www.stringrecordings.com/img/classic/princess-of-the-north-wind.php 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. 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.
Carbon 14 is used for this example: which was put out by Dr. Hovind. . Believe it or not, a number of creationist attacks against radiometric decay rates are. With our focus on one particular form of radiometric dating—carbon .. Because of C's short half-life, such a finding would argue that carbon.
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. 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. 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? Stonehenge, as dated by carbon, was built over a period from BC to BC -- long before the Druids came to England. Astronomer Gerald Hawkins found, after careful computer calculations, that the arrangement of the stones at Stonehenge are aligned with key positions of the sun and moon as they were almost years ago.
Weber, , p. Thus, we have another remarkable confirmation of the C method. When did the volcano that destroyed Thera and probably the Minoan culture as well explode? Radiocarbon dating of seeds and wood buried in the ash, done by scientists at the University of Pennsylvania, pointed to no later than BC. Being that this was one of the biggest volcanic eruptions in recorded history, it almost certainly caused worldwide cooling which would, in turn, affect tree growth. Sure enough, the growth rings among oaks buried in Ireland's bogs show the effect of unusual cooling from BC.
Nor was that just an effect of local weather conditions. The bristlecone pines in the White Mountains of California show the same thing. A third estimate came from studies in Greenland. Thus, we have a remarkable agreement between three different methods, all within two or three percentage points of each other! Trees buried by the last advance of glacial ice at Two Creeks, Wisconsin were dated at 11, years.
Strahler, , p. Between those trees, which are buried in Valders red till, and an earlier, deeper layer of till, the Woodfordian gray till, lay the remains of a forest bed! What is a forest, including developed soil and rooted stumps, doing between two advances of ice?
That could be an interesting question for someone who believes in only one "ice age. By careful counting and cross-checking he was able to determine that the oldest glacial lakes, which would have formed at the start of the retreat of the ice, were 12, years old.
The technique hinges on carbon, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate. Organisms capture a certain amount of carbon from the atmosphere when they are alive. By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon decay can be worked out, thereby giving an age for the specimen in question.
But that assumes that the amount of carbon in the atmosphere was constant — any variation would speed up or slow down the clock. The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the Nobel Prize in Chemistry. Various geologic, atmospheric and solar processes can influence atmospheric carbon levels. Since the s, scientists have started accounting for the variations by calibrating the clock against the known ages of tree rings.
As a rule, carbon dates are younger than calendar dates: The problem, says Bronk Ramsey, is that tree rings provide a direct record that only goes as far back as about 14, years. Marine records, such as corals, have been used to push farther back in time, but these are less robust because levels of carbon in the atmosphere and the ocean are not identical and tend shift with changes in ocean circulation. Two distinct sediment layers have formed in the lake every summer and winter over tens of thousands of years.
The researchers collected roughly metre core samples from the lake and painstakingly counted the layers to come up with a direct record stretching back 52, years.