The skeptical inquirer considers . . .
What is proposed in terms of miraculous image formation?
There are many who believe that the images are the byproduct of the Resurrection of Jesus; that somehow, the miracle impressed the image on the cloth. Most of these speculations propose that radiation or elementary particles caused the image. Others suggest plasma from an electrical corona discharge. Such a miracle cannot be scientifically verified. But beyond this, it is doubtful from a chemical point of view.
Chemist Ray Rogers (see: Ray Rogers FAQ) writes:
The primary effect of all kinds of radiation is to heat the material it hits. This statement includes electromagnetic radiation (visible, ultraviolet, and infrared radiation); ionizing particles such as protons, electrons, and alpha particles; and non-ionizing particles such as neutrons. You can feel the heat when you hold a lump of plutonium, a flask of tritium, or a recently irradiated accelerator target. Intense irradiation can cause enough heat to explode explosives and burn metals (think of laser effects).
Cellulose molecules are folded back and forth in a fairly regular arrangement, and they show the properties of crystallinity. This is called a "fibrillar structure." When you rotate the stage of a petrographic microscope with crossed polarizers while looking at a linen fiber, straight lengths change from black through colored to black again every 90 degrees. The fiber is birefringent and has an ordered structure.
When cellulose fibers are heated enough to color them, whether by conduction, convection, or radiation of any kind, water is eliminated from the structure (the cellulose is "dehydrated"). When water is eliminated, C-OH chemical bonds are broken. The C? free radicals formed are extremely reactive, and they will combine with any material in their vicinity. In cellulose, other parts of the cellulose chains may be the closest reactants. The chains crosslink. Crosslinking changes the crystal structure of the cellulose, and you can see the effect with a polarizing microscope.
When cellulose starts to scorch (dehydrate and crosslink), its characteristic crystal structure becomes progressively more chaotic. Its birefringence changes, and not all parts of a straight fiber go through clear transitions from dark to light at the same angle. Zones of order get smaller and smaller. It finally takes on the appearance of a pseudomorph and just scatters light. A significantly scorched fiber does not change color as the stage is rotated between crossed polarizers.
The crystal structure of the flax fibers of the Shroud shows the effects of aging, but it has never been heated enough to change the structure. It has never suffered chemically significant irradiation with either protons or neutrons. No type of radiation that could produce either color in the linen fibers or change the 14C content (radiocarbon age) could go unnoticed. All radiation has some kind of an effect on organic materials.
This proves that the image color could not have been produced by thermal or radiationinduced dehydration of the cellulose. Image formation proceeded at normal temperatures in the absence of energetic radiation of any kind.
Even so, strong beliefs persist about radiation from a miracle being the cause of the images. Supporters point to certain x-ray-like impressions of the teeth and the finger bones in the images.
