Problems with Radiometric Dating?

I always find it incredible that people who know absolutely nothing about radiometric dating, but are willing to swallow the falsehoods promuloated by other ignorant (or lying) people, are so eager to post on message boards and reveal exactly how little they know. Not even close. In geological dating, the original amount of radioactive material does not enter into the dating equation(s). It's irrelevant. You mean "We must know how much daughter isotope material we have started with". That is true &hellp; but there is lots of information available that can tell us the amount. Isochron methods use the chemical/mechanical identity of various isotopes of the daughter product to produce the initial quantity of daughter product as a result of the anlysis, not a premise. The most widely used method, U-Pb concordia-discordia, is applied to materials (mostly zircons) that just don't incorporate any significant amount of daughter material at solidification … even if the solidifying zircon is immersed in a sea of molten lead. (A fact which, BTW, was explicitly recognized by the RATE group). The widely used Ar-Ar method is similar to isochron methods in that it is not affected by any premises about the amount of initial daughter. The K-Ar method, beloved of creationists because it is possible for it to be fooled but not used much anymore, relies on the premise that the gaseous daughter product escaped from the liquid melt. Rational sample selection (e.g. avoiding the situations in which this is known to be problematic) almost always leads to reliable dates, and shown by the excellent agreement of K-Ar dates with more robust methods. Irrational and fraudulent sample selection, often practiced by creationists, can produce obviously false results; but this is a problem with creationists, not with the method. Again a mis-statement. You mean "There is no relevant material that has moved in or out during or after the formation of the substance." Daughter product moving in or out could be (but is not) a problem. If you made the effort to actually learn something about radiometric dating, you would know exactly how in the world we determine this. It's quite clever. Isochron, U-Pb, and Ar-Ar methods essentially always indicate as a result of the analysis whether or not relevant material has been gained or lost. And Ar-Ar and U-Pb methods can often produce a reliable date even when relevant material has been gained or lost! Well, you finally got one right (although "4 million years" is not a decay rate or any kind of rate). Did you bother to do the analysis of how much an error in radioactive decay rates would affect dating? Real scientists have. The uncertainty in dates due to uncertainty in decay rates is a percent or two, not the several orders of magnitude you're looking for.Of course, what you are looking for is a gigantic change in decay rates in the past. Alas for you, there are three wildly different mechanisms that are called radioactive decay. It's pretty much unthinkable that they would change in exactly the concerted manner required to maintain the agreement between different dating methods. Of course, it's possible. But, again alas for you, these mechanisms also involve very fundamental physical processes and any change in them would have widespread and easily detectable consequences. We've looked of lots of these consequences. They aren't there. The rates of radioactive decay has been constant within much less than a percent for 13-ish billion years. For example, see The Constancy of Constants and The Constancy of Constants, Part 2Of course you got it off some creationist website, that's the only source for such erroneous information. It's not erroneous because you got it off some creationist website, it's erroneous because it is based on multiple fundamental misunderstandings of the methods of radiometric dating.There'a alot you need to learn before you are prepared to critique radiometric dating, and a discussion board is a terrible medium for teaching the subject. But I'll give you some pointers.In the unlikely event that you want to learn about radiometric dating, Radiometric Dating: A Christian Perspective is a very good place to start. The Age of the Earth is excellent, covering all major methods well. Isochron Dating is a bit more advanced. The U-Th-Pb system: zircon dating is definitely advanced material, but I don't know of a better web reference on U-Pb dating.

This is not true for the vast majority of geological dates. You should have read message 35, just above:

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…there is lots of information available that can tell us the amount. Isochron methods use the chemical/mechanical identity of various isotopes of the daughter product to produce the initial quantity of daughter product as a result of the analysis, not a premise. The most widely used method, U-Pb concordia-discordia, is applied to materials (mostly zircons) that just don't incorporate any significant amount of daughter material at solidification … even if the solidifying zircon is immersed in a sea of molten lead. (A fact which, BTW, was explicitly recognized by the RATE group). The widely used Ar-Ar method is similar to isochron methods in that it is not affected by any premises about the amount of initial daughter. The K-Ar method, beloved of creationists because it is possible for it to be fooled but not used much anymore, relies on the premise that the gaseous daughter product escaped from the liquid melt. Rational sample selection (e.g. avoiding the situations in which this is known to be problematic) almost always leads to reliable dates, and shown by the excellent agreement of K-Ar dates with more robust methods. Irrational and fraudulent sample selection, often practiced by creationists, can produce obviously false results; but this is a problem with creationists, not with the method.

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It's not an estimate. To reinforce what Ned wrote, your ignorance of how it's done is not an indicator that it can't be done. The major one is correlations between methods. We know what can affect different methods, and what affects method A may not affect method B. SO if we measure an age by methods A, B, and C, and each method is not affected by what might affect the others, and the three methods produce the same result, we have a good date.And, of course, we have lots of evidence that the fundamental physics of the universe have been the same for a very long time. The only way that the hundreds of thousands, perhaps millions, of radiometric dates could all be wrong is to make tremendous changes in the fundamental physics of the Universe, including lots of tremendous changes required to hide the original change from what we see today. IOW, a gigantic series of miracles (another fact that the RATE group acknowledges). If there is indeed a God, He could have done that, but it simultaneously makes him a trickster God (which is a problem for most believers) and removes the question from the purview of science.