Shroud of Turin: the scientific case for fresh carbon dating tests

Shroud of Turin: the scientific case for fresh carbon dating tests

Michael Gilchrist

On 10 April 2010, the latest exposition of the Holy Shroud opened in the Turin Cathedral, with one of the highlights of the exposition, which ended on 23 May, being the visit of Benedict XVI who celebrated Mass in the city's Piazza San Carlo on 2 May.

Coincidentally, recent scientific research, incorporated in a new documentary screened on SBS, titled Turin Shroud: The New Evidence, has made a strong case for fresh carbon dating tests to be undertaken on the Shroud, believed by millions of Christians to be the burial cloth which wrapped the body of Jesus Christ following his death.

Carbon dating tests carried out in 1988 had concluded the Shroud was no more than 700 years old.

The Turin Shroud is a pure linen cloth in a fishbone weave measures 4.37 metres by 1.11 metres, contains the full frontal and dorsal imprints of a supine man and has carmine- coloured stains corresponding to blood.

The man in the image is about 180 centimetres tall and has long hair, a beard and moustache. The eyes are closed, the hands and forearms crossed, and the body bears signs of torture that correspond with the Gospel accounts of Jesus' passion and death.

The piece of cloth that has been in Turin since 1578 is thought to have been in Constantinople between 944 and 1204 and before that in the city of Edessa (now Urfa, Turkey), at least since 544. The historical record before then is unclear.

New theory

Professor Christopher Ramsey, the director of the Oxford University Radiocarbon Accelerator Unit involved in the 1988 tests, has now said he is treating seriously a new theory suggesting that the sample tested was not from the original cloth.

An expert in the use of carbon dating in archaeological research, Professor Ramsey recently conducted fresh experiments in order to explain how a genuinely old linen could produce 'younger' dates.

The original carbon dating was carried out on a small sample from the Shroud by researchers working separately in laboratories in Zurich, Arizona and Oxford.

Until now there have been numerous theories seeking to explain how the carbon dating could have produced false results, but they have all been rejected by the scientific establishment.

However, in 2005, Philip Ball, who had been the Senior Editor for Physical Sciences of the Nature Journal of Science at the time it published the results of the 1988 carbon 14 dating of the Shroud, discussed new studies that challenged those tests. He cited the late Raymond N. Rogers, a Fellow of the Los Alamos National Laboratory, University of California.

Rogers had just published an article in the peer-reviewed scientific journal Thermochimica Acta (Volume 425 pp. 189-194) that proved that the 1988 carbon 14 dating did not date the original cloth. Rogers found that the carbon 14 sample was taken from a mended area of the cloth that contained significant amounts of newer material.

The sceptically-minded Rogers had previously debunked every other argument so far offered to explain why the 1988 carbon 14 dating might be wrong and thought he could easily disprove the latest one. He had to admit he was mistaken.

Simultaneously, John L. Brown, formerly Principal Research Scientist at the Georgia Tech Research Institute's Energy and Materials Sciences Laboratory at the Georgia Institute of Technology, independently confirmed many of Rogers' findings.

In 2008, Robert Villarreal, the Los Alamos National Laboratory chemist who headed a team of nine scientists also argued that the 1988 carbon dating was invalid. According to Villarreal, 'The age-dating process failed to recognise one of the first rules of analytical chemistry that any sample taken for characterisation of an area or population must necessarily be representative of the whole ... Our analyses of the three thread samples taken from the Raes and C-14 sampling corner showed that this was not the case.'

In addition various studies conducted between 2001 and 2008 have demonstrated that what was tested in 1988 was chemically different from the rest of the cloth. Splices and the presence of dyestuff and cotton fibres suggested that the carbon 14 samples were taken from a repaired section of the cloth.

Other researchers, Sue Benford and Joe Marino, independently explored this idea with several textile experts, as well as Ronald Hatfield of the radiocarbon dating firm Beta Analytic, since there seemed to be clear visual evidence of 'invisible reweaving'.

A subsequent analysis of the sampled area led to identification of newer cotton fibres used in the invisible mending. They had been dyed to match the colour of the linen of the rest of the Shroud.

Fresh tests

While all of the three radiocarbon dating laboratories that carried out the 1988 tests obtained similar results, concurring on the range of dates from 1260 to 1390, each of them had received pieces from the same sample taken from the repaired edge of the Shroud.

Following this study it was recommended that fresh carbon dating tests should be conducted which ensured that the sample analysed this time represented the original main shroud image area, that is the fibres had to be all linen and not contain any cotton or other materials.

It was suggested on the SBS Shroud documentary that the charred parts resulting from a 1532 fire would be ideal as any sample has to be burned to ashes prior to carbon dating. At this stage the Church has not decided whether to release the Shroud for further tests.

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