by Anthology
(Keep in mind that it’s still impossible—according to our current knowledge of space, time and good ol’ fashioned physics—to travel faster than the speed of light, but traveling at any fraction of the speed of light is still allowed in physics. The engineering of such a machine, on the other hand, would require some pretty epic propulsion technology behind it.)
“If you go fast, your clock runs slow relative to people who are still. As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future,” he said.
Cox is basically describing a famous thought experiment taught to university students around the world as the “Twin Paradox.”
Imagine twins, one stays on Earth (Twin A) while the other (Twin B) boards a spaceship and flies off at relativistic speeds. Compared with Twin A’s timeframe, Twin B’s timeframe will slow. If time is running slower for Twin B, then he/she will return to Earth where a lot more time has passed and Twin A has aged significantly more than Twin B. The mechanism behind this is “time dilation” and it has a stronger effect as you travel closer and closer to the speed of light.
So far, Cox has described a time machine (a.k.a. a relativistic spaceship) stuck in fast forward. What would it take to wind back the years and test out the “Grandfather Paradox”? (Warning: If you just so happened to find yourself in the past don’t bother testing out this paradox. Spoiler: It could end very badly for you.)
Well, that would require some pretty fancy and exotic physics.
“In General Relativity, you can do it in principle,” said Cox. “It’s to do with building these things called wormholes; shortcuts through space and time. But most physicists doubt it. Hawking came up with the ‘chronology protection conjecture’—physics we don’t yet understand that means wormholes are not stable.”
A consequence of some of Einsteins relativity equations predict the existence of wormholes—but they are not traversable wormholes (i.e. you can’t pack your bags and jump into one of these quirks of spacetime), they are short-lived, small scale anomalies. To create a wormhole from science fiction, you’d need an exotic form of matter that can stabilize the mouth of a wormhole using negative energy.
Currently, such a form of matter is pure theory, but if it were to be discovered or manufactured, it would be pretty useful for time travel and, potentially, interstellar travel.
For now, the only conceivable time machine is one that’s stuck in fast forward.
NEBOGIPFEL AT THE END OF TIME
Richard A. Lupoff
The first of them to appear came from the sky. There was a flash like ball lightening, there was a clap of thunder, there was the rush and flutter of great heavy wings, and he was there—a gleaming, godlike figure with streaming golden hair, perfect features, a torso all sinew and strength.
With his wings he pressed himself upward through the thick, weary air, surveying the water and its gray, ragged rocks, the black graveled beach, and dun mazy dunes. A few horrid creatures slid through the dark oily waters, their sharp senses tuned, their quick brains devoted to the endless quest of nourishment gained ultimately at one another’s expense.
The gleaming newcomer tilted his pinions, banked, swept lower over the face of the water. Behind him, sunk perpetually half below the horizon, a fat misty sun glared redly across dim, dispirited ripples. Greedy tentacles whipped upward from beneath the surface of the sea. The tentacles were as thin as wires, as agile as wolf eels, as powerful as woven steel. The great winged man eluded them with casual ease, rose a short distance above the dark, coarse beach, and dropped softly onto the cinder-like gravel.
At once a spider crab the size of a man’s doubled hands sprang from its lair and shot at his softest parts, black pebbles clattering back against the beach. The man seemed not to notice the predator. Carelessly, he turned to stare in moody silence across the dull dunes, his shadow long and black before him outlined by the dim red glare of the dying sun. The man’s turning, easy and nonchalant, seemed somehow to disconcert the leaping predator. The man’s hand caught it an almost accidental blow and sent it skittering back onto the gravelish beach, where it landed with a clatter on its back and began at once to struggle frantically. Even so the crab had not righted itself before a dozen rival predators had attacked it from all sides, tearing away its waving claws and then boring through the exposed opening in its carapace to find the soft nourishment inside.
A hundred strides down the beach, there was a sudden pop as a globe like a shimmering great soap bubble appeared just over the black cinders, hovered and shook briefly, then exploded softly. From within it a couple set foot upon the strand. They stood, gazing tentatively for a while at the winged man, then began carefully on quivering pipestem legs to make their way toward him.
The winged man advanced to meet the newcomers, his great muscular strides devouring the distance that their tiny thin legs could barely nibble at. The couple seemed to be man and woman, but each showed only vestigial characteristics of gender—or of their animal nature at all. Their heads were huge and domelike, with only the lightest suggestion of down above the ears. Their ears were huge and moved as if of their own will; their eyes were tiny and deep sunken, but still they blinked and squinted in the dim red sunlight.
Above there was a screaming roar as a great black ellipsoid half-appeared, circling over the beach, growing alternately more and less solid in appearance. The noise that the object made faded and grew in concert with its growing and lessening solidity. Great aerial screws held the thing above the beach, and multi-faceted gemlike surfaces slowed and dimmed as it moved this way and that through the heavy air.
Slowly the machine seemed to stabilize in the air, then to lower itself carefully until it had come to rest on the strand. One of the jewels in its skin revolved slowly then, rolled away from the ellipsoid and lay against the black, dull surface of the machine.
A small party of people slowly emerged from the machine. They wore dark, form-fitting garments marked with red hexagonal insignia. Their outfits included black pointed hoods that largely concealed their faces; what could be seen of these showed them to be as black and dull as the clothing and the ship in which they had arrived.
For what seemed like hour upon hour they arrived. Some by strange, grotesque vehicles. Some by spectacularly announced projection. Some by chronion gas, or drugs, or spiritual exercise, or by sheer mental power. Some involuntarily. Some unknowingly. At one point not far inland from the beach, across the first row of dim, ugly dunes, there suddenly appeared an entire city. Its towers were of white marble and shining glass, its gates were of yellow horn and blackened teak. Its people had pale yellow skin and wore robes of indigo and gold.
When it appeared inland of the beach, the city’s rulers climbed to the highest point of its highest tower and gazed into the center of the glowing, half-hidden sun, and sent his chief advisor to have himself let out through the yellow horn and teakwood gates, and make his way to join the others on the beach, and confer with them.
We are here, the man from the city of towers said as he approached the others standing on the beach. It seemed a pointless comment; he did not himself know what he meant.
The nearest to him, a woman of the black ellipsoid, turned her black-hooded face toward him. She nodded. All, we are all here. Your master and your people will not leave their city?
The other shook his head in the universal sign, his indigo robes rustling.
It is time that he arrive, another voice said. The two turned to see whose it was. The speaker was one of the wizened couple. It is time, the speaker’s companion added. Time, the first said. They nodded.
He is coming, a voice asserted. There was a rustling all up and down the beach. He is coming, is coming, is coming, voices echoed, whispered, shivered back to silence.
It is time, the golden, winged man said. He raised a muscled arm, pointed across the oily sea. Where half the sun’s blood-red disk stood in changeless demi-sunset, a black circle had rolled along the
horizon and now stood in the center of the sun like a black hole punctured in a red bull’s-eye target.
A chorus of intaken breaths were drawn.
The travelers on the beach—there were scores now—drew themselves into a great half-ring. The tiny, spindly-legged couple from the shimmering bubble stationed themselves facing each other, forty paces apart at the edge of the sea. Tiny wavelets lapped at the edges of their soft-shod feet, leaving a residue of pinkish foam on the pliant, leathery slippers that the wore.
Between them, strung in a gentle curve, were all the others. The black-clad, hooded figures from the gem-doored ellipsoid, the men and the women who had arrived by time-gas and by time-drug, by time-quake, and by time-slip, those who had arrived by machine, those who had arrived by mind, one who had risen naked and weeping from a great glass coffin of cushions and of blossoms, and one who had struggled wild-eyed and screaming from a barrow beneath the black cindery beach itself, the indigo-robed seer from the city of towers, and the winged godling from the sky above the water.
There was a hush as they all stared at the black disk upon the red disk, the stripes of color reflecting from them across the face of the oily sea to the edge of the black cindery beach. Then a voice broke the silence. How will we know him, the voice asked.
By his face, one replied. By his haggard face, his bruised face, his face of despair.
By his clothing another said. By his quaint clothing, his rough cloth trousers and oddly buttoned jacket and the strange cloth cap he wears on his head and the stranger cloth streamer that he ties about his throat.
By his machine, a third claimed. By his strange, squat, ugly machine that looks all askew with its ivory bars and its brass railings, its shining rod of quartz and its odd ugly saddle.
And how will he know us, the seer from the city of towers asked to know.
We will call him by name. We will call him Nebogipfel.
Nebogipfel.
It was as if the name had summoned the man from out of time’s grasp. In the center of their half-circle he appeared. The time traveler and the time machine. The machine was truly squat and ugly and askew. The traveler bore his face of despair.
He rose from the saddle of his machine, slid the starting level carefully into a notched position and locked it there. He stepped onto the crunching gravel, stared at the black disk that stood before the sun’s blood-red demicircle for a little while, then wheeled slowly, gazing at the face of each of the many who had waited to greet him.
He shook his head sadly.
Is this—? He gestured with both hands, holding them as far apart as his feet were spread on the black cinders. The palms were turned toward each other.
Is this—all? Is this—the end? The end of it all?
He pointed at the red, dying sun with the round black blemish now rolling slowly past its center, toward the edge where the dim glare faded into the blackness of the sky. He moved his hand so that the eye that followed was led across the oily surface of the sea, where only the occasional furious eruption of predator and prey broke the red-trimmed mourning field.
All striving, all dreaming, all thought and suffering bring us to—this?
He gave a shrug of hopelessness. A rictus tugged his face into momentary hideous grin.
But we had greatness, one of the others challenged. In my time—in my time men built cities that towered above the tallest trees, filled their halls with philosophers and actors, musicians and tumblers, and living, naked tableaux. Our glories were recorded on parchment and canvas, in marble and in granite. The world he beheld us and—
Trembled? Nebogipfel supplied.
No, the other shook his head. No one trembled before us. The world smiled in joy, traded its goods for our art, sang the praises of our creators. We were beloved of the whole world. This was our greatness.
And now? Nebogipfel asked. And now? What is there now of your greatness?
The other was silent.
In my day, a different voice spoke; in my day, we marched! The voice was harsh, strong, confident. All who stood before us, we slew! The rest we made slaves! In my day none could resist! We were the bravest, we were the strongest, we were the hardest! We were never beaten! Never! Never! Never!
Well, said Nebogipfel. I bow to your splendor. I am dazzled by your might! Your empire stretches before me and I cringe in awe. He swept an arm, encompassing black cinders, blood-red waters, black sky.
In my day, another claimed, we saw these limits. Yes, we had our time on the earth. We dug and we learned and we saw that we had not been the first, and we knew that we would not be the last, either, unless we burned the world and left behind only a dead stone. So we built. Not cities! No! Not fortresses! We built argosies to other worlds, ships to sail to other stars, bolts to carry our seed from the loins of this world to the wombs of a million waiting mothers scattered across God’s whole realm! Down into the dust for us, down into the dust, but our children live! Yes, they live yet on a million stars in every direction!
And yet we just begin! A million stars? What did your age know of the universe, Nebogipfel? How many worlds did you visage? Seven? Seventy? Seventy thousand?
A billion worlds, Nebogipfel, a billion worlds in one cinder!
The speaker bent and lifted a blackened pebble from beneath his feet.
What are a billion of these Nebogipfel?
He hurled the cinder at the tweed-suited time traveler in the center of the ring. The cinder struck Nebogipfel on the cheek, split the skin above the bone and fell, clattering onto the beach. A narrow trickle of blood dribbled down the time traveler’s face and soaked into his soft shirt collar.
The time traveler smiled.
A billion suns? Nebogipfel asked. What are ten billion billion suns? How long will they burn? Ten billion billion years? And then—what?
He threw out an arm, gesturing across the sea.
This?
The black disk had transited the half-set redness; a little warmth returned to the tired, musty air.
And after this? In another hundred thousand years, or another hundred million, even this ends.
He pulled his soft cloth cap from his head. Straw-colored hair stuck up in all directions. The time traveler drew the cap across his face so the smooth silken lining covered his eyes. He bowed his head, face still covered, shoulders slumped, the image of a mourner to his own inevitable end.
But our children! The other exclaimed.
Nebogipfel did not move.
The other stared, stricken, at the dying sun. Around him the ranks of the assembled time travelers stood silent and motionless.
Then our grandchildren! Our great-grandchildren!
Nebogipfel did not move.
The travelers remained in silence.
One of the two pipestem-legged travelers advanced across the black cinders, unsteady limbs quavering with every step. The figure halted, facing Nebogipfel, staring up at Nebogipfel, who stood twice the height of the other.
The taller figure lowered the cap from before his eyes and stood, holding it in his hand, looking downward into the great, solemn, squinting-eyed countenance. An involuntary grin worked its way across Nebogipfel’s features.
Yes?
We knew you were coming here today, Nebogipfel. Why do you think this assemblage awaited you? Do you think that these travelers from so many eras, so may races, so many civilizations, all happened to arrive here on this beach, today, by chance?
The tiny mouth drew back in a wry expression.
Nebogipfel tugged his cloth cap back onto his straw-colored head. I suppose there was a plan of some sort, then, he said. He drew himself up to his full height so he towered more than ever over the tiny figure. This is the end of my journey, Nebogipfel said. I miss the London of my era. I lost my Weena. I hate the world of AD 802,701, and every later age I ever visited only made me more laden with gloom, more burdened with hopelessness.
All I want is to go back to my home. Here—
He slapped
a hand on the saddle of his time machine, setting the whole thing to quivering and tipping as if it were about to tumble into the black cinders or the blood-red water.
That is precisely what you must not do, the tiny figure piped.
I shall board again with Mrs. Watchett, Nebogipfel said. I shall contribute another seventeen papers on physical optics to the Philosophical Review. I shall become the most ordinary of men among ordinary men. No more shall I see the white sphinx.
There you are wrong! the little being piped. Officiously, he gestured and men and women moved forward from the semicircle that stood surrounding Nebogipfel. Strong arms seized the original time traveler. Cords appeared and he was bound and placed on the saddle of his machine.
We are all time travelers, Nebogipfel, the little being said. But you are the prototype, you are the ideal of whom we are all faint reflections. You say that you despair of the ultimate end of life. What would you call it? Some would say, the ultimate entropy. Some would say, the heat death of the universe. Some would say, the cosmic nirvana.
But your own philosophy says, there is no forever. There is nothing that endures unending. When the universe reaches its end, Nebogipfel, what lies beyond the end? What lies beyond the end?
Again the little being gestured. A hand moved an ivory bar on Nebogipfel’s time machine. Another turned the glittering quartz rod.
Nebogipfel shouted. No! Send me back! Send me back!
But the other said, Yes! You must go on, Nebogipfel! Once you have tasted of futurity, there is no returning! You must go onward, not back! What lies beyond the end, Nebogipfel? What lies beyond the end?
A tiny hand gestured. A powerful hand reached, unlocked the starting lever of Nebogipfel’s time machine. The lever was thrown. Nebogipfel shouted. The machine and its rider flickered, faded, disappeared from the beach.
The tiny figure returned to its place at the edge of the pink foaming sea.
None of us will know, one of the people standing there said.
Nebogipfel knows, another said.