This also seems a bold move by a pope–to declare something authentic that it is well within the realm of science to later declare a fraud (though so far no conclusive proof has been given).
I pulled out my copy of Rag and Bone: A Journey Among the World’s Holy Dead by Peter Manseau, co-founder with Jeff Sharlet of our sister site, Killing the Buddha, to find this quote:
Even if an object is not genuinely what believers profess it to be — such as Chaucer’s feather of the angel Gabriel — it becomes the locus of belief for centuries. And it is in this belief that faith is made. For the faithful, to pray to a relic displayed in its reliquary — even to a blackened and shriveled tongue — is like shining sunlight through a magnifying glass. A relic concentrates the beliefs surrounding it until they can be seen: it is faith so intense it has, at times, set the world on fire.
Meanwhile, Gregory Paul says the image on the shroud has a brain the size of a caveman’s.