In 2005, Turin Shroud proponent Ray Rogers claimed that earlier carbon-14 tests of the shroud linen—showing it to date from between 1260 and 1390 and to thus be a fake—were invalid because, he hypothesized, the samples must have been taken from a “medieval patch.” Rogers and I had an exchange of arguments in the Skeptical Inquirer. But a new paper by three Italian chemists, in the same journal in which Rogers published, shows who was right.
Rogers had claimed that his analysis of two pyrolysis spectra showed a difference between the area selected for C14 dating and the remainder of the cloth—a finding that led some to suggest the C14 sample must have come from an area of “invisible reweaving.” This was hypothesized to have been done in the Middle Ages, thus invalidating the C14 tests, but I concluded that Rogers’ claims were “cut from whole cloth.” (Sadly, Rogers died while our latest exchange was in press.)
Now, chemists Marco Bella, Luigi Garlaschelli, and Roberto Samperi have published a paper that concludes (with its title), “There is no mass spectrometry evidence that the C14 sample from the Shroud of Turin comes from a ‘medieval invisible mending.’”
Their abstract explains: “A close-up analysis of the pyrolysis mass spectra reported in the original paper [by Rogers] reveals that the differences found between the samples coming from different parts of the Shroud are just due to the presence of a contaminant with a long aliphatic chain. Except for the presence of the contaminant, the two pyrolysis-mass spectra look alike rather than different. Therefore, the pseudoscientific theory stating that the C14 sample might come from a ‘medieval invisible mending’ remains unsupported by evidence.” (See Thermochimica Acta 617 : 169–171.)
So once again, attacks on the accuracy of the radiocarbon testing have been discredited. Some shroud believers invoked the supernatural, suggesting that an imagined burst of radiant energy from Christ’s resurrection had altered the carbon ratio. One scientist claimed a microbial coating on the cloth had caused an erroneous date; however, not only had the samples been thoroughly cleansed before testing, but for the date to have been altered by thirteen centuries, there would have had to be twice as much contamination, by weight, as the cloth itself!
The carbon-dating was conducted “blind”—along with control samples from ancient cloths of known date—by three labs, at Oxford, Zurich, and the University of Arizona. The dates were in close agreement. The time span, 1260–1390, is consistent with the shroud’s lack of history before about 1357 when, according to a later bishop’s report, an artist confessed to having “cunningly painted” it with the front and back images of an apparently crucified man. The world-famous microanalyst, Walter McCrone, detected red ocher pigment composing the “body” area and red ocher and vermilion tempera paint making up the “blood.” (See my Inquest on the Shroud of Turin, 1998 and The Science of Miracles, 2013.)