Source: One Episcopalian on Faith
Over and over, we read in newspapers and blogs that the shroud was carbon dated thus proving it was medieval. Sometimes, a reporter will mitigate by mentioning that some people question the results. But what we should be reading, if scientific accuracy is important, is that the carbon dating is well understood to be invalid.
What is being reported in peer-reviewed scientific journals and at scientific conference is very different than what is being reported in main stream media. Why? Because, invariably, any reporting about the shroud falls under the general category of religion which is often a subcategory of something called lifestyle. Not that it shouldn’t be so categorized, but journalists who write these stories invariably have only a sketchy and often outdated understanding of the science of the shroud. So much has happened in the twenty years since the shroud was carbon dated. It warrants consideration. That carbon dating exercise warrants more than a mild “some people question” attempt at balanced reporting. There are always people to question anything. What exactly are the questions? And who are the some people?
Fortunately, many readers know the answer. Thanks to the Internet, many of today’s readers are well informed and this makes reporters’ stories that mostly rely on regurgitated old information look lame.
The new information, well documented in ethical scientific journals, doesn’t prove that the shroud is authentic. Far from it. But it does show that the single scientific argument having any peer-reviewed gravitas, has crumbled. Now, other arguments from history and other scientific disciplines that suggest that the shroud is much older warrant consideration and mention.
It’s likely that the Shroud of Turin’s wasn’t really carbon dated.
To still accept the carbon dating of the shroud, we must imagine that Robert Villarreal and his team of nine scientists at the prestigious Los Alamos National Laboratory were wrong when they showed that the carbon dating violated the first principle of carbon dating: the sample must represent the whole. They demonstrated that the sample area was significantly unlike the rest of the shroud. In other words it is almost certain that the shroud itself was not carbon dated. (Reported August 15, 2008, at the Ohio State University Shroud of Turin scientific conference).
To still accept the old carbon dating, we must also imagine that a comprehensive twelve page article in the scientific journal Chemistry Today (Jul/Aug 2008) is simply wrong. Do we imagine the authors Sue Benford and Joe Marino are wrong? Do we imagine the reviewers and editors who scrutinized the article, are also wrong?
To believe in the tests, we must also ignore Christopher Ramsey, the current head of the Oxford Radiocarbon Accelerator Unit, a lab that participated in the original carbon 14 dating of the Shroud. In March of 2008, he said that because of new information “further research is certainly needed.” He went on to say:
It is equally important that experts assess and reinterpret some of the other evidence. Only by doing this will people be able to arrive at a coherent history of the Shroud which takes into account and explains all of the available scientific and historical information.
To still accept the old carbon dating, we must imaging that chemist Raymond Rogers was wrong when he found significant chemical difference between the carbon dating sample material and the rest of the shroud — he had set out to prove the opposite. He found extraordinary evidence of medieval mending that explains the chemical differences. He also found clear chemical reasons to believe that the cloth is several centuries older than the carbon dating results. He published his findings in the peer-reviewed journal Thermochimica Acta (Vol 425 (2005) 189–194).
We must imagine, too, that Georgia Tech’s Principal Research Scientist, forensic materials chemist John L. Brown was wrong when with a scanning electron microscope he found clear evidence of mending. (“Microscopical Investigation of Selected Raes Threads From the Shroud of Turin,” Jan 2005)
Why is mending an issue?
To measure the age of the shroud, a single sample was cut from a corner of the cloth. That sample was divided among three radiocarbon dating laboratories and a reserved piece was set aside in case it was needed. The labs, in turn, divided their pieces into sub-samples in order to run multiple tests. Each sub-sample was then burned with oxygen to produce carbon dioxide. An Accelerator Mass Spectrometer was then used to measure the ratio of carbon 14 to carbon 12 isotopes. Because carbon 14 decays over the years, it is possible to used the ratio determines the age of the sample.
A problem arises if the sample consists of older original cloth thread and newer threads from mending because the carbon dioxide gas is a mixture of gas having different ratios.
Several textile experts examined documenting photographs of the radiocarbon samples and found what they believed was visual evidence of reweaving. Based on estimates from these photographs and on a historically-plausible date for reweaving, Ronald Hatfield of Beta Analytic, a leading radiocarbon dating firm, provided estimates that show that the original cloth might, in fact, date to the first century.
With all of this evidence in hand, researchers combed records looking for other evidence. It is startling to look back at the clues that were there and ignored:
- Giovanni Riggi, the person who actually cut the carbon dating sample from the Shroud stated, “I was authorized to cut approximately 8 square centimetres of cloth from the Shroud…This was then reduced to about 7 cm because fibres of other origins had become mixed up with the original fabric …”
- Giorgio Tessiore, who documented the sampling, wrote “…1 cm of the new sample had to be discarded because of the presence of different color threads.”
- Edward (Teddy) Hall, head of the Oxford radiocarbon dating laboratory at the time of the 1988 carbon dating noticed fibers that looked out of place. A laboratory in Derbyshire concluded that the rogue fibers noticed by Hall were cotton of “a fine, dark yellow strand.” Derbyshire’s Peter South wrote: “It may have been used for repairs at some time in the past…”
- Gilbert Raes when he examined some of the carbon 14 samples noticed that cotton fibers were contained inside the threads. This cotton is unique to the carbon dating sample area. There is no cotton elsewhere on the shroud.
- Alan Adler at Western Connecticut State University found large amounts of aluminum in yarn segments from the radiocarbon sample; up to 2%, by energy-dispersive x-ray analysis. Why aluminum? That was an important question because it is not found elsewhere on the Shroud. It may have been aluminum hydroxide, a common mordant used in dying; possibly used to make a repair invisible to the naked eye.
- Remi Van Haelst, a chemist, statistically showed that the sample was not homogeneous, hence suspiciously not a good sample.
- Bryan Walsh, a statistician, confirmed Van Haelst’s analysis and found that different pieces of the sample, the sub-samples, contained different levels of the carbon 14 isotope. In other words, different parts of the sample produced starkly different ages, which is consistent with the argument that the samples were from a medieval repair to the cloth.
In light of this does it suffice to simply say that some people question the results? It does sound balanced. It is the sort of balance in reporting that diffuses. If someone is inclined to believe the shroud is real, he or she can continue to do so. If not, he or she can continue to believe in the carbon dating. But has the reader been given any real information?
Balance, when it comes to different opinions, as in politics, is a good thing in journalism. Balancing facts with fiction is not. Diffusing truth is never helpful.
One test for balance is to reverse the argument. Try this: the carbon dating is now understood to be invalid (a fair statement) but some question this. Okay, who?
Well there is Joe Nickell, a book author and writer for Skeptical Inquirer magazine. Nickell is not a scientist and has expressed a disdain for scientific methods. He attempts to use biblical-literalist arguments to refute the shroud’s authenticity, which is quite peculiar for an atheist. He likes to remind us, also, that three labs dated the shroud and obtained identical results. He fails to mention that the three labs performed the same test on pieces of the same sample. They should have achieved near-identical results but in reality the results were statistically different enough to call the results into question.
There is also Steven D, Schafersman, who is a scientist. His primary line of argument in defense of the carbon dating is that scientists make mistakes (presumably only those who question the results) and invariably they will continue to do so. He has attacked Rogers for relying on a non-peer-reviewed paper. That simply isn’t true. Rogers was attempting to disprove the hypothesis in that paper and found, to his surprise, that it was correct. Philip Ball, who for many years was the physical sciences editor for Nature, that most prestigious of peer-reviewed scientific journals, the same journal that published the 1988 carbon dating results, agrees that Rogers was trying to disprove the mending hypothesis. In fact, the public record shows that Rogers initially believed that the proponents of mending were part of a “lunatic fringe” in shroud research.
So who else is defending the carbon dating? Is there anyone from the original team of scientists who did the testing that is now defending it. Are there any voices at all emerging from the radiocarbon dating laboratories other than that of Christopher Ramsey who calls for further research, who thinks it is equally important look at other scientific and historical evidence?
And what might that evidence be?
There is historical evidence that traces the shroud, with a high degree of certainty back to the 6th century, with plausibility back to 4th century and possibly to the time of Christ.
There is the definitive proof that the images are not light-reflective images as are paintings or photographs. Rather, they are topographical graphs that just happen to look like images. In this sense, it is not unlike a sonogram of a fetus in a womb. This is not to suggest that it is sonogram. But, as with a sonogram, it looks like a light-reflective image. But because it is topographical data, it is possible to plot rotatable 3D images with graphics software. You can’t do this with a painting or a photograph.
This leads to a vexing problem. No one knows how the images on the shroud are formed. The brown color of the image is a dehydrated and oxidized organic substance. The fibers of the shroud are coated with a fine polysaccharide layer, possibly a soap residue from washing the cloth after weaving. In places, inexplicably, that layer has turned into a caramel-like or Maillard substance forming the images.
Known artistic techniques are ruled out. It’s not painted. That is proven. All this leads to another vexing problem. It is easy, thus, for some people to imagine that the images are miraculously or supernaturally formed. But this is unscientific. It’s akin to God-of-the-gaps thinking now so popular in Intelligent Design theory. Many shroud researchers, including Rogers, think that images, might have been naturally formed and that there is no basis for assuming miracles.
Philip Ball offers a helpful perspective in Nature Online. He explained Rogers’ findings that the carbon dating was invalid. He explained, too, that Rogers credentials were impeccable, his approach was unbiased and his science was solid. And of the shroud, he said:
The scientific study of the Turin Shroud is like a microcosm of the scientific search for God. It does more to inflame any debate than settle it . . . . And yet, the shroud is a remarkable artifact, one of the few religious relics to have a justifiably mythical status. It is simply not known how the ghostly image of a serene, bearded man was made.
In that, there should be a story. It is arguably the most studied artifact in all of history and, frankly, we don’t know how old it is or how the images were formed. With all the technology we have, we don’t know how to create such images. We could carbon date it again but will anyone believe the results the next time given all that has happened before?
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