This subject came up in another thread where I discuss that there might be serious problems with historical timelines. Anyway, here is an argument, feel free to discuss it: "Radiocarbon dating has precision of +/-1800 yearrs at its best: There are a host of problems with radiocarbon dating. It assumes the isotope always decayed at the same rate. You simply cannot make those assumptions and call yourself a scientist. In many instances, items with known dates were given to several labs to be tested and the dates came back way off. So far off, in fact, to make radiocarbon dating a joke. It also does not take into consideration a different prehistoric atmosphere which would inhibit the sun's radiation from hitting the earth, thereby making radiocarbondating extremely tentative. It relies on too many assumptions to make it scientifically accurate."
You gonna attribute that to the creationist you quoted? What type of radiocarbon dating? How did the number +/- 1800 years come up? Are there? Because that's the only one you offer. Why would isotopes decay at different rates? There's no evidence to suggest that they do. In fact, very few factors affect decay rates. Do you have a source for those studies? Explain. Most of science is based on assumptions. Most of human knowledge is assumptions. Atoms have never been seen, but based on our assumptions and predicted behavior, we know them to exist.
Eh??? I didn't quote any creationist. The opening post was a quote from somebody else, I didn't write it. There were times when an artifacts were given to 2-3 different labs and they came back with quite a wide range of dating periods... By the way, this post is not about retiming the age of Earth, but rather just how accurate is RC dating, if different group of scholars come up with different dates. Also there is the calibrating problem of RC dating...
OK, I did a little further reading on the subject. Looks like it is really creationists who question the validity of RC dating. My concern was really with the not so old artifacts. Let's say in the last 1-2000 years. Because if RC dating has a rather small 1-2% correctness ratio then by using it, Fomenko's theory mentioned in another thread can be disproved rather easily. So I would rephrase my question: What is the correctness % of RC dating when going back only 1-2000 years? Just how accurate it is?
First let me say I haven't touched this topic in forever. Radio carbon dating is very real, it works. The real problem with dating any material is the calibration like you pinted out, that depends on the lab, materials used, and nature itself. In any experiement there is always a margin of error, but if you look closely all outputs are always within a certian acceptable range. No, not all isotopes decay at the same rate. Carbon dating is the best means of measurement there is today. The real problem with dating materials is not the age itself, but the era, and that is where most of the mistakes are made. Take for instance 1 million years from now a group of new species find homo sapien human remains. There know that the life span of a human is about 100 years average, but they would also need to find out how long ago sapiens last walked the earth, and carbon isotopes have a limited range. But I am guessing they have other methods for stuff like that Almost 100%.The current maximum radiocarbon age limit lies in the range between 58,000 and 62,000 years http://en.wikipedia.org/wiki/Carbon_dating
Also there is a problem with contaminents i.e. a body found in a bog could absorb the carbon14 from the surrounding material and give a false reading. Equally something can be contaminated by coming into contact with a newer source. Other than that I believe nuclear decay is not affected by temperature and pressure etc. A halflife is only an average though and has a tolerance.
OK, so I take it that in a 1-2000 years period its range of error is only a few years, maybe a decade. That is good enough. So Fomenko makes a lots of claims like this: "Apocalypse was written after 1486." So if we have a piece of anything that can be C14-ed and it says the piece is at least 8-900 years old that would disprove Fomenko's claim rather easily.. I wonder if we do have such an artifact....
Here is another example to be checked by C14: "Roger Sinnott, studied astronomy at Harvard and is an editor at the respected Sky & Telescope Magazine checked Fomenko's calculations for the famous trio of eclipses from Thucydides's account of the Peloponnesian War. The three eclipses are conventionally dated to 431, 424, and 413 BC. Fomenko finds these dates as non adequate to narrative of Thucydides's and finds exact solutions as late as in 1133, 1140, and 1151 AD." Now I am not an expert on the Peloponnesian War, but if we have some kind of artifacts from that time, the approximate dating of the war should be rather easy...
Eh? Could you explain more? Eclipses can be calculated backwards in time from our knowledge of orbits etc.
Some artifact's age are further determined by other clues, such as writings, geograhy, and civil activities. For example, it will be useless using cabon dating to tell the age of a human because a human only lives 100 years or so, in that case I think the skeleton, brain maturity, and organs will make better predictions. Thats just my guess, and thats why Forensic anthropology is not exact science.
That is exactly what Fomanko did. Now just because he found other 3 years were 3 eclipses occured that doesn't mean the the P. war didn't happen between 431-413...
My missus is an archaeology graduate; she tells me about something called 'Calibrated Radiocarbon dating'. http://en.wikipedia.org/wiki/Radiocarbon_dating#Calibration From that link; So the inaccuracies in the method are well known. But tree-rings come to the rescue; If dendrochronology needs a little more explanation, here is a page about it; http://en.wikipedia.org/wiki/Dendrochronology Calibrated Radiocarbon dating and Dendrochronology together are remarkably reliable.
Syzygys, your going to have to explain fumentos position more- merely saying that the conventional dating of the eclipses is non adequate doesnt say much. If he said that there were no eclipses at all at those dates, and the calculations have been independently verified, then he might be onto something. (Assuming that an eclipse wasnt put in just for narrative portent)
Guthrie, you are correct, but I haven't read the book yet. Now, his claim that the conventional dating is incorrect can be falsified rather easily...
Radiometric dating is only accurate to 50-60,000 years ago because Carbon-14 has a half-life of 5,730 years. Radiocarbon labs generally report an uncertainty of 3000±30 BP (before present) and indicate a standard deviation of 30 radiocarbon years. Radiocarbon dating also needs to be calibrated, and yes of course, there is always a +/- range depending on how it is calibrated and why (differences in source and atmosphere, etc.). Radioactive decay rate depends on chemical evolution. There is also what's called a "cosmic noise reduction" in radiocarbon measurements due to cosmic rays entering the atmosphere that undergo transformations and production of neutrons. This is basically the way it works: When the organism is alive, the percentage of C14 is the same as in the atmosphere. This is because the food that we eat ultimately comes from plants, and the carbon present in plants is produced from atmospheric CO2 during photosynthesis. When the organism dies, intake of carbon ceases and C12 and C13 are the stable isotopes that accumulate as C14 decays. By measuring the amount of C14 left, the age of a fossil and bones can be calculated as the remaining C14 decays into its isotopes. Sensitivity and accuracy of carbon dating have been greatly increased by the use of mass-spectrometric techniques, where the 14C atoms can be counted directly. Raw radiocarbon measurements are usually reported as years "before present" (BP). This is the number of radiocarbon years before 1950, based on a nominal (and assumed constant - see "calibration" below) level of 14C in the atmosphere equal to the 1950 level. "Radiocarbon labs generally report an uncertainty, e.g., 3000±30BP indicates a standard deviation of 30 radiocarbon years. Traditionally this includes only the statistical counting uncertainty and some labs supply an "error multiplier" that can be multiplied by the uncertainty to account for other sources of error in the measuring process. Additional error is likely to arise from the nature and collection of the sample itself, e.g., a tree may accumulate carbon over a significant period of time and the wood turned into an artifact some time after the death of the tree. It is sometimes stated that burnt material can be reliably dated to the time of burning....The raw BP date can not be used directly as a calendar date, because the assumption that the level of 14C absorption remains constant does not hold true in practice. The level is maintained by high energy particles interacting with the earth's upper atmosphere, which may be affected by changes in the earth's magnetic field or in the cosmic ray background. In addition there are substantial reservoirs of carbon in organic matter, the ocean, ocean sediments (see methane hydrate), and sedimentary rocks; and changing climate can sometimes disrupt the carbon flow between these reservoirs and the atmosphere. The level has also been affected by human activities -- it was almost doubled for a short period due to atomic bomb tests in the 1950s and 1960s and has been reduced by the release of large amounts of CO2 from ancient organic sources where 14C is not present -- the fossil fuels used in industry and transportation. The BP dates are therefore calibrated to give calendar dates. Standard calibration curves are available, based on comparison of radiocarbon dates with other methods such as examination of tree growth rings (dendrochronology), ice cores, deep ocean sediment cores, lake sediment varves, coral samples, and speleothems (cave deposits). The difference between the Julian calendar and the Gregorian calendar can be ignored, because it's insignificant compared to the measurement uncertainty. The calibration curves can vary significantly from a straight line, so comparison of uncalibrated radiocarbon dates (e.g., plotting them on a graph or subtracting dates to give elapsed time) is likely to give misleading results. There are also significant plateaus in the curves, such as the one at 10,000 radiocarbon years BP, which is believed to be associated with changing ocean circulation at the end of the Younger Dryas period. The accuracy of radiocarbon dating is lower for samples originating from such plateau periods." http://www.whatis.tv/Radiocarbon_dating.html The Principles of Radiocarbon Dating: "William Frank Libby and his team developed the principles of radiocarbon dating during the 1950s. By 1960 their work was complete and in December of the same year Libby was presented with the Nobel Prize for Chemistry. One of the scientists who nominated Libby for the award commented: "Seldom has a single discovery in chemistry had such an impact on the thinking of so many fields of human endeavour. Seldom has a single discovery generated such wide interest. Libby discovered that the unstable radioactive component of carbon (C14) disintegrated at a predictable level against the stable elements of the carbon composite (C12 and C13). All three of these isotopes occur naturally in our atmosphere in the following proportions: C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%. The stable isotopes of carbon (12 and 13) were formed when all of our planet's atoms materialised --a long, long time ago. C14 is formed, albeit on a miniscule level, due to bombardments of cosmic rays that hit our planet, on a day-to-day basis, and interact with our atmosphere. These rays strike the earth's existing atoms and break them up leaving the neutrons of these atoms to float around our atmosphere. A carbon 14 isotope is formed when one of these floating neutrons merges with the nucleus of a nitrogen atom. Radiocarbon, therefore, is a kind of Frankenstein isotope, a fusion between different atomic elements. These rogue carbon 14 isotopes, which are produced at a steady rate, are then oxidized and absorbed into the biosphere through the process of photosynthesis and the natural food chain. Consequently all living things incorporate the atmospheric ratio of C14 to C12 in their geographical area, which is maintained by their metabolic rate [8]. Once dead, however, living organisms stop absorbing carbon and it is the behaviour of C14 after this point that is interesting. Libby discovered that radiocarbon decays with a half-life of 5568 years. This means that after 5568 years or so, half of the original amount of C14 would have disintegrated from the sample. After another 5568 years, again, half of what is left dies. Therefore, with the original amount of C14 to C12 being a geological constant , the age of a sample can be determined by measuring the residual C14 present. For example, if one quarter of the original amount of C14 is present then the organism in question died two half lives ago (5568 + 5568), which equates to an age of 10, 146 years. Herein lie the basic backbone principles of radiocarbon dating as a tool of science and archaeology. It is a fact that radiocarbon is absorbed into the biosphere. It is a fact that when an organism dies no more C14 is absorbed. It is a fact that C14 spontaneously dies after this point. It is a fact that this process can be measured. See: http://www.grahamhancock.com/forum/HancockS1-p2.htm
Recent Calibrations Valich: Thanks for keeping the readership aware of the extensive data on C-14 dating, and its accuracy. Allow me to embellish slightly over an otherwise excellent post. The introduction of mass spectrometry 25+ years ago allowed for much smaller samples of material to obtain an accurate reading. Instead of having to have lots of C-12 and C-13, in order to get enough C-14 to measure its decay rate (and hence the amount present), the amount of C-14 is directly measured by magnetic separation of the C-14 from the lighter isotopes via a 'mass spectrograph'. As mentioned, tree-ring dating of known samples of wood of definite age have allowed for accurate calibration of C-14 dating going back some 3-1/2 millenia (oldest wood available), giving accuracies to +/- 50 years for young material of 3-4 millenia in age or younger. In the much older materials, the accuracy diminishes considerably, which is where the +/- 1,000 years accuracy as to the age comes into play. 'Recently' (circa 1982) there was an article (in Science or Nature?) about calibrations of C-14 dating using bottled wines and cognacs going back 2-3 centuries. Those calibrations (tree-ring or otherwise) are necessary, because the basic assumption that solar-originated cosmic ray bombardment of the Earth's atmosphere is constant over time is not entirely true; i.e. there is some fluctuation in the bombardment due to increases and decreases over time of the solar output. Walter
Nice clarification. Some say the accuracy is only good to about 50,000 years ago; others go back as far as 65,000. In any case, accuracy diminishes and the +/- increases proportionally. I'm assuming you read that at 60,000 it's ± 1,000.
As long as the artifacts are carbon-based (charcoal, bone, shell, etc.) then C-14 can be used to analyze them. What's typically done, is artifacts like ceramics and lithics (which preserve well) are relatively dated to bits of carbon-containing material in the same strata. A burnt layer in a village or city is ideal, since its easy to date and, thus, assign a date to a given stratum. With enough of these, artifacts found between are easily given a date range, since they had to be deposited before one layer but after another. This is why you might be reading a text that acknowledges an artifact dated to between 600-550 BCE (as an example). It wasn't because the radiocarbon had an error rate of +/- 50 years, but because the two layers that were accurately dated were 50 yrs apart.
Those who find this topic interesting (as I do) might be interested to examine the dating of the eruption of Thera which blasted 30 cubic kilometers of the island of Santorini into the atmosphere sometime around . . . ? Well, now, just when did it happen? I suspect that the dating of this event has come under more scrutiny by both historians and carbon-daters than any other. There is really convincing historical/archaeological evidence that the eruption occurred in about 1550BC (or later), and really convincing carbon-dating evidence (by now based on many dozens of individual samples) that it took place about 75 years earlier. Google "Thera eruption" for more information on this puzzle (though there's also loads more stuff not on the Internet).
According to the Encyclopedia Britannica, which the extensive descriptions and consequentual overlays would be hard to doubt: "About 1500 the volcano on the island of Thera, long, it seems, quiescent, erupted to bury the settlements there under many feet of pumice and ash. The story of Atlantis, if Plato did not invent it, may reflect some Egyptian record of this eruption, one of the most stupendous of historical times. Knossos was shattered by a succession of earthquakes that preceded or accompanied the eruption, while great waves resulting from it appear to have damaged settlements along the northern coast of Crete. Ash identified as coming from the eruption has been found in coastal sites as far away as Israel and Sardis in Anatolia. The wind may have been blowing from the south or west. Later Greek traditions, such as the story of Deucalion's flood, may enshrine a memory of similar waves that swept the coasts of the mainland at this time. Some Cretan settlements might have been wrecked by the blast from the eruption, although Thera lies about 70 miles (110 kilometres) away from Crete. Whatever the damage caused, it appears to have been soon repaired and not to have disrupted the course of local culture. Damages to pastures and livestock were apparently minimal. Similarly, in the Cyclades there are few signs of any gap in occupation as a result of the eruption. The settlements on Thera, however, lay buried deep in pumice. The largest of these, at Akrotíri, opened by excavations since 1967, offers a unique picture of a Bronze Age town. The walls of its houses stand in places two stories high, with paintings miraculously preserved on them, and the floors with storage jars and other objects are as they were left when the inhabitants escaped from the eruption or from the earthquake that is thought to have preceded it. The wonderful preservation of delicate frescoes and of foodstuffs, from snails to olives to grain, makes Thera a tantalizing closed deposit of Aegean life. Many houses have flagstone floors upstairs, with columns supporting the roof, and rooms with multiple windows. Below there are storage bays filled with jars, looms, medicine chests, and grain and oil stores. There is delightful local pottery with swallows, dolphins, wild goats, and caper and saffron plants. The wall paintings have a garden quality and may often have religious associations or celebrate festivals and seasons, city or country life, and sea voyaging. Only a small part of the town has been excavated. The work has been slowed by the engineering problems of keeping the two- or three-story houses from collapsing and crushing the painted walls and delicate contents sealed from damage for centuries. After the eruption, Crete appears to have enjoyed comparative prosperity for a time, while the influence of Cretan civilization continued to spread on the mainland. Alongside vases with plant and flower designs, the Cretan potters began to decorate others in an attractive marine style, with octopuses and other sea creatures. The marine style may have originated at Knossos, but vases with this type of decoration, many of them of a ritual character, were exported all over Crete, as well as to the Cyclades and the mainland. About the middle of the 15th century, however, a generation or so after the eruption of Thera, most of the important sites in central and southern Crete were destroyed by fire. Destruction was not confined to palaces and towns but extended to country houses, farms, and rural shrines. Many settlements were never inhabited again, such as that at Mochlos, where excavators found the remains of numbers of people who had perished in the destruction. The site of the destroyed town at Gourniá was eventually occupied by a scatter of houses, but the palace there was not rebuilt. The large palaces at Mallia and Zákros were also destroyed by fire and afterward abandoned."
