yellow.
“Ian, I know how you feel It would be damned interesting to omit your message. But no one knows what that would mean. It might prevent us from doing what you want—namely convey the ocean information.”
Renfrew underlined these sentiments with a “Damned right!” and turned back to the apparatus.
Peterson’s eyelids lowered, as though he was deep in thought. “A good point. You know, for a moment there I thought there could be some way of finding out more that way.”
“We could,” Markham agreed. “But unless we do only what we understand…”
“Right,” Peterson said. “We rule out paradoxes, agreed. But later…” He had a wistful look.
“Later, sure,” Markham murmured. It was odd, he thought, how the players had reversed roles here. Peterson was supposedly the can-do administrator, pressing for results above all else. Yet now Peterson wanted to push the parameters of the experiment and find out some new physics.
And opposing this were Renfrew and himself, suddenly uncertain of what a paradox might produce. Ironies abounded.
An hour later the fine points of logic had faded, as they so often did, before the gritty details of the experiment itself. Noise smeared the flat face of the oscilloscope. Despite earnest work from the technicians the jitter in the experiment would not diminish. Unless it did, the tachyon beam would be uselessly diffuse and weak.
“Y’know,” Markham murmured, leaning back in his wooden lab chair, “I think your Caltech stuff may bear on this, Ian.”
Peterson looked up from reading the file with a red CONFIDENTIAL stamped across it. During the lulls he had been steadily working his way through a briefcase of paperwork. “Oh? How?”
“Those cosmological calculations—good work. Brilliant, in fact. Clustered universes. Now, suppose someone inside them is sending out tachyon signals. The tachyons can burrow right out of those smaller universes. All the tachyons have to do is pass through the event horizon of the closed-off microgeometry. Then they’re free. They escape from the gravitational singularities and we can pick them up.”
Peterson frowned. “These… microuniverses… are other other places to live? They might be inhabited?”
Markham grinned. “Sure.” He had the serene confidence of a man who has worked through the mathematics and seen the solutions. There was a blithe certainty that came from first comprehending the full Einstein field equations, arabesques of Greek letters clinging tenuously to the page, a gossamer web. They seemed insubstantial when you first saw them, a string of squiggles. Yet to follow the delicate tensors as they contracted, as the superscripts paired with subscripts, collapsing mathematically into concrete classical entities—potential; mass; forces vectoring in a curved geometry—that was a sublime experience. The iron fist of the real, inside the velvet glove of airy mathematics. Markham saw in Peterson’s face the hesitant puzzlement that swam over people when they struggled to visualize ideas beyond the comforting three dimensions and Euclidean certainties which framed their world. Behind the equations were immensities of space and dust, dead but furious matter bending to the geometric will of gravity, stars like match heads exploding in a vast night, orange sparks that lit only a thin ring of child planets. The mathematics was what made it all; the pictures men carried inside their heads were useful but clumsy, cartoons of a world that was as subtle as silk, infinitely smooth and varied. After you had seen that, really seen it, the fact that worlds could exist within worlds, that universes could thrive within our own, was not so huge a riddle. The mathematics buoyed you.
Markham said, “I think that may be an explanation for the anomalous noise level. It’s not thermally generated at all, if I’m right. Instead, the noise comes from tachyons. The indium antimonide sample isn’t just
“A background?” Renfrew asked. “From what?”
“Let’s see. Try the correlator.”
Renfrew made a few adjustments and stepped back from the oscilloscope. “That should do it.”
“Do what?” Peterson demanded.
“This is a lock-in coherence analyzer,” Markham explained. “It culls out the genuine noise in the indium sample—sound wave noise, that is—and brings up any signals out of the random background.”
Renfrew stared intently at the oscilloscope face. A complex wave form wavered across the scale. “It seems to be a series of pulses strung out at regular intervals,” he said. “But the signal decays in time.” He pointed at a fluid line which faded into the noise level as it neared the right side of the screen.
“Quite regular, yes,” Markham said. “Here’s one peak, then a pause, then two peaks together, then nothing again, then four nearly on top of each other, then nothing. Strange.”
“What do you trunk it is?” Peterson asked.
“Not ordinary background, that’s clear,” Renfrew answered.
Markham said, “It’s coherent, can’t be natural.”
Renfrew: “No. More like…”
“A code,” Markham finished. “Let’s take some of this down.” He began writing on a clip-board. “Is this a real-time display?”
“No, I just rigged it to take a sample of the noise for a hundred-microsecond interval.” Renfrew reached for the oscilloscope dials. “Would you like another interval?”
“Wait till I copy this.”
Peterson asked, “Why don’t you just photograph it?”
Renfrew looked at him significantly. “We have no film. There’s a shortage and priority doesn’t go to laboratories these days, you know.”
“Ian, take this down,” Markham interrupted.
Within an hour the results were obvious. The noise was in fact a sum of many signals, each overlaid on the rest. Occasionally a short stuttering group of pulses would appear, only to be swallowed in a storm of rapid jiggling.
“Why are there so many competing signals?” Peterson asked.
Markham shrugged. He wrinkled his nose in an unconscious effort to work his glasses back up. It gave him an unintentional expression of sudden, vast distaste. “I suppose it’s possible they’re from the far future. But the vest pocket universe sounds good to me, too.”
Renfrew said, “I wouldn’t put much weight on a new astrophysical theory. Those fellows speculate in ideas like stock brokers.”
Markham nodded. “Granted, they often take a grain of truth and blow it up into a kind of intellectual puffed rice. But this time they have a point. There are unexplained sources of infrared emission, far out among the galaxies. The microuniverses would look like that.” He made a tent of his fingers and smiled into it, his favorite academic gesture. At times like these it was comforting to have a touch of ritual to get you through. “That scope of yours shows a hundred times the ordinary noise you expected, John. I like the notion that we’re not unique, and there is a background of tachyon signals. Signals from different times, yes. And from those microscopic universes, too.”
“It comes and goes, though,” Renfrew observed. “I can still transmit a fraction of the time.”
“Good,” Peterson said. He had not spoken for some while. “Keep on with it, then.”
Renfrew said, “I hope the fellows back in 1963 haven’t got the detector sensitivity to study this noise. If they stick to our signals—which should stand out above this background, when we’re transmitting properly—they’ll be all right.”
“Greg,” Peterson mused, his eyes remote, “there’s another point.”
“Oh? What?”
“You keep talking about the small universes inside ours and how we’re overhearing their tachyon messages.”
“Right.”
“Isn’t that a bit self-centered? How do we know we, in turn, are not a vest pocket universe inside somebody else’s?”
