radioactive decay emissions from a quite large sample.
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However, because it has too many neutrons for the number of protons it contains, it is not a stable atom.