Mechanical ond opto-chemical dating of the Turin Shroud

Abstract. The TS (Turin Shroud) is a linen cloth which enveloped the dead body of a tortured and crucified man that is believed by many to be the burial cloth of Jesus Christ. The linen fabric has been radiocarbon dated in 1988 to the Middle Age but a recent robust statistical analysis shows that the resulting age appears flawed by a systematic effect. The present paper discusses the results obtained using innovative dating methods based on the analysis of mechanical parameters (breaking strength, Young modulus and loss factor) and of opto- chemical ones (FT-IR and Raman). To obtain mechanical results it was necessary to build a particular cycling-loads machine able to measure the mechanical parameters of single flax fibers 1-3 mm long. A least squares multi linear regression (MLR) has been applied to the measured mechanical data estimating a TS age equal to 260 AD. Furthermore, two opto- chemical methods have been applied to test the linen fabric, obtaining a date of 250 BC by a FT-IR ATR analysis and a date of 30 AD by a Raman analysis. These two dates combined with the mechanical result, weighted through their estimated square uncertainty inverses, give a final date of the Turin Shroud of 90 AD ±200 years at 95% confidence level. While this date is both compatible with the time in which Jesus Christ lived in Palestine and with very recent results based on numismatic dating, it is not compatible with the 1988 radiocarbon measurements that should be repeated after the necessary clarifications relative to the possible environmental factors that could have biased the results.