"But there has to be," said Crane.
"No. I'm afraid the true explanation lies beyond. You see, certain…artifacts have been retrieved." And at this, Asher nodded to the silent man in the lab coat. The man walked toward a far wall, knelt, and opened a plastic locker that sat there. He withdrew something, rose, and handed it to Asher.
Crane looked on curiously. It was a cube-shaped object, encased in some kind of metal shielding. Asher glanced toward him, met his eyes.
"Remember what I told you, Peter," he said. "About the threshold." And then, gently, he pulled away the shielding and offered the cube to Crane.
It was hollow, made of transparent Plexiglas. Every edge was carefully sealed. Something was inside. Crane took it from Asher's hands, drew it close-then gasped aloud in surprise.
Floating in the dead center of the cube was a small object, no larger than a domino. It emitted a laserlike beam of light, pencil thin and intensely white, toward the ceiling. Impossibly, the object itself was of no single, definable color, but rather a coruscation, shimmering and rainbow hued: gold and violet and indigo and cinnamon and other colors Crane had never imagined, all in a constant state of change. The colors seemed to come from deep within the object, rising outward from some central core, as if the little object burned with some strange inner fire.
He turned the Plexiglas cube over and over, staring at the thing within it. No matter how he turned it, the object inside stayed dead center. He peered at the makeup of the cube itself, searching for hidden wires or magnets. But it was a simple cube of clear plastic-there were no tricks.
He shook the cube, first gently, then with severity. The glowing, pulsing thing at its center bobbled ever so slightly up and down at this treatment, always coming to rest in the exact center, where it continued to float serenely, its thin beam of white light pointing straight upward.
He brought the cube up close, staring at the object with openmouthed curiosity. He noticed the edges of the domino-sized thing were not, in fact, exactly defined. Rather, the object seemed to pulsate faintly: edges grew sharp, then softened again. It was almost as if the object's mass and form were in continuous flux.
He looked up from the cube. Asher was standing there, smiling, hand outstretched. After the briefest hesitation, Crane reluctantly handed him the cube. The chief scientist replaced it inside the shielding and gave it to his assistant, who returned it to the storage locker.
Crane sat back, blinking. "What the hell is it?" he asked after a moment.
"We don't know its purpose is, exactly."
"What's it made of?"
"Unknown."
"Is it dangerous? Could it be the source of the problems here?"
"I wondered the same thing, of course. We all did. But, no: it's harmless."
"You're sure about that?"
"The very first tests we did were to see if it was throwing off any radiation other than light. But it's not. It's completely inert-all subsequent tests have confirmed that. The reason I placed it inside that Plexiglas cube is because it's a little hard to deal with otherwise-it always finds the precise center of a room in which to hover."
"Where'd you get it?"
"It was uncovered during the excavation of the shaft. Along with well over a dozen others to date." Asher paused. "Our job when we started was clear-cut: dig as quickly as possible, within safety parameters, down toward the source of the signal. He gestured toward the locker. But then, when we began to discover those…well, things grew more complicated."
He sat down again, leaned in, and continued in a conspiratorial whisper. "They're remarkable, Peter-even more remarkable than they look. For one thing, they seem to be essentially indestructible. They're impervious to anything we've subjected them to in controlled environments. Some kinds of damage, like radiation, they absorb; others they reflect. And another thing: they seem to act as capacitors."
"Capacitors?" Crane repeated. "Like batteries?"
Asher nodded.
"What kind of power output?"
"We haven't been able to measure the top end. When we put conductors on them, they red-lined even our most powerful measuring devices."
"And what was the measurement?"
"One trillion watts."
"What? That little thing? Storing a thousand gigawatts' worth of energy?"
"You could put that in a car and it would provide enough electricity to power the vehicle for its lifetime-one hundred thousand miles. And there's something else." Asher reached into a pocket of his lab coat, pulled out a small manila envelope, and handed it to Crane.
Crane opened it and pulled out the sheet within. It was a computer printout, a repeating burst of short numbers:
"What's this?" he asked.
"That beam of light the marker's emitting? It's not continuous; it's actually pulsing, millions of times a second. The pulses are very regular: on and off."
"Ones and zeros. Digital."
"I believe so. It's what drives every computer on every desktop in the world. It's how neurons fire in our brains. It's a fundamental law of nature. This little device might be incredibly sophisticated, but why wouldn't it communicate digitally?" Asher tapped the sheet. "A sequence eighty bits long, repeating over and over. It's substantially shorter than the other message, by the way-the one transmitted from beneath the Moho, the one that was initially discovered."
"The other message, you say. So you think this pulse of light is trying to tell us something?"
"Yes I do-if we can decrypt it."
Crane raised the sheet. "May I keep this?"
Asher hesitated. "Very well. But don't show it to anybody."
Crane returned the sheet to the envelope, placed it in his desk. "These artifacts-"
"We call them markers. Or sentinels."
"Why sentinels?"
"Because it's almost as if they've been waiting, watching, all these years, to offer us something."
Crane thought for a moment. "So you're digging toward the source of the signal. What then?"
"There, too, things have gotten a little more complicated." Asher paused again. "Ultrasonic sensors we've lowered into the shaft…they've picked up evidence of something below the artifact field. A large object, buried even more deeply than the source of the signal."
"What kind of object?"
"We know it is torus shaped. We know it's extremely large-miles across. Beyond that, nothing."
Crane shook his head. "But you must have some theories."
"About what it's doing here? Certainly." Asher seemed a little more at ease now, like someone who'd unburdened himself of a painful truth. "After extensive discussion, the consensus among the scientists and the military here was that something has been left behind for humanity to discover, when sufficiently advanced."
"You mean, like a gift?"
"You could call it that. Who's to say which discoveries mankind is responsible for, and which were given us, one way or another? Who's to say, for example, that fire wasn't a gift from beyond the stars? Or iron? Or the know-how for building pyramids?"
"A gift from beyond the stars," Crane repeated dubiously.
"The Greeks believed fire came from the gods. Other peoples have similar myths. Maybe there's a pattern here? Once we had technology advanced enough to pick up a signal from beneath the Moho-once we could actually dig down to the beacon-we would be considered ready for the next leap forward."
"And so this buried object you're digging toward contains useful technology of some kind? Benevolent technology we can discover once we're ready to make use of it?"