YESTERDAY'S ENTROPY
by NorrisThePony
Twilight Sparkle let out a gleeful shout and dashed from her study into the main section of her castle's library, where Spike was idly flipping through the latest issue of Power Ponies with his feet on a newly polished glass table
"I did it!" She screamed with delight, grabbing the startled baby dragon and spinning him around her in a magical aura. "It took me weeks, but I finally did it!"
"That...that's great, Twi." Spike managed once the overjoyed alicorn finally set him back down, his head spinning. "Did what, exactly?"
Much to Spike's annoyance, Twilight didn't answer him directly and instead grabbed him in another magical aura and began dashing back to her study.
Twilight's private study was a smaller section of the main library, the walls lined to the roof with spells, scrolls, and history books. Nestled in one corner was a lit fireplace, with two large armchairs facing the roaring flame. Spike groaned in frustration at the sight of dozens of books thrown carelessly throughout the room, and the large mountain of crumbled parchment paper next to an overflowing trash can. Twilight herself was in a similar state of disarray, her mane wild and disheveled, and deep bags under her bloodshot eyes.
"Have you been in here all night?" Spike asked, glancing at one of at least fifty clocks mounted on a wooden desk.
"Oh, much longer than that!" Twilight said matter-of-factually, while sifting through a sea of paper sloppily tacked to a cork-board. Finding what she was looking for, she thrust the page towards Spike wearing a massive grin which, coupled with her twitching blood-shot eyes and wild hair, was quite intimidating.
"This is what you've been doing all week?" Spike questioned, not even bothering to take the page being handed to him. From a quick glance, he saw nothing but scribbled numbers and equations, and he really didn't care enough to try and figure out what they meant. "Twilight, half of Ponyville thinks you've gone missing. What can possibly be this important?"
"I was hoping you'd ask me that!" Twilight laughed hysterically, whipping around, nearly tripping over an overturned coffee table, and grabbing a ruled notebook. Spike saw more complicated calculations as Twilight leafed through the notebook while explaining in a voice that seemed to be growing higher in pitch by the second.
"You might remember about a month ago when Celestia gave me this." Twilight sprinted across her study, grabbing a framed parchment from the floor and placing it on the desk in front of Spike and herself. "Would you like some coffee, Spike?"
Spike looked at the kettle of boiling water atop the fireplace and the dozens of paper cups strewn around the room and shook his head.
"Isn't this...the time travel scroll from the Starswirl the Bearded Wing, at the Royal Canterlot Archives?" He asked, grabbing the framed parchment and inspecting it closer.
"No..." Twilight replied. "Although it looks just like it, I agree. This is a different scroll altogether, but it's still a creation of Starswirl the Bearded. And it's purpose is...similar...to say the least."
"Oh no..." Spike muttered, clearly seeing what Twilight was suggesting. "You don't mean..."
"It's a time travel spell! But, unlike the one in the Canterlot Archives, this one is untethered."
"Untethered? What does that mean?"
"It means, when a pony uses it to send themselves back in time, they won't be pulled back to whatever time they came from after a few seconds. They'll be stuck in whatever time they chose to travel to."
"And where does all this come in?" Spike motioned to what was once an organized study room.
"It was one of Starswirl the Bearded's unfinished spells, dating back to 267 After Luna. Most ponies doubted it even existed, because nopony could ever find it. Starswirl himself claims that it vanished, and he knew precisely where, but he refused to ever tell anypony. Most ponies concluded he made the whole thing up to give himself more credibility, and the scroll was forgotten. That is, until a few months ago, when Celestia found it amongst her paperwork and letters. Despite its random appearance, Celestia wasted no time in sending it to me to complete...and, Spike, I think I have!"
"You....you WHAT?"
"It's all pretty hard to explain, and I'm not sure how to test it per-say. Like I said, its untethered, which means you need a time travel spell to bring you back to whatever time you came from. I'm working on reversing the polarity of this particular spell so that we can travel into the future as well as the past...Spike, this just might be the most important scientific discovery in Equestrian history!"
"I'm happy for you, Twi." Spike said, and despite his skepticism, he truly meant it. "But I think you really need to come out of the library. Everypony is worried sick about you, the kitchen is completely empty, there's a pile of paperwork from Canterlot you need to sign, the Mayor needs your approval for repair work on the Ponyville-Canterlot express train..."
"Yes, yes!" Twilight seethed impatiently. "Tell her yes. I haven't forgotten my duties as a Princess, you know! But I'm still a student of magic, and a student of magic sees matters like these through to the end!"
"Just...don't do anything crazy, Twilight."
ONE WEEK LATER
"So...what exactly is it Twilight wants us here for?" Rainbow Dash groaned, tapping a hoof against her chair impatiently. All five of Twilight Sparkle's closest friends were seated in a circle in the main throne room of Twilight's Castle. Spike and Twilight's thrones were the only unoccupied spots, and they had been for the entirety of the thirty minutes they had been there.
"She didn't say, specifically." Rarity replied, glaring at Rainbow's atrocious etiquette but choosing not to criticize it. "Although she made it sound quite urgent in her letter."
"Well, if its so urgent, why is it taking her FOREVER to come out of that library? Why invite us for diner, not actually eat diner, and instead stay locked in her library for the whole night?"
"What if something happened?" Fluttershy asked, casting a suspicious glance down the hall towards the library. "M...maybe we should go check to make sure she's alright. I haven't seen her all week, maybe something really bad happened..."
"Fluttershy does have a point. I'm going to ask what the hay is going on." Rainbow declared, rising from her seat and stretching.
"Rainbow, it is simply rude to—"
"Ah'm with Rainbow and Fluttershy on this one," Applejack said, rising to her own hooves and following Rainbow Dash and Fluttershy down the hall. Pinkie Pie took one glimpse at her departing friends and quite literally bounced into action, following close behind. With a mighty sigh, Rarity gave up and pursued the rest of her friends.
As the five ponies approached the library of the castle, the faint sound of small objects being thrown around recklessly rung out from beyond a half-closed door.
"What the..." Rainbow muttered, slowing her pace and glancing back at her equally bewildered friends. Twilight's ranting voice could be heard even through the loud banging of objects against the wooden floors. Although her words were indecipherable, it was clear to everypony in the hall that she was extremely upset about something.
The creaking of the library door caused nearly every pony but Rainbow Dash to jump in fright, and Spike regarded the gathered ponies first with surprise, and then relief. Carried in his arms were piles of scrolls and broken quills, all worn down due to what must have been some seriously intense writing.
"Oh, thank Celestia." He said, using his tail to close the door behind him, slightly muffling Twilight's inane rambling.
"What the hay is goin' on?" Applejack questioned, raising an eyebrow as a particularly loud crashing noise echoed through the hall.
"Twilight's completely lost it, that's whats going on." Spike sighed, setting the scrolls down gently. "I was just about to ask you girls to go in and talk to her, but she said to wait until 'precisely 7:37 PM.' I'm not joking...I don't think I've ever seen her get this worked up about anything."
Rainbow Dash took a cautious step towards the library door, taking a deep breath before pushing the door open.
Twilight Sparkle was still muttering to herself, a dozen scrolls and quills hovering around her while she wrote interchangeably on every single one. Several abacuses were also caught up in the hurricane of writing utensils. She stopped immediately as she saw Rainbow standing in the doorway, and allowed all the materials floating around her to tumble to the floor of the library, which was once wood but now was comprised of paper and books.
"Uhh...heya, Twi..." Rainbow started nervously.
"You're here! But...but, of course you're here, I invited you. I did, right?"
"Y...yeah?"
"But that was..how long ago? Rainbow, tell me how long ago I asked you to come to the library."
"I don't know...about an hour ago? Maybe a little longer?"
"Have you noticed anything? Anything at all about how long its felt as opposed to how long the clocks say its been?"
Rarity cleared her throat gently stepped further into the library, Twilight for the first time noticing her other friends and giving them a curt nod.
"Twilight, darling. What ever are you talking about?"
"Entropy!" Twilight seethed, and in an instant she was again pacing, the tornado of supplies instantly coming back to life around her. "That's what I'm talking about! I...I've made a big mistake...I need to fix this before it's too late."
"Fix what?" All five of Twilight's friends cried out in unison.
"Entropy. The arrow of time." Twilight replied, once again letting her supplies fall and instead teleporting a black board across the room towards her. In a frenzy, she grabbed a piece of chalk and drew a straight arrow down the middle of the black board. "This is time, right? This is how it flows? Forwards. Its always flowed forwards. Even now, its flowing forwards." Twilight pointed to one of a dozen clocks placed on a slanted table. "Look at them. Pay attention to them. Remember EXACTLY what time each one of them reads."
"Twilight!" Rainbow practically shouted. "Snap out of it! This is 'Smarty Pants' all over again!"
"In her defense..." Fluttershy whispered in Rainbow's ear. "We were sort of ignoring a big problem that time."
"This is bigger than big!" Pinkie Pie said urgently from across the library, peering at one of Twilight's notebooks on the floor. "This is, like, the biggest problem ever!"
"How did she hear..." Rainbow gawked, and Fluttershy shrugged her shoulders. "Ergh, never mind. Pinkie, you know what Twilight's talking about?"
"Well duh, it's obvious, isn't it?"
"Umm, not really." Fluttershy replied, walking further into the library but deliberately keeping her distance from Twilight and the articles orbiting around her. Twilight's ears perked up at Pinkie's last statement, but she made no move to acknowledge the discord unfolding amongst her friends.
"Twilight is worried because the flow of time is all wibbly-wobbly!"
"Exactly!" Twilight screamed in relief, dashing over the Pinkie Pie and catching her in a violent hug which Pinkie gladly returned. "So you HAVE noticed! Good, good. Now then—"
A sudden, loud ringing cut Twilight off mid sentence, and the panicking alicorn dropped everything she was doing to sprint over to the table of clocks, motioning for every pony to look as well.
"What is it, Twilight?" Fluttershy asked, leaning forward to analyze the clocks further. "What are you—"
"Shh, shh! Not me, the clocks! Look at the clocks, remember the times on the clocks!"
With an exasperated sigh, Rainbow turned away and started back towards the door while everypony else stood transfixed at the clocks in front of them.
"Amazing." Twilight muttered, jotting something down onto a nearby notepad. "Exactly one minute and four seconds behind."
No pony spoke except for Twilight, who continued to speak aloud as she wrote more and more meaningless numbers onto random scrolls and notebooks. Rainbow turned back and was perplexed to see her four other friends still staring at the clocks. Rarity's mouth was open slightly in disbelief, while Applejack whispered something into Fluttershy's ear which caused the pegasus to let out a quiet exclamation of surprise.
"I see you've noticed." Twilight said apathetically, without even looking at her friends. Rainbow felt her frustration growing, until she felt like she was about to explode.
"Noticed what?!"
"How long until it happens again?" Pinkie Pie finally asked, breaking her silence and joining Twilight's panicked pacing.
"What haven't I noticed?!" Rainbow Dash practically screamed.
"An entire minute. Actually, a little more than a minute. It just...it just repeated. You...well, technically, everypony, just traveled back in time one minute and six seconds. It's been happening at such short time intervals that nopony, not even me, noticed. But I'm certainly noticing now."
Seeing the speechlessly confused expression on the cyan pegasi's face, Twilight facehoofed and motioned once again at the black board with the arrow.
"This is time, right? Time is like an arrow, it flies in one straight, linear, progressive line. This is how it's supposed to be."
"Yeah...?"
"Well, it isn't an arrow anymore. Time is still...well, it's still flowing forwards, but it's also skipping backwards. Like a scratched record, jumping back a bit, but then continuing forward. It's been happening every half hour. Time flows ordinarily for half an hour, and then jumps back..."
"A minute." Rarity cut in, pointing at the slow clock in front of her. "But...why are you so...frazzled about this, Twilight? I mean, surely there is no harm in simply repeating a singular minute for a few hours until we fix this?"
"I would agree with you, Rarity." Twilight said gloomily, slumping onto the ground in defeat. "But it isn't just a minute. It started as just one second. And then, every half hour, it multiplied. After an hour, we were going back four seconds. After two hours, a minute. The next jump will be four minutes and sixteen seconds."
"O...OK." Rarity stuttered, internally running the calculations through her head. "So, the jumps are multiplying by four..."
"I'm sorry." Fluttershy said. "But I still don't see why it's such a big deal...can't we just go to Canterlot tomorrow and—"
"Because there won't be a tomorrow! We're going forwards a half hour and only back a minute now, but that time will keep multiplying. So what will happen when that time is more than half an hour?"
"We..."
"We'll be going backwards!" Pinkie screamed in Fluttershy's ear, somehow directly beside her despite being with Twilight a fraction of a second ago.
"Exactly." Twilight sighed, pacing back to her black board and erasing the arrow with a burst of magic. "In only an hour, we'll be jumping back seventeen minutes and four seconds. In two, we'll be going back four hours and thirty three minutes. In ten..." Twilight consulted one of her notebooks and immediately closed it again. "In ten hours, we'll be going backwards at more than two million years per half hour."
Twilight's statement was immediately followed by yet another set of dumbfounded glares from her friends, as everypony thought of some way to respond to such preposterous news.
"...but...Twilight..." Applejack piped up finally. "How old is Equus..."
"A little more than one million."
"Then what would happen if..."
"What do you think I'm trying to prevent?!" Twilight huffed, motioning around her at the insane disorganization that suddenly didn't seem so insane. "If we don't correct time, then we're going to completely overshoot the creation of...well, everything!"
Once again, dumbfounded silence met Twilight's grim predictions, as seconds ticked into minutes of wasted time. Twilight Sparkle would not allow herself to become too distraught with her own dark knowledge of their eventual outcome...no, she would stop this before it ever had a chance to happen. A simple reversal of the spell was all she needed...except...
"Couldn't you just reverse the spell?" Rainbow inquired. "That...that is possible, right?"
"Theoretically, yes. Practically...no."
"Why not?"
"Because I destroyed the spell!" Twilight snapped, her eyes beginning to water and her voice cracking slightly. "I...it was an accident. I wasn't trying to reverse time or anything. And I definitely underestimated the power of that stupid box!"
"Box?"
"Yeah, box! The one that this whole castle grew from! I've been using it to power this place for months...free electricity is free electricity. So when I used it to help me rewrite that scroll, I really should have known—"
"Wait, wait." Rainbow Dash groaned. "You used ELECTRICITY to rewrite a scroll? Are you telling me that this sucker is electrical?"
"No, no, no. This sucker is magical. But I needed to use the electricity to reverse the direction of the time scroll. You see, it's great being able to time travel backwards into the past, but I needed to find a way to allow for the user to return to their own time when they were done. I thought it would be a simple case of just duplicating the spell and using the electricity to negatively charge the scroll. I...may have overloaded it. It was an honest mistake!"
"You negatively charged the universe," Rainbow said, chuckling without much humor. "I think that gives the word 'mistake' a whole new definition. So what do we have to do to fix this mess?"
"Step One! We need to remain calm! Panic and confusion isn't going to help under any situation, unless that situation is a problem that can only be solved by panicking and being confused. Step Two...I honestly don't know. The time travel scroll was set on fire as soon as I started my experiment, and without it, I just don't know what to do."
Time Elapsed: 2hrs 17min
Next Temporal Displacement: 4m16s per ½h
A loud rumbling was the only sound as a colorful train sped towards Canterlot, trees and small farmhouses darting past the windows. A few stray stars were already cutting through the deep blue expanse of the cloudless darkling sky.
The train was moving much swifter than it normally would have been allowed to travel, let alone what was standard recommended safety procedure, but it was difficult to argue with the Princess of Friendship's very own instructions, which were that she and her friends arrive in Canterlot within exactly half an hour.
Mostly all of the carriages had been full of business ponies returning home from Canterlot, but now they were completely void of life as the train returned home on its final evening voyage. Not a single pony could be seen in any of the carriages, with the exception of the rear-most caboose, which housed six mares sitting in deathly silence.
"How long till we jump back again, Twilight?" Rainbow asked, staring at the trees darting by.
"Thirteen minutes. That...that isn't going to be enough time, is it?"
"You tell me, Princess of Calculations. I can safely tell you that we're moving preeeety slow by my standards, but that doesn't necessarily help you earthbound slow-pokes, does it?"
"At least half of us can fly, Rainbow. It doesn't take a Princess of Calculations to figure that out."
"Um...Twilight?" Fluttershy inquired, shuddering noticeably with every hard bump the swiftly moving train hit. "Can I ask a question..."
"Of course. Go ahead."
"What happens to us when we start going back in time?"
"Well, we already sort of have, technically, even now..." Twilight began, but trailed off when Fluttershy began shaking her head.
"I mean...what happens to us? Will we start...forgetting each other?" Fluttershy was hiding behind her mane now, and her last words were almost lost under the rumbling of the train.
"Ah, I see. You're afraid that every time we jump back in time we're going to start forgetting about each other, getting younger and younger until we jump past our birth dates and cease to exist."
"That's one way of putting it. So...will we?" Every pony was looking at Twilight with the same intense gaze as Fluttershy, and Twilight could have sworn she saw traces of fear and anger in their eyes, as well as what looked like...blame.
"No. Certainly not. We've already gone back a total of almost six minutes, and we all remember that time perfectly well. We should age properly, too, since we're directly in the eye of a complete temporal hurricane. I caused this mess, so I'm pretty much the exception to the rule. Along with all of you, since we're all still directly connected by the Elements of Harmony. Everypony else though...even Celestia, Luna and Discord...yeah, they're going to age backwards and eventually cease to exist."
"This is heavy duty." Rainbow muttered, and was met with agreeing sighs and Applejack's instinctively inherited quoting of 'Eeyup.'
"That's all a worst case scenario, girls! Because Celestia will have a solution, and we'll be back in Ponyville before morning."
"I must agree with Twilight. You are all overreacting." Rarity scoffed, looking out the window at the blur of shapes rushing past. "What indication do we have that this is a problem Celestia herself can't deal with?"
"Of course, us being exempted to the rules of time has its ups and downs." Twilight continued. "Yes, we will be able to stay alive and aware even after we've skipped before our birth dates, but in the event that we fail then we will be trapped in limbo for all eternity without the possibility of ever being freed by anything or anyone."
"We'll have each other, at least!" Pinkie Pie said in an attempt to brighten the growing looks of despair on her friends faces. "A whole eternity to talk and talk and talk..."
"Oh Merciful Celestia..." Rarity whispered to herself, traumatic flashbacks arising from the hellish handcar ride in Dodge Junction.
In time, the sound of the train wheels screaming against the rails changed in pitch and Twilight dashed to the window. With a frustrated sigh, she watched as the blur of trees began to slow until the train was moving at its normal speed, which given the situation at hand, felt to Twilight like a snails pace. She knew the conductor must have been reducing speed for a reason, but nevertheless she found herself storming out of the carriage towards the engine.
One of the train workers made a move to stop her from entering but ceased when he saw just who he would be denying permission to. Instead, he bowed in acknowledgment and Twilight responded with an embarrassed nod.
"Good evening, again." Twilight greeted the conductor, who turned around to look at her the second he heard the door open. He looked at her from beyond thick, round goggles, and was completely covered in coal dust and grime.
"Princess Twilight! Surely you must be wondering why we are slowing, given your orders! I can explain!"
"Of course you can. Please, go ahead."
"You see, we're approaching Saddle Lake Pass...we must reduce speed or we risk derailing on one of the many sharp turns. I am very, very sorry..."
"This isn't the usual route to Canterlot..." Twilight observed for the first time, raising an eyebrow at the thick red x on a typical route map tacked to the wall. "You never told me we would be switching routes."
"I thought you knew. Did you not approve the construction work on Bridle Canyon Bridge?"
"I...I did..." Twilight facehoofed at her own forgetfulness. Of course she had! How had she forgotten this all ready? No wonder there had been so few ponies on the train this evening, and so many departing taxi chariots. On this route, they would be an extra twenty minutes getting into Canterlot, even longer given the fact that they had reduced speed. "I'm...I'm sorry to interfere with your work here."
"Not a problem, Princess. We'll get you and your friends to Canterlot as swiftly as we can, but I can't guarantee we'll get there in half an hour as requested."
Twilight nodded in understanding and thanked the conductor, before turning and trotting through the half-dozen carriages and exploding through the door into the caboose.
"Rainbow, Fluttershy, come on! We need to get to Canterlot ourselves!"
"Oh...my..." Fluttershy reluctantly said, stretching out her wings and trying her best to keep her flight camp memories at bay.
"Fly to Canterlot Twi? From here? At full speed?" Rainbow let out a loud chuckle and shook her head. "I don't think even I can do that, let alone Fluttershy and you! You'd have to have the endurance of a griffin to expect to fly that distance at that speed!"
"But...but...we need to try! We need to get to Canterlot on our own!"
"Alrighty then, let's try. But don't say I didn't warn you." Rainbow led the way to the back of the caboose and opened the door to the outside gangway, her hair immediately exploding in a frenzy of rushing wind. Twilight readily unfurled her wings while Fluttershy looked desperately at Rainbow Dash.
"I'm sorry." Rainbow mouthed in response, seeing the terror in her timid friends expression. Even she didn't feel particularly fond of leaping out of the caboose and taking part in a sudden marathon flight led by a pony who had lived 90% of her life without the faintest idea of how flight even worked. Twilight was currently stretching her legs, logic which perplexed Rainbow Dash considering she would not be using them at all. "And yeah, if you want to stay here, she most certainly won't notice."
Fluttershy looked back and forth from the supportive looks of Rarity, AJ, and Pinkie Pie, and the determined expression of Twilight, and shook her head. She couldn't just back out because she was scared when there was so much at stake.
Time Elapsed: 2hrs 29min
Next Temporal Displacement : 4m16s per ½h
"Thirty seconds." Rarity announced, causing both Applejack and Pinkie Pie to halt in the middle of their conversation and join Rarity in staring at a double-bell alarm clock Twilight had left behind. Along with the clock was a notebook detailing all the future time travel intervals they would be jumping over, a communication spell intended for Rarity, and a newly purchased biography of Starswirl the Bearded that Twilight had grabbed while waiting for the train. Rarity handed these items to Applejack who placed them into her large saddle-pack which still smelled of freshly picked apples.
All three ponies silently anticipated the upcoming time-leap, watching out the window for the tell-tale signs of the previous landmarks once again rushing past exactly as they had been a minute prior. Pinkie Pie was staring directly ahead at the unfurling tracks, while Rarity and Applejack were focused on the trees rushing by. On one side of the tracks was a rock cliff which separated the tracks from the trees high above, on the other was a huge gorge which ended in a roaring river hundreds of feet down.
"Hey! Look!" Pinkie Pie called out. "Those ponies in the dirt look just like—"
Suddenly, the double-bell alarm rung out loudly from within the saddle-pack, interrupting Pinkie Pie and causing everypony to brace themselves for the next skip.
However, what they had NOT been expecting was to be thrown inexplicably into empty space and into the dirt at the side of the train tracks. The three mares crashed into the ground at an alarmingly swift velocity, three separate skid marks trailing several feet behind them.
"My...my MANE!" Rarity seethed, her formally perfect mane and tail now a mess of dirt and sticks that looked more akin to a robins nest than a fashion designers pride and joy. "That seems to be the extent of my injuries, however. Pinkie, are you alright?"
"Ship-shape!" Pinkie said happily, her mane and coat almost completely free of dirt, a fact which Rarity did not understand but envied greatly. "Where's AJ though? Applejack!"
"Oh my..." Rarity said urgently, looking around frantically. "Applejack, where are you!"
"Right here." Applejack's voice rung out, as an exasperated grunt. Rarity and Pinkie Pie still were looking around frantically as Applejack dragged herself up from the edge of the tracks, her hindlegs still dragging precariously over the gorge.
"My goodness, Applejack!" Rarity gasped, noticing her friend and darting over, offering a hoof and helping to drag Applejack back onto the tracks. Once everypony was safe, the three of them all collapsed onto the ground once again, ignoring the rocks and boards that made it up.
"So...does anyone have a clue what in tarnation just happened?" Applejack sighed, breaking about two minutes silence.
"Your guess is as good as mine. Although I imagine that when we everything was hurled through time, we simply did not. Which is why we were so rudely thrown into the mud and dirt!"
"Wait...ya mean we're back in time...on the train tracks..."
"I knew I recognized the ponies on the tracks!" Pinkie Pie giggled, rising to her feet. "Because they were US! How cool is that?!"
Slowly, reluctantly, Applejack and Rarity met each others similarly petrified gazes and turned back to face down the tracks, which had started to vibrate lightly signalling the approaching train.
"Woah nelly..."
"Which way do we go?" Rarity hissed, looking frantically back and forth from the tall rock cliff to the deep gorge and the water far below.
Ahead, the Ponyville-Canterlot express train tore around the corner roughly a hundred feet down the track and bounded down upon the three terrified mares, getting closer by the second.