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Author | Topic: Radioactive carbon dating | |||||||||||||||||||||||
RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
I read his reply, and the responses, but John has said little new after that. http://www.theologyweb.com/campus/showthread.php?t=103916 quote: No it doesn't, this is hyperbole. There are several existing explanations for this problem. One must always remember that radiocarbon dating is based on the C12 and C14 coming from atmospheric carbon, where the C14 is due to solar activity converting N14 to C14. There are other sources of carbon and other ways to make C14 (C13 can be converted during nuclear reactions, as can "expired" C14 having again become N14 in the samples). These would necessarily be rare events in buried samples, and thus produce only low levels of new C14, such as those found in coal and diamonds in the RATE paper. Thus when anything is dated - particularly samples over 50,000 years - by this method it is imperative to eliminate other sources for carbon and for production of new C14. A background level of radiation will produce a background level of C14 with the level depending on the level of radioactivity involved. This is well known by Baumgardner et al, and thus it is no surprise that they make use of this fact. It is relatively easy to search out radioactive sites and intentionally find samples that appear to throw dating into question. The problem for these people is that even if such "contamination" of samples is common in the world of archaeological samples that do come from sources that obtained their C12 and C14 from atmospheric carbon, that the level of error produced is still within the margin of error for the dating methods, and radioactivity can be eliminated in most cases relatively easily. Take the Lake Suigetsu clay\diatom varves, with some 35,000 annual layers and samples of organic debris found in the layers: because of the manner of formation of the varves there is no source of radioactivity that could change the age of those samples, and the varve layer age would still correlate with the radiocarbon date properly. Even if the level of C14 in very old samples is due to cosmic radiation penetrating the earth, the level produced is necessarily small as there is limited material to convert to C14 (C13 and N14 being is very small quantities). The end result either way is that the system cannot be used to date things much older than 50,000 years with the accuracy that samples younger than 50,000 years have. That is not a hardship. It does not show that coal or diamonds are young, nor that radiocarbon dating is filled with massive errors. Enjoy, Edited by RAZD, : . Edited by RAZD, : not nothing compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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Chiroptera Member Posts: 6399 From: Oklahoma Joined: |
Progress in human affairs has come mainly through the bold readiness of human beings not to confine themselves to seeking piecemeal improvements in the way things are done, but to present fundamental challenges in the name of reason to the current way of doing things and to the avowed or hidden assumptions on which it rests. -- E. H. Carr
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RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
http://radiocarbon.library.arizona.edu/radiocarbon/ On-line access to radiocarbon issues from 1959 to 2004. And three additional articles on Lake Suigetsu, and a couple on the Cariaco Basin that provide another correlation, this one provided by John: http://geopubs.wr.usgs.gov/prof-paper/pp1670/pp1670.pdf
Yep, but then when you are trying to defend a false position it is hard to use real evidence. Enjoy. compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click) we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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Chiroptera Member Posts: 6399 From: Oklahoma Joined: |
Progress in human affairs has come mainly through the bold readiness of human beings not to confine themselves to seeking piecemeal improvements in the way things are done, but to present fundamental challenges in the name of reason to the current way of doing things and to the avowed or hidden assumptions on which it rests. -- E. H. Carr
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sikosikik5 Junior Member (Idle past 3683 days) Posts: 5 Joined: |
1. the earths atmosphere has reached equilibrium 2. and c14 has always burned at a constant rate
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molbiogirl Member (Idle past 385 days) Posts: 1909 From: MO Joined: |
Both of your "concerns" have already been discussed at length.
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RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
Nope. (1) we know that the production of 14C varies from year to year due to the solar sunspot cycle, and thus the amount will always vary about an average, and never reach an "equilibrium. We can, hoverver, assume that we can use average over the 11 year cycle applies with sufficient accuracy for dating purposes. Then we can check radiocarbon dating based on this assumption against items where we know the dates from other methods and see if the assumption holds up. This has been done, resulting in a correlation curve. See IntCal04 (ToC) and related articles through Radiocarbon archives for details. You can also look at IntCal98 for similar calibration work. (2) Carbon-14, 14C, does not "burn" - it is radioactive and decays along an exponential curve based on its half-life (5730 years). We have found no reason to believe that radioactive rates have changed in the past, no evidence for it, even though this has been considered. If someone tells you different, the likelihood is either (1) they are ignorant themselves, (2) they are lying to deceive you, (3) they are deluded about reality. Enjoy. ps - as you are new: type [qs]quotes are easy[/qs] and it becomes:
or type [quote]quotes are easy[/quote] and it becomes: quote: also check out (help) links on any formating questions when in the reply window. we are limited in our ability to understand by our ability to understand RebelAAmericanOZen[Deist ... to learn ... to think ... to live ... to laugh ... to share.
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kbertsche Member Posts: 1426 From: San Jose, CA, USA Joined: |
http://www.asa3.org/ASA/education/origins/rate-pscf.htm#4 An expanded analysis of the RATE claims, about 5x longer, is also available here: Kirk Bertsche
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RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
This thread is now closed due to length, however this choice piece of typical creationist misrepresentation of carbon-14 dating problems should be addressed. There never will be an "equilibrium" level of C-14 in the atmosphere. The reasons are simple, but the failure (ignorance, misunderstanding, intentional misrepresentation, whatever) to come to terms with this simple fact betrays a lack of learning the simple basics of the method and the reasons for the variations. The Carbon-14 EnvironmentCarbon-14 is a radioactive isotope of carbon. http://www.infoplease.com/ce6/sci/A0857174.html (1) quote: http://www.c14dating.com/int.html (8) quote: http://science.howstuffworks.com/carbon-14.htm/printable (5) quote: This takes energy to accomplish, and the decay releases this energy: Carbon-14 decays back to Nitrogen-14 by beta- decay: http://education.jlab.org/glossary/betadecay.html (7) quote: Thus cosmic ray activity produces a "Carbon-14 environment" in the atmosphere, where Carbon-14 is being produced or replenished while also being removed by radioactive decay due to a short half-life. This results is a variable but fairly stable proportion of atmospheric Carbon-14 for absorption from the atmosphere by plants during photosynthesis in the proportions of C-12 and C-14 existing in the atmosphere at the time. The level of Carbon-14 has not been constant in the past, as it is known to vary with the amount of cosmic ray bombardment and climate change. Because the level of cosmic ray radiation level is always changing, based on several independent cycles (one is 19 years long), there will never be a point where the level of 14C is in equilibrium. Instead the level of 14C will rise and fall, lagging behind but in response to the rise and fall of cosmic ray radiation levels. It will never reach a steady level. Anyone who tells you it should be in equilibrium is either lying or doesn't understand how 14C is produced and how equilibrium is reached. Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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shalamabobbi Member (Idle past 592 days) Posts: 397 Joined: |
quote:
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Coyote Member Posts: 6099 Joined: Member Rating: 2.8 |
http://www.answersingenesis.org/articles/nab/does-c14-disprove-the-bible Because their religious belief tells them that radiocarbon dating is in error, they look for any possible facts or quotes to misrepresent or misunderstand in order to confirm that belief. This web article is a very good example. As is often the case with creationist websites, it makes junk science seem downright respectable. As is generally the case with creationist "science" this article is inaccurate. Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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kbertsche Member Posts: 1426 From: San Jose, CA, USA Joined: |
quote: From the AiG link:
This is partly true, but the facts are being twisted. Yes, Libby assumed equilibrium. An equilibrium assumption works surprisingly well (maximum error less than 15% over the last 45,000 years) due to our large atmospheric and terrestrial carbon reservoirs which dilute the effects of non-equilibrium production rates. But with tree ring calibrations, equilibrium does NOT need to be assumed. The only assumptions are that 1) we can count annual tree rings, and 2) the trees used for calibration and the unknowns breathed the same atmospheric radiocarbon. There is NO assumption of equilibrium, original concentrations, etc. (BTW, this also gets around any claims of changes in the decay rate.) These details are mostly unknown by YECs, who persist in claiming that radiocarbon rests on many unproven assumptions. I was quizzed on this just last week by a fairly knowledgeable YEC, who seemed surprised by these details. Edited by kbertsche, : No reason given.
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RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
One also needs to consider the history of carbon-14 dating: http://home.tiac.net/~cri/1999/c14hist.html quote: Creationists using old information when science has developed significantly since then? Shocking. What this shows is that (A) the assumption of a constant level was reasonable at the beginning, and (B) it still works due to the variation in 14C production being cyclical around an average value. http://www.c14dating.com/int.html quote:
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Coyote Member Posts: 6099 Joined: Member Rating: 2.8 |
quote: There are several problems here. 1) When you say "radiocarbon dating" you probably mean "radiometric dating." Radiocarbon dating is one of the most familiar forms of radiometric dating, but it extends back in time only about 50,000 or 60,000 years. And, it works only on those things which contain carbon. But since you asked about radiocarbon dating, and that is something I have worked with a lot over nearly 40 years as an archaeologist, I will address that one method. 2) You probably read that radiocarbon dating was based on several assumptions, and the creationist source you read implied that those assumptions were faulty. Actually, none have been shown to be faulty by creation "science" or even real science. Radiocarbon dating relies on the assumptions that a) the decay constant has remained constant over the 50,000 or 60,000 years that the method addresses, and that b) the initial amounts of radiocarbon are known. a) There is currently no evidence that the decay constant varies by any significant amount. This is established by physicists and other scientists, not by "evolutionists" who are out to "prop up" Darwin's theory. But a few years ago creation "scientists" gathered over a million dollars of creationist money and set out to "prove" the decay constant wasn't. The R.A.T.E. Project, as it was known, failed. They found that scientists were right all along, but they refused to believe their own data. Creationists can't accept scientific data because they have chosen to accept scripture as the highest form of knowledge, so they had to reject the data they themselves generated! Creation "science" as usual, eh? Source: Assessing the RATE Project: Essay Review by Randy Isaac b) Creationists make a big deal out of the fact that atmospheric levels of carbon 14 vary because of variations in cosmic rays and other factors. They use this to cast doubt on the accuracy of the method. But don't you think scientists have noticed this variation and dealt with it? De Vries, in 1958, published on this problem and proposed solutions. Since then, a calibration curve has been established for North America using dated tree rings from the standing dead bristlecone pines of the White Mountains of southern California. That curve differs by only a bit over 10% at its greatest from the measured radiocarbon ages. But just in case that calibration curve is not representative, other curves have been worked out. They have used oaks in Europe and even coral growth and glacial varves in lakes, and the answers all come out pretty much the same. So in answer to your question, radiocarbon dating is not based on several faulty assumptions. The assumptions are as accurate as science can make them. What is faulty is creationists' efforts to discredit particular sciences because their religious belief requires it. For the most part they know little about science, but think they can overturn entire fields based on their faulty understanding and a few "gotcha" points that are repeated over and over. Those points have also been refuted over and over, and are thus called PRATTs (points refuted a thousand times). This is what you have most likely read. And check earlier posts on this thread. If I remember correctly there will be a lot of good information for you. If you have any specific questions, let us know. There are several folks here who are quite knowledgeable in this field. Edited by Coyote, : Boo-boo Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.
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RAZD Member Posts: 19478 From: the other end of the sidewalk Joined: Member Rating: 2.1 |
This is one thread where you can discuss what you think are problems with dating methods, specifically what you think is wrong with 14C dating. In Message 1 you say:
You can believe what you like, unfortunately (for your) it has no effect on reality. The earliest agricultural evidence is circa 10K years ago: http://en.wikipedia.org/wiki/Neolithic_Revolution quote: That makes the evidence of agriculture older than your YEC world. It is not the only thing older than your YEC world (see Age Correlations and An Old Earth, Version 2 No 1 for a number of things that make your YEC concept invalid).
Seeing as 14C (not Co14 -- there is no 14Cobalt isotope, Cobalt - Co - has 27 protons) is vastly validated as a method of determining dates, including correlations with annual layer systems that extend to 35K+ years, and 45k to 50k years is the practical limit for using 14C dating. Modern humans are closer to 200,000 years old on this planet. http://www.berkeley.edu/news/media/releases/2003/06/11_idaltu.shtml quote: And that doesn't even begin to touch the age of ancestor species of hominids. Note that 14C was not used, but two independent methods, one radiometric and one chemical, and the dates of the two methods agreed. This is the common approach to any find - using different methods and comparing results. What this means is that you need to explain how both methods can be exactly wrong by precisely the same amount. Now, perhaps, you would like to present us with the information that you think makes 14C dating invalid. Provide sources and quotes, not just assertions, as this is a science thread and you have been challenged to provide scientific evidence. Good luck. Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. • • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •
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