Gregory Benford - Timescape

“There’s a rumor the Chinese are way ahead on them.”

“Oh? Well, I can scotch that one. The Council had an intelligence report on precisely that point last month.”

“They gather intelligence on their own members?”

“The Chinese are formal members, but—well, look, the problems of the last few years have been technical. Peking has enough on its hands without meddling into subjects where they have no research capability.”

“I thought they were doing well.”

Peterson shrugged. “As well as anyone can with a billion souls to care for. They’re less concerned with foreign matters these days. They’re trying to slice up precisely equal portions of an ever-diminishing pie.”

“Pure communism at last.”

“Not so pure. Equal slices keeps down unrest due to inequality. They’re reviving terraced farming, even though it’s labor-intensive, to get food production up. The opiate of the masses in China is groceries. Always has been. They’re stopping use of energy-intensive chemicals in farming, too. I think they’re afraid of side effects.”

“Such as the South American bloom?”

“Dead on.” Peterson grimaced. “Who could’ve foreseen—?”

From the crowd there came a sudden, rattling cry. A woman surged up from a nearby table, clutching at her throat. She was trying to say something. Another woman with her asked, “Elinor, what is it? Your throat? Something caught?”

The woman gasped, a rasping cough. She clutched at a chair. Heads turned. Her hands went to her belly and her face pinched with a rush of pain. “I—it hurts so—” Abruptly she vomited over the table. She jerked forward, hands clutching at herself. A stream of bile spattered over the plates of food. Nearby patrons, frozen until this moment, frantically spilled from chairs and backed away. The woman tried to cry out and instead vomited again. Glasses smashed to the floor; the crowd moved back. “He—elp!” the woman cried. A convulsion shook her. She tried to stand and vomited over herself. She turned to her companion, who had retreated to the next table. She looked down at herself, eyes glazed, and pressed her palms to her belly. Hesitantly she stepped back from the table. She slipped suddenly and crashed to the floor.

Peterson had been shocked into immobility, as had Markham. As she fell he leaped to his feet and dashed forward. The crowd muttered and did not move. He leaned over the woman. Her scarf was tangled about her neck. It was twisted and sour with puke. He yanked at it, using both hands. The fabric ripped. The woman gasped. Peterson fanned the air around her, creating a breeze. She sucked in air. Her eyes fluttered. She stared up at him. “It… it hurts… so…”

Peterson scowled up at the surrounding crowd. “Call a doctor, will you? Bloody hell!”

The ambulance had departed. The Whim staff were busy mopping up. Most of the patrons were gone, driven off by the stench. Peterson came back from the ambulance, where he had followed, making sure the attendants had a sample of her food.

“What did they say it was?” Markham asked.

“No idea. I gave them the sausage she’d been eating. The medic said something about food poisoning, but those weren’t any poisoning symptoms I’ve ever heard about.”

“All we’ve been hearing about impurities—”

“Maybe.” Peterson dismissed the idea with a wave of his hand. “Could be anything, these days.”

Markham sipped meditatively on his stout. A waiter approached bearing their food. “Tongue for you, sir,” he said to Peterson, placing a platter. “And sausage here.”

Both men stared at their meals. “I think…” Markham began slowly.

“I agree,” Peterson followed up briskly. “I believe we’ll be skipping these. Could you fetch me a salad?”

The waiter looked dubiously at the plates. “You ordered this.”

“So we did. Surely you don’t expect us to choke it down after what’s just happened, do you? In a restaurant like this?”

“Well, I dunno, the manager, he says—”

“Tell your manager to watch his raw materials or I’ll bloody well have this place closed down. Follow me?”

“Christ, no reason to—”

“Just tell him that. And bring my friend here another stout.”

When the waiter had backed away, obviously unwilling to confront either Peterson or the manager, Markham murmured, “Great. How’d you know I’d prefer another stout?”

“Intuition,” he said with weary camaraderie.

They had both had more drinks when Peterson said, “Look, it’s Sir Martin who’s really the technical type on the British delegation. I’m a nonspecialist, as they call it. What I want to know is, how in hell do you get around this grandfather paradox bit? That fellow Davies explained about the discovery of tachyons right enough, and I accept that they can travel into our past, but I still can’t see how one can logically change the past.”

Markham sighed. “Until tachyons were discovered, everybody thought communication with the past was impossible. The incredible thing is that the physics of time communication had been worked out earlier, almost by accident, as far back as the 1940s. Two physicists named John Wheeler and Richard Feynmann worked out the correct description of light itself, and showed that there were two waves launched whenever you tried to make a radio wave, say.”

“Two?”

“Right. One of them we receive on our radio sets. The other travels backward in time—the ‘advanced wave,’ as Wheeler and Feynmann called it.”

“But we don’t receive any message before it’s sent.”

Markham nodded. “True—but the advanced wave is there , in the mathematics. There’s no way around it. The equations of physics are all time-symmetric. That’s one of the riddles of modern physics. How is it that we perceive time passing, and yet all the equations of physics say that time can run either way, forward or backward?”

“The equations are wrong, then?”

“No, they’re not. They can predict anything we can measure—but only as long as we use the ‘retarded wave,’ as Wheeler and Feynmann called it. That’s the one that you hear through your radio set.”

“Well, look, surely there’s a way to change the equation round until you get only the retarded part.”

“No, there isn’t. If you do that to the equations, there’s no way to keep the retarded wave the same. You must have the advanced wave.”

“All right, where are those backward-in-time radio shows? How come I can’t tune into the news from the next century?”

“Wheeler and Feynmann showed that it can’t get here.”

“Can’t get into this year? I mean, into our present time?”

“Right. See, the advanced wave can interact with the whole universe—it’s moving back, into our past, so it eventually hits all the matter that’s ever born. Thing is, the advanced wave strikes all that matter before the signal was sent.”

“Yes, surely.” Peterson reflected on the fact that he was now, for the sake of argument, accepting the “advanced wave” he would have rejected only a few moments before.

“So the wave hits all that matter, and the electrons inside it jiggle around in anticipation of what the radio station will send.”

“Effect preceding a cause?”

“Exactly. Seems contrary to experience, doesn’t it?”

“Definitely.”

“But the vibration of those electrons in the whole rest of the universe has to be taken into account. They in turn send out both advanced and retarded waves. It’s like dropping two rocks into a pond. They both send out waves. But the two waves don’t just add up in a simple way.”