Wednesday, November 14, 2012

One Last Time—Radiocarbon Dating is Inaccurate – Part II

Just about everyone has heard of carbon dating, but have you wondered what “Carbon dating” (Radiocarbon or radiometric dating) means and why it is so important? Well, first off, it is used to tell the age of an old object, whose origin and age cannot be determined exactly by normal means. Because of this method Chemistry has become intertwined with History, Archeology, Anthropology, and Geology. 
Many items that have been thought to come from one time have been tested and found out to actually come from a different time—sometimes older, most times younger. According to Lynn and Gray Poole in Carbon-14 (1961), places where historians believed that human civilization came to exit say, only 2,000 years ago, have actually been "proven" to have had some form of human civilization more than 4,000 years ago.
Despite its widespread acceptance in the scientific community, some scientists still question its validity for various reasons. One particular reason is the fact that the technique assumes the amount of carbon-14 in the atmosphere is constant. Carbon-14 is measured in comparison to carbon-12, however this ratio may fluctuate overtime and is somewhat unpredictable. For example, the quantity of carbon-14 in the atmosphere compared to other carbon isotopes was predominantly affected by the Industrial Revolution from mid-seventeenth to mid-eighteenth centuries, which had a profound effect on the amount of carbon released into the atmosphere. In addition, the extensive atmospheric testing of nuclear weapons in the 1950s and 1960s added "artificial" radiocarbon to the atmosphere—the huge thermal neutron flux produced by nuclear explosions and weapons testing reacted with nitrogen atoms present in the atmosphere that simulated atmospheric production of carbon 14 in unnatural quantities. This increase of “bomb carbon” reached 100% by 1965, actually doubling the amount of Carbon-14 in the atmosphere, which has continued to be affected due to later weapons testing. Although nuclear testing has been banned, the past bomb effect still remains.
Nuclear weapons testing in the 1950s and 1960s nearly doubled the atmospheric carbon 14 content as measured around 1965. The level of bomb carbon was about 100% above normal levels between 1963 and 1965. The level of bomb carbon in the northern hemisphere reached a peak in 1963, and in the southern hemisphere around 1965
In addition, other environmental conditions may also affect how much carbon-14 is present in an object. Different plants absorb carbon-14 differently, since animals consume these plants, something as simple as an animal’s diet can alter the amount of carbon-14 found—as an example, an animal that ingested plants with relatively low C-14 proportions would be dated older than its true age.
Once again, since this dating of ancient specimens is so critical to the argument regarding the age of all past living things (people, flora, fauna, etc.), we need to cover more of how erroneous the findings can be, especially since these dates have now been pushed back about 100,000 years as a result of cyclotrons and tandem accelerator techniques, and applied to a sample as small as a milligram.
First of all, carbon dating is a variety of radioactive dating that is applicable only to matter which was once living and presumed to be in equilibrium with the atmosphere, taking in carbon dioxide from the air for photosynthesis. Since living organisms continually exchange carbon with the atmosphere in the form of carbon dioxide, the ratio of C-14 to C-12 approaches that of the atmosphere; and since the carbon-14 forms at a rate which appears to be constant, by measuring the radioactive emissions from once-living matter and comparing its activity with the equilibrium level of living things, a measurement of the time elapsed can be made.
The problem arises, in the several assumptions that must be made by those doing the measurement, that will determine the findings (see past posts). The most critical assumption is that carbon-14 is in equilibrium in the atmosphere—something that all agree takes about 30,000 years to achieve. However, we  have already shown in past posts that 1) Dr. Willard F. Libby found out through his own measurements that it was not; that the amount of Carbon-14 entering the atmosphere was 12% greater than the amount decaying, which means carbon 14 was not in equilibrium, however he chose to ignore this all important fact; 2) Today the rate of production of Carbon-14 has been found to be greater than the rate of disintegration, in test after test of scientists trying to find an equilibrium. This obviously shows that the atmosphere not yet in equilibrium.
The important fact is simply this: if we do not ignore this all important information—that a 12% error margin exists, which is a very large error margin—as Libby and his colleagues did, then the age of the Earth is under 30,000 years old by their very own measurements, and the measurements obtained through Radiocarbon Dating (C-14 atomic clock). In fact it is closer to about 12,000 to 15,000 years of age.
This is an important fact upon which the entire concept of radiocarbon dating and the age of all past living things is based. It should not be ignored, but scientists, from Libby to the present, have set aside this fact, which has resulted in incorrect measurements. In fact, R. E. Lee in “Radiocarbon: Ages of the Earth,” published in the Anthropological Journal of Canada in 1981, stated: “The troubles of the radiocarbon dating method are undeniably deep and serious—it should be no surprise then that fully half of the dates are rejected. The wonder is surely that the remaining half come to be accepted.”
Nor can it be said that the methods of measurement have been improved over the decades since—though newer techniques have aided in the process, as long as an equilibrium base is used, which all Radiocarbon Dating does, as Libby said, “Everyone knows the Earth is more than 30,000 years old,” then the results will be inaccurate.
As insurmountable a problem this is, it is only one of the many problems found with Carbon-14 testing. Another is that fact that in order to know how long a sample of radioactive material had been decomposing we need three variables defined: 1) How much of the sample we have left now, 2) What the half-life of the sample is, and 3) How much of the sample did we start out with.
While we already have experimentally measured the amount of Carbon-14 left, and Libby has already measured the half-life of Carbon-14 to an acceptable exactness, we are still stymied by the third factor. That is, we simply do not know, and cannot know, how much Carbon-14 existed in the specimen at the time of death. As an example, with a piece of wood buried in the ground 5,000 or 10,000 years ago it is simply beyond our ability to determine how much Carbon-14 was in the specimen—and the same is true for a Sabre-toothed tiger that died 100,000 to a million years ago, or a horse found in the La Brea Tar Pits, etc., etc., etc. (By the way, bones of a sabre-toothed tiger, theorized to be between 100,000 and one million years old, gave a Carbon date of 28,000 years).
We do know that the amount of Carbon-14 in an organic body is constant with the amount of Carbon-14 in the atmosphere. Thus specimens have the same amount of carbon-14 in them as the rest of the atmosphere at the time that the specimen lived and at the moment it died. However, if we could measure the amount of Carbon-14 in the atmosphere when they lived, we would be living during the time and there would be no reason for dating. Anything beyond that age, cannot be known!
(See the next post, “One Last Time—Radiocarbon Dating is Inaccurate – Part III,” for more information with the fallacy of Carbon-14 Dating)

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