European statisticians cast doubt on C-14 dating of Shroud of Turin

Rome, Italy, Apr 12, 2010 / 12:06 pm

Results of radiocarbon dating carried out by three laboratories in 1988 which placed the origins of the Shroud in the 13th or 14th century cannot be considered as "conclusive," according to the Italian Society of Statistics (SIS). A recent "robust statistical analysis" run by a group of statisticians claims to debunk the original results, which they say contain huge inconsistencies.

Four professors, three Italian and one English, published an article in the online SIS Magazine on March 31 that revisited the original data reported in "Nature" magazine, by Damon et al. from laboratories in Tuscon, Zurich and Oxford.

Errors that Damon and his colleagues found in their 1988 test were found not to be significant, and the results were deemed to provide "conclusive evidence" of the Shroud's medieval origins.

According to the professors' calculations in their recent SIS article, these conclusions should be revisited.

The statisticians cited by SIS write that if Damon et al.'s numbers are subject to more thorough testing the margin of error in the results is proven to be greater than originally thought. They propose that if the data from the original 12 tests carried out to determine the age of the Shroud are re-run through a "robust statistical analysis," the "non-uniform," but linear results show the probable presence of contamination.

They do not venture a guess at the source of the contamination, but propose that it could be the source of a trend in the numbers that shows a significant, "non-negligible" variation.

All of the samples from 1988 were taken from a single section of the cloth measuring less than a centimeter.

According to the professors, if the systematic inconsistencies present in the statistics were to be applied to the entire four meters of the Shroud, the results for the dating could vary by up to 20,000 years.

They also mentioned that according to Willard Libby, who developed the Carbon-14 dating process along with colleagues from the University of Chicago in 1949, the technique cannot give a reliable result for organic materials subject to unknown environmental factors that may have influenced them in the past.

The Shroud of Turin may have previously been exposed during outdoor exhibitions and was subjected to extreme heat during a fire in 1532.

Pilgrims are currently able to view the Shroud, which is on exhibition for the first time since 2000. The current exhibition runs from April 10 – May 23 at the Turin Cathedral.