Harry looked off into the distance as if he were reliving the events he was about to describe.
“Twentysomething years ago, Karl and I were together on a dig near the southern tip of Chile, in Cabo de Hornos, near the southernmost tip of the Tierra del Fuego archipelago. One of our students thought she’d found something of interest.” Bickford leaned forward across his desk and almost whispered. “She came to me a few days later, pretty worked up. She said she’d found something crazy. ‘Students!’ I thought. ‘Always overexcited about something.’ But this girl had found something extraordinary, under a pile of rock scrabble we later dated back to the Eemian. It was a piece of what looked to me like black metal, firmly affixed to the rock below it, itself seemingly carved into a smooth pillar with a perfectly flat stone top. Over the next few days, we carefully cleared away the dirt and rock that had covered it for 100,000 years. The top surface of the object was ruler flat, as if it had been machined. And there was writing on that surface—symbols, pictures, diagrams etched in relief. The plaque itself was about a meter wide, half a meter long. After a few days’ work, we were able to chip away the rock it was attached to and free the material from its mount. We hoped to bring it back with us to the university, but that never happened. The Chilean government had inspectors swarming over the dig, and they confiscated the piece.”
“What happened to it?”
Bickford shrugged his bony shoulders in her direction. “Probably buried in a drawer in some museum in Santiago. We did manage to break off a piece, and smuggle it out of Chile and into the lab to date it and run a materials analysis.” He looked at them both. “You can probably guess what it was made of.”
“Graphene,” Sam said. He realized that he wasn’t asking.
“Satsky went nuts, and has been on a mission ever since to discover the origins of what we found,” said Bickford. “His treasure.”
Sam and Julia looked at each other. Sawyer turned back to Bickford. “And you?”
“I knew right away what it was.” He shook his head. “The evidence we found that day confirmed what I have suspected for decades.” He chuckled. “Karl wouldn’t believe me, despite the evidence staring us both in the face. That was soon to change.”
The room was deathly quiet as they waited for him to continue. Bickford twiddled his thumbs and again stared at the ceiling, apparently gathering his thoughts. Somewhere, a clock ticked. Bickford took a deep breath and seemed about to continue, and Sam gripped the arms of his wooden chair.
“All right.” Bickford’s wide gaze returned to them. “The last glacial thaw took place about 12,000 years ago. Earth came out of its deep freeze, and our accepted history is that humans moved from caves and nomadic hunting to begin what we call civilization. Everything we think of as modern mankind’s history—the invention of the wheel, the control of fire, agriculture, permanent dwellings, cities, industry—has taken place in the last 12,000 years. And as you both know, in the grand scheme of things, that’s a pretty short span of time, even for a species as recent as Homo sapiens.”
Bickford leaned forward, his old chair groaning in protest. “We’d like to believe that the two-and-a-half-million years it took primates to climb down out of the trees and step into a spacecraft was a straightforward, linear progression. It was not. Along the way there were thousands of twists, turns, dead ends, missteps, successes, failures. The fact is, we know so little of humans’ actual history. Most of what we think we know is based on best guesses about the rare fossils we find.
“Like the Neanderthals?”
“Exactly, Sam. Exactly. They actually looked like us, not like brutish thugs. If one of them walked down the street, you wouldn’t be able to pick him out of the crowd.”
“Oh, sorry,” said Bickford. “As Sam here knows, how we think of Neanderthals is mostly due to the errors of one man, Marcellin Boule. In 1911, he reconstructed the first skeleton of a Neanderthal—a Neanderthal who just happened to be severely arthritic. Based on that single skeleton, he and the world’s academics assumed that all Neanderthals were degenerate, slouching cavemen. But later discoveries told a very different story. The DNA of 99.7% of modern humans includes some Neanderthal DNA. We’re their direct descendants. They were, for all intents and purposes, modern humans. Hell, the cranial volume of many of them was larger than our own. There’s every biological reason to think they were capable of the same level of intelligence as we are—perhaps greater. We know they had medicines, had mastered fire, and varied their diet as we do, with meat and cooked vegetables. They were as closely related to us as you might be to a relative.”
“Where is all this goin’?” asked Sam.
“To the Eemians,” said Bickford. “It took a lot of evidence and persuasion but, over time, both Karl and I are convinced theirs was a modern industrialized civilization 100,000 years ago. It was their industrialized civilization that raised the levels of greenhouse gasses so quickly and the planet warmed because of them, just as it is warming now because of us. We’ve each been searching for more evidence of them in our own ways ever since that original discovery in Chile.”
“But . . . if there were others before us, wouldn’t we have found evidence by now?” Julia sounded bewildered. “Cities? Artifacts? Anything?”
Harry laughed. “You’re enough of a scientist to know the aphorism that an absence of evidence is not evidence of absence.”
“No, you’re thinking with your human pride, not your smarts. Look, the time any modern civilization might have existed would have been relatively short. Probably. Look at our own society. Since around 1800, we’ve gone from fewer than a billion people, relying on animals and steam, to nearly eight billion, using spacecraft, smartphones, and computers. On an evolutionary timescale, changes of even a few thousand years are very small, let alone hundreds of years. Human fossil remains from 100,000 years ago are rare finds indeed. What few people understand—though I’m sure it’s clear to you two—is that everything we conclude about our ancestors is, unfortunately, based on tiny amounts of evidence and a lot of speculation. In some cases, we’ve had to make educated guesses about an entire species based on little more than a tooth or a thighbone. That past human civilization was here and gone in a blink of an eye, relatively speaking, leaving behind little else than their carbon footprint.”
Bickford leaned forward in his seat, planted his elbows on either side of his keyboard, and rested his big head on two knuckles of his right hand. “If you were an archaeologist in the far future, digging through sedimentary rock for evidence of past civilizations, you’d be hard-pressed to notice that even we had ever been here. The layer of the Earth’s surface recording the entire history of human civilization would be no thicker than a piece of paper. Time is cruel to manmade objects. Not much survives 100,000 years. We’d be easy to miss. So, too, would any past human civilization.”