The authenticity of the Shroud of Turin has been in question for centuries and scientific investigations over the last few decades have only seemed to muddle the debate. Is the revered cloth a miracle or an elaborate hoax?
Now, a study claims neutron emissions from an ancient earthquake that rocked Jerusalem could have created the iconic image, as well as messed up the radiocarbon levels that later suggested the shroud was a medieval forgery. But other scientists say this newly proposed premise leaves some major questions unanswered.
The Shroud of Turin, which bears a faint image of a man's face and torso, is said to be the fabric that covered Jesus' body after his crucifixion in A.D. 33. Though the Catholic Church doesn't have an official position on the cloth, the relic is visited by tens of thousands of worshippers at the Turin Cathedral in Italy each year. [Religious Mysteries: 8 Alleged Relics of Jesus]
Carbon and quakes
Radiocarbon dating tests conducted at three different labs in the 1980s indicated the cloth was less than 800 years old, produced in the Middle Ages, between approximately A.D. 1260 and 1390. The first records of the shroud begin to appear in medieval sources around the same time, which skeptics don't think is a coincidence. Those results were published in the journal Nature in 1989. But critics in favor of a much older date for the cloth have alleged that those researchers took a sample of fabric that was used to patch up the burial shroud in the medieval period, or that the fabric had been subjected to fires, contamination and other damaged that skewed the results.
All living things have the same ratio of stable carbon to radioactive carbon-14, but after death, the radioactive carbon decays in a predictable pattern over time. That's why scientists can look at the carbon-14 concentration in organic archaeological materials like fabrics, bones and wood to estimate age. Carbon-14 is typically created when neutrons from cosmic rays collide with nitrogen atoms in the atmosphere (though it can be unleashed by manmade nuclear reactions, too).
The group of scientists, led by Alberto Carpinteri of the Politecnico di Torino in Italy, suspect high-frequency pressure waves generated in the Earth's crust during this earthquake could have produced significant neutron emissions. (They simulated this by crushing very brittle rock specimens under a press machine.)
These neutron emissions could have interacted directly with nitrogen atoms in the linen fibers, inducing chemical reactions that created the distinctive face image on the shroud, the scientists say. The reactions also could have led to "a wrong radiocarbon dating," which would explain the results of the 1989 experiments, Carpinteri said i