"Uh huh. I did."
"And the noise is still there."
"I checked. Ran the whole sequence."
"That's bullshit."
Cooper sighed elaborately. "So you found out about it, huh?"
Gordon frowned. "Found out what?"
"I know you're a stickler for carrying an experiment through, A to Z, with no delays, Dr. Bernstein. I know that." Cooper shrugged apologetically. "But I couldn't finish the whole thing last night. So I went out and had a few beers with the guys. Then I came back and did it all over."
Gordon wrinkled his brow. "There's nothing wrong with that. You can always take a break. Just so you keep everything steady, don't let the preamps or the scopes go off their zero adjustments."
"No, they were still okay."
"Then–" Gordon spread his hands, exasperated "–you've screwed up somewhere. It's not the beer-drinking I care about, it's the experiment.
Look, the conventional wisdom is that it takes four years minimum to get out. Do you want to make it that fast?"
"Sure."
"'Then do what I say and don't slack off."
"But I haven't."
"You must've. You just haven't looked. I can—"
"The noise is still there," Cooper said with a certainty that stopped Gordon in mid-sentence. Gordon abruptly realized that he had been browbeating this man, only three years younger, for no reason whatever, aside from frustration.
"Look, I–" Gordon began, but found the next word catching in his throat. He felt suddenly embarrassed. "Okay, I believe you," he said, making his voice brisk and businesslike. "Let's see the chart recordings you took."
Cooper had been leaning against the blocky magnet that enclosed the kernel of their experiment. He turned and threaded his way through the lanes of cables and microwave guides. The experiment was still running.
The silvery flask, suspended between the poles of the magnet and all but obscured by cable lead-ins, had grown a coat of ice. Inside it liquid helium frothed and bubbled, boiling away at temperatures only a few degrees above absolute zero. The ice was water frozen out from the air around the jacket, and it made an occasional snap as the equipment expanded and contracted to relieve stress. The brilliantly lit laboratory hummed with electronic life. A few meters away the sheer heat of the banks upon banks of transistorized diagnostics made a warming wall of air. From the helium, though, Gordon could feel a gentle, chilling draft. Despite the coolness Cooper wore a torn T-shirt and blue jeans. Gordon preferred a blue long-sleeve button-down shirt, Oxford broadcloth, with corduroy slacks that belted in the back, and a tweed jacket. He had not yet adjusted to the informality of laboratories here. If it meant going as far downhill as Cooper, he was certain he never would.
"I took a lot of data," Cooper said conversationally, ignoring the tension that had hung in the air only moments before. Gordon moved through the assembly of scopes and wheeled cabinets to where Cooper was methodically laying out the automatically recorded graphs. The paper was gridded in bright red, so that the green jiggling lines of the signal stood out, making the page almost three-dimensional from contrast.
"See?" Cooper's thick fingers traced the green peaks and valleys. "Here's where the indium nuclear resonance should be."
Gordon nodded. "A nice fat peak, that's what we should find," he said.
But there was only a chaos of narrow vertical lines, made as the recorder pen had rocked back and forth across the paper, under the action of random nudges.
"Just hash," Cooper murmured.
"Yes," Gordon admitted, feeling the air wheeze out of him as he said it, his shoulders sagging.
"I got these, though." Cooper laid out another green rectangle. It showed a mixed pattern. At the right was a clean peak, its sides smooth and untroubled. But the center and left of the page was a meaningless jumble of scratchings.
"Damn," Gordon whispered to himself. On these graphs the frequency of emissions from the indium antimonide sample increased from left to right. "The noise wipes out the high frequencies."
"Not always."
"Huh?"
"Here's another try. I took it just a few minutes after that one."
Gordon studied the third x-y output sheet. On this one there was a reasonably clear peak on the left side, at low frequencies, and then noise to the fight. "I don't get it."
"I sure don't either."
"We've always got flat, constant noise before."
"Yep." Cooper looked at him blankly. Gordon was the professor here; Cooper was tossing the riddle over to him.
Gordon squinted, thinking. "We're getting the peaks, but only part of the time."
"That's what it looks like."
"'Time. Time," Gordon muttered distantly. "Hey, the pen takes about, say, thirty seconds to move across the sheet, right?"
"Well, we could change that, if you think–"
"No, no, listen," Gordon said rapidly. "Suppose the noise isn't always there? In this one—" he shuffled back to the second sheet "–there was some source of noise when the pen was recording the low frequencies.
About ten seconds later it vanished. Here— " he planted a stubby finger on the third x-y graph. "–the hash started in as the pen reached high frequencies. The noise was returning."
Cooper wrinkled his brow. "But ... I thought this was a steady state experiment. I mean, nothing changes, that's the whole point. We keep the temperature low but constant. The scopes and amps and rectifiers are all warmed up and holding to pattern. They–"
Gordon waved him into silence. "It's nothing we are doing. We've spent weeks checking the electronics; that's not malfunctioning. No, it's something else, that's my point."
"But what?"
"Something from outside. Interference."
"How could-"
"Who knows?" Gordon said with new energy. He began his characteristic nervous pacing. His shoe soles squeaked on the floor at every turn. "What's happening is, there's another source of signal in the indium antimonide. Or else the indium is picking up a time-varying input from outside the lab."
"I don't understand."
"Hell, I don't either. But something's screwing up the nuclear resonance detection. We've got to track it down."
Cooper squinted at the erratic lines, as though measuring in his mind's eye the alterations that had to be made to study the problem further.
"How?"
"If we can't remove the noise, study it. Find out what it's coming from.
Is it occurring in all the indium antimonide samples? Does it filter in from some other lab here? Or is it something new? That sort of thing."
Cooper nodded slowly. Gordon framed a few quick circuit diagrams on the back of one of the sheets, sketching in the components with a pencil.
He could see fresh possibilities now. An adjustment here, a new piece of equipment there. They could borrow some components from Lakin down the hall, and probably talk Feher out of his spectrum analyzer for a day or two. Gordon's pencil made a small scratching sound against the background chugging of roughing pumps and the pervasive hum of the electronics, but he heard nothing. The ideas seemed to come up out of him and squeeze through the pencil onto the page, jotted down almost before he had thought them through, and he felt that he was on the track of something in this noise problem. There might be a new structure hiding behind the data like big game in a dense thicket. He was going to find out; he was sure of that.
Gregory Markham cycled past the fragrant buildings devoted to Veterinary Medicine and swooped into the driveway of the Cavendish Laboratory. He liked the soft brush of moist air as he arced around the curves, shifting his weight in a careful rhythm. His aim was to find a minimum curve which would deposit him at the lab entrance, a geodesic for this particular local curvature of space. One last burst of pedaling and he dismounted at a respectable speed, trotting alongside, using the bike's energy to roll it into one of the concrete wheelstands.
He straightened his brown Irish jacket and took the steps two at a time, a habit which gave him the appearance of being always late for something.
He absently pushed his glasses back up his nose, where they had worn a red mark, and combed fingers through his beard. It was a well-defined beard, following the conventional course along his sharp jaw from sideburns to moustache, but it seemed to get mussed every hour or so, as did his hair. He was puffing from the bike ride more than usual. Either he had put on some weight in the last week, he deduced, or the simple erosion of age had nicked a little deeper. He was fifty-two and kept in moderately good condition. Medical research had shown enough of a correlation between exercise and long life to keep him at it.
He pushed open the glass doors and headed for Renfrew's laboratory.
Every week or so he had come round to peer judiciously at the equipment and nod, but in truth he learned little by the visits. His interests lay in the theory behind the electronic maze. Gingerly he entered the busy ball of sound that was the lab.
He could see Renfrew through the office window–stocky, rumpled as usual, his shirt un-tucked, his mouse-brown hair falling untidily over his forehead. He was shuffling papers round on his cluttered desk. Markham did not recognize the other man. He assumed it was Peterson and was amused by the contrast between the two. Peterson's dark hair was smoothly in place and he was expensively and elegantly tailored. He looked suave and self-confident and, thought Markham, altogether a tough bastard to deal with. Experience had taught him that it was hard to get through to that type of cool, self-contained Englishman.
He opened the office door, giving it a perfunctory knock as he did so.
Both men turned towards him. Renfrew appeared relieved and jumped up, knocking a book off his desk.
"Ah, Markham, here you are," he said unnecessarily. "This is Mr.
Peterson from the Council."
Peterson rose smoothly from his chair and extended a hand.
"How do you do, Dr. Markham."
Markham shook his hand vigorously.
"Glad to meet you. Have you looked at John's experiment yet?"
"Yes, just now." Peterson looked faintly perturbed by the speed with which Markham came to the point. "How does the NSF feel about this, do you know?"
"No opinion so far. I haven't reported to them. They asked me only last week to act as liaison. Can we sit down?"
Without waiting for an answer Markham crossed the room, cleared the only other chair, and sat down, putting one ankle up on his knee. The other two men resumed their seats, less casually.
"You're a plasma physicist, is that right, Dr. Markham?"
"Yes. I'm here on sabbatical leave. Most of my work has been in plasmas until the last few years. I wrote a paper on tachyon theory long ago, before they were discovered and became fashionable. I suppose that's why the NSF asked me to be here."
"Did you read the copy of the proposal that I sent you?" Peterson asked.
"Yes, I did. It's good," Markham said decisively. "The theory's fine. I've been working on the ideas behind Renfrew's experiment for some time now."
"You think this experiment will work, then?"
"We know the technique works. Whether we can actually communicate with the past–that we don't know."
"And this set-up here—"Peterson swept an arm towards the laboratory bay, "–can do that?"
"If we're damned lucky. We know there were similar nuclear resonance experiments at the Cavendish and a few other places, in the States and the Soviet Union, functioning as far back as the 1950s. In principle they could pick up coherent signals induced by tachyons."
"So we can send them telegrams?"
"Yes, but that's all. It's a highly restricted form of time travel. This is the only way anyone's figured out how to send messages into the past. We can't transmit objects or people."
Peterson shook his head. "I did a degree involving social issues and computers. Even I'm—"
"Cambridge?" Markham broke in.
"Yes, King's College." Markham nodded to himself and Peterson hesitated. He disliked the American's obvious putting of him in a category. He did the same thing himself, of course, but certainly with more genuine reason. Slightly irritated, he seized the initiative. "Look, even I know there's a paradox involved here somewhere. The old thing about shooting your grandfather, isn't it? But if he died, you wouldn't exist yourself. Someone on the Council brought that up yesterday. We almost booted the whole idea out because of that."
"A good point. I made the same error in a paperback in 1992. It turns out there are paradoxes and then, if you look at things the right way, paradoxes go away. I could explain, but it would take time."
"Not now, if you don't mind. The whole point, as I understand it, is to send these telegrams and tell somebody back in the 1960s or so about our situation here."
"Well, something like that. Warn them against chlorinated hydrocarbons, sketch in the effects on phytoplankton. Getting a lead on certain kinds of research could give us the edge we need now to–"
"Tell me, do you think this experiment might be of any real help?"
Renfrew stirred impatiently but said nothing. "Without being melodramatic," Markham said slowly, "I believe it would save millions of lives. Eventually."
There was a moment's silence. Peterson recrossed his legs and picked an invisible piece of lint from his knee.
"It's a question of priorities, you see," he said at last. "We have to take the large view. The Emergency Council has been in session since nine this morning. There has been another full-scale dieback in North Africa due to drought and lack of food reserves. You'll hear more about it in the news in due course, no doubt. Meanwhile, this and other emergencies have to take priority. North Africa's not the only trouble spot. There's a large diatom bloom off the South American coast, too. Thousands of people are dying in both places. You're asking us to put money into an isolated experiment that may or may not work–one man's theory, essentially–"
Markham interrupted swiftly. "It's more than that. The tachyon theory is not new. There's a group at Caltech right now–the gravitational theory group–working on another angle of the same problem. They're trying to see how tachyons fit into the cosmological questions–you know, the expanding universe picture and all."