Peanut Gallery for Great debate: radiocarbon dating, Mindspawn and Coyote/RAZD

Don't get me wrong; I joined this site because it seems to be at least sparsely populated by creationists who were more than usually willing/able to have a real, evidence-based debate. I applaud Mindspawn and all others who are able to carry on this sort of debate. But it is nevertheless frustrating when someone expends a great deal of effort building a strong, evidence-based argument only to have to the interlocutor eventually disappear without providing a rebuttal or a concession.Perhaps my post did not clearly convey what I intended i.e. that despite my suspicion, having been informed of his posting schedule by NoNukes, I am currently giving him the benefit of the doubt. This is what I meant to convey (perhaps too laconically) by "fair enough".

two things:(1) I concur with NoNukes that this is within his typical posting periods, it's too early to consider it an effect of cognitive dissonance, and I am willing to wait a few more days,and(2) Posts are as much for the lurkers as they are for the participants, and there often are lurkers who benefit even when the participants don't.Enjoy

MIndie still hasn't read his own reference or the paragraph that RAZD posted.

Actually, RAZD left him the opening he is using. Sorta. Many of the methods for determining the half life of U234 do rely on assumptions of secular equilibrium which means that enough time has passed to reach that condition. That period is longer than 6000 years.Of course there are multiple methods of determining the half life of U234 and Th230 give similar results. And at least one of the methods does not have the issue he relies on.Easily closed with the references you and I provided.

Can't secular equilibrium be measured in the lab?

Perhaps it can, but doing so would require independently measuring the activity of U234 and U238 which is difficult. It is simpler to assume secular equilibrium based on other considerations. But I would not try to convince mindspring that those assumptions were correct. Way to hard.As the references you and I located show, isolating the isotope and making the difficult activity measurement is not impossible. And in fact those measurements were made decades ago. Not only do the measurement confirm the half lives as measured using the easier methods with way more accuracy than needed to end this sorry spectacle, the direct measurements also confirm that the assumptions of secular equilibrium for U238/U234 samples and U234/Th230 samples were completely warranted.And of course the half life of U238 has been measured directly as well.So not only does U234/Th230 dating confirm some points on the upper end of the C-14/dendrochronology curve, the measurements of half life themselves require the earth to be at least millions of years old, and that the solar system is at least billions of years old.ABE:Mindspawn is left with another coincidence to explain; a coincidence that I doubt even he would use identical monthly rainfall patterns to explain.Edited by NoNukes, : Grammar plus additional summaryEdited by NoNukes, : No reason given.

Yeah, you're probably right.It's also obvious that Mindie doesn't understand the U-Th dating is a disequilibrium method which depends on the half-lives of both isotopes.

Yeah, but give the man his due. He did have a point.ABE:Mindspawn is asking for an independent determination of the half life of U238. That should not be needed given the independent determinations of U234 and TH230 already available, but here is a link anyway:http://prc.aps.org/abstract/PRC/v4/i5/p1889_1

quote:

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New determinations of the half-lives of 235U and 238U have been made. Improved techniques have allowed the half-life values to be measured with greater accuracy than has been heretofore achieved. Samples were prepared by molecular plating and counted in a intermediate-geometry α-proportional counter with an extremely flat pulse-height plateau. The small amount of residual nonplated uranium was counted in a 2π counter.

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Energy analysis with a silicon-junction detector was used to measure the presence of "foreign" activities. For 235U, the measured specific activity was (4798.13.3) (dis/min)/(mg 235U), corresponding to a half-life of (7.03810.0048) 10^8 yr. For 238U, the specific activity was measured as (746.190.41) (dis/min)/(mg 238U), corresponding to a half-life of (4.46830.0024) 10^9 yr. Errors quoted are statistical (standard error of the mean), based upon the observed scatter of the data. This scatter exceeds that expected from counting statistics alone. We believe that systematic errors, if present, will no more than double the quoted errors.

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Edited by NoNukes, : ABE added citation.

From RAZD's Message 51, I don't think this diagram from Archaeological Tree Ring Dating at the Millennium is very easy to interpret: Does Mindspawn understand that this is a super-closeup of about 2½ tree rings? That the little squares represent the tiny growth cells that make up a tree ring? That there's a difference between early growth cells (thin walled) and late growth cells (thick walled)? If he doesn't understand this then he won't understand how it is that double-rings can be so easily identified.--Percy

Mindspawn doesn't need to know all that stuff. He knows it is all wrong, so what's the point?And no matter what evidence RAZD presents, it's all wrong too.This really demonstrates Heinlein's comment, "Belief gets in the way of learning."

Apparently only untrained novices like mindspawn or marc9000 are sufficiently distanced from science to be able to identify obvious issues. It could not possibly be that scientists have anticipated and ruled out such things. It could not possibly be that independent indications of age and historical events has already eliminated any significant error.Mindspawn claims that he doesn't believe in a conspiracy, but for scientist to ignore the stuff he claims causes the errors, there'd simply have to be a conspiracy.

Evidently this, from Mindspawn's Message 57, is what he considers a pleasant exchange of ideas: Dendrochronologists are incompetent and purposefully draw conclusions that support evolutionary timeframes because they fear ridicule. The scientific establishment has a religious fervour in support of evolution that mocks objections and suppresses true science.All just a pleasant exchange of ideas, certainly nothing anyone should take offense at.I wonder what will give out first, Mindspawn's increasingly detailed questioning of evidence, or RAZD's willingness to produce patient and well-researched essays.I also wonder if Mindspawn has any idea where he is going. He plods mindlessly on challenging one thing after another without seeming to consider that what he has conceded we know already rules out a young Earth and even a merely old Earth. If everything he questioned did turn out to be wrong to the maximum degree possible it would still point to an ancient Earth. It's like he doesn't understand the magnitude of the errors he needs.Does anyone know of any dendrochronological evidence from Biblical sites of known age? It would be interesting to get Mindspawn's reaction.--Percy

I think this Great Debate is an opportunity for RAZD to expound with enthusiasm. I don't see any evidence that he's even losing patience. In the end, we'll get a nice compilation of a couple of branches dating science.Meanwhile, I see that mindspawn is trying to claim that the magnetic field has the same affect on U-Th dating that it has on C-14. That, along with relying conspiracy theories, denigration of science, and whining looks like a last gasp, straw clutch.Mindspawn will never explicitly concede that he's lost the debate. These tactics of peeing on the evidence are the concession.

Mindie's trying to claim that magnetic field variation (on the order of +/- 50% could affect decay rates. The classic paper on constancy of decay rates is Emery, Perturbation of Nuclear Decay Rates.

quote:

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One of the paradigms of nuclear science since the very early days of its study has been the general understanding that the half-life, or decay constant, of a radioactive substance is independent of extranuclear considerations. Early workers tried to change the decay constants of various members of the natural radioactive series by varying the temperature between 24 K and 1280 K, by applying pressure of up to 2000 atm, by taking sources down into mines and up to the Jungfraujoch, by applying magnetic fields of up to 83,000 Gauss, by whirling sources in centrifuges, and by many other ingenious techniques. Occasional positive results were usually understood, in time, as the result of changes in the counting geometry, or of the loss of volatile members of the natural decay chains. This work was reviewed by Meyer & Schweidler (1), Kohlrausch (2), and Bothe (3). Especially interesting for its precision is the experiment of Curie & Kamerlingh Onnes (4), who reported that lowering the temperature of a radium preparation to the boiling point of liquid hydrogen changed its activity, and thus its decay constant, by less than about 0.05%. Especially dramatic was an experiment of Rutherford & Petavel (5), who put a sample of radium emanation inside a steel-encased cordite bomb. Even though. temperatures of 2500C and pressures of 1000 atm were estimated to have occurred during the explosion, no discontinuity in the activity of the sample was observed.

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83,000 Gauss is 270,000 times stronger than the Earth's current magnetic field at the surface on the equator, on the order of magnitude of a high resolution research MRI, and 3-6 times the strength of a clinical MRI (Wikipedia).References 1-3 are all to German books. The interested reader can look them up.

Not off the top of my head. maybe I'll Google around a little.There is King Hezekiah's tunnel. Hezzie ruled circa 715 to 686 BCE by conventional chronology. He had a tunnel dug to supply water to Jerusalem. Recently a team dated it using a leaf embedded in the plaster (obviously older than the tunnel or the same age) with 14C (700-800 BCE) and stalactites (obviously younger than the tunnel) with U-Th (400 BCE). (There are a few who still think the tunnel was dug much earlier).It would be interesting to recalculate those dates based on Mindie's fantasies. He hasn't really been explicit enough, but if one takes is stated period of about 4500 BCE to 300 CE for decay speedup (which would of course kell everything) and assume a constant speedup factor ...