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| | : Yeah, you do have to lecture me if you think the laws of physics, including the decay rate for C-14, has never changed. And after you lecture me, lecture every physicist who ever studied the Big Bang, and all their students. And then lecture every one who has ever studied [[Karl Popper]] and understands what science is. And then nominate yourself for the Nobel Prize!--[[User:Aschlafly|Aschlafly]] 00:01, 6 May 2007 (EDT) | | : Yeah, you do have to lecture me if you think the laws of physics, including the decay rate for C-14, has never changed. And after you lecture me, lecture every physicist who ever studied the Big Bang, and all their students. And then lecture every one who has ever studied [[Karl Popper]] and understands what science is. And then nominate yourself for the Nobel Prize!--[[User:Aschlafly|Aschlafly]] 00:01, 6 May 2007 (EDT) |
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| | + | == From radiocarbon dating == |
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| | + | This is from an older entry entitled "radiocarbon dating". Please identify any information here that you feel might improve this entry. A redirect from radiocarbon dating is being inserted to send it to "carbon dating" |
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| | + | '''Radiocarbon dating''' is a method for estimating the age of organic material by measuring the ratio of carbon-14 to carbon-12 present. |
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| | + | The method is based on the fact that the carbon-12 [[isotope]] of carbon is more stable, and therefore more common, than the [[radioactivity | radioactive]] carbon-14 isotope. Most<!-- is this correct? --> of the carbon in the earth is buried deep underground, where any carbon-14 [[radioactive decay | decays]], leaving behind carbon-12. Nitrogen-14 atoms in the stratosphere are often struck by neutrons, converting them to carbon-14 atoms. But carbon-14 in the atmosphere mixes with ordinary carbon-12 and finds it way into all living creatures. Therefore the concentration of carbon-14 is higher in living creatures and in the atmosphere than it is in dead or buried forms of carbon. |
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| | + | Thus, archaeologists use radiocarbon dating to measure the age of dead bodies, fossils, and burnt wood. If the concentration of carbon-14 is almost as high as in the atmosphere, then the specimen was recently alive. If it is much lower, then the specimen has been dead a long time. |
| | + | The mathematical formula that is used to figure the time since death depends on the the measured concentration of carbon-14 in the atmosphere, and also on the [[half-life]] of carbon-14 (the time it takes for half the carbon-14 in a given sample to decay). The half-live of carbon-14 is commonly given as 5730 ± 40 years; however a global standard half-life of 5568 ± 30 years is also often employed. |
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| | + | Obviously, this formula depends on the atmosphere remaining roughly constant in its composition over time. Insofar as the natural level and distribution of carbon-14 varies over time, due to to atmospheric disturbances, the formula will need to be adjusted. For example, in the last few decades, testing of [[nuclear bomb|nuclear weapons]] in the atmosphere has increased the concentration of carbon-14 in the Northern Hemisphere. To account for this, standard calibration curves are used to take account of known chronological fluctuations, and results can be obtained which are rarely more than 700 years out. |
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| | + | Other isotopes with longer half-lives can also be used to date objects. However, each method has its own drawbacks. |
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| | + | [[Young Earth Creationism|Young-Earth creationists]] point out that the atmospheric ratio of carbon-12 to carbon-14 would have been affected by the [[Great Flood|global flood]], as the flood buried massive quantities of living things,<ref>Batten 2007, p. 71.</ref> thus invalidating dating results from that era as secular science does not allow for this. As such dating results ''presume'' that there was no flood, the resulting dates are not ''proof'' that there was no flood, as anti-creationists often charge. |
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| | + | ==See also== |
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| | + | [[radiometric dating | Radiometric dating methods]] |
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| | + | == Bibliography == |
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| | + | * Quarternary Dating Methods, by M. Walker (Wiley & Sons, 2005). |
| | + | *Isotopes: Principles and Applications, by G. Faure and T. Mensing (Wiley & Sons, 2005). |
| | + | [[Category:Earth science]] |
| | + | * Batten, Don et. al., [http://www.creationontheweb.com/images/pdfs/cabook/chapter4.pdf ''What about carbon dating?''], Chapter 4 of ''The Creation Answers Book'', Creation Book Publishers, 2007, ISBN 978-0949906625. |
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| | + | == Notes == |
| | + | <references /> |