The Time Traveler's Almanac (6 page)

“Progress,” he said bitterly, and his voice was an aching whisper in the phantom ship. “The Flying Dutchman takes to the universe.”

RIPPLES IN THE DIRAC SEA

Geoffrey A. Landis

Geoffrey A. Landis, who appears later in this anthology with “At Dorado,” is a NASA scientist whose first novel,
Mars Crossing,
was published by Tor Books in 2000, winning a Locus Award. He has also won the Analog Analytical Laboratory Award for the novelette
The Man in the Mirror
(2009). A short-story collection,
Impact Parameter and Other Quantum Realities,
was published by Golden Gryphon Press in 2001. His 2010 novella
The Sultan of the Clouds
won the Sturgeon award for best short science fiction story. “Ripples in the Dirac Sea” was first published in
Asimov’s Science Fiction Magazine
in 1988 and won the 1989 Nebula Award for best short story.

My death looms over me like a tidal wave, rushing toward me with an inexorable slow-motion majesty. And yet I flee, pointless though it may be.

I depart, and my ripples diverge to infinity, like waves smoothing out the footprints of forgotten travellers.

*   *   *

We were so careful to avoid any paradox, the day we first tested my machine. We pasted a duct-tape cross onto the concrete floor of a windowless lab, placed an alarm clock on the mark, and locked the door. An hour later we came back, removed the clock and put the experimental machine in the room, with a super-eight camera set between the coils. I aimed the camera at the X, and one of my grad students programmed the machine to send the camera back half an hour, stay in the past five minutes, then return. It left and returned without even a flicker. When we developed the film, the time on the clock was half an hour before we loaded the camera. We’d succeeded in opening the door into the past. We celebrated with coffee and champagne.

Now that I know a lot more about time, I understand our mistake, that we had not thought to put a movie camera in the room with the clock to photograph the machine as it arrived from the future. But what is obvious to me now was not obvious then.

*   *   *

I arrive, and the ripples converge to the instant
now
from the vastness of the infinite sea.

To San Francisco, June 8, 1965. A warm breeze riffles across dandelion-speckled grass, while puffy white clouds form strange and wondrous shapes for our entertainment. Yet so very few people pause to enjoy it. They scurry about, diligently preoccupied, believing that if they act busy enough, they must be important. “They hurry so,” I say. “Why can’t they slow down, sit back, enjoy the day?”

“They’re trapped in the illusion of time,” says Dancer. He lies on his back and blows a soap bubble, his hair flopping back long and brown in a time when “long” hair meant anything below the ear. A puff of breeze takes the bubble down the hill and into the stream of pedestrians. They uniformly ignore it. “They’re caught in the belief that what they do is important to some future goal.” The bubble pops against a briefcase, and Dancer blows another. “You and I, we know how false an illusion that is. There is no past, no future, only the now, eternal.”

He was right, more right than he could have imagined. Once I, too, was preoccupied and self-important. Once I was brilliant and ambitious. I was twenty-eight years old, and I made the greatest discovery in the world.

*   *   *

From my hiding place I watched him come up the service elevator. He was thin almost to the point of starvation, a nervous man with stringy blonde hair and an armless white T-shirt. He looked up and down the hall, but failed to see me hidden in the janitor’s closet. Under each arm was a two-gallon can of gasoline, in each hand another. He put down three of the cans and turned the last one upside down, then walked down the hall, spreading a pungent trail of gasoline. His face was blank. When he started on the second can, I figured it was about enough. As he passed my hiding spot, I walloped him over the head with a wrench, and called hotel security. Then I went back to the closet and let the ripples of time converge.

I arrived in a burning room, flames licking forth at me, the heat almost too much to bear. I gasped for breath – a mistake – and punched at the keypad.

NOTES ON THE THEORY AND PRACTICE OF TIME TRAVEL:

1) Travel is possible only into the past.

2) The object transported will return to exactly the time and place of departure.

3) It is not possible to bring objects from the past to the present.

4) Actions in the past cannot change the present.

One time I tried jumping back a hundred million years, to the Cretaceous, to see dinosaurs. All the picture books show the landscape as being covered with dinosaurs. I spent three days wandering around a swamp – in my new tweed suit – before even catching a glimpse of any dinosaur larger than a basset hound. That one – a theropod of some sort, I don’t know which – skittered away as soon as it caught a whiff of me. Quite a disappointment.

My professor in transfinite math used to tell stories about a hotel that had an infinite number of rooms. One day all the rooms are full, and another guest arrives. “No problem,” says the desk clerk. He moves the person in room one into room two, the person in room two into room three, and so on. Presto! A vacant room.

A little later, an infinite number of guests arrive. “No problem,” says the dauntless desk clerk. He moves the person in room one into room two, the person in room two into room four, the person in room three into room six, and so on. Presto! An infinite number of rooms vacant.

My time machine works on just that principle.

*   *   *

Again I return to 1965, the fixed point, the strange attractor to my chaotic trajectory. In years of wandering I’ve met countless people, but Daniel Ranien – Dancer – was the only one who truly had his head together. He had a soft, easy smile, a battered secondhand guitar, and as much wisdom as it has taken me a hundred lifetimes to learn. I’ve known him in good times and bad, in summer days with blue skies that we swore would last a thousand years, in days of winter blizzards with drifted snow piled high over our heads. In happier times we have laid roses into the barrels of rifles, we laid our bodies across the city streets in the midst of riots, and not been hurt. And I have been with him when he died, once, twice, a hundred times over.

He died on February 8, 1969, a month into the reign of King Richard the Trickster and his court fool Spiro, a year before Kent State and Altamont and the secret war in Cambodia slowly strangled the summer of dreams. He died, and there was – is – nothing I can do. The last time he died I dragged him to a hospital where I screamed and ranted until finally I convinced them to admit him for observation, though nothing seemed wrong with him. With X-rays and arteriograms and radioactive tracers, they found the incipient bubble in his brain; they drugged him, shaved his beautiful long brown hair, and operated on him, cutting out the offending capillary and tying it off neatly. When the anesthetic wore off, I sat in the hospital room and held his hand. There were big purple blotches under his eyes; he gripped my hand and stared, silent, into space. Visiting hours or no, I didn’t let them throw me out of the room. He just stared. In the grey hours just before dawn he sighed softly and died. There was nothing at all that I could do.

*   *   *

Time travel is subject to two constraints: conservation of energy, and causality. The energy to appear in the past is only borrowed from the Dirac sea, and since ripples in the Dirac sea propagate in the negative direction, transport is only into the past. Energy is conserved in the present as long as the object transported returns with zero time delay, and the principle of causality assures that actions in the past cannot change the present. For example, what if you went in the past and killed your father?

Who, then, would invent the time machine?

Once I tried to commit suicide by murdering my father, before he met my mother, twenty-three years before I was born. It changed nothing, of course, and even when I did it I knew it would change nothing. But you have to try these things. How else could I know for sure?

*   *   *

Next we tried sending a rat back. It made the trip through the Dirac sea and back undamaged. Then we tried a trained rat, one we borrowed from the psychology lab across the green without telling them what we wanted it for. Before its little trip it had been taught to run through a maze to get a piece of bacon. Afterwards, it ran the maze as fast as ever.

We still had to try it on a human. I volunteered myself and didn’t allow anyone to talk me out of it. By trying it on myself, I dodged the university regulations about experimenting on humans.

The dive into the negative energy sea felt like nothing at all. One moment I stood in the center of the loop of Renselz coils, watched by my two grad students and a technician; the next I was alone, and the clock had jumped back exactly one hour. Alone in a locked room with nothing but a camera and a clock, that moment was the high point of my life.

The moment when I first met Dancer was the low point. I was in Berkeley, a bar called “Trishia’s,” slowly getting trashed. I’d been doing that a lot, caught between omnipotence and despair. It was 1967. ’Frisco then – it was the middle of the hippy era – seemed somehow appropriate.

There was a girl, sitting at a table with a group from the university. I walked over to her table and invited myself to sit down. I told her she didn’t exist, that her whole world didn’t exist, it was all created by the fact that I was watching, and would disappear back into the sea of unreality as soon as I stopped looking. Her name was Lisa, and she argued back. Her friends, bored, wandered off, and in a while Lisa realized just how drunk I was. She dropped a bill on the table and walked out into the foggy night.

I followed her out. When she saw me following, she clutched her purse and bolted.

He was suddenly there under the streetlight. For a second I thought he was a girl. He had bright blue eyes and straight brown hair down to his shoulders. He wore an embroidered Indian shirt with a silver and turquoise medallion around his neck and a guitar slung across his back. He was lean, almost stringy, and moved like a dancer or a karate master. But it didn’t occur to me to be afraid of him.

He looked me over. “That won’t solve your problem, you know,” he said.

And instantly I was ashamed. I was no longer sure exactly what I’d had in mind or why I’d followed her. It had been years since I’d first fled my death, and I had come to think of others as unreal, since nothing I could do would permanently affect them. My head was spinning. I slid down the wall and sat down, hard, on the sidewalk. What had I come to?

He helped me back into the bar, fed me orange juice and pretzels, and got me to talk. I told him everything. Why not, since I could unsay anything I said, undo anything I did? But I had no urge to. He listened to it all, saying nothing. No one else had ever listened to the whole story before. I can’t explain the effect it had on me. For uncountable years I’d been alone, and then, if only for a moment.… It hit me with the intensity of a tab of acid. If only for a moment, I was not alone.

We left arm in arm. Half a block away, Dancer stopped, in front of the alley. It was dark.

“Something not quite right here.” His voice had a puzzled tone.

I pulled him back. “Hold on. You don’t want to go down there—” He pulled free and walked in. After a slight hesitation, I followed.

The alley smelled of old beer, mixed with garbage, urine, and stale vomit. In a moment, my eyes became adjusted to the dark.

Lisa was cringing in a corner behind some trash cans. Her clothes had been cut away with a knife, and lay scattered around. Blood showed dark on her thighs and one arm. She didn’t seem to see us. Dancer squatted down next to her and said something soft. She didn’t respond. He pulled off his shirt and wrapped it around her, then cradled her in his arms and picked her up. “Help me get her to my apartment.”

“Apartment, hell. We’d better call the police,” I said.

“Call the pigs? Are you crazy? You want them to rape her, too?”

I’d forgotten; this was the sixties. Between the two of us, we got her to Dancer’s VW bug and took her to his apartment in The Hashbury. He explained it to me quietly as we drove, a dark side of the summer of love that I’d not seen before. It was greasers, he said. They come down to Berkeley because they heard that hippy chicks gave it away free, and get nasty when they meet one who thought otherwise.

Her wounds were mostly superficial. Dancer cleaned her, put her in bed, and stayed up all night beside her, talking and crooning and making little reassuring noises. I slept on one of the mattresses in the hall. When I woke up in the morning, they were both in his bed. She was sleeping quietly. Dancer was awake, holding her. I was aware enough to realize that that was all he was doing, holding her, but still I felt a sharp pang of jealousy, and didn’t know which one of them it was that I was jealous of.

NOTES FOR A LECTURE ON TIME TRAVEL

The beginning of the twentieth century was a time of intellectual giants, whose likes will perhaps never again be equalled. Einstein had just invented relativity, Heisenberg and Schrödinger quantum mechanics, but nobody yet knew how to make the two theories consistent with each other. In 1930, a new person tackled the problem. His name was Paul Dirac. He was twenty-eight years old. He succeeded where the others had failed.

His theory was an unprecedented success, except for one small detail. According to Dirac’s theory, a particle could have either positive or negative energy. What did this mean, a particle of negative energy? How could something have negative energy? And why don’t ordinary – positive energy – particles fall down into these negative energy states, releasing a lot of free energy in the process?

You or I might have merely stipulated that it was impossible for an ordinary positive energy particle to make a transition to negative energy. But Dirac was not an ordinary man. He was a genius, the greatest physicist of all, and he had an answer. If every possible negative energy state was already occupied, a particle couldn’t drop into a negative energy state. Ah ha! So Dirac postulated that the entire universe is entirely filled with negative energy particles. They surround us, permeate us, in the vacuum of outer space and in the center of the earth, every possible place a particle could be. An infinitely dense “sea” of negative energy particles. The Dirac sea.