Bob Ross wrote:I've understood that it's ok plus or minus 500 years or so. But then I read the following:
Neil Courtney wrote:The dating of recent samples was muddied somewhat (a lot) in the '50's when all and sundry were letting off atomic bombs in the atmosphere. I don't know if this makes dating of stuff from the last 50 odd years more or less accurate that prior to the bomb era.
From another source, the half life of C-14 is 5,730 years approximately, so here is another source of error. The scientists themselves don't know what figures to use.
Dan Smothergill wrote:Robin, where did you get these guys?
And what do they know about wine?
Bob Ross wrote:Has carbon dating become much more accurate recently?
Sam Platt wrote:Bob, Sorry for posting twice. Itchy trigger finger after a couple weeks of vacation. Don't discount the possibility that God made the sherry to appear old just because he felt like it. I'm sure that sherry aging is right at the top of his priority list just now. Oops! Just heard a clap of thunder!
Bernard Roth wrote:Let me explain why the C14/C12 ratio in the latter 20th century is distorted from previous epochs that are within reach of the carbon dating technique.
The amount of CO2 in the atmosphere now is at least 50% higher than ever measured before. That means that more C14 is being produced in the atmosphere now (and in the recent decades) than in the previous few mellennia.
It is necessary to understand that the fossil fuels themselves do not contribute C14. But the C12 they contain goes into the atmosphere when burned, and cosmic rays convert a small fraction to C14. Since there is more C12 in the atmosphere - and given a constant rate of conversion to C14 - this causes more C14 (a higher concentration) than is normal.
I think the italic statement by Howie is wrong. 20th century lifeforms will appear to be younger (high C14 ratio) than would be expected given the ratio of prior centuries. The implication is that (without historical correction), scientists in 1000 years could be befuddled by an apparent gap between life from 20th century on and that before. If scientists in the future assume that the proper calibration is to a higher ambient C14 ratio (as it is now), then it would appear that pre-20th century lifeforms were older than they really are.
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