How old is the Shroud of Turin?
In 1989 it looked for a moment as though the link between the Turin Shroud and the burial of Christ was finally broken. Three independent teams of scientists had been given scraps of the linen, which they analysed using radiocarbon dating - a technique that uses the decay of a natural, radioactive form of carbon to figure out how long ago a once-living sample ceased to be alive (and thus in this case when the cloth was made from plant fibres). The verdict: the shroud dates from between about 1260 and 1390. It was a medieval item.
But almost at once, objections were raised. Some argued that the samples tested had come from later additions to the original cloth. Others said that the radiocarbon "clock" had been reset by a fire in the 16th Century that damaged parts of the shroud, or that the findings were distorted by the more recent growth of bacterial or fungal "biofilms" on the threads. The authors of the 1989 paper have discounted those possibilities, but the controversy won't die down. In 2013 Giulio Fanti described dating studies on the shroud using a non-standard method involving spectroscopy (absorption of light of different colours), which he says place the age instead between 300 BC and 400 AD: perfect for true believers.
