“By 2012 scientists will not have developed an explanation for how images on the Shroud of Turin came to be on the cloth -an explanation that satisfies all of the physical and chemical properties of the images and does not violate basic laws of physics.”

No one yet can explain how the images on Shroud of Turin, with all their unusual physical and chemical properties, came to be on the cloth without violating basic laws of physics.

I remember, many years ago, the claim of some, that according to the laws of aerodynamics it is impossible for a bumblebee to fly. “Forget that you see one flying,” a physics professor of mine had said, “it is impossible for it do so.” What he meant, of course, is that a scientific explanation still eluded scientists. We now know, with the aid of very high-speed photography, of the unusual of motions of the bumblebee’s wings that enable it to fly. And the laws of aerodynamics stand. Are the mysteries of the Shroud’s images, like that of the flight of the bumblebee? Is it that a perfectly good explanation simply eludes scientists, for now? Perhaps. But the properties of the images are astounding to my way of thinking. I cannot imagine an explanation that will meet the criteria. I must bet against the proposition.

It is important, nonetheless, to seek an explanation for how the images came to be on the cloth because untold numbers of people throughout the world believe that the Shroud is the authentic burial cloth of Jesus. Current thinking about the Shroud has the potential to significantly effect long term theological and philosophical thinking. For some, this belief is by faith alone, scientific and historical evidence not withstanding. But there are many others who argue for authenticity on the basis of scientific and historical evidence. Among them are archeologists, historians, chemists, physicists, botanists, palynologists, forensic pathologists, image analysts, art historians, textile experts, and technical photographers. Many are from leading academic institutions or from prestigious scientific establishments including the Los Alamos Laboratory, the Israel Antiquities Authority, Sandia Labs, the Jet Propulsion Laboratory, and the Enrico Fermi Institute at the University of Chicago. Their work, which is well documented, formidable in detail, and carefully peer reviewed, warrants consideration.

Other are convinced that the Shroud of Turin is a medieval fake relic. In 1988 scientists at three prominent radiocarbon dating laboratories used carbon 14 dating to show that the fabric of the Shroud was very likely produced between 1260 and 1390. To these scientists who claimed that they were 95% certain about their findings – and to many others as well – it was preposterous to think that anyone would still believe that the Shroud was the real thing.

But controversy rages, and the Shroud’s age and provenance is uncertain. There is significant forensic, scientific, and historical evidence that suggested that the cloth is much older than the carbon 14 date. And serious questions have surfaced about the accuracy of the carbon 14 testing. It was discovered that the fibers of the Shroud have, over many years, developed a plastic-like biofilm of microorganisms significant enough to skew the dating process. Other evidence has come to light suggesting that the samples used for the carbon dating the cloth include newer thread from reweaving and mending of the cloth. With the carbon 14 dating in question, scientists have focused on mysteries about the images; the faint front and back images of a man, apparently in burial repose, who seems to have been scourged and crucified. These images are unique. In works of art, among ancient artifacts, and in descriptions in the annals of history, there is nothing like the Shroud of Turin with its unusual images -- images . . .

1) that are the result of numerous discrete and discontinuous lengths of discolored fibrils of the linen thread, the result of dehydration and oxidation of the cellulose molecules – a chemical change to the linen itself – which produces discoloration. The length of the image fibrils ranges from 200 microns to 1000 microns. The discoloration is uniform over their lengths suggesting that the chemical change was abrupt and complete.

2) in which the discoloration is a single shade of color. What we see with the unaided eye, or in photographs, as darker and lighter shades of color is actually the result of the density of the minuscule lengths of discolored fibrils in any given area – not unlike the half-tone process used for printing pictures in newspapers and magazines and not unlike the technique of etching lines in engravings. With the Shroud, however, this method of shading is implemented at a microscopic level.

3) that are superficial, meaning that the discoloration is limited to only the topmost crown fibrils of the cloth’s thread. There is no image beneath any cross threads, and no patterns of capillarity, ruling out the possibility of any liquid chemicals or paints being used.

4) that are like photographic negatives which when photographed as a negative produce positive images. This was discovered by an amateur photographer, Secondo Pia, in 1898 and was confirmed by numerous photographers over the years. Today, anyone with a home computer can prove this property using simple graphics software.

5) images that contain realistic three-dimensional information relating image density at any particular point to the distance between the cloth and the body at that point. Further, this apparently projective information can be shown to be collimated and anisotropic as demonstrated by the lack of any side images. The data points, being the density of discolored fibrils at places on the images (represented in photographs as grayscale values), can be plotted to produce a realistic isometric image of a human form from different angles. This can be demonstrated on a personal computer with conventional ray tracing graphics software. No known painting or other work of art (nor a photograph of the human form) will produce such results.

Although we do not have any confirmed explanations for these properties, they have been used to test a number of artistic rendering and naturalist hypotheses. All have failed to meet the criteria. Methods include albedo imaging as in conventional photography, engravings and paintings of various types, artistic sketches, chemical or pigment contact prints, thermal images from statues, vaporous chemical stains and bas-relief rubbings. The most popularized hypothesis was that the images were painted. This hypothesis was advanced by the discovery of minute particles of paint pigments that were in common use in medieval Europe. But various tests, including x-ray and spectrographic chemical analysis, show that nowhere on the cloth are there sufficient densities of the paint pigments to produce a visible image. What is there is likely contaminants from the practice of placing paintings onto the Shroud and other relics for sanctification (a common medieval practice) and from miniscule flecks of paint always falling from frescoed ceilings of churches and cathedrals. Most importantly, a painted image cannot meet the image properties cited above.

In recent years, some theoretical physicists (and some highly polemic authors) have advanced the possibility that a dematerializing body formed the images. Such a method, some argue, would meet the image properties. But such a method would defy the laws of physics, as we understand them. Considering Einstein’s law about the conversion of matter into energy – and what else could a bodily dematerialization be – the resulting explosion would leave us without a Shroud to wonder about and a crater in the Middle East the size of ancient Jerusalem.

I am betting that an image formation explanation will not be forthcoming in the years ahead, at least not one that meets the criteria and conforms to the laws of physics. It may be that a perfectly acceptable naturalistic process will be found, one not thought of yet. It may be some yet unknown artistic method will be discovered. But short of an answer, for as long as it may be that there is no answer, people will be able to speculate about the possibility of a miracle – a miracle being the plausible alternative to a naturalistic or artistic method.

The great philosopher of empirical skepticism, David Hume, some two hundred and fifty years ago, challenged very effectively (but never disproved) the possibilities of miracles when he wrote, “No testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous than the fact, which it endeavors to establish.” It could be that Hume’s skepticism is now being put to the test. The criteria, for now, suggest that it is a miracle by Hume's own standard. But that is so only because an explanation so far eludes scientists. I contend that an explanation will continue to elude scientists.