imageA reader writes:

I notice that you give no voice to alternate theories about why the carbon dating is wrong. I am particularly interested in John Jackson’s theory that carbon monoxide contaminated the shroud thus increasing the c14 content. I hope you will discuss this in the future.

I’m happy to entertain any arguments and will entertain guest postings that offer substantive arguments. So far, I have heard of many hypotheses but have not seen substantive arguments in support of any of them. Even so, it seems unlikely that they would negate the overwhelming evidence that what was tested was a materially intruded sample created by mending thread: the invisible reweaving theory.

As for Jackson’s (pictured with his wife Rebecca in a Catholic News Agency photograph) hypothesis the only meaningful commentary I have seen, other than what Jackson has written, argues against it. Christopher Ramsey, the head of the Oxford Radiocarbon Accelerator Unit has written:

[T]here are also a number of reasons to think that carbon monoxide contamination is not likely to have had a significant effect. . . . So far the [=experimental] linen samples have been subjected to normal conditions (but with very high concentrations of carbon monoxide). These initial tests show no significant reaction – even though the sensitivity of the measurements is sufficient to detect contamination that would offset the age by less than a single year. This is to be expected and essentially confirms why this sort of contamination has not been considered a serious issue before.

Keep in mind that Ramsey has also written:

There is a lot of other evidence that suggests to many that the Shroud is older than the radiocarbon dates allow and so further research is certainly needed. It is important that we continue to test the accuracy of the original radiocarbon tests as we are already doing. 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.

I would love to explore this subject more. Send arguments, citations, literature. For now, you, the reader, may want to read A New Radiocarbon Hypothesis by John Jackson.