“Actually,” Stefan said, “we should be able to get closer than a hundred years. If it’s a good sample, an AMS test—accelerator mass spectrometry—can tell us the age plus or minus forty years.”
“Wowzer,” Miranda marveled. “I’m used to time-since-death estimates of days or weeks, not millennia. How does it do that?” It was one of Miranda’s favorite multipurpose utterances; sometimes it meant “Explain, please,” but sometimes—in response to, say, a 3-D laser hologram or a fiery sunset—it meant simply “That’s amazing!”
Stefan laid down the Corsican grilled cheese sandwich he’d been nibbling on, and he smiled the smile of a man who loves hearing himself explain things. “The machine, the spectrometer, counts the carbon atoms in the sample,” he said, “and it calculates the ratio of three different isotopes—three different forms of carbon. The ratio of those isotopes is like a signature . . .” He trailed off, frowning, then held up a finger, recalibrating his explanation, and resumed. “Non, the ratio is like a time stamp—the time stamp on an e-mail or a security-camera photo—that we can match to the ratio in the atmosphere at any point in time.”
“Call me dense,” Miranda persisted, “but how do you know what the ratio in the air was two thousand years ago?”
“Ah,” he beamed, “because the rings in trees have recorded the ratio in the air, year by year. And we have analyzed tree rings all the way back to ten thousand years ago.”
“We have?” Miranda arched her eyebrows. “We, you and I? Or we, you and other people?”
Stefan’s eyes narrowed in annoyance. “We, the scientific community,” he said testily. I dabbed at my mouth with my napkin, hiding my smile. “So when we find which tree ring has the same ratio as the bones, voilà, we know that the man died the same year the tree ring was formed.”
“I like it,” Miranda said. “An atomic stopwatch. A wood-burning atomic stopwatch. And it’s really that accurate, that reliable?”
“Oui, sure. You know the Shroud of Turin, the so-called burial cloth of Jesus?” Miranda and I both nodded. “You remember when the fabric from it was carbon-dated?”
“I remember that,” I said, “but Miranda was probably still in diapers. Wasn’t that, like, twenty years ago?”
“It was in 1988,” Stefan preened.
“I’ll have you know I was wearing big-girl pants in 1988,” Miranda said. “But I was too busy watching Sesame Street to tune in to the Vatican News Network.”
“So,” Stefan began, warming up for another mini-lecture. “Millions of people believe the Shroud of Turin is two thousand years old, oui?” God, I thought, he does love to hear himself talk. Was it just his smugness I objected to? Or was I jealous of him at some level—resentful of his tightness with Miranda, afraid he was taking my place in her esteem? Whatever the reason, I was starting to wish I hadn’t agreed to stay on and help the two of them. “But it was seen for the first time,” he went on, “the first time we can be sure of, anyway, here in France, in 1357. The C-14 samples were cut—”
“Wait, wait,” Miranda interrupted. “The Shroud of Turin started out as the Shroud of France? No kidding?”
“No kidding,” he said impatiently. “It was first shown in the village of Lirey, near Paris, in 1357. But the believers say non, the Shroud is much older than 1357. So finally, in 1988, the Vatican allows scientists to make a C-14 test. A small bit of the cloth is cut from one corner”—he made a snipping motion with his fingers—“and pieces are sent to three different laboratories. And voilà, all three labs say the same thing: The Shroud is from the fourteenth century.” He smiled wickedly as he pointed at me. “Ha! From the same century as Bill!” Miranda giggled, and my face flushed.
I pushed back from the table. “You know what, guys? Ancient relic that I am, I’m really beat,” I said.
“Oh come on, Dr. B,” Miranda cajoled, looking contrite. “It was a joke. Don’t leave.”
I waved off any further conversation. “It’s okay. Stay; enjoy your dessert. I can find my way back from here.”
That much was true—I had no trouble finding my way back. It was finding my way forward that seemed difficult at the moment.
Chapter 4
I PEERED OVER MIRANDA’S SHOULDER AT THE SCREEN of her laptop. “Okay,” I said, “push the button. Let’s see what the verdict is.”
It was nearly noon, though no speck of sunlight could penetrate the depths of the palace’s subterranean subtreasury. We’d spent the morning taking measurements of the bones, a task that was tedious, time-consuming, and therefore welcome: a convenient excuse to ignore how awkwardly dinner had ended.