I eventually managed to find an excellent article see the top of this post using pandasthumb. That led me to this non-technical article,. I think the news item on their front page refers to a much older event. What happened, from what I recall, is that someone hacked TalkOrigins and managed to get the site to display hidden spam links at the bottom of pages, making Google think it was a spam site and thus getting it removed from Google.
They fixed that issue a while ago. PZ Myers says they've had some technical issues. I am working my way through Kirk Bertsche's 9 page essay on the subject. Thanks DH for this link. This article does a good job at explaining the technical complexities of measuring the very small amounts of C14 present in these ancient samples and why non-zero amounts are measured. I'm a complete non-expert in this field of radiometric dating, but it strikes me reading this how contamination by modern carbon introduced during sample preparation seems to be a severe issue.
I'm wonder whether they've extracted samples under an inert atmosphere and then used laser ablation to ionize samples in their mass spectrometers? I'm probably teaching grandmother to suck eggs, as the old saying goes. Getting back to my OP - I feel that some definitive work needs to be done in this area. It's easy to see that the sceptical creationist is simply going to see the scientific response as making excuses for the data instead of holding up some hard data that either explains or explodes the anomaly. Another thing I've heard from creationists is that fossils made by soaking samples in tar pits appear to be extremely old.
Of course, the problem is that this process results in contamination with old carbon, making the sample appear older. In the case of old samples with almost no C, even the tiniest bit of contamination would make the sample appear far younger. Always remember that C dating is not a magical process; it is a measure of C and the age interpretation depends on a few assumptions.
It's also worth noting that C is only useful for a bit more than , years. The vast majority of fossils aren't dated using C at all, but other radioisotopes. Science has several very reasonable explanations for levels of modern carbon in very old samples. Although this satisfies the scientist, who for all sorts of other reasons quite reasonably assumes that these samples are truly old, it leaves enormous scope for the creationists to reinforce their followers' faith that the earth is young.
I still feel that some definitive experiments in this area would be useful to test the various rational explanations for the c14 anomaly. I can see though that science has problems taking on creationists because of the perceived risk of lending credibility to their ideas.
Scientist Realizes Important Flaw in Radioactive Dating
Bit of a dilemma there. Also as soon as one creationist idea is exploded, they just move on to another area where uncertainty in the science offers them the opportunity to mislead. That begs the question that an anomaly even exists. What does exist are limits to the applicability of 14 C dating techniques. Several of the test results touted by creationists were definitive experiments to assess those limitations.
There is no arguing with young earth creationists. They are immune to logic and evidence. Broadly speaking I agree with you. But, reading the experts' explanations of the "anomaly" read to me, as a non-expert in this field, like perfectly reasonable explanations as long as you accept the "old earth" explanation. If you don't, such dismissive arguments as 'the extra C14 could be due to uranium decay' leave enough wriggle room uncertainty for the creationist to thrive in. You're right though, I'm probably being naive in thnking they will be convinced.
Even so, it is always good when creationists have been casting doubt in some area to be able to completely explode their reasoning. How a rock is formed is important to understanding its isotopic make-up and any dates derived.
Radiometric dating problems - CreationWiki, the encyclopedia of creation science
The isotopic make-up of original material is important, as is mixing of magma with surrounding material. The conditions of formation are also important, because both the cooling rate and the opportunities for mixing affect isotope ratios. Quick cooling or not having contact with the air can affect theoretical mechanisms for "resetting" the clock.
Some soil from the Moon has been dated as more than a billion years older than the uniformitarian age for the Moon. It was explained by the processes of heating and cooling that the soil had been through. Potassium-Argon and Argon-Argon Dating. Some rocks have been measured with negative radiometric ages , in some cases in terms of millions of years.
Isochron dating can also produce negative ages, by producing a negative slope. K-Ar and Ar-Ar can result in negative ages when atmospheric argon is considered. Was one of them removed from the rock by some unknown process? The isochron is supposed to take care of such issues. Essentially, rather than looking at the amounts of Rb and Sr, we look at their ratios compared to Sr The ratio of Sr to Sr is graphed versus the ratio of Rb to Sr for several different parts of the rock.
How does that help? Thus, it provides an independent analysis of the rock that does not depend on the radioactive decay that is being studied. The amount of Sr that was already in the rock when it formed, for example, should be proportional to the amount of Sr that is currently there. Since the data are divided by the amount of Sr, the initial amount of Sr is cancelled out in the analysis.
He says that there is one process that has been overlooked in all these isochron analyses: Atoms and molecules naturally move around, and they do so in such as way as to even out their concentrations. A helium balloon, for example, will deflate over time, because the helium atoms diffuse through the balloon and into the surrounding air. Well, diffusion depends on the mass of the thing that is diffusing. Sr diffuses more quickly than Sr, and that has never been taken into account when isochrons are analyzed. Hayes has brought it up, we can take it into account, right?
If the effects of diffusion can be taken into account, it will require an elaborate model that will most certainly require elaborate assumptions. Hayes suggests a couple of other approaches that might work, but its not clear how well. So what does this mean? If you believe the earth is very old, then most likely, all of the radioactive dates based on isochrons are probably overestimates.
How bad are the overestimates? Most likely, the effect will be dependent on the age. I would think that the older the sample, the larger the overestimate. As a young-earth creationist, I look at this issue in a different way. Certainly not enough to justify the incredibly unscientific extrapolation necessary in an old-earth framework. This newly-pointed-out flaw in the isochron method is a stark reminder of that. A good isochron was supposed to be rock-solid evidence pun intended that the radioactive date is reliable.
We now know that it is not. Wile, I was waiting for you to comment on this, because I wanted to ask if you think this problem can be extrapolated to other isotopes such as lead and argon. If so, it seems to be a pretty big deal. As I said, carbon dating is an exception, but most other modern radiometric dates are produced using an isochron. Are the samples we see in the RATE study, for example, just anomalies, existing on the ends of the bell curve, or are these indicative of an endemic misunderstanding of the process? Are there any theories that could account for the accelerated decay rate or how the daughters could have gotten in to the samples?
Thus, any significant amount of daughter product will produce a very old date. In my view, if two different dating schemes give significantly different answers, then either one of them is wrong or both of them are wrong. Scientists exclude what we think are anomalous data all the time. Unfortunately, that discarded data might be what gives us real insight.
Young-earth creationists have a hard time explaining the general results of long-lived isotopes and their daughter products being present. On the other side, old-earthers have a hard time explaining all the discordance.
If radioactive dating is so reliable, why do different methods yield different results? Why are some of those differences really, really large? As is often the case, there are problems on both sides.
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The side you end up coming down on often depends on which problems you are most comfortable trying to deal with. Physicists already theorize that dark matter would affect nuclear decay rates; what if the leftover energy went to the dark matter?source url
Radiometric dating problems
The heat problem occurs everywhere there are radioactive isotopes, so throughout the crust and mantle of the earth, for example. The dark matter would have to be there in order to take the heat. You can think of dark matter here as a lot like the luminiferous ether: Since its interaction with normal matter is incredibly weak, it can very easily pass through the earth. Not to mention that different models of dark matter would lead to different interactions. Are we able to calculate the mass of the earth from our knowledge of its contents, and not just the gravitational force we detect?
I think if there were much dark matter in the earth, it would be noticeable. We also know the overall composition of the crust and mantle from samples. Thus, the only real unknown is the composition of the core. Using the mass and all those other measurements, we deduce that the core is mostly iron with some nickel.
I fear it is more a matter of philosophy rather than hard science: The problem with that, is that, in the first case, there appear to be no transitional fossils when there should be millions , and to make the assumption previously herein stated, evolutionary conclusions are more akin to a combination of wishful thinking combined with a sympathetic magic mindset, than to observable examples.
Evolution is taught as established fact, and scientific enquiry is severely trammelled by those who prefer a status quo.