Author's Note

This story begins around the middle of Season 3. It will probably end in the middle of Season 4. I will do my best to make everything as consistent with canon as I can.

1. Parallel Experiments

Monday, September 13, 2021

"Let's hope this works", Twilight said as she surveyed her latest invention. She had been working on building a lasting portal between her treehouse home in Ponyville and the Magicians' Guild laboratory in Canterlot for weeks now. Teleportation worked well as a means of quick transportation, but it required recasting the spell every time, and was very tiring to do frequently. With a portal, Twilight hoped, she and others could move quickly and easily between faraway places with only minimal effort. Unfortunately, portals had proven to be maddeningly difficult to produce. Maybe it had something to do with the fact that nopony had ever done it before, not even the greatest unicorns.

Twilight's first attempt had been the simple brute force approach to magic: just keep throwing more and more power at something, with minimal direction, until it does what you want. That method worked for a few simple things, but more often than not the power simply released in the form of an entirely different spell than the one intended. Twilight had read many horror stories about uncareful unicorns setting fire to their homes or to themselves. Twilight had no intention of letting that happen to her. But sadly, even the Element of Magic herself can't get her way just by flooding an area with too much magical energy. There were no fires to deal with, but one wall of Twilight's basement was now twisted and warped into a beautiful, but rather unhelpful, non-orientable surface.

After that, Twilight had tried using an ancient style of magic that hardly anypony used anymore: geometrical rune magic. The unicorns of the ancient era, before Celestia, before even Discord's rule, had drawn diagrams and pictures to help them focus their magical energy. According to the one book Twilight had on the subject, anyway. Not much of recorded history had survived the age of chaos. Mostly it came in the form of spoken tales passed down over the generations, such as the story of the founding of Equestria and the first Hearth's Warming.

Every still-flat wall in Twilight's lab was covered in various diagrams and designs. She tried a pentagram, most commonly used for summoning spells, to see if she could somehow “summon” another place and anchor it to the place she was standing. There was no effect at all. She drew a triquetra, a trefoil knot with a circle wound through its loops, symbolizing the three kinds of ponies and their interconnectedness. Twilight speculated that this bond was related to the magic of friendship that she studied, so perhaps she could extract something useful from the shape. But even this was not to be. The three loops of the knot flared different colors, and then the entire triquetra faded into nothingness.

Twilight had really liked the triquetra idea, and she kept returning to it in the hope that somehow, this time would be different. It never was, apart from the varying colors of the disappearing shape. But there had to be a way. Maybe if the magic number 5 from the pentagram was not enough, and the power of 3 from the triquetra wouldn't do the job either, maybe she could somehow combine them.

A few days and many pages of abandoned drawings later, Twilight had come up with a new idea. A figure that had either threefold or fivefold symmetry depending on the way you looked at it. A shape the geometers and mathematicians respected and feared, for it wreaked havoc on countless otherwise elegant theories. A figure so full of magic that Twilight was surprised she had never read about anypony using it in a spell before. The Petersen graph.

“This had better give me a portal,” Twilight muttered to herself. “It's a counterexample to so many nice ideas; now let's make it an exception to space itself.” She concentrated on the chalk figure and began to perform the latest version of the spell. She pictured in her mind a perfect image of her intended destination, just like for a teleport spell. Her horn began to glow a soft purple. Instead of the usual trick of envisioning the destination image expanding into the space all around her and using a surge of power to make it a reality, Twilight tried to “push” the picture out of her mind –not like forgetting it or thinking of something else, but literally moving the image of the Canterlot lab out of her head and onto the wall in front of her.

The unicorn's horn glowed brighter. "Just a little farther," she whispered. "Just another hoof and I'll have it on the graph. Then comes the really difficult part." She allowed herself a small sigh, careful not to break her focus. She pushed her mental image onto the diagram and locked it in place with a parallel spell, as she had grown accustomed to doing in previous trials.

With the destination established, Twilight turned to the next stage of the spell: providing the power necessary to twist space and move all that annoying distance out of the way. Where that distance would go afterward, she had no idea. Anywhere but between her and Canterlot. She glared at the wall as if daring it to defy her will, and flexed her magic equivalent of muscles as hard as she could. Her horn's glow intensified through several more shades of purple and started emitting white sparks. Every surface the sparks touched seemed to distort just a little bit, as if trying to break free of reality's grip but being quickly brought back into line.

Twilight noticed a strange sensation spreading throughout her body, a sort of lightness. Maybe the floor had been replaced with clouds and she was somehow standing on them, or even floating in midair. She didn't dare look down to check. Fringes of black crept into the edges of her vision. It was only then that Twilight realized she had been holding her breath since the spell began and was about to pass out. She quickly relaxed her hold on the spell and forced some air into her lungs. The cool, crisp air felt wonderful, but she was still a little lightheaded. She closed her eyes for a moment and–

"Twilight! Twilight! Are you there?" A faraway voice called to her. Twilight opened her eyes, but saw only the stone floor and the bottom of a table in front of her. The area under the table was filled with a truly surprising number of dust bunnies. Mental note: add “clean basement” to tomorrow's checklist, Twilight thought. Better yet, add it to the monthly schedule. This place is disgusting. She would have been perfectly happy to plan out the entire new schedule right there on the floor, if not for that voice again, calling to her. “Twilight? What are you doing down there? That's a strange place to take a nap.”

Twilight quickly scrambled to her hooves and turned around to see Spike standing on the stairs. “I– I was working on a spell... I guess I was trying a little too hard. How long have I been down here?”

The dragon stopped to think. “Um... a few hours at least. You came down here to work on that spell again right after breakfast today, and it's a little after noon already. Want to get some lunch?”

“Oh, I'm sorry, I'm not really that hungry at the moment,” Twilight replied. “Magic can be hard work, but it's not really the kind that gives you a big appetite. Why don't you go get yourself something nice to eat, and I'll join you a little later. I want to try this one more time.”

“Okay! See you later, Twilight!” Spike made his way back up the stairs and disappeared onto the main floor of the library.

Now, where was I? That's right, the Petersen variant. I could feel the power in that one; it should have worked. Twilight sighed in frustration. I can be so stupid sometimes. Seriously, forgetting to breathe –who does that? She positioned herself in front of the diagram again. Breathe in. Breathe out. Destination visualized... placed on graph... locked in. Breathe in. Breathe out. Magic energy building up... a single white spark appears. Breathe in. Breathe out. More power, more sparks. Twilight willed the magic energy toward her target and watched in satisfaction as more and more sparks landed on her diagram. She heaved another deep breath and prepared for the final push of energy.

Twilight's horn was enveloped in a brilliant sphere of light. White beams spread outward in every direction. The lines on the wall in front of her each glowed with constantly shifting iridescent color patterns. In the center of the diagram, Twilight saw what looked like a ragged hole appear and slowly grow to fill the entire graph. Through the hole, nothing was visible, just perfect blackness. The black was deeper than any Twilight had even seen before: blacker than King Sombra in a cave on a cloudy night, blacker than the view through closed eyes while blindfolded. It was as if, within the hole, light simply did not exist.

That doesn't look like Canterlot... Twilight was confused. She was sure she had cast the spell correctly. Maybe it's not possible to bring distant places into perfect contact, and this is the minimum possible separation. Something anypony can step through easily if they try but enough to prevent accidental crossings. I'll have to study this in detail later –but for now, I should just go through. Despite her confusion at the odd appearance of the portal, she was elated at the thought that finally she had done it. Twilight Sparkle had invented the first portal spell! That was a major point on the checklist she could finally check off.

Still, there was something vaguely unsettling about that region of nothingness. Twilight couldn't quite place the reason, but nevertheless she briefly entertained doubts about whether this portal really was what it claimed to be. Come on, Twilight, don't be scared of your own magic. What could possibly go wrong? She asked herself the question that must never be asked. For that question demands an answer, and the universe is rarely merciful in providing one. Twilight, oblivious, stepped forward and entered the blackness.

۞ ۞ ۞

It was an important day at the SMAC lab. The newly built Superheavy Matter-Antimatter Collider was scheduled to be turned on for the first time that afternoon, and physicists everywhere were waiting in suspense to see if it would work as planned, and making bets with each other about the kinds of new discoveries that would be made. As with every new particle accelerator, the media worried about the formation of Earth-swallowing black holes, or cancer-causing stray radiation, or countless other wild speculations not grounded in reality. The unanimous opinion of the experts, that there was absolutely nothing to worry about, was not sensationalist enough to merit being printed. The truth was, operating at only 102 tera-electronvolts, SMAC was still a hundred million million times too weak to produce a black hole. The goal was to search for extremely high-energy sleptons and bosinos: the final test of the popular, but so far unsupported by evidence, theory of supersymmetry.

“Five minutes to beam.” An announcement came over the loudspeakers. The control room, already buzzing with excitement, was stirred into an even greater frenzy. Everyone crowded toward the middle of the room to get a better view of the main screen, which would be showing a real-time visualisation of the first beams and collisions. Everyone except Dr. Csilla Ziegler, that is –as director of the research program, she had to be at her desk to start the beams. There was no dramatic oversized lever to pull; instead it was simply a mouse click.

“It's almost time... Let's get this thing started.” Zai, a physicist, looked at her watch impatiently. The watch's second hand ticked slowly around. Too slowly. For what seemed like an eternity, Zai stared at the little glass face. Eight fifty-six. Eight fifty-seven. Eight fifty-eight. Three seconds before the eight fifty-nine mark, another announcement was made. One minute to beam, it said. I knew that watch was going too slow!, Zai thought triumphantly. Three whole seconds behind. But sadly, even setting every clock in the world forward wouldn't make time pass any faster.

Finally the moment came. “First beam activated,” blared the loudspeakers. All eyes turned to the screen on the front wall. The screen showed five circles of widely varying size, representing the SMAC tunnel and all the smaller accelerators that came before it, all connected together. A blue dot appeared in the smallest circle and began circling around faster and faster. After a few seconds, the beam of lead nuclei reached the top speed that little accelerator could provide, and whizzed off into the next one in the sequence to circulate even faster. And then the next, and the next after that. The beam was now in the second-to-last circular tunnel, the old Large Hadron Collider, and was crossing back and forth over the Swiss-French border eleven thousand times per second. Finally the SMAC circle on the screen lit up with a brilliant blue glow. The biggest machine ever built was working properly.

“Second beam activated,” Dr. Ziegler announced. This time, a red dot appeared on the screen, meaning anti-lead nuclei. The dot circled through the smaller rings until it reached the LHC, and then it too passed into the largest tunnel, but in the opposite direction from the first beam. The director made another anticlimactic mouse click to adjust the magnetic fields in the ring ever so slightly, then turned to her microphone again. “We have collisions. The Superheavy Matter-Antimatter Collider is operational.”

The crowd of physicists, mathematicians, and engineers erupted into cheering. Around the world, similar groups opened bottles of champagne, and the optimistic among them collected their bet winnings. All attention was focused on the screen, so nobody noticed the small black spot hanging in midair behind the crowd, slowly growing. A spot of such perfect black that its exact shape was impossible to determine, for no light reflected off of it to give an impression of depth. The emptiness grew to more than a meter across, then stopped. But it was no longer empty, for a figure moved within, a nearly invisible shape of regular black set against the infinite darkness all around. The being approached the edge of the hole, hesitated for a second, then stepped out into the room.

۞ ۞ ۞

Twilight was lost. She had never seen or read about this place before and had no idea where she might be. Around her, there was only blackness, but in the distance she could see lights. She looked down and there was no ground, only black space with more shapes of light far below. Behind her there was a single light, seeming to be much closer than the rest. In the center there was a pentagonal region through which she saw her laboratory in Ponyville, and all around it Twilight could see other places in Equestria, diminishing in size the farther out she looked from the center.

Could this really be all of Equestria laid out before her at once? A great glowing disk hanging in the nothingness, and Twilight was above it all. Was this the aether, where the sun, moon, and stars resided? But that was impossible –according to Rainbow Dash, a pony could go as high into the sky as she wanted and never get any closer to the stars. She knew because she had tried it. Twilight looked closer and thought she could make out some tiny points of light, mostly obscured by the face of Equestria behind them. They looked almost like stars, except they were between her and the ground. But then she saw two great shining circles, one golden and one silver, which could be nothing else but the sun and moon. There could be no more doubt: Twilight was on the other side of the heavens.

How did this happen? She thought frantically, heart pounding as the realization sank in. I wasn't trying to go here. I didn't even know this was possible. Does Princess Celestia know about this place? She turned and began walking toward Equestria, but stopped after a few steps. She turned back and looked around at all the other patches of light all around. Was every one of these a whole world like Equestria? Maybe writing to the Princess about this place can wait a little. I should try to learn more before I go back. Twilight sat down on the nonexistent ground. That seemed like as good a start as any, figuring out why she could stand and sit and walk in the midst of all this nothing.

Twilight looked down at where the ground should have been, only to find that she could not see her hooves. She twisted around to look at the rest of her body, but that too was seemingly missing. She held up one hoof in front of her face. She had the distinct sensation of having one hoof held up, but she saw nothing where it should have been. She waved the hoof in front of a distant world and sighed in relief as the point of light was blotted out –that meant she was not invisible or incorporeal, just somehow coated in the same blackness that filled this place. I hope this washes off, she thought. I don't really want to be solid black forever. And Rarity would throw a fit if she saw me like this.

The thought of her friends made Twilight start to worry again. It seemed like ages since she had left Equestria, though she knew it had only been a few minutes. Sure enough, the sun and moon had not moved at all. Spike probably hadn't even finished eating lunch yet. Twilight decided she should go take a closer look at one of these other nearby worlds. But which one? From this far away, they all looked mostly the same. The only distinguishing characteristics seemed to be the overall shape of the world and the type of heavenly bodies above them.

Maybe that spherical world over to her left, with a sun and three moons –a white one, a red one, and a black one. A round world would be an interesting contrast to Equestria's flatness, and four Princesses would surely have interesting things to say. Twilight was walking over to the other world when suddenly a great flash of light came up from below her. She looked down in alarm and saw that the light seemed to be originating on the surface of yet another spherical world far below. On second thought, maybe that one would be the best world to visit. But how would she get down to it?

Twilight screamed in surprise and dismay as the “floor” under her vanished. She was falling through the nothingness at an alarming rate. Don't panic, she told herself. It will be okay. There's no bottom to crash into. But that was little consolation, for she could easily imagine falling forever, never able to return to Equestria. Her friends would miss her, never knowing where she had gone. And Twilight would miss them too. And what if Equestria needed her magic again? Twilight didn't want to keep falling forever.

And suddenly, she was standing on solid nothing again, instead of falling endlessly through the blackness. That's strange, she thought. Strange, but good. I stopped falling! She grinned and did a little dance. All she had to do was really want to stop, and she did. Twilight realized that her descent had started at the exact moment she decided she wanted to go downward. Maybe I have more control over this place than I realized. Let's try this... I want to go to the source of that flash of light. Twilight immediately found herself flying in the direction of that strange world. The sensation was not nearly as pleasant as Rainbow Dash always said flying was –in fact, the unicorn was starting to feel a little nauseous. Change of plans, she thought. I don't want to go toward the light, I want to already be at the light.

And so she was. With no effort at all, she had teleported across a vast distance and was now standing before the foreign world. With an event that powerful and unusual-looking going on below, somepony probably needed help, and now Twilight Sparkle was here to provide it. She thought about opening a gate into that world, really wanted a gateway inside to open up... and one did. A pentagonal region just like the one she had created in Equestria. She stepped forward cautiously, unsure of what she might find on the other side. Just before the portal, she hesitated –was this really a good idea? It was, she told herself. Now that she knew how that strange nothingness worked, she could return to Equestria at any time if she needed to. For now, she wanted to help out the ponies of this other world, and learn from them. She took a deep breath and took her first steps into the unfamiliar surroundings.