• Published 11th Jan 2012
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Equestria's Twilight - Sapidus3



This is the story of the end. This is the story of the death of Equestria.

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Knight Protector of the Crown

Chapter 7 - Knight Protector of the Crown

Twilight looked at the desk. She had cleared off the climate report, but it still had the outdated report and half started letter of Celestia’s as usual. In addition there was a book sitting open on the wooden surface. It was Diary No. One Hundred and Thirty Seven. Over the years she had read through it dozens of times, but it had occurred to Twilight that somewhere in the pages of entries might be some offhoofed comment that she had missed the previous times that could shed some light on what it was like to be an alicorn.

Ultimately, it was of no real significance, but Twilight was technically the only one of her kind, and she would like to know if her experience was typical. So far she had not found anything. Twilight looked at the open entry.

-going well. I have had the unicorn, I suppose I should start thinking of her as my student, move into the palace. She has so much potential, but my schedule makes our lessons occur at irregular hours. I decided it was easiest to just always have her on hoof. I can at least get a lesson in a day, and when I am busy she can study with the professors at the school.

I admit that she is growing on me. However, I think it might have been too many years since I last dealt with a young filly. I find myself rusty.

The other night there was a knocking on my door as I was preparing for bed. On the other side were two embarrassed guards and a timid purple unicorn. I suspected she used her “big eyes” on them. She has not yet turned her weapon on me, but I have seen it used effectively on some of the palace staff. I should inform the guards to not feel bad about granting my student- yes I do think I like the sound of that- granting my student an audience. I do need to look into how she got past all of the other guards, however. If a single filly can bypass every guard in the palace just be looking adorable, it seems like it could pose as a security hole.

Twilight smiled. When she was younger, she had the palace staff wrapped around her hoof. Fortunately for them, she had not realized just how much influence she had.

-meeting tomorrow. But back to last night. Twilight was standing there with that doll of hers and promptly fell over herself bowing. She was so afraid that she had disturbed my sleep or upset me. After finally reassuring my student, I discovered the heart of the matter. She missed her parents and could not get to sleep.

I walked her back to her chamber and offered to tell her a bedtime story. I am afraid that is where I erred. It has been too long. I was surprised to hear that her mother never indulged in the practice of telling bedtime stories, and endeavored to come up with a good one. Apparently over the last few hundred years either what constitutes a bedtime story has changed or I have forgotten.

I told her the tale of the Ghostly Princess.

Twilight still remembered that night and the end of the story. It had been terrifying. She could imagine Celestia’s face in the dim light as she spoke. “And so the princess who had lost herself, lost her friends, and lost her kingdom finally lost her mind. Now she is doomed to wander all the lands because she cannot remember what it is that she has lost. They say that every now and then, some part of her remembers what it was like to talk to real ponies, and in a flash of light and a whoosh of wind she will appear. You can hear her distorted cries as she tries to remember what it was like to talk. But as she reaches out to ponies you can see her burning away in her pain, and as fast as she appeared she will be gone. There is no hope for the ghostly princess, because she has forgotten that hope is found in the hearts of others.”

-still remember when he first told Luna and I the story when we just fillies. He had always told it as if he had known the ghostly princess, as if she was somepony we should feel sorry for. Perhaps he knew from the start what was to become of his mind.

Twilight had found that to bit of rambling reminiscence the most interesting in the entry, but unfortunately nothing else helped to illuminate it, or who the he was, any further.

-not the most prudent thing. I am sure at some point in the future I am reading over this and laughing. Just remember, you’re going to slip up again at some point, and it will probably be even more embarrassing.

What had Celestia been thinking telling her that story? She had nightmares for a week. Twilight could hardly believe that the Princess had thought it an appropriate bedtime tale if she had not read the diary herself.

-wouldn’t stop screaming that the ghost princess was going to get her. I never had the same talent at dream magic as Luna, but at least I was able to keep Twilight from remembering the nightmares. There was an odd flavor to them, but I suspect that I am even more out of practice with dream magic as I am bedtime stories. I will need to be sure, however, to find a more modern book of stories appropriate for a young filly. I believe Twilight had mentioned something about a Doing Dare book.

Twilight shook her head at her mentor as she closed the book. It had taken the diary and reflection over her memories to realize that her mentor could be just as goofy as Princess Luna sometimes. She supposed that eccentric was a kinder word, and wondered how many years it would take before ponies talked about the “eccentric Princess Twilight.”

“She made a mistake telling a young filly that story.”

Twilight remembered Applejack’s words when they last met, “A’h’l always be here for you hon. But you need to remember to look in here.” She poked her hoof against Twilight’s chest. “You’ve always known what’s right in your heart. Now you’ve got two of them. Maybe it will be twice as easy.”

Twilight stared at the diary still before her. “But what if my hearts lead me astray. We made the right call with Witherton, but… Ponies died. Even Celestia made mistakes… How am I supposed to do this?”

Twilight threw herself away from the desk and galloped across the room towards the bed and dived nose first into Celestia’s old blankets. She buried her snout and hoped that the fabric would absorb her tears.

“Did your mistakes ever get ponies killed?”

She knew the answer. Even during Celestia’s rule things were not always peaceful.

“What should I do when I kill ponies?”

Twilight imagined a response from the blankets, “You do your best, just as you have always done.”

“But you were perfect, and even your best wasn’t always good enough. How am I supposed to deal with this? I just can’t forget. I can’t… Every decision…”

Their dead faces stared at her. The entire village was dead.

Twilight imagined another gentle comment, ”You know I wasn’t perfect.”

“Close enough. With the difference between us, you might as well have been. I’ve been having more nightmares about them. I thought… I thought talking to AJ, Dash, and Rarity about things more would help, but...”

“They always say that it wasn’t your fault?”

“But it was my fault. They are trying to be nice, but they’re wrong.”

Twilight dug herself deeper into the pile looking for comfort.

“I mean. It’s not the first time I’ve made decisions that ended in ponies dead. It’s not even the first time I’ve gotten a lot of ponies killed… Not even the first time that there were dead fillies.”

Twilight remembered the burning caravan wagons and Fluttershy’s sobbing form.

“I’ve always had nightmares, and have been haunted, but…”

”You have alway been able to keep going for Equestria.”

“Why is this different? I did my best. I went with what seemed like the most logical course of action.”

”But you had reservations. You were concerned, if only for a while, that you might have been leaving Witherton shorthooved.”

And the imaginary Celestia had finally given Twilight her answer.

“Took you long enough subconscious.”

She sat up on the bed. She felt a weight come removed from her withers and the old haunted house in Equestria seemed a little less crowded. The bodies and faces were still there, but the windows and blinds were no longer distracting her with their rattling.

It was not that she was losing herself. She had just forgotten to listen.

“I promise I’m not going to ignore my gut. I’m not going to do what seems right if it doesn’t feel right.”

Twilight released a heavy sigh.

“I suppose that means I should tell Professor Cold Ice that he should publish his report and I need to tell ponies about the moon.”

As Twilight was thinking a green puff of smoke formed in front of her and materialized into a letter. She snatched it out of the air before gravity even had a chance to take home. Twilight hastily unrolled the expected letter. It simply read, “Home soon. –S”

In a burst of teleportation magic the Sun Study was empty.

When she rematerialized, Princess Twilight Sparkle stood on a large balcony in Canterlot. Her sun shone almost directly ahead and was imperceptibly brighter because of her excitement. That was something she needed to become better at. Since gaining her wings, her emotions tended have a larger effect on the flow of magic to the sun than she would have liked. The muscles in the alicorns legs flexed and unflexed as she barely restrained herself from hopping with excitement.

Her wings, however, remained motionless on her back. She could feel them weakly attempt to flutter once, but then nothing else. Recently she had begun flying lessons with Rainbow Dash. Years of training recruits had made her a skilled, if hard, teacher. Twilight’s wings were not yet quite strong enough to provide the lift required to fly, but that had not stopped the rainbow maned pegasus from being a slave driver.

By the end of her lessons, the muscles that worked her wings would be too tired to move. As long as she scheduled the lessons in the morning, it made controlling her wings in court much simpler. Of course, she would have preferred not to have to live with the soreness it left in her back.

She squinted her eyes, but still could not see him. Her Knight Protector of the Crown was returning. Spike had been away for over six months on his mission, and he had not yet seen her new form. Twilight could not wait to show off her wings. Any minute the alicorn expected to see the dragon coming across the horizon. She had cleared her schedule for her former assistant’s return.

Her former hatchling was so important to her. Spike had always been something like a younger brother to her - though it was much more complicated than that. However, like many older sisters, she had not fully appreciated Spike when she had been younger. Too often the dragon had been her assistant first and her family second.

It was when she had realized the implications of her immortality that Twilight truly began to appreciate her dragon. Within another half a century, her friends would all be dead. She would make new friends. In fact, she HAD made some new, younger friends. Just the other day she had a nice brunch with Silver Dancer. However, all ponies would fade and die. She suspected that as time wore on, their lives would begin to pass like that of a mayfly. The burden of her immortality already seemed heavy, and she had not yet even lived longer than a normal lifetime.

She wondered how Celestia had handled taking Twilight on as a student. She wondered if Princess Celestia had cut herself off from her emotions. Maybe the love she had felt from her mentor had been a facade.

No.

Twilight remembered the Princess's last words. She would never forget them.

Spike, however, would be a rock in the storm of centuries and eons that would pass. Dragons were known to live hundreds or even thousands of years. There would be times when her precious knight would need to give himself over to the great slumber. But for an immortal being, what would a hundred years without her eternal companion seem? It would eventually be but a blink of an eye. At least that is what Twilight hoped. The same thing that would make relationships with normal ponies so painful would make the time without Spike bearable.

She had committed a non-trivial amount of time studying dragon physiology, and there was no known record of a dragon dying of old age. It seemed the creatures did not succumb to natural causes. They died in battle or cataclysmic events. The eldest of them simply disappeared, perhaps interring themselves for a slumber that would stretch on for eons.

Spike was her friend. Spike would live on with her.

When she realized just how badly she had treated the dragon who had been like a brother to her, she had become determined to put things right. He had deserved more than being her simple assistant. So the princess of Equestria had created a new post, Knight Protector of the Crown. Technically he was her bodyguard. However, in practice, he would go where she could not. He spoke with her voice and acted on her authority.

The appointment was one of the worst decisions she had made.

It had made the dragon thrilled. The pride in his eyes had made her think she had made the right choice. But he was no longer a baby dragon. While Spike was still young, he was strong and powerful. As Knight Protector he was frequently away. She was constantly sending him into danger. Whenever he flew away from Canterlot, Twilight could not help but remember how most dragons met their end.

She could not stand to lose him.

Then there was also the fact that he took his duties far too seriously. He was like Rainbow Dash in that respect. Though, at least he would drop the formalities when they were not in public. Still, whenever he was gone she would just want her old assistant back. Twilight could never do that too him though. He was proud of his position, and he was good at it as well.

She could see a purple and green blob in the distance now. It was flanked by smaller specks that she assumed to be the pegasi that had gone with him. She counted nine forms in all. They had taken casualties it seemed.

It was normal for them to exchange letters, but this mission Spike had only sent a few, and the status reports had been brief at best.
Twilight considered it only fair that she had not mentioned the whole ‘alicorn thing’ in her letters back to him. It was just too bad that she was not yet skilled enough at flying to go out and meet him. She smiled as she imagined what the look on his face would be like.

The clopping of armored hoofsteps approached her from behind. She recognized the rhythm. The princess hoped that her captain of the guard was only there to wait with her. She really did not want to deal with another crisis at the moment.

“You must be looking forward to his arrival Princess. Your wings certainly seem excited.”

“What!”

Twilight craned her head trying to look at her wings. Twisting around, practically losing her crown, she could see her wings sitting motionless with not a flutter. Out of the corner of her eye she saw Rainbow Dash’s smirk.

“If you can’t tell whether or not your wings are doing something perhaps we need to step up your training. My goal is to eventually get you to be the second best flier in Equestria.”

“I would be happy if I could just get off the ground.”

She knew she was pouting, but the princess did not particularly care.

“It’ll be good to see Spike again. Think you’re going to let him stick around long enough that he will be able to help me break in the new recruits?”

Rainbow Dash had no idea how much the lighthearted comment hurt her.

“I would like to keep him around, but we need to make sure nothing happens to Witherton again. I still can’t... We can’t let anything happen to the new ponies moving there. He will keep them safe.”

There was silence before the pegasus’s voice softly replied.

“You’re still thinking about that? It was nearly… No, it was before you got your wings... Twilight, it wasn’t your fault. You couldn’t have known that-”

Twilight whirled on her friend in frustration. She thought she had finally worked the issue out.

“But I should have! If I had taken the time. I can expand and project my senses out beyond my physical form. I can erect barriers and level mountains. I’m the most powerful being alive, and I can’t even protect a single village? Don’t make me laugh. I failed Dash, plain and simple. The ponies in Witherton depended on me. I let them down. I let them die because I didn’t trust my own judgement.”

She shook her head before continuing, “I can still remember their dead faces. I walked through a village that had been slaughtered to the last pony. Their deaths had been pointless.”

“Twilight-”

“I gave the order to reduce the guard. I signed off on the paperwork. Their blood is on my hooves.”

“You only went along with the decision because we told you that Trottingham needed an increased guard - and it did. If we hadn’t changed the guard assignments we might have ended up with two tragedies on our hooves instead of one. I don’t like it, but we have limited resources.”

“Exactly, I did it because other ponies told me that I should even though I knew it was a bad idea. I should have protected them...”

“Nopony can do everything.”

They were shouting now.

“Celestia could!”

“Celestia is dead!”

They were both silent. The words had been said. It was Rainbow Dash who first mustered up the courage to say something again.

“You’re not Celestia, Twilight. You can’t keep comparing yourself to her. Of course you are going to fall short. She had at least a thousand years of experience on you, probably a lot more. You’re still growing. Give yourself a chance.”

“But I should have kept them safe...”

“Don’t be stupid Twilight! What are you supposed to do? Be everywhere at once?”

“If that’s what it takes.”

Rainbow Dash sighed at what she had interpreted as a petulant response.

“Twilight. you can’t be ‘on’ all the time. You need to relax at some point. Nopony is meant to hold onto things like this. Not everything bad that happens in Equestria is your fault. You think I didn’t feel some of the blame, that I don’t wish things had gone differently? But we need to move on, unless we want Equestria to grind to a stop. We’re going to find the things that attacked Witherton. When the survivors wake up, they’ll be able to help us with their accounts. However, things like this will probably happen again. Just know that I will be by your side when they do. You don’t need to carry it all yourself.”

Twilight did not cry. She had not cried once over the ponies of Witherton. She had only felt anger and shame.

Nearly seven months ago they had received reports from Trottingham, reports of something new. Guard ponies were transferred from Witherton in response. By the end of a month Witherton was gone. The buildings remained intact. The belongings of ponies had not been touched. But each and every pony had been killed. They had been telekinetically crushed or torn to pieces. There were only three potential witnesses and they were all in comas. Twilight had made it a point to memorize the faces of all those who had died there, however, she had not yet been able to bring herself to visit the three survivors.

It did not matter what Rainbow Dash said. Twilight had failed her little ponies.

“Dash, when I’m not on I let things like Witherton happen. I let things like the Ponyville-Trotingham Caravan hap-”

“Are you still holding on to that!”

For a second Twilight thought that Rainbow Dash was about to punch her.

Twilight shook her head, but she was not sure why. “I need to do more.”

Ponies had died because of her before. But this had been different. It had been the greatest tragedy in Equestria since the death of the two alicorn sisters, occurring just days before the ceremony for Apple Seed. Worst of all had been the way in which the ponies had died.
Most of the creatures that called the night their domain attacked with tooth or claw. If something fell upon a caravan, the ponies would be torn to shreds, not crushed to a pulp. Until she could shove the memory aside, the thought of caravans reminded Twilight of the loss Fluttershy had suffered.

The ponies of Witherton had not been attacked by timberwolves, or manticores. Nor had it been a Taraxippus or a Lamia. It could not been any of the dozens of horrible creatures that creeped about once her sun set. The ponies of Witherton had been killed by magic. It was the type of magic a pony might use, such as a unicorn.

Or an alicorn.

Or something like an alicorn.

Twilight remembered the creature from her dreams, from her nightmares - the nightmares that came more frequently now. She had destroyed it, erased it from existence. But where had it come from? Were there others?

“There is something you could do to help. The armor Moon Dreamer used to make for the guard was really something else. The enchantments have saved more than one ponies life. If you would let him go back to crafting equipment for us, well, the new recruits would be much more effective.”

Twilight looked at her friend with a hint of betrayal. They had discussed the issue before. Rainbow Dash knew how she felt. Was her captain attempting to use her vulnerable state to manipulate her into changing her mind?

That was ridiculous, Dash was her friend.

Dash was just being insensitive.

“The project he is working on is too important. He’s already moved past the initial planning stage.”

“Yea, the Magisterium is not too happy with him shutting down streets just to carve them up.”

Twilight sighed. There were only a handful of unicorns in Equestria who could even understand the magnitude of what Moon Dreamer was taking on.

“The rune patterns need a lot of space. It just so happens that the streets of Canterlot are laid out along where the main rune lines need to be placed. I suspect that when Princess Celestia first had this city built, it was with this ultimately in mind. It’s just too much of a coincidence otherwise. I don’t know why it was never finished, but the streets are perfect to serve as the framework for a limitless amplification matrix. I just wish I could find some documentation from the city’s construction.”

“Still, it's very disruptive to day to day life.”

“Roads are closed for maintenance all the time, the ponies can deal with it. Besides, when he finishes with a street, the runes will melt into the stone and will hardly be noticeable. Oh, and you can tell the Magisterium that they should feel free to direct their complaints to me if they are dissatisfied with Moon Dreamer’s actions.”

“This is more than just maintenance. There is all sorts of magical disruptions, and the roads he is working on are-”

“Ponies can deal with it. This won’t cost anypony their lives or put anypony at risk, but it might save lives.”

“Twilight, I-”

Both ponies were caught off guard by a sudden ‘whoosh’ of wind followed by a thud as a dragon landed besides them. The creature was an imposing sight, easily the size of a carriage. His growth over the past decades had not been caused by greed as it had been on that one chaotic day when he was just a little dragon. The fire that had driven this more recent growth had been loyalty, honesty, and generosity. It had been tempered by laughter and kindness. Friendship had ensured that his growth was slow and proper. He was easily stronger than greedy or wrathful dragons three times his size. A moment later five battered pegasi touched down as well.

If they had not been veterans before leaving, they were now. In her mind she picked up the feathers of the ponies who had not returned from Spike’s basket. She would put them in the abandoned house, more ponies that died following her orders.
The Princess gasped at the sight of her Knight Protector. A long scar ran across Spike's face. The chest plate of his enchanted armor was missing and bandages were wrapped across his chest. It looked like they were bleeding through.

“Spike!”

She ran to the dragon in concern.

“Don’t worry, it looks worse than it is. We can talk about it more inside.”

Twilight could tell that his now deep voice was hiding something. He had not even mentioned her wings.

Rainbow Dash dismissed the pegasi, giving them leave until they would be called for debriefing. The captain, the knight, the princess, and her ever-present guards then made their way inside.

As they walked through the archways leading off the balcony, the collar around Spike’s neck glowed with magical power. His form distorted and shrank until he was only a little bit larger than Twilight. It had been a gift from Moon Dreamer, and the design was absolutely brilliant.

She was not certain how it had happened, but her dragon and her student had bonded deeply. When Moon Dancer realized how much the dragon’s size was an inconvenience, he had set his mind out to fix things. The unicorn had needed Twilight’s help to make the collar. The task had been beyond his ability at the time, but Twilight had not even realized how much Spike’s size was bothering the dragon.

The hallways in Canterlot were all very big. He had not seemed that large.

Twilight did not know the exact limits of the collar. Spike described it as feeling ‘tight’ - like wearing a suit that was a bit too small. She suspected that as Spike grew, the tightness would increase. Eventually she would probably need to look at other options.

They were in her study. Rainbow Dash was right; she did need to relax. She used her magic to heat up a pot of tea.

“Spike, let me call the doctors to look at that.”

“I don’t think it will help.” He was unwinding the bandages. “It’s been like this for months now.”

Twilight and Rainbow Dash both gasped at the wound. It was along the side of his chest, as if some powerful force had torn into him. It seemed to have been caused by a glancing blow. A feeling of dread went through her as she imagined what would have happened if it had hit Spike straight on.

Rainbow Dash asked the obvious question.

“The shade dragons did this?”

They had been reported to be non-aggressive. But this wound was deep and ugly. It was slowly oozing blood. The scales around it were turned and twisted. She could see that it looked like some of the tissue was rotting.

“No. The shade dragons will basically just sit there no matter what you do to them. I don’t think they can be hurt by anything but sunlight. I saw one destroyed by the dawn. But otherwise, they just curl up in their caves sapping energy from the soil and earth. We weren’t able to figure out if they are intelligent or not, or where they are coming from. Basically the mission was a big failure. No, this wound was caused by something else. It took out half our squad before we even realized what hit us. It was only when dawn came that the attack let up.”

“Why didn’t you go and see a doctor? You weren’t that far from Hoofington.”

Twilight was worried about her not-so-little Spike. She could not lose him.

“I did go see a doctor. Several in fact. This was the best they could do, even with magical healing. Something’s wrong with it - interfering with their magic. By the way, nice new wings. Could’ve mentioned them in one of your letters.”
Spike had a grim smile on his face. She wondered how much the wound hurt him.

“You could've told me you were hurt... May I?”

Spike nodded his head. Twilight was not a healer, but she had studied healing magic. Perhaps she would need to study it some more. If the wound was infected with foreign magic then perhaps raw power would work where skill and experience had not.

Hesitantly Twilight reached out with her magic. When the glow enveloped the wound, she recoiled in horror. She did not even notice her spilled tea. She recognized the feeling of the wound.

It felt...

Wrong.

Author's Note:

Bam, super special second Sunday update!

I wasn't looking forward to writing this chapter at first, but by the end, I really liked it.

The next chapter involves Twilight having to deal with something sad.

In two chapters we see another member of the mane 6.

The below is more ramblings about the possible science in Equestria. I was bored today.

So I have a more detailed analysis of the ‘science’ behind my version of Equestria. There is a lot of wiggle room (for example, if Twilight made the sun a disk as opposed to a sphere, that would pretty much save Equestria based on this). This is all more idle musing than anything else. It won’t really affect the story and you can safely skip it. If you are interested in a summary, there is one near the bottom.

Here are my assumptions. You can argue with some of them, because there are other possibilities. However, I needed to limit the number of variables to do anything useful.

-The apparent brightness of Earth’s sun is the same as that as the sun controlled by Celestia.
-The apparent size of Earth’s sun is the same as the sun controlled by Celestia.
-The blackbody curve of Earth’s sun is the same as the sun controlled by Celestia.
Based on the show, these first three all seem to be true to within a margin of error.
-Equestria’s need for pegasi maintained weather is due to the planet being geologically dead. This has caused it to have a mostly stagnate climate (with places like the Everfree forest being the exception because of various factors (mountain ranges, bodies of water, ect...)).
-Celestia’s sun was not a true star. Assuming Equestria is geologically dead would mean that it has no protection from coronal mass ejections (unless the moon has a magnetic field).
-Celestia’s sun requires a constant flux of energy to maintain. It is not simply ‘running’ of of a preexisting well of energy. This rules out class F white dwarfs. This means Celestia needs to constantly feed the sun energy. This also means her sun needs to be relatively small (so that gravitational pressure is not causing fusion).
-The fact that Celestia’s cutie mark is a sun, would lead me to believe maintaining the sun is her special talent. I will assume her efficiency is 100%, ie, all of the energy she pours into her sun is converted to luminous output.
-Celestia would put her sun in a position as to minimize the burden it would place upon her.
Those last five assumptions are much more subjective. You could easily argue with them.
-Because the geothermal energy flux of Earth, is several orders of magnitude lower than the solar energy flux, for the purpose of energy calculations we do not need to worry about if Equestria is geologically active. Any discrepancies that exist could be accounted for by higher levels of green house gas (perhaps also helping to explain the lift generation of pegasi).

That last one is not so much a assumption as it is an approximation I will be making to simplify things. If you want you are free to look up and compare the energy fluxes.

So let us begin. For simplicity, ESun will mean Earth’s sun. CSun will mean Celestia’s sun

The brightness multiplied by 4pi times the distance squared will give us the luminosity (or energy output). We assumed that the brightnesses are the same so we can find the luminosity as a function of solar distance. So as to reduce the required energy to run the sun, we will be assuming that Celestia keeps it close to the planet. I am assuming a Low Earth Orbit (or in this case Low Equestria Orbit), of 2000km.

This gives us that the power output (Luminosity) of the CSun needs to be 70 Petawatts (there abouts). I will put this in perspective a bit, but we can now use the Stefan-Boltzmann law to find the size of her sun.

We find that it is 9.4km. This is only about twice the size of Manhatten (quite small). It is only about 0.5% the size of our moon. This puts it on par with Neutron Stars in terms of size. I should also mention that at LEO it is significantly closer than the moon.

So we have a good understanding of what the sun might be like. I would assume it’s mass is only large enough to hold it together against the outwards energy flux (I haven’t done those calculations yet, and it may well turn out it will need to be massless).

To put the energy output into perspective:

70 Petawatts is how many joules of energy per second the sun is emitting. Not all of it reaches Equestria, some just goes out into space.

Humanity is used on average 16 Terrawatts of power (or 16 terrajoules of energy a second) during 2010.

This is 4000 times less than our value of 70 Petawatts.

Things Celestia could accomplish by redirecting the energy she sends to the sun for one second:
-Power a hurricane for 8 minutes.
-Cause a 20 megaton explosion (the largest hydrogen bomb ever detonated was 50 megatons, most are much smaller than that. She can do this once every second).
-Launch a billion killograms to the moon (about two billion pounds).

Now since her special talent is the sun, not sending things to the moon, causing hurricanes, or blowing things up, she is probably less efficient at those things. However, even assuming 1% efficiency at non-solar activities, it is still impressive.

EDIT: Woops, I squared a pi. Multiply that 70 petawatts by about 3. So Celestia is even more impressive. I fixed the error in the numbers below. I’ll go back and fix the affected numbers above in a bit.

So, now onto Twilight. I’ve put a lot less thought into these calculations, so I might have overlooked something important or my approximations might be off.

The Earth emits energy like a blackbody of about 250 kelvin. Assuming the same for Equestria, we need to take a guess on Equestrias size. I’m going to say it has about 50% Earth’s radius which works with it being geologically dead. It also makes gravity weaker. This makes it easier for pegasi to fly and more likely Twilight could survive an anvil falling on her head (that was what fell on her in feeling pinky keen, right? People are free to watch the episode and figure out how much force it hit her with, assuming lowered gravity and other reasonable estimates).

This means the planet Equestria is on is losing heat at a rate of about 54 Petawatts. (Assuming similar temperature to Earth) as a blackbody. Since we now know that Equestria is cooling down, that means Twilight’s star is providing less than 54 Petawatts of power. (Equestria had only been receiving about 56 Petawatts from Celestia’s sun, the rest going out into space). This means that Twilight’s sun is outputting at most 200 pettawats.

So if Twilight was just barely falling short, and Celestia could just barely maintain her own sun, Twilight is 95% the strength of her mentor (that 5% sure does make a big difference). Of course that is assuming Twilight has the same 100% efficiency as Celestia

So lets see if we can narrow things down.

Equestria likely has around a fifth to a tenth of the stored geothermal energy as the Earth. This means it has 10^30 Joules of stored energy. Lets assume that its only going to loose 10% of the that energy during this ice age (I could be way off with that number, I can’t use Earth as a model because we are still geologically active), so Equestria needs to shed 10^29 Joules of energy.

A 100,000 year ice age cycle (I should probably adjust the words ‘centuries’ in the last chapter to’ eons’) means its loosing 32 petawatts on average during that time period.

That means Twilight is probably delivering something like 20 someodd petawatts, putting the total output of her sun at around 76 Petawatts. That’s only a third as luminous as Celestia’s sun (and given that, the 32 petawatt loss was an average over 100,000 years, her sun is probably even weaker at the time of the story - however without determining the growth rate of her magic its hard to determine).

Depending on how inefficient Twilight is at powering a sun, she might actually meet or exceed the lower bounds on Celestia’s power.

One final thing. Assuming Twilight has placed her sun no closer to the planet than Celestia did, her sun is either redder, or smaller than Celestia’s. If it is the same size, then her star is an orangeish color. If I wanted to make the sun red, I would need to make it appear large in the sky.

One thing to take away from this, is that energy conservation cannot apply or else Twilight and Celestia would have appetites like a parasprite swarm.

Also, none of this takes into account the energy required to maintain the orbits of the star.

To Summarize:

Twilight’s sun is about a third as powerful as Celestia’s and about a tenth as bright in the sky as well as orange.

Celestia was at least capable of generating a 60 megaton explosion every second.
Worst case scenario Twilight is able to currently generate a 20 megaton explosion every second - this information may come in useful for me later in the story :)

Regarding Twilight’s power in season 1:

So based on what I remember of the ursa minor’s size, and assuming its density is the same as a pony (I want to say its lower based on its transparency, but its filled with stars and stuff, so who knows), the ursa minor weighs around a hundred thousand kilos. This puts Twilight’s peak energy output in the episode at around one megawatt (assuming that her apparent struggle is not an issue of finesse, or control - also assuming magic is not affected by distance (and as I write, that seems unlikely, so maybe her output is even greater)).

Even given a geometric doubling of her power each year leading up to Celestia’s death, her power would still be about nine orders of magnitude too low to make anywhere near a decent sun. So Twilight must have had a large power boost between boast busters and the creation of her own sun.

This also helps explain why the council of unicorns aren’t able to help very much. It would take a million unicorns as powerful as Twilight was in Boast Busters to even begin to make a difference (I suspect the average power output of a skilled unicorn is closer to one killowatt, so it would take even more unicorns).

Rewrite posted 1/1/2015