CSI and the Shroud of Turin
December
5, 2008
It occurred to me recently that something strange and rather wonderful has happened to TV crime shows. A decade or so ago, they stuck to an old, rather threadbare formula, following homicide detectives or private eyes as they pounded the pavement, grilled witnesses, and chased down suspects. More often than not, the heroes made a brief appearance at a morgue or lab, where someone quirky in a white lab coat summed up the gory details of the crime.
Things are different now: the lab plays a starring role in series like CSI. The staff are still quirky, but in a marvellously attractive way, and their labs look like fun places to hang out. Better yet, we all get to see what they are peering at so earnestly through the microscope. What was previously invisible is now trotted out in almost hallucinogenic detail; what was once dismissed as hopelessly dull and boring now proudly takes center stage.
Something similar – although far less dramatic—has also happened in the world of archaeology. While a few archaeologists continue to make big discoveries in the field—turning up royal Maya tombs or Renaissance shipwrecks—the most fascinating finds generally come from the lab, where specialists spend their days peering at ancient dental plaque, starch grains, intestinal parasites, pigment flakes, fish bones, tree rings, and many other strange things for clues to ancient lives.
I was reminded of this by a new exhibition at the Arizona State Museum, which explores some of the lesser-known wonders of archaeological labs. “Beyond the Naked Eye: Science Reveals Nature’s Art” displays a series of images, many quite beautiful, taken by researchers trying to solve archaeological conundrums. Each image tells a story: my favorite one comes from a photo of the Shroud of Turin taken by Rachel Freer, an expert in the analysis of archaeological textiles at the Arizona State Museum.
Many believe the Shroud of Turin is the winding cloth that covered the body of Jesus of Nazareth after his crucifixion. It bears a faint and terribly sad image of a man. In 1988, the Catholic Church gave the University of Arizona and two other institutions the task of dating the Shroud of Turin, hoping to shed light on its mysterious origins. On the morning of April 21, 1988, a group of scientists and clerics convened in the sacristy of Turin Cathedral to trim tiny samples from the famous shroud. Each of the labs then received four identical stainless steel containers, one holding a shroud sample and three containing samples from other ancient textiles to allow blind studies.
The labs ran Accelerator Mass Spectrometry (AMS) tests on snippets from samples. These tests revealed that the shroud was much younger than previously believed. It dated to the medieval period, between A.D. 1250 and 1390. The faithful were much dismayed. So recently, explains Freer, the University of Arizona began running further tests on tiny swatches of the shroud sample. The researchers hope to determine whether contaminants on the cloth had skewed the accelerator dates, or whether the samples came from a medieval repair to the shroud.
In search of answers, Freer examined the fibers by polarized light microscopy. The resulting image, an almost psychedelic cascade of arching blue, orange and green lines, revealed fibers made from plant stems—most likely linen produced from flax. And Freer’s other studies showed that the sample’s overall weave structure was identical to that of the rest of the textile, likely ruling out the theory of a later repair. She is now working on an analysis of possible contaminants.
I think this is very cool work: archaeological sleuthing that would do even the CSI gang proud.
Heather Pringle
