Hence at least some of the missing rings can be found. Even so, the missing rings are a far more serious problem than any double rings. Other species of trees corroborate the work that Ferguson did with bristlecone pines. Before his work, the tree-ring sequence of the sequoias had been worked out back to BC. The archaeological ring sequence had been worked out back to 59 BC. The limber pine sequence had been worked out back to 25 BC.
The radiocarbon dates and tree-ring dates of these other trees agree with those Ferguson got from the bristlecone pine. But even if he had had no other trees with which to work except the bristlecone pines, that evidence alone would have allowed him to determine the tree-ring chronology back to BC. See Renfrew for more details. So, creationists who complain about double rings in their attempts to disprove C dating are actually grasping at straws.
If the Flood of Noah occurred around BC, as some creationists claim, then all the bristlecone pines would have to be less than five thousand years old. This would mean that eighty-two hundred years worth of tree rings had to form in five thousand years, which would mean that one-third of all the bristlecone pine rings would have to be extra rings. Creationists are forced into accepting such outlandish conclusions as these in order to jam the facts of nature into the time frame upon which their "scientific" creation model is based.
Barnes has claimed that the earth's magnetic field is decaying exponentially with a half-life of fourteen hundred years. Not only does he consider this proof that the earth can be no older than ten thousand years but he also points out that a greater magnetic strength in the past would reduce C dates.
Now if the magnetic field several thousand years ago was indeed many times stronger than it is today, there would have been less cosmic radiation entering the atmosphere back then and less C would have been produced. Therefore, any C dates taken from objects of that time period would be too high. How do you answer him?
Like Cook, Barnes looks at only part of the evidence. What he ignores is the great body of archaeological and geological data showing that the strength of the magnetic field has been fluctuating up and down for thousands of years and that it has reversed polarity many times in the geological past. So, when Barnes extrapolates ten thousand years into the past, he concludes that the magnetic field was nineteen times stronger in BC than it is today, when, actually, it was only half as intense then as now.
This means that radiocarbon ages of objects from that time period will be too young, just as we saw from the bristlecone pine evidence. But how does one know that the magnetic field has fluctuated and reversed polarity? Aren't these just excuses scientists give in order to neutralize Barnes's claims? The evidence for fluctuations and reversals of the magnetic field is quite solid.
Answers to Creationist Attacks on Carbon Dating | NCSE
Bucha, a Czech geophysicist, has used archaeological artifacts made of baked clay to determine the strength of the earth's magnetic field when they were manufactured. He found that the earth's magnetic field was 1. See Bailey, Renfrew, and Encyclopedia Britannica for details. In other words, it rose in intensity from 0. Even before the bristlecone pine calibration of C dating was worked out by Ferguson, Bucha predicted that this change in the magnetic field would make radiocarbon dates too young.
This idea [that the fluctuating magnetic field affects influx of cosmic rays, which in turn affects C formation rates] has been taken up by the Czech geophysicist, V. Bucha, who has been able to determine, using samples of baked clay from archeological sites, what the intensity of the earth's magnetic field was at the time in question. Even before the tree-ring calibration data were available to them, he and the archeologist, Evzen Neustupny, were able to suggest how much this would affect the radiocarbon dates.
There is a good correlation between the strength of the earth's magnetic field as determined by Bucha and the deviation of the atmospheric radiocarbon concentration from its normal value as indicated by the tree-ring radiocarbon work. As for the question of polarity reversals, plate tectonics can teach us much. It is a fact that new oceanic crust continually forms at the mid-oceanic ridges and spreads away from those ridges in opposite directions.
When lava at the ridges hardens, it keeps a trace of the magnetism of the earth's magnetic field. Therefore, every time the magnetic field reverses itself, bands of paleomagnetism of reversed polarity show up on the ocean floor alternated with bands of normal polarity. These bands are thousands of kilometers long, they vary in width, they lie parallel, and the bands on either side of any given ridge form mirror images of each other.
Thus it can be demonstrated that the magnetic field of the earth has reversed itself dozens of times throughout earth history.
Barnes, writing in , ought to have known better than to quote the gropings and guesses of authors of the early sixties in an effort to debunk magnetic reversals. Before plate tectonics and continental drift became established in the mid-sixties, the known evidence for magnetic reversals was rather scanty, and geophysicists often tried to invent ingenious mechanisms with which to account for this evidence rather than believe in magnetic reversals. However, by , sea floor spreading and magnetic reversals had been documented to the satisfaction of almost the entire scientific community.
Yet, instead of seriously attempting to rebut them with up-to-date evidence, Barnes merely quoted the old guesses of authors who wrote before the facts were known. But, in spite of Barnes, paleomagnetism on the sea floor conclusively proves that the magnetic field of the earth oscillates in waves and even reverses itself on occasion. It has not been decaying exponentially as Barnes maintains. When we know the age of a sample through archaeology or historical sources, the C method as corrected by bristlecone pines agrees with the age within the known margin of error.
For instance, Egyptian artifacts can be dated both historically and by radiocarbon, and the results agree. At first, archaeologists used to complain that the C method must be wrong, because it conflicted with well-established archaeological dates; but, as Renfrew has detailed, the archaeological dates were often based on false assumptions. One such assumption was that the megalith builders of western Europe learned the idea of megaliths from the Near-Eastern civilizations.
As a result, archaeologists believed that the Western megalith-building cultures had to be younger than the Near Eastern civilizations. Many archaeologists were skeptical when Ferguson's calibration with bristlecone pines was first published, because, according to his method, radiocarbon dates of the Western megaliths showed them to be much older than their Near-Eastern counterparts.
However, as Renfrew demonstrated, the similarities between these Eastern and Western cultures are so superficial that. So, in the end, external evidence reconciles with and often confirms even controversial C dates. One of the most striking examples of different dating methods confirming each other is Stonehenge. C dates show that Stonehenge was gradually built over the period from BC to BC, long before the Druids, who claimed Stonehenge as their creation, came to England.
Hawkins calculated with a computer what the heavens were like back in the second millennium BC, accounting for the precession of the equinoxes, and found that Stonehenge had many significant alignments with various extreme positions of the sun and moon for example, the hellstone marked the point where the sun rose on the first day of summer. Stonehenge fits the heavens as they were almost four thousand years ago, not as they are today, thereby cross-verifying the C dates. What specifically does C dating show that creates problems for the creation model? C dates show that the last glaciation started to subside around twenty thousand years ago.
But the young-earth creationists at ICR and elsewhere insist that, if an ice age occurred, it must have come and gone far less than ten thousand years ago, sometime after Noah's flood. Therefore, the only way creationists can hang on to their chronology is to poke all the holes they can into radiocarbon dating. However, as we have seen, it has survived their most ardent attacks.
Origin and Destiny of the Earth's Magnetic Field. Prehistory and Earth Models. Max Parrish and Co. Fictitious Results with Mollusk Shells. Critique of Radiometric Dating. Geological Evolution of North America, 3rd Edition.
- How Good are those Young-Earth Arguments: Radiocarbon Dating!
- How Good Are Those Young-Earth Arguments?.
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He has followed the creation-evolution controversy for over a decade. Copyright by Christopher Gregory Weber. National Center for Science Education, Inc. Yes, the atmospheric content of carbon can vary somewhat. The dipole moment of the earth's magnetic field, sunspot activity, the Suess effect, possible nearby supernova explosions, and even ocean absorption can have some effect on the carbon concentration. However, these factors don't affect the radiocarbon dates by more than about percent, judging from the above studies. Of course, when we reach the upper limit of the method, around 40, years for the standard techniques, we should allow for much greater uncertainty as the small amounts of C remaining are much harder to measure.
Tree-ring data gives us a precise correction table for carbon dates as far back as 8,, years. The above study by Stuiver shows that the C fluctuations in the atmosphere were quite reasonable as far back as 22, years ago. The earth's magnetic field seems to have the greatest effect on C production, and there is no reason to believe that its strength was greatly different even 40, years ago.
For a refutation of Barnes' argument see Topic Therefore, atmospheric variation in C production is not a serious problem for the carbon method. The evidence refutes Dr. Hovind's claim that the C content of our atmosphere is in the middle of a 30,year buildup. Thus, we can dismiss this young-earth argument. It is painfully obvious that Dr. Hovind knows next to nothing about carbon dating!
Changes in the sunspot cycle do have a noticeable, short-term effect on the rate of C production inasmuch as sunspots are associated with solar flares, which produce magnetic storms on Earth, and the condition of the earth's magnetic field does affect the number of cosmic rays reaching the earth's upper atmosphere. Carbon is produced by energetic collisions between cosmic rays and molecules of nitrogen in the upper atmosphere. Sunspots have absolutely nothing to do with the rate of C decay , which defines the half-life of that radioactive element.
Hovind has confused two completely different concepts. Quantum mechanics, that stout pillar of modern physics, which has been verified in so many different ways that I couldn't begin to list them all even if I had them at hand, gives us no theoretical reason for believing that the C rate of decay has changed or can be significantly affected by any reasonable process.
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We also have direct observation:. That radiocarbon ages agree so closely with tree-ring counts over at least years, when the observed magnetic effect upon the production rate of C is taken into account, suggests that the decay constant itself can be assumed to be reliable.
Since years is almost two half-lives for carbon, it's half-life being years plus or minus 40 years , we have excellent observational evidence that the decay rate is constant. We also have laboratory studies which support the constancy of all the decay rates used in radiometric dating. A great many experiments have been done in attempts to change radioactive decay rates, but these experiments have invariably failed to produce any significant changes. It has been found, for example, that decay constants are the same at a temperature of degrees C or at a temperature of degrees C and are the same in a vacuum or under a pressure of several thousand atmospheres.
Measurements of decay rates under differing gravitational and magnetic fields also have yielded negative results. Although changes in alpha and beta decay rates are theoretically possible, theory also predicts that such changes would be very small [ Emery, ] and thus would not affect dating methods. There is a fourth type of decay that can be affected by physical and chemical conditions, though only very slightly. This type of decay is electron capture e. Because this type of decay involves a particle outside the nucleus, the decay rate may be affected by variations in the electron density near the nucleus of the atom.
For example, the decay constant of Be-7 in different beryllium chemical compounds varies by as much as 0. The only isotope of geologic interest that undergoes e. Measurements of the decay rate of K in different substances under various conditions indicate that variations in the chemical and physical environment have no detectable effect on its e.
Believe it or not, a number of creationist attacks against radiometric decay rates are aimed at a kind of "decay" called internal conversion IC , which has absolutely nothing to do with the radiometric dating methods Dalrymple, , p. Harold Slusher, a prominent member of the Institute for Creation Research, claimed that "Experiments have shown that the decay rates of cesium and iron 57 vary, hence there may be similar variations in other radioactive decay rates.
These are both stable isotopes so there is no decay rate to be changed. This statement merely reveals Slusher's ignorance of nuclear physics. Gamma decay of an excited state of iron 57 has been studied, but this has nothing to do with the kinds of decays used in radiometric dating. DeYoung [ ] lists 20 isotopes whose decay rates have been changed by environmental conditions, alluding to the possible significance of these changes to geochronology, but the only significant changes are for isotopes that "decay" by internal conversion.
These changes are irrelevant to radiometric dating methods. Keep an eye on those creationists! They will switch tracks faster than you can say "tiddlywinks. Morris claimed that free neutrons might change the decay rates. However, Henry Morris, that icon of creationism, only demonstrated that he knew no more about radiometric dating than does Dr. Free neutrons might change one element into another, but the decay rates all remain true to their elements. Morris [ ] also suggests that neutrinos might change decay rates, citing a column by Jueneman 72 in Industrial Research.
The subtitle of Jueneman's columns, which appear regularly, is, appropriately, "Scientific Speculation. Jueneman describes a highly speculative hypothesis that would account for radioactive decay by interaction with neutrinos rather than by spontaneous decay, and he notes that an event that temporarily increased the neutrino flux might "reset" the clocks.
Jueneman, however, does not propose that decay rates would be changed, nor does he state how the clocks would be reset; in addition, there is no evidence to support his speculation. There was also an attempt by Slusher and Rybka to invoke neutrinos. Those mysterious neutrinos seem to be a hot topic! Slusher and Rybka also propose that neutrinos can change decay rates, citing an hypothesis by Dudley 40 that decay is triggered by neutrinos in a "neutrino sea" and that changes in the neutrino flux might affect decay rates. This argument has been refuted by Brush 20 , who points out that Dudley's hypothesis not only requires rejection of both relativity and quantum mechanics, two of the most spectacularly successful theories in modern science, but is disproved by recent experiments.
Dudley himself rejects the conclusions drawn from his hypothesis by Slusher and Rybka , noting that the observed changes in decay rates are insufficient to change the age of the Earth by more than a few percent Dudley, personal communication, , quoted in 20, p. Thus, even if Slusher and Rybka were correct--which they are not--the measured age of the Earth would still exceed 4 billion years. Dalrymple goes on to debunk several other creationists attacks on the reliability of the radiometric decay rates used in geochronology. Judging from the above, it is easy to see that creationists are indulging in wild fishing expeditions.
Compare their flighty arguments to the solid support provided by theoretical work, laboratory testing, and, for the shorter half-lives, actual observation, and add to that the statistical consistency of the dates obtained, including numerous cross-checks between different "clocks," and only one conclusion is left.
The radiometric decay rates used in dating are totally reliable. They are one of the safest bets in all of science. With at least one notable exception on the books, plants and animals get their carbon from the atmosphere. Plants take it in directly, and animals eat the plants. Thus, it gets passed up the food chain. It is not surprising, therefore, to find that the carbon in living plants and animals is in reasonable equilibrium with the atmospheric carbon Some creationists, however, have claimed that certain plants can reject carbon in favor of carbon Because of the chemical similarity of carbon and carbon, it is unlikely that such plants could deviate much from the ratio of C to C found in the atmosphere.
Neither freak cases nor small deviations pose much of a problem for radiocarbon dating, which, after all, works well with a wide variety of plant and animal species. Hence, we only have to worry about the initial concentration of C in the atmosphere. Topic R1 shows that the level of C in the atmosphere has not varied appreciably over tens of thousands of years. Therefore, the initial C content is known for any reasonable sample! The notable exception involves certain mollusks, which get much of their carbon from dissolved limestone. Since limestone is very old it contains very little carbon Thus, in getting some of their carbon from limestone, these mollusks "inherit" some of the limestone's old age!
That is, the limestone carbon skews the normal ratio between C and C found in living things. If one dates such mollusks, one must be extra careful in interpreting the data. Not every mollusk shell presents such problems, and the dating of other material might yield a cross-check. Further study might even allow correction tables. The discovery has strengthened the carbon method, not weakened it! By the way, shouldn't the creationist be worried over the old, carbon age of the limestone? Why is it that limestone has so little C in it? Partial contamination, say of a block of wood, may affect its different parts to different degrees.
Insect burrows, cracks, and partial decay may allow contamination later on to affect those portions of the sample unequally. However, there are laboratory techniques, often ingenious, for dealing with such problems. If the sample shows evidence of being hopelessly contaminated it is pitched. Some samples, such as a section of a tree trunk, may well contain material of considerably different ages.
A Close Look at Dr. Hovind's List of Young-Earth Arguments and Other Claims
The interior portion of a tree trunk could easily be several hundred years older than the outer portions. In summing up this point, we do know within good limits what the initial C was for any reasonable sample. A sample will not have different ratios of carbon unless it has been contaminated or reflects a genuine range of ages. In the case of carbon dating, the daughter product is ordinary nitrogen and plays no role in the dating process. We are only interested in tallying the original C still present in the sample, the surviving "parent" isotope.
The C that is incorporated in the carbon structure of cellulose and the other structural materials of living plants and animals is not going to do much migrating after burial. If structural carbon migrated easily there soon wouldn't be any cellulose, lignin, chitin or other structural carbon compounds left in the soil! A piece of wood, for example, would soon turn into a formless cloud of graphite or soot in the soil, with perhaps a little ash marking the original shape!
Clearly, that is not something which normally happens. Residues or solutions which do migrate can usually be washed out of the structural matrix of the sample with various chemicals. To put it another way, we might imagine a piece of buried wood as being something like a sponge. Any carbon-containing liquid originally possessed by that sponge might well leak over time and be replaced by something else.
Answers to Creationist Attacks on Carbon-14 Dating
However, unless the sponge itself disintegrates, the carbon which holds its fibers together must stay put. Thus, by choosing a sample that is structurally intact, one may rule out any significant loss of C If the liquid impurities in our sponge can be washed and squeezed out, or estimated in some way, then we may be able to date the sponge structural component of our sample itself and get a good date even if non-structural carbon had been lost in a manner that would upset the isotope ratio.
A sample, of course, can be contaminated if organic material rich in fresh atmospheric C soaks or diffuses into it. Such contamination may occur in the ground or during the processing of the sample in the laboratory. However, such contamination will make the sample appear younger than its true age. Consequently, with regards to carbon dating, creationists are barking up the wrong tree on the contamination issue!
Laboratories, of course, do have techniques for identifying and correcting contamination. There are various methods of cleaning the material, and the activity of each rinse can be measured. Lab contamination and technique can be checked by running blanks.
A careful choice of samples will often minimize contamination. Dating various portions of a sample is another kind of check that may be performed. Often there are cross-checks. Samples from top to bottom of a peat bog gave reasonable time intervals Science , vol.
The calibrated C method confirmed Egyptian records, and most of the Aegean dates which were cross-dated with Egyptian dates were confirmed American Scientist , May-June The marvelous agreement with tree-ring data, after correction for variations in the earth's magnetic field, has already been mentioned.
Carbon dating thus presents a deadly challenge to young-earth creationists. If an old date is reasonably accurate, they're out of business; if an old date is bad due to contamination, then they are still out of business because the true date is most likely older still. It hardly seems fair, but that's the way it is. With that in mind, let's look at a few carbon dates. Egyptian barley samples have been found which date to 17,, years old Science , April 7, On page the author explains some of the professional care which stands behind his use of the carbon method. A wooden walkway buried in a peat bog in England has been dated to about BC by the carbon method Scientific American , August , p.
Odd, that Noah's flood neither destroyed it nor deposited thick sediments on top of it! Jennifer Hillam of the University of Sheffield and Mike Baillie of Queen's University of Belfast and their colleagues were able to date the walkway by a second method, i. They found out that the walkway, known as the Sweet Track, was built from trees felled in the winter of BC.
Pretty close agreement, huh?