Radiometric dating is a method of calculating the ages of solid geographic materials (rocks) by measuring the ratio of radioactive molecules and their decay products. It is popularly known as as "carbon dating," after the isotope carbon-14, but carbon dating is only one method of radiometric dating. Carbon-14 decays very quickly, and it is appropriate for archaeological digs of recent sites when biological material is involved (the grain textile in the Shroud of Turin was carbon dated). Carbon dating compares the amount of carbon-14 in a dead biological sample against the natural amount of material expected in living organisms. But other elements are used to date materials much older, with a slightly different method. When rocks are in a molten state, the decay products of radioactive isotopes are loose in the hot liquid and they immediately escape. But, when the rock hardens, the decay products become trapped, and a very elegant method of dating rocks from the time of freezing becomes available to chemists who know the decay rates and who have access to a mass spectrometer to measure the parent and product elements, as though it is a gift from God.

Mass spectrometers are expensive and rare machines. Only a handful of them are available around the world. So geologists do not do the radiometric dating themselves. When a team needs a date on an important layer at a site, they send their samples to a laboratory, and they await the values. Usually, a single layer is radiometrically dated, and the other layers are given dates in reference to it--higher layers are assigned a younger value, and lower layers are assigned an older value. To eliminate much of the guess work, index fossils are used--a species in a known time period can be used to narrow the exact date of a layer. This is not circular reasoning, since it all begins with radiometric dating. If the mass spectrometer returns a value for a sample from the trilobite layer that actually matches the theoretical age of the dinosaurs, then there is a big problem.

In 1993, a survey was done to collect the age values of samples from various layers thought to represent the K-T boundary. The K-T boundary is a thin geological layer found all over the world that marks the border between the Cretacious Period and the Tertiary Period, or the age of the dinosaurs and the subsequent rise of birds and mammals. It is typified by high concentrations of iridium, shocked quartz, and tektites--clues that the mass extinction was caused by a large asteroid impact. The survey collected those values, and it was reported by G. Brent Dalrymple in his article, "Radiometric Dating Does Work!", of the anti-creationist NCSE website (I do not have immediate access to the original article: Dalrymple et al; Argon/Argon9 age spectra and total-fusion ages of tektites from Cretaceous-Tertiary boundary sedimentary rocks in the Beloc Formation, Haiti). He produced a table containing those ages (and standard deviations) seen here:



A mixture of different dating methods, samples and sites were apparently used--four different decay pairs (Argon-40:Argon-39, Rubidium:Strontium, Uranium:Lead, and Potassium:Argon), three different materials (tektites, biotite/sanidine, zircon/sanidine), from five different sites (Haiti, Mexico, Montana, and two sites in Canada).

I input the values into Excel and calculated the mean and standard deviation of the 25-count array (neglecting the initial standard deviations). I found a mean of 64.7 Ma (million years ago) with a standard deviation of 0.5 Ma. What does this say? It means that a randomly-chosen sample has a 68.3% chance of falling within the range of 64.2 Ma and 65.2 Ma. Not bad. Just for fun, I found that 2 of the 25 initial values were outliers (greater than 2*standard deviation away from the mean). Not bad. 2 outliers were also found when I took 25 readings on a level rod with a leveling instrument in a land surveying lab last quarter.

The mutual corroboration of this set of values is strong evidence for their legitimacy. The corroborations are a counterstrike against the various criticisms that are blithely thrown against it from creationists--that it is selectively reported, that it makes mistakes, that it is inaccurate, and so on. What really seals the deal is that the strength of the evidence is unintentionally confirmed by the Institute of Creation Research, the Creation Research Society and Answers in Genesis. They proposed the following (Carl Wieland, AiG):

Because of the testimony of God's Word, billions of years of radioactivity could not have occurred, so there must have been a speeded-up decay sometime in the past. Never mind that there is no cogent reason why this would have occurred, not in science, not in the Bible, not in theology, not in philosophy--but they have data that needs explaining, and as always they have a miracle-mechanism that can do just that. It may be hard to understand how twisted this seems from my perspective. Thinking about the bare substance of the claim, it seems almost as though the leading young-Earth creationists are fulfilling the dire predictions of their enemies, that their dogmas and methods of argument undermine all sound philosophy of knowledge-building science. To illustrate, the most irritating and offensive caricature of creationism (and seemingly the most politically powerful) is the Flying Spaghetti Monster. The thing that set off all the Internet buffoonery, Bobby Henderson's letter to the Kansas school board, contained this satirical jab:

At the time I read this, I thought it was very over the top. Creationists don't really believe that God changes the results of scientific measurements, do they? But, in light of the proposition upheld by a consortium of creationists, that God for a very unknown reason at an unknown time caused radioactive decay rates to speed up, how radical is this caricature really? I want to give creationists the benefit of the doubt. I want to believe that they are not their enemy's caricature, that they can recognize inane nonsense when it is handed to them by their leadership. But now how can I continue to sustain that belief?

Yes, there is a layer of iridium found in some parts of the world, though not all over the world. This is considered to be the KT boundary, only problem with this, is that evolutionist half hazardly unknowingly disproved it. By this I mean, they found that type of layer with the same iridium, ash, crystal composites on top of some fossilized mammoths, rhinocerous, and some other modern animals with the KT type boundary over them. These mammals were found with mostly complete skeletons, and in a group. I saw a special on the discovery channel about this one or two years ago.

It just now occured to me what they found. They speculated that ANOTHER asteroid impacted the earth AFTER the dinosaurs to justify this KT boundary found on top of the mammals. Though we do have impact craters, but none a sufficient size to cause a mass extinction. This is one of the main reasons I dont trust mainstream scientist, simply because all of their fossil finds are interpreted in evolutionist terms. When a creationist could pick up that same fossil and interpret it in creationist terms. But this mammal find i guess, simply flew over their heads, and their the ones who found it.

Another reason I dont trust radiocarbon dating is because the results always vary, they get the result sheets back, and find that the fossils or dirt they dated has different dates on it ranging from 125million - 65 million years, some all the way to 10,000 to 6000 years. They simply just pick and choose which date fits their textbook knowledge of the geoligical time column. Same goes with any fossil they find. I really havent seen any evidence or proof of cretaceous limestone, jurassic mudd, or triassic sand. How do we know that those evolutionist arent just saying, well the textbook says this fossil is 65million years old, so this dirt is obviously 65million years old, and if its not we will keep radiocarbon dating it until we get results that we like, or we will use potassium argon... just to prove it can be dated to be millions of years old.

Simply put, to actually prove that radiocarbon dating works, we have to date something that has a known date on it. A date we actually know before we radiocarbon date something. Has this been done? Or are we just supposed to take those millions of years as precise accurate science? Again, we need to date something thats already got a known date of say 2456 years ago on the 1st day of October. If we get that exact date, or something 2 or 3 years off then yes radiocarbon dating could be accepted. But, if we get results of choices between 300,000 / 65 million or just a plain ole 2456 then it cannot be trusted.

Also with the shroud of Turin, we dont really know if it was made 300 years ago or 2000 years ago, since results varied through the tests. Picking and choosing your favorite dates is not science, but this is exactly how it appears.

This also goes back to the Grand Canyon, which has layers, but evolutionist claim they are billions of years old, simply because the geological time column isnt found in it. Overall, a in order geological time column has never been found. A Mountain of fossils must be found, with cambrian on bottom, all the way to the top to the cretaceous, or at least in the middle jurassic, anywhere found with those layers in order with bones and fossils would prove this as scientific fact. This simply has yet to be found, and if you do go about replying about the geological time column, you MUST provide real pictures of the layers in order to prove it exist not just drawn textbook pictures. This is necessary, and I ask for this soley because the way the evolutionist portray it as scientific fact. But i am perfectly ok with them presenting the geological column as a theory.

I just havent seen any legitamite evidence that radiocarbon dating is valid in any form, unless you can provide unbiased evidence that the date found was not handpicked. Also because radiocarbon dating dates by millions upon millions of years that should go off as a warning anyways because millions might just be the biggest most obvious mistake in the way its dated. Because seriously, even 1 million years off from 60 million years is way off. Also, in the beginning of evolutionist thoughts, 65 million years was predetermined before carbon dating was even used to date things, so really how do we know that set of results wasnt just hand picked, from another set of results, that tested it to be 150 million years old. Because this happens, almost every time.

Measurements no, peoples interpretation of them,... maybe...... After a certain level of them rejecting him, God will harden peoples hearts, and send them a deluding influence to believe what is false. You are probably in that camp.....



Well, that's up to him, and there is measurable evidence that he did just that.

Terry

scott, I am very humbled that you put so much critical thought into this stuff. I really can not prove that geologists certainly do not take many different values of measurement and choose the ones they think best fits. Of course I find it very unlikely based on my intuitions and observations of the group as a whole, but I am an outsider to the whole field, and I do think it would help to have an inside look about the way things are really done.

I would suspect that carbon-14 dating is more suspect than other types of radiometric dating, since carbon-14 dating requires the measurement of carbon-14 and calibration with the surrounding environment at the time, whereas, say, uranium-lead dating requires only the two measurements of uranium and lead within a sample. One geologist/physicist was heroic enough to give a very strong detailed defense of all types of radiometric dating methods in an online article, including corroborations with other reliable non-radiometric dating schemes, which is like what you asked for. It includes tree rings, annual ice layers, and annual lake sediments. The article is right here: http://www.asa3.org/ASA/resources/Wiens.html#page%2023

I do have a slight objection with your point that "even 1 million years off from 60 million years is way off." Certainly that would be a good point if we were trying to date something recent like the bombing of Nagasaki or whatever. But, as a passionate student of mathematics, I know that 1 million years off a 60 million year estimate fits very neatly within normal margins of measurement error. It would be just a 2% error in measurement. Compare that to those who say that God created the Earth anywhere from 6000 to 10000 years ago. That would be equivalent to 8000 +/- 2000, which means a whopping 25% error.

After looking at the assumed ages for the half lives, in billions of years, which they have no proof of, simply because no one has reliably witnessed a trillion, billion, million, or 75,000 years for that matter. They are going by the assumed ages of the half lives.... BEFORE they date it with carbon 14. This is totally expected from an old earth point of view. Its like me saying, well I assume these half lives are going to be 6,000 years, hmm out of 15 test of our rock, the 2 test that fit closest were 5,000- 10,000 years, the other 13 test were way over a billion. So offcourse I chose what seemed more reasonable to me based on my assumption on how old the earth was to begin with.

Quite frankly, I just dont believe it, we have no solid proof that it works, and I see no solid evidence as to why I should trust it. Carbon 14 dating is supposed to be the magic cure for cancer, by this I mean, what they are getting at is they throw a rock they found in the driveway into this microwave type machine, and out pops a long list of printed results telling you exactly how old it is. Offcourse it would suprise me if it worked, simply because we have come into the age of know it alls. To me, a radiocarbon dating machine is just like one of those booths you go into in a circus, put your hand on the crystal ball, and you get told what your future is. Except this crystal ball tells the past.

You may see it differently, but this is the way I see it, even from a studied point of view.

scott, I don't know how many times they take a measurement before they pick value that fits. Maybe they do pick just the right date out of 15 or so widely varying values. How should I know? The reason I would find it very unlikely is that it would be explicitly bad science, not the sort of methodology that a high school dropout would find acceptable, let alone men with doctorates. But the authorities of science don't always behave honestly, I suppose, and I do wish that the way they do their work would be more accessible. Did you read any of that ASA article? Anything you object to? There was a mention of corroborating an argon40-argon39 dating method with the historically dated 1st century eruption of Mt. Vesuvius. I think you wanted something like that. There is a news story that claims that the argon dating technique nailed it to within 7 years. My personal problem would be that it doesn't seem to be a "blind" study. The researchers knew beforehand what date they needed, which, I know from my experiences in college physics labs, may skew the reported results.

Well, the one thing that struck me as odd in the ASA article, is how they thought they could fool someone into thinking that, " we have been studying the measurements directly for the last 40 to 100 years". Again they have no evidence that they did this. How do you observe the measurements directly without using carbon 14 dating, or another type of radiation dating. They are trying to say that they actually knew the isotope decay rate, before they used the carbon 14 dating. This simply is not true. In all reality, no man knows what the isotopes dates really are, or if you can actually date them in the first place, because no one can directly measure their dates simply because you would actually need a time machine to go 106 billion years into the past directly.

They also claimed that the polar ice layers were observed to be 160,000 to 60,000 years old. This cannot be observed to be that age, because someone living 60,000 years ago would actually have to observe it, and pass this information down throughout the generations, which is hard to believe. I also dont know of any rocks beside man made ones that are 25 years old.

I'd say instead of Doubters still try, I would say people who think they actually know the isotope decay rate still try.

Also, if we actually knew the isotope decay rate of something, before we carbon 14 dated it, then why would we need to carbon 14 date in the first place? Radiation dating isnt really a direct form of dating, but more like an indirect form of dating.

Thanks, scott. You have good reasons for doubting. You will only believe it when the evidence is strong. The polar ice cores have annual layers, and the age of a particular layer is determined by counting the layers that precede it. A layer that is 5,000 layers deep is presumably 5,000 years old. Whatever objection you might have to the accuracy of this method, it provides mutual corroboration with the radiometric dates, reportedly. Same with tree rings. It doesn't really seem to matter that nobody was there taking measurements 160,000 years ago.

"Also, if we actually knew the isotope decay rate of something, before we carbon 14 dated it, then why would we need to carbon 14 date in the first place?"

The isotope decay rate is the speed at which a particular radioactive isotope decays into another isotope. The dating is done by measuring the amount of each child and parent isotope (more child and less parent means older age). Maybe I don't understand what you mean.

Half-life (more or less) Physicists are stirred by claims that the sun may change what’s unchangeable—the rate of radioactive decay

It’s nuclear physics 101: Radioactivity proceeds at its own pace. Each type of radioactive isotope, be it plutonium-238 or carbon-14, changes into another isotope or element at a specific, universal, immutable rate. This much has been known for more than a century, since Ernest Rutherford defined the notion of half-life—the time it takes for half of the atoms in a radioactive sample to transmute into something else. So when researchers suggested in August that the sun causes variations in the decay rates of isotopes of silicon, chlorine, radium and manganese, the physics community reacted with curiosity, but mostly with skepticism.

In one experiment, a team at Purdue University in West Lafayette, Ind., was monitoring a chunk of manganese-54 inside a radiation detector box to precisely measure the isotope’s half-life. At 9:37 p.m. on December 12, 2006, the instruments recorded a dip in radioactivity. At the same time, satellites on the day side of the Earth detected X-rays coming from the sun, signaling the beginning of a solar flare.

The sun’s atmosphere was spewing out matter, some of which would reach Earth the day after. Charged particles would contort the planet’s magnetic field, disrupt satellite communications and pose a threat to astronauts on the International Space Station.

But that dip in the manganese-54 radioactivity was not a coincidental experimental fluke, nor was it the solar flare discombobulating the measurements, the Purdue researchers claim in a paper posted online (arxiv.org/abs/0808.3156). In West Lafayette the sun had set while X-rays were hitting the atmosphere on the other side of the globe, and the electrically charged matter that created electromagnetic disturbances worldwide was still in transit. After a solar flare has begun, “the charged particles arrive several hours later,” points out theorist Ephraim Fischbach, coauthor of the paper with his Purdue colleague Jere Jenkins.

In a separate paper, also posted online in August, Fischbach, Jenkins and their collaborators compared puzzling and still unexplained results from two separate experiments from the 1980s—one on silicon-32 at the Brookhaven National Laboratory in Upton, N.Y., and the other on radium-226 done at the PTB, an institute that sets measurement standards for the German federal government. Both experiments had lasted several years, and both had seen seasonal variations of a few tenths of a percent in the decay rates of the respective isotopes.

change of less than a percent may not sound like a lot. But if the change is real, rather than an anomaly in the detector, it would challenge the entire concept of half-life and even force physicists to rewrite their nuclear physics textbooks