Hi, everybody. There's something I could use your help with. I'm attempting to jive MLP's sun and moon motion with real life physics tweaked with some additional storytelling elements to fix some of the unworkable variables. I could really use your help as a science sub-community to come up with some of the variables and equations involved in this effort.

My assumption with Equus (which may or may not be the official name of the planet of MLP) is that it is considerably smaller than the earth, if for no other reason than how much the show plays fast and loose with travel times around Equestria itself. Travel to the frozen north, for instance, seems to be a quick affair, whereas travel to northern Canada from the middle of the USA would be a hell of a train ride. At any rate, I'm making a base assumption that Equus is something like 25% the diameter of Earth, or roughly the size of our moon, and yet, with enough mass to make its surface gravity 1g. I'm not concerned with what material the core is made of to achieve this -- it could be gold for all we know. But if the mass is high enough, mathematics does allow a stable 1g surface gravity on such a small planet, given a significantly higher average density.

Here are the basic mechanics I'm shooting for:

* The planet Equus is roughly 3500km in diameter, and its surface gravity is 1g.

* The sun is like a singularity constantly expelling energy. It has a magical energy shield surrounding it which accounts for the sun's apparent size as well as regulating its energy output.

* The moon is more like an asteroid, but its exact size, density, and altitude I have not determined.

* The sun, the moon, and Equus itself all repel one another through some fictional force similar to how magnets repel one another when you bring like poles together.

* As a result of this repelling effect, combined with gravity, the sun and the moon are locked into a specific altitude above the planet's surface where the two forces balance out.

* The angular diameter of the sun and moon (how big they appear in the sky) would roughly match that of Earth's sun and moon as viewed from the planet's surface.

* The sun and the moon need to be of sufficient size and distance to be visible from a large portion of the planet's surface at once.

* The atmosphere of Equus should extend much further than Earth's atmosphere, to the point where the sun and moon hover within the upper atmosphere.

That's my basic premise as far as the physical geometry. There are many implications of this model. First, neither the sun nor the moon are "in orbit" above Equus. Orbits are a balance between gravity and "falling" sideways so fast that the distance to the surface is maintained. No such mechanics exist here. The balance is between the repelling force and the force of gravity, so even if the moon came to a stop in the sky, it would just hover there.

The key here is the idea of the sun and moon's altitude placing them within the upper atmosphere. This means there is drag on their motion. Thus, they need a boost twice a day to continue on their paths which create the day/night cycle for Equus. This boost is activated by the pair of alicorns ruling Equestria. The power to do this itself is immense, and it does not come from the alicorns, but they do wield it in a limited fashion. I won't be getting into the mechanics of that in this post, however. Just assume that the alicorns are able to apply enough energy to the sun and moon to get them moving, but this needs to be repeated every half day, once at sunrise and once at sunset, roughly, Equestria time.

Possible concerns would be elements of physics such as the inverse square law, the density of the atmosphere, the rigidity of the moon, and several other variables. Most of it I'm not concerned with because I'm happy to adjust variables such as density of all bodies to make the math work.

One thing I'm really unsure about is whether I can justify a higher atmosphere above the planet's surface than what we see on Earth. Or perhaps the distance to the upper atmosphere from the planet's center would be the same for both Earth and Equus, but since the surface of Equus is so much closer to the core than Earth, its atmosphere can extend much further out. If anyone can shed some light on this aspect, I'd like to hear it.

I'm definitely thinking the moon's overall density would be fairly low, but its rigidity would be high to withstand the stresses involved in its motion as well as its deceleration due to drag. I'm also unsure whether or not this drag would create incandescent effects in the atmosphere itself. Hopefully not.

Also I'm not concerned with the problem of forming spherical bodies of low mass. In this case, I'm assuming that the Equus system was artificially engineered rather than formed by chance.

Anyway, those are my initial thoughts. I'd love some input which could make this model work and align with known laws of physics.

6066400
You're taking the difficult route. The only true way this could possibly work is if the sun was 100% artificial. In fact, it would have to be an extremely small ball of hydrogen held together by magic and compressed at the core by magic just enough to induce fusion but not enough to use up all the hydrogen. Same deal with the moon -- make it orbit as close to the Earth as the ISS, allowing it to be extremely small. Additionally, to explain why they need to actively give energy to the sun or moon, you could invent a type of extreme 'drag' caused by magic in space that accelerates objects in the opposite direction of their velocity, meaning you have to counteract this force.

The atmospheric drag ides is good, but it would just cause the atmosphere to ignite.

6066402

The only true way this could possibly work is if the sun was 100% artificial.

Correct. That's part of my premise. I mentioned that the whole system was artificially engineered.

Specifically, I don't have it as a fusion reaction at all. I wasn't going to get into this, but I have a whole rather complex metaphysics model for how magic works in this universe. But what the heck. For the purposes of this discussion, there's another realm where all the magical energy comes from. In the case of the sun, it enters into the physical universe through a tiny aperture or puncture. There is a very powerful shield around it which provides the same sort of effect that an incandescent light bulb has with its frosted glass that evens out the intensity.

Same deal with the moon -- make it orbit as close to the Earth as the ISS, allowing it to be extremely small.

I was going to go with this idea initially, but the problem there is that the ISS can only see about 3% of the earth's surface at any given time. Its altitude is so low that the earth's curvature prevents people from seeing the ISS until it is fairly close, and even then, only for a tiny amount of time before it's gone again. Only satellites in high earth orbit are visible for the better part of a day.

invent a type of extreme 'drag' caused by magic in space

The problem with this is that in the distant future, there's space travel and distant world colonization. Conflicts, wars, massive battling space fleets, etc. I'd like space to work pretty much just how we're familiar with it in real life, but with Equus being uniquely constructed and not operating like other star systems with actual hydrogen fueled suns and actual orbiting planets.

Overall, a small Equus serves the story quite well. The world being Earth-sized complicates matters in terms of storytelling, especially the way MLP portrays distances. I'm not 100% on that aspect, but 1/4 the size means 1/16 the surface area (though 40% ocean coverage), and I figure standard city sizes would be about 1/10 scale with human cities as well. A major metropolis would be close to a million ponies. But all that is outside the scope of this exercise.

6066407
I concede your points. Well done.

6066400
A planet with the same surface gravity as Earth but only half the diameter would have a quarter the mass. This means that the planet would have a thinner atmosphere, not a thicker one. A sun or moon in this atmosphere would be too close to be visible from a large portion of the planet at once, which means that there are going to either be strips of land that never see sunlight, or that the sun and moon must move in some strange pattern that allows the entire planet to be covered.

As for a repelling force balancing out gravity, that could work. Something similar happens between, for example, atoms in a molecule, which have an equilibrium separation distance. If you try to push them closer, they repel, while if you try to separate them, they attract. In the case of Equus, this repelling force needs to be something that is stronger at close distances and weaker at farther distances than gravity. An inverse-cube force could serve this purpose.

One possibility for imposing 'drag' on the sun and moon without them needing to be in the atmosphere would be to make them electrically charged. Charges that are accelerated (as is the case when an object moves in a circle) produce electromagnetic radiation and lose kinetic energy in the process. This would cause the sun and moon to slow down over time, requiring the princesses to give them constant boosts.

6066425

Mmm. That's unfortunate. I'm genuinely surprised that it would be a quarter the mass for half the diameter, maintaining 1g at the surface. But perhaps it's best to not try and force the sun and moon inside the atmosphere. I have a feeling that would produce further complications, namely incandescent effects as well as a rather wicked particle wind on the moon's surface, thus making any future lunar colony a bit unfeasible.

I definitely appreciate the alternate suggestion, though it involves scientific principles I've actually never heard of. I'll need to read up on this. I wonder if it would have any other negative side effects. I imagine it might be difficult to produce sufficient drag to need boosting twice a day in the form of raising and lowering each body. I may have to fudge some things, though I definitely prefer to keep it realistic. As far as realism can go in MLP, that is.

6066400
I don't have the time right now to do a detailed read, I'll do that later. But the travel times are short due to the magic of editing, same as in movies. Additionally, the U.S is gigantic. European countries are way closer to one another, England is closer to France than I am another state. I put equestria as maybe England size, not US size.

Generally speaking, I assume that, at one point, their system DID obey orbital mechanics. It's just that something-presumably discord-broke said orbital mechanics, at least within their system. Beyond the solar system, orbital mechanics may or may not function normally. Despite this, their sun and moon are normal sized.

There's actually some evidence in favor of my theory; some of it comics, some of it non-comittal WoG, some of it from the show.

Although...with the recent reveal that eternal night=/=extinction event (though the details are not known), the case for this hypothesis is somewhat weaker.

6066473
6066449
Personally, I believe in the "Equestria is Earth" theory, which, when heard, actually makes perfect sense. Plus, we all know that Equestrian magic is the reason why the main characters of the "Equestria Girls" franchise can "pony up." By the way, the Friendship Express doesn't travel a shorter distance than Earth trains at the same speed, it travels the SAME distance at a FASTER speed. The long and short of the explanation: The Friendship Express is powered by magic, and, like Fractalman said, the reason for the sun and moon needing Celestia and Luna in order to move is most likely Discord. Here's the link to the "Equestria is Earth" theory: https://www.youtube.com/watch?v=_z9EmNkD88w

Sunbeam out!

6066777
That's cool and all, but I'm trying to make the astrophysics as-stated. I've already got a hell of a lot of lore established around things like Discord's origins and the origin of the Equus system, origin of ponykind, etc. It's all pretty much set and solid. I'm just trying to justify why they have to keep putting energy into moving the sun and moon in a universe which operates under our laws of physics plus a rational, measurable magic force that obeys its own specific laws.

6066777
That video has a few interesting points, but ultimately I don't think that's the case. The tech argument isn't great, it doesn't really explain why they're using human tech instead of modifying it and making their own. I also completely disregard anything in Equestria Girls and any argument that calls them Human. I'm not quite sure that the trains we see in MLP run off of magic. If it runs of magic, then why would they have a steam engine on the front? It doesn't really make sense.
Personally, I use the dying world hypothesis. Equestria and potentially the solar system (i'm still developing this hypothesis) suffered a massive cataclysm (as in several times stronger than the KT event and involving the material found in the changeling throne, so no Discord). Ponies are trying to keep the planet functional by artificially setting the weather and raising/lowering the sun.

6066400
For the size of the planet, you don't have to make it smaller to account for travel time, there are at least two other ways to get around that.
1. Magic: all Pony's, even earth pony's, seem to have latent magic. This allows them to travel great distances faster than we would expect.
2. Plot needs: if Equis (or whatever) is a real place somewhere in the multiverse then the show we watch is either a documentary based on real events produced by pony's OR the writers are psychically viewing events and are basing the show on them. Either way editing out the boring and mundane parts of any story is completely valid without having to shrink the planet to make sense. When I tell the story of the family trip to Australia (from Canada) I skip over the 29 hour plane ride there and back for the sake of efficiency.

There is another issue.the reason Earth has a tropical equator and a frozen tundra at the poles is because of its size. The equator is significantly closer to the sun than the rest of the planet. If Equis is smaller than Earth then that difference in distance would also be smaller, drastically reducing the range of possible temperature zones. Given that Equis is fairly similar to earth, it seems that its physical size should be pretty close to Earth. Iam curious, other than the travel times, why else did you feel the need to shrink the planet?

For the star system, an artificial sun and moon make sense. I think that given the need for magic to maintain the weather and grow crops it's possible that Equis was an uninhabitable rock (with organic matter?) that some Alicorns came across and used magic to create an artificial sun and moon to heat the planet and churn the oceans (tides) respectively. Fromthere, the various species were either created or transplanted from another world/worlds. This is a heliocentric system relies on magic to continue being stable,the magic producing life forms rely on the system to stay alive.

6067592

The tech argument isn't great, it doesn't really explain why they're using human tech instead of modifying it and making their own. I also completely disregard anything in Equestria Girls and any argument that calls them Human.

Absolutely agree. In the verse we're building, EQG isn't even a thing. It's just too inconsistent with everything else to be considered valid.

I'm not quite sure that the trains we see in MLP run off of magic. If it runs of magic, then why would they have a steam engine on the front? It doesn't really make sense. 

Although I just thought of a new problem I have to solve. How would the day/night cycle work in my universe prior to the first alicorns showing up. hmm... I'll have to put some thought into this. Perhaps the issue with drag on the sun and moon built up over many thousands of years.

6067740

Plot needs: if Equis (or whatever) is a real place somewhere in the multiverse then the show we watch is either a documentary based on real events produced by pony's OR the writers are psychically viewing events and are basing the show on them.

I definitely am not including our real-life universe in this model. This is entirely separate and self-contained.

There is another issue.the reason Earth has a tropical equator and a frozen tundra at the poles is because of its size. The equator is significantly closer to the sun than the rest of the planet.

Sorry, I'll have to correct you on this one. The tropical equator of Earth has nothing to do with it being "closer" to the sun. The sun is 93 million miles away. The equator is only about 3000 miles closer to the sun than the poles. An insignificant difference. The reason for the equator being tropical is because it has more direct sunlight than the poles. Overhead sun is much more intense than sun on the horizon. And at the poles, the sun is never very far overhead. This wouldn't be any different on Equus.

Other reasons to shrink the planet are mostly for storytelling purposes. Having a relatively smallish planet makes global exploration less of an issue. At the time of MLP, their transportation technology is roughly on par with human technology in the late 1800's. Having a smaller world fits the narrative better. It's a subjective thing.

I think that given the need for magic to maintain the weather and grow crops it's possible that Equis was an uninhabitable rock (with organic matter?) that some Alicorns came across and used magic to create an artificial sun and moon to heat the planet and churn the oceans (tides) respectively. Fromthere, the various species were either created or transplanted from another world/worlds. 

Curiously, the various species created or transplanted angle is absolutely a part of our universe! Though with a whole lot of lore surrounding it explaining exactly why this took place. Very interesting you'd say that.

6066400

Here is the official map of Equestria (and neighboring Griffonstone and Dragonlands). While it doesn't show the entire world, we do know that other places exist that aren't shown on the map (Saddle Arabia for example).

You can also get a sense of scale of things from the Cutie Map, which you can occasionally see good angles/views of in the show.

As for "loose and fast with travel times" more time passes in the show than is explicitly shown usually. Getting on the train seems to be done not strictly for speed reasons, but for conservation of stamina and cargo capacity reasons. In Over a Barrel and in Mmmmystery on Friendship Express, for example, we saw "slow travel times" where they slept on the train to get to their destination.

Pegasi, for example, can easily fly around Equestria in short order, particularly Rainbow Dash. Twilight was able to make the trip between Ponyville and Canterlot by wing, while carrying a passenger (first Spike, then Pinkie) in Amending Fences, and it didn't really take her all that long based on the implied passage of time involved. But you'd be hard pressed to get all of Rarity's stuff along for the trip without a vehicle.

Overall though, Equestria "the country/continent" doesn't seem to be all that big. So your "small planet" theory makes decent sense on that front. Though I'm not sure that would create the same short variance in climate that you're expecting in and of itself. The planet could be huge. What makes for the climates we see on Earth is not just the size of the planet, but the distance from our Sun and how much heat gets to us. How long a particular piece of land is facing the sun directly, and so on. Even the change in angle from Summer to Winter puts enough of a difference in how much energy the surface gets bombarded with to account for our seasons.

Meanwhile, over in Equestria, the seasons are explicitly changed over by the ponies themselves. Either with magic in Canterlot or manually as seen in Ponyville. We've also seen the sun and moon behave oddly in the sky: Twilight shakily rose the sun in the S4 premier while Celestia and Luna were off waiting to be rescued. Hearthswarming Eve suggests that unicorns moved the sun and moon prior to the founding of Equestria, and presumably for some indeterminate period of time between then and the arrival of the two alicorn sisters.

So, while you didn't go into too much detail about the mechanics you have in mind for the magical manipulation of the sun and moon, it explicitly is not limited to just Celestia and Luna, nor is it limited to alicorns (Discord in particular isn't one, but you may dismiss that as a pedantic example since most consider him as/more powerful than an alicorn). Further, we've seen unicorns as/nearly as powerful as alicorns: Starlight Glimmer and Starswirl the Beareded come to mind. Overall, it probably takes "a lot of energy" to do it, but there is nothing specifically about Celestia or Luna, or about alicorns that lets them do it. They just have the appropriate amount of power. And, for them, it isn't that difficult of a task. They didn't break a sweat.

Last, but not least, we've seen that windigos are considered real creatures in Equestria. Even though the two places they're mentioned (Hearthswarming play and Snowfall Frost's story) could be fiction, we're led to believe they are either generally real or based on real events. Historical fiction at worst. That said, what keeps Equestria warm isn't the sun itself really, but the happiness and friendship of ponies. Otherwise active forces blanket the land in ice and snow.

Rather than a small planet or some muckity-muck with the sun being a certain size, distance, and temperature to still function the way ours does but scaled down, just treat it as a light in the sky. It makes more heat if it needs to (as seen in Daring Don't), but by and large, ponies are responsible for the weather, climate, seasons, time of day, and so on. And those places that are permanently frozen up north are ruled by the windigos.

6066400
there's some problems with the drag (if you want to get a rough number, I can give you equations). First, you only get drag when you're moving, so that means that your sun is also moving. Any significant motion implies an orbit (if your moving and have a roughly fixed distance you need to fall to keep the distance the same). Then this drag is going to impart a lot of energy into the atmosphere. i'm not a meteorologist, but I can't imagine this working out well. Your idea of Celestia and Luna to impart energy into the system isn't great. Ideally, you provide a constant force to counteract the drag. This makes the net force zero so the energy doesn't decay. If you have a twice daily boost, the sun and moon will start to fall as time goes on. This makes for really funky orbital mechanics and i'm not quite sure what would happen.

Rigidity of the moon wouldn't be an issue (assuming a rock like material). In terms of the inverse square law, I don't really see it being an issue. One thing to keep in mind with this is to use distance from the center, not the surface.

Like I said earlier, I'd also be hesitant to say that the planet is smaller. I'm not against it in general, but you need a different better explanation than what you have.

6067890

Although I just thought of a new problem I have to solve. How would the day/night cycle work in my universe prior to the first alicorns showing up. hmm... I'll have to put some thought into this. Perhaps the issue with drag on the sun and moon built up over many thousands of years.

you may want to look at uranus. Its axis of rotation is at 97 degrees compared to the orbit. This means that the north pole isn't "up" like earth.

6067899

The problem with applying constant energy (which makes more sense from a physics standpoint for sure) is that this is not how it is depicted in MLP. It is depicted as if there is some... thing that the princesses do to "raise" and "lower" their respective celestial bodies. They are seen applying some kind of intentional force or trigger at both dawn and dusk. There is also the problem where Celestia says to Luna as she becomes Nightmare Moon, "You must lower the moon!" Why? Why does the moon being up prevent Celestia from also raising the sun? Hence the idea that the moon and sun repel one another somehow, and must remain on opposite sides of the planet (no phases or eclipses, sadly if that's true). TBH, the whole thing is fubar. I've put way more time into justifying how it could work in a universe with consistent physical laws than I probably should have. Still, I'd prefer to get it as close as possible to a logical, consistent model.

Another factor to consider regarding the size of the world is that the official map of Equestria (as provided by 6067896 ) shows a significant climate variation between the top of the map and the bottom. The top indicates a pole of sorts, where the bottom of the map indicates a hot, dry zone similar to Mexico perhaps. Presumably, going further south would reverse this until one got to the southern pole. This would be the zebra continent in my universe, tropical and bordering southern Equestria. But if you look at this map and try to imagine that taking up the appropriate percentage of the planet's surface, there are suddenly very large distances between every single city. Between Ponyville and Canterlot, you'd have hundreds of miles. The whole thing appears to be very compressed compared to our real world. Hence the smaller planet.

6067938
The problem is that we're trying to make it work with our physics. Whatever universe Equestria is in could easily have an extra few fundamental forces of nature that are just messing with our ability to figure stuff out because it breaks our intuition.

6067896
All very good points. I do account for pretty much everything you brought up in the lore of the universe.

Distance between established cities remains a significant reason that Equestria is physically much smaller than its USA counterpart in real life. Given that thought, it's hard to justify the climate disparity between the top of the map and the bottom of the map unless the planet was quite small.

I'll grant that ponies do alter their own climate locally, though clearly, not globally.

The force behind moving the sun and moon I've got covered. It's a mechanism which requires a massive amount of energy, as one would expect to move objects that size. I go into detail about why the sisters can do it but not anyone else, though it's a bit complex to get into here. Discord could likely do it as well, though he has not been on Equus since day one. And neither have the alicorns, though they began showing up after a few thousand years from the very start. I do think I'll need to state the sun and moon as being "maintenance free" in the beginning, with a degenerative scenario causing the need for intervention and maintenance much further down the road, which is the current scenario. Eventually, I'll set the sisters free from their responsibility to manually maintain the sun and moon every single day, but that won't come until around the space age.

6066449
The required mass follows from Newton's Law of Gravitation. The force between two objects is G m₁m₂/r². For spherical masses, the relevant distance is the distance between their centers. The gravitational acceleration, g, at the surface of a planet is thus G M / R² where M is the mass of the planet and R is the planet's radius. If you halve the radius of a planet (thus moving the surface closer to the center), the planet's mass has to decrease by a factor of 2² to keep g the same. Note that this also means that the planet will be twice as dense (halving the radius of a sphere cuts its volume by a factor of 8).

Regarding radiating charges, you can read more about that here: https://en.wikipedia.org/wiki/Larmor_formula

Another solution might be to magnetize the sun and moon and have a strip of metal running around Equus. The two moving magnets would induce currents in that strip (just like in an electric generator) and slow themselves down in the process.

6067963

And that's a perfectly valid point. What I'm doing is trying to determine precisely what logical, consistent laws of physics would produce what we observe while still being largely intuitive for the reader and making for good storytelling elements.

I've already built the magical metaphysics model to great detail. There's just a few loose ends to tie up.

6067592
What Discord did to Equestria during definitely explains why the sun and moon need Celestia and Luna to move. Remember: Discord has chaos magic.

6068024
No, not Discord (at least for my headcanon) Remember the changeling throne? Discord's magic does have limits.

6068024

I wonder if I could use that. Like... Discord broke something, resulting in the sun and moon requiring constant maintenance. Kind of a sad origin story to what ended up being thousands of years of daily duty. The magnificent spectacle of raising the sun and moon would be reduced to a begrudged hack job to keep day and night working after that prankster screwed everything up.

[edit] Nah, I can't do that. Hearth's Warming in my verse predates Discord by like 150,000 years.

6067992
I don't think you can get a hard answer. The important thing is to be consistent and logical with the application of magic as this is the foundation of the world around us and physics. At some point, you have to just wave your hands and say magic. You may be near that point.

6068047

lol yes that's definitely a factor to consider. But currently, the model, lore, and history of the universe is very tight and 100% internally consistent. I'm really happy with it. Just got a few loose ends.

6067981
Let me clarify on one point I touched on briefly, but apparently didn't communicate well as a result.

In S4, Twilight raises the sun, on screen, because Celestia's power (along with Luna and Cadance's) is contained in her at the moment (so Celestia can't). Twilight's "handling" of the sun resembles me trying to draw a straight line in painting program using a mouse after drinking too many energy drinks (hint: I really suck at drawing). On topic, the sun was wobbled about the sky in an erratic fashion. This was done, partially, as a show of Twilight having way too much power inside her to handle well, but it also showed that the sun isn't, like, stuck on some path like an orbit. It is moved the exact same way unicorns move other objects: using telekinesis. Celestia has been doing this for centuries, so she makes it look pretty good.

Discord, on the other hand, just sort of pops the sun and moon up at whim during Return of Harmony. Both are in the sky at once, they don't seem to have any real force towards or against each other. They just sort of go wherever he felt like putting them.

And in the S4 premier,

They remained as such until the end and Celestia and Luna are freed. This appears to be what happens to them if they're not properly raised/lowered in the morning.

The idea that it merely takes "a lot of energy" seems off. Again the task was, according to reasonably believable canon-legend, performed by unicorns in the past. It seems more accurate to say that it takes primarily a particular spell (probably some kind of magical security feature on the sun and moon). Discord can do it not merely because he is "strong enough" but because he basically bypasses that security via chaos and generally not respecting "rules/scientific laws."

That spell might also need a fairly large amount of power, as we've only seen it performed by Celestia, Luna, Twilight, and Discord, all of whom are (assumed) to bemagically strong. I have heard theories in the past from other fans that back in the pre-unity days that several unicorns acting in concert performed the task. But how much force is needed to get the sun and moon moving doesn't appear to overly task Celestia, Luna, or Discord, while moving an ursa minor through the air did tax S1-Twilight Sparkle pretty heavily. Alicorn Twilight+3 more princesses worth of magic could shove the sun around easily, and indeed had trouble controlling it precisely due to too much force.

Another factor that this all boils down to is how much power does one alicorn have in her? When it comes to Celestia and Luna, we've only really seen them do two things: move the sun and moon (assumed to be a high-power feat) and a flashback fight between the two of them where they blow chunks of masonry up shooting at each other. We've now also seen Flurry Heart toss out a lot of power. Discord does a lot of seemingly powerful things, if you attempted to rate them in terms of raw energy overcoming physical forces.

But we have seen quite a few powerful unicorns do great things too. Starswirl the Bearded was so strong that Celestia and Luna respect him, Twi is his biggest fan, and so on. Shining Armor encased all of Canterlot in a powerful shield. Starlight Glimmer can fight (with substantial defensive advantage) Twilight to a stalemate, and the two duel for play/practice now. Pumpkin Cake can use her magic to go through objects and fly as an infant. Trixie, under Starlight's guidance, picked up transformation spells and teleportation (of other objects) with ease.

All in all, magic in Equestria doesn't really seem to operate under too much of a "if you have a bigger battery, you do more impressive stuff" mechanic to it. It appears more to follow a "if you know how to shape/craft your magic right, you can do impressive stuff." (also, if you mess with magic you don't understand well, there are bad side effects). Imagine instead that there is a whole lot of magic in the land, and knowing how to poke/push/prod it certain ways efficiently is how spells work, rather than "if I throw enough force at it, it does what I want."

So, my theory is that Celestia, Luna, Twilight, Cadance, Discord, and Flurry Heart are all substantially weaker than most people seem to think of them as, and they don't actually have access to "big giant batteries" to power what they do. Most of their more impressive magic comes from knowing how to do things right, not as a result of having enough magical force to. (in the case of Flurry and Pumpkin it is probably more due to having the raw emotions of a baby, as emotion seems to play a big role in how magic works too).

Overall, I guess the big contention I have with the "system" you're laying out, is that it relies on the idea that "it takes a whole lot of magic/effort." Things have to be small/dense, lots of force applied, etc. When in reality it seems more that ponies are all just magical, do magic stuff, and literally do a lot of jobs that our own natural forces do in a mathmatically consistent way.

There are hostile, powerful, and cold-loving forces making the region of the north cold. Not due to a distance from the sun as seen on our Earth. On a small planet like you propose, if the north pole was far enough from the sun/heat source to make it as frigid as it is around Yakyakistand and the Crystal Empire, then why isn't the entirety of Equus frozen? How is the "equator" close enough to the sun to be thawed out and tropical, while so close to the permafrost? A small planet has less room for extremes.

Indeed, the way the Crystal Empire works is that the Crystal Heart keeps the frozen climate out by channeling the "love and light" of the populace. Love, friendship, harmony, and their opposites are real forces in Equestria, and they have a real impact, magically, upon the land and denizens.

So, again I say, I don't think a "small planet" and accompanying physics answers the show setting. A large planet also fits. We're in agreement that their sun is nothing like ours. It clearly is not a large mass that Equus orbits. It does indeed appear to be a small bright object that they move around using magic, and may or may not have any physical laws governing its default behavior. It might be programmed to go a certain way or something. Maybe it tries to do a particular route, but it needs to be recharged each day, then put into sleep mode at night. But "follows strict physical laws, and needs lots of force applied to get it to behave each day" doesn't seem to fit at all.

Lastly, I am not sure where you get the idea that the sun and moon needing to be controlled is a "recent" thing. Again, pre-Equestria, the three tribes worked together, and the unicorns were able to demand tribute in return for raising and lowering the sun and moon (just as the pegasi received tribute for being protectors of the other two tribes).

6068086

This is such a fantastic post, and it thrills me to have discussions like this because I live for systems building and absolutely love designing this kind of thing. You made a tremendous number of really great points, so I want to reply to each of them, but I'm afraid it's going to be a rather lengthy reply.

I should probably start off by reiterating what I said a few posts up though, in regards to how regional climates work. Tropical vs arctic climate zones have nothing to do with the distance to the sun. It's all about the angle the sun appears in the sky. At the poles, the sun never gets very high in the sky where it can radiate a lot of heat onto the ground. In the tropical regions, the sun is very high in the sky for a long time, making the climate very hot. This is regardless of the size of the planet. It's all about shape and angles, not size and distance. A small planet has sharp climate zones just like Earth. I'll just get that out of the way so I can focus the next reply on the more interesting things you said.

6068086

First up, let's talk about Twilight's wobbly sun controlling efforts. I treat this with the same degree of seriousness that I treat the following moment from the show:

So... it's canon that Pinkie's head can swell up like a balloon when she holds her breath, and she can float off. Seriously, is that canon? Are we to take it seriously like this can actually happen? No, not really. Not if we are trying to be consistent and rational, which is something the show simply isn't. Often, we have to bend or completely ignore established instances of canon in order to maintain absolute consistency.

Moving the sun and moon about in the sky willy nilly because of "lack of know how" presents several consistency problems, not the least of which is "why the hell didn't Celestia bring the sun to hover over the Crystal Empire when Flurry broke the Crystal Heart and the blizzard started overwhelming everyone, creating a city-wide evacuation emergency? Really. Yes, we do see the alicorns attempt to fight the storm, but wouldn't it have helped to park the sun overhead to cut down the majority of the storm's fury? What this is, is the fact that the writers are simply not concerned with absolute continuity in the show. They will conveniently forget certain facts and limitations for the sake of new plots. This happens regularly.

Why is it important that the sun and moon not be able to be up at the same time? Probably because the more established canon lore is that Nightmare Moon refused to lower the moon, thus preventing Celestia from raising the sun, resulting in endless night. Celestia said to her, "Luna, you must lower the moon!" Luna's refusal to do her part prevented the sun from being raised, somehow. It's not explained, but we do know this to be the source of the main Nightmare Moon conflict, which is arguably the most fundamentally important conflict in the entire show. Luna was not in charge of the sun. She was in charge of the moon. Thinking that through, these are the conclusions we must face, inconvenient as they are.

But since Discord was the one responsible for the example you gave, I'm going to give this a pass anyway because Discord is more powerful than Celestia and Luna combined, clearly. It is a demonstrable fact, and in my lore, I explain exactly where he got this power from.

Next, let's talk about the unicorns of the ancient past controlling the sun. I'm going to have to agree with this, as much as I don't want to. In the Hearth's Warming legend, Spike narrates that the unicorns demanded tribute for their services of creating night and day via their magic. Sure, the unicorns may have been bullshitting everyone. Maybe they weren't actually doing a thing. But I'd say it's likely that they did control the sun and moon as a collective effort of perhaps a thousand or more unicorns. The problem I'm presented with is from the days when there were fewer than a thousand unicorns living. My history goes all the way back to the very creation of the universe, and if the Equus system required magical manipulation for day and night to exist before the ponies were numerous enough to achieve this, it's a little bit of a problem. Fortunately, I can get around this because the designer of this planetary system would have accounted for that issue. Likely, the architect of Equus made the sun and moon maintenance free for the first thousand years or so until pretty close to the Unification event. It's a minor issue, but I like my lore to be 100% airtight, so I do spend time pondering solutions to these things.

Next, I'll address the whole "powerful enough to do x" issue. My original statement was oversimplified. The model I'm using is actually much more nuanced than I insinuated. Moving the sun and the moon would require immense magical energy, but this energy is wielded rather than generated by the alicorns. It's similar to how we wield engines of cars which produce much more power than our muscles can. There is a mechanism which moves the sun and the moon, but it requires a certain degree of power as well as skill to access it. I can elaborate if necessary, but that's the very short version. Importantly, there's a certain type of magic that no mortals have access to which is required for tremendous feats such as this. More on that later.

You're absolutely right in that it isn't a significant effort for Celestia and Luna to move the sun and moon. Again, this is because they have access to wield the power necessary. And they do not have full freedom to use that power however they wish. They can't apply it in a battle, for example, to defeat a very powerful foe. My metaphysics model goes into great lengths to explain the nature of this pair of alicorns and why they can do certain astounding things while they seem so limited in other areas. It's an inconsistency in the show which bothered me so much that I felt the need to break it down and rationalize it. I can say with certainty, now, that it all makes perfect sense. At least, apart from the blatant "alicorns are weak" episodes, which I shamelessly ignore. When I see the royal sisters quite obviously impotent, I object in the highest regard.

I define very precisely how much power the "mundane alicorns" (which is the name I give to the type of alicorn the royal sisters are) have. This type of alicorn has approximately 10-50 times as much strength both physically and magically as a mortal unicorn. In a fight with a mortal, it is no contest. In a fight with a whole army of mortals, especially if they have potent weapons, that is another story. The mundane alicorns are not all powerful by any means. The ascended alicorns are even less powerful, sitting at approximately 50% greater physical and magical strength than a mortal unicorn. This would be Twilight and Cadence, having much less strength than the royal sisters. They are the most fragile of the Immortals, and their strength is demonstrated as relatively in the same ballpark as very strong unicorns.

Flurry Heart is yet another story, since she is what I call a natural alicorn. Natural alicorn children are a mixed bag. They start out as children wielding similar strength of magic as adult mortal unicorns. Apart from Flurry Heart, the only example I have is Nyx in the story Past Sins, who wields exceptional magic at a very young age. The royal sisters grew up as natural alicorns until they matured and settled into their current state after a complex series of events which could have resulted in them becoming much, much more powerful than they are now, but they chose instead to remain with the mortal ponies. I can elaborate on all this if necessary, but it's a lengthy story.

You mentioned a few other characters worth noting. Pumpkin Cake clearly has some exceptional gifts, especially in the area of phase space. It's similar to the "bypass shields" in Fallout Equestria. Unicorns are occasionally prodigies, like Twilight. Pumpkin likely has a very interesting future, though I haven't given it a lot of thought. As for Trixie, she's one of what I call "Multi-Talented Unicorns". Unicorns tend to be able to study only one certain field of magical application, but occasionally, a unicorn is born who is able to learn any field of magical study, making them "multi-talented". They are a jack of all trades, but not particularly skilled in any one area. Extremely useful for story characters who can be relied upon to produce tricks that get the characters out of a difficult situation. MacGuyvers of ponykind. Trixie is one, and Twilight is also one since she is so versatile. Twilight is also a magical prodigy, which makes her even more unique among unicorns.

I break down unicorn magic into three key attributes. Capacity, throughput, and skill. Each of these operates independently to define the "power" of a unicorn. Capacity is how much magical energy they store. Throughput is how rapidly they can apply energy to a spell. Skill is the knowledge of how to apply this energy. These three principles of magic are critical to my lore and determine what every character is capable of.

You mentioned Starswirl. He's a character I've gone round and round about what to do with. I finally decided to make him the most influential character in all of ponykind because he was the creator of ponykind. His true form is as a magnificent alicorn, and his realm is external to the physical universe. He is a member of the type of living beings known as "Eternals" which are timeless. They created the physical universe, and the only way they can interact with the people within the universe is by entering as avatars. Starswirl's usual avatar is an elderly bearded unicorn with the funny outfit. He appears in several key points thoroughout ponykind's lengthy history over the course of countless millennia, but nobody truly knows where he comes from or where he goes when he's not around, or especially why legends exist of him interacting with ponies so far apart in the timeline. As an Eternal, Starswirl is literally capable of anything, though his influence is limited by the fact that too much interference or intervention in ponykind's history would have prevented their ultimate success as a species. Sometimes, he needed to allow terrible things to happen for their ultimate fate to turn out favorably. He also was not the only Eternal who created sapient life in the universe. Some created races which were allies to the ponies. And some races were mortal enemies.

Sometimes, the show gives us instances of ponies doing things which break the overall narrative by creating an irreconcilable imbalance of power. A good example of this is Shining Armor's city-wide shield. Honestly, that is way overpowered. If Shining is capable of such a thing, there is no excuse for not employing him in any crisis which could be solved by a massively powerful shield caster. But we don't see this used any time other than that one moment (when the plot needed it). In cases such as this, I view that as a writer contrivance rather than a canon fact that can be applied universally.

Another example is what happened with Tirek. Tirek is blatantly incompatible with my verse. Why? Because Tirek's whole schtick was "stealing magic" from ponies. And in a way which left them permanently incapacitated. But that's just not how magic works in my universe. Ponies recharge their magical stores continually from the environment (something called the Lifestream). So it is physically impossible to permanently steal their magic. Sure, you can drain them to the point where they burn out. But give them two hours, and they're fine again. So Tirek's whole style is incompatible and thus I've left him out of my story's lore and history. Which is unfortunate because so much was influenced by that attack. It's a major headache to work around it.

Regarding the "big giant batteries" angle, that's a yes/no situation. I've got a realm known as the Aether, which is a source of infinite energy. It is where the Eternals live. But this energy is not just available to anyone. One must have a "link" to the Aether to draw power from it directly, and the nature of that link determines both how fast power can be drawn as well as what application it can be used for. Celestia, Luna, and Discord all have links to the Aether, though Discord's is stronger. Objects can also have links to the Aether, such as the Elements of Harmony. In fact, Discord was the original bearer of the Element of Magic some 5000 years ago, and he used its power on himself to alter his capabilities, essentially like someone who tells the genie "I wish for infinite wishes". He was originally about as powerful as Twilight, but he gave himself a link to the Aether, thus granting him astounding levels of power. Discord was originally planted on Equus by the Windigo, kidnapped from his home planet where other Draconequus live. His love of chaos fit the Windigo's scheme perfectly in the hopes that he would eventually disrupt Harmony enough for them to attack once more. The story of how he was originally defeated is rather interesting. I've only recently finished working out that scenario.

Regarding the Crystal Empire, I've got that as an ancient mining community which was originally established prior to Discord's invasion. The frozen north is a massive crystal biome, and ponies originally set up mining outposts to mine both inert and magical crystals for use in Equestria proper. These mining outposts were difficult to maintain, and so a major operations hub was set up to govern them all. This became known as the Crystal Empire (because an empire requires many small satellite entities which it has jurisdiction over). The city-state applied for, and was granted, independence from Equestria under the condition that it would maintain permanent trade relations with the mainland. The Crystal Heart is an artifact that has a strong link to the Aether. Its power is used to maintain the artificial weather dome which keeps the city comfortable and warm. It also was tuned to provide sustinence for the entire population of changelings, which had suffered a famine during the war a decade or so after MLP.

That seems to cover most of the main talking points you raised! I hope this helps paint a consistent and rather intriguing picture of the whole universe. It's a very small peek into the overall lore, but those are the bits pertinent to what you mentioned.

6067890

Sorry, I'll have to correct you on this one. The tropical equator of Earth has nothing to do with it being "closer" to the sun. The sun is 93 million miles away. The equator is only about 3000 miles closer to the sun than the poles. An insignificant difference. The reason for the equator being tropical is because it has more direct sunlight than the poles. Overhead sun is much more intense than sun on the horizon. And at the poles, the sun is never very far overhead. This wouldn't be any different on Equus.

I think you are right... and wrong. The angle definitely has something o do with it, but so does the distance. I took the liberty of googleing 'why is it warmer at the equator?' and the first hit was this:

Because the equator is closer to the sun. ... Because the sun's rays hit the earth's surface at a higher angle at the equator. e. Because the sun is always directly overhead at the equator.

It's not just the angle, it's also the distance. I learned something new! That being said, controlling the size of the world for the sake of your plot is totally fair. Keep up the good work!

6072030
Thanks! There's definitely much, much more where that came from. It's good to see people enjoying it, believe me.

I took a look at the link from your google search which you mentioned. Here's a quote from it:

One of the most common and persistent scientific misconceptions is that Earth's seasons are caused by Earth's distance from the sun. A closely related and perhaps more common misconception is that the equator is warmer than the poles because the equator is significantly closer to the sun than are the poles (i.e. the equator "bulges out" toward the sun).

Though here's a helpful link for you.

The Earth's perihelion is five million kilometers closer to the sun than its aphelion. That means the earth's orbit varies by 5,000,000 km over its entire cycle. Yet the difference between the equator and the pole in distance to the sun at any given time is a mere 5000km. And the perihelion vs aphelion difference makes effectively no difference in the Earth's weather. Compared to 93 million miles, it's pocket change. Trust me, it's purely the angle of the sun in the sky, not the distance to the sun. When you consider how far the sun is from us, the poles are only 0.00538% further away than the equator. Going by the inverse square law, that means the sun's radiation (in space) at the distance the equator sits vs the sun's radiation (in space) at the distance the poles sit isn't even enough to make a hundredth of 1 degree difference.

6072043
I haven't read it yet, but I opened it in a tab to be read when I have time.

Don't seasons change from Summer to winter etc... because the earth tilts on its axis?

6068353
At some point in our conversation I realized you were having this discussion for the purpose of creating/polishing your own AU, rather than attempting to explain canon in some manner. I lost most of my interest in the conversation at that point.

Overall, seems like you're either well thought into it or well on your way to getting to that polish. I wish you luck in you project. Most of what you've described seems internally consistent and workable. What few objections I had to it have been satisfactorally answered, such as the "amount of energy needed to move the sun." Most of that energy being outside the unicorn/alicorn doing it, and merely being directed/nudged by the pony is pretty much in line with what I was suggesting ought to be the case.

Re: canon facts vs visual gags: you are working with a source material more keen on its jokes than its own internal mechanics. I'd be generally wary of chalking up things as visual gags unless doing so is unavoidable. As long as you're aware of which ones you're deciding are and which ones you are deciding are not, and why, and remain consistent about it, then your AU should be fine. Also, what is and isn't canon has very little importance to an AU.

Everything else consider conceded without caveat or expansion.

6073343

That's exactly right. The earth's rotational axis is tilted at 23.5 degrees from its orbital plane. Since the earth's axis always points at the same absolute position in space, the north and south hemispheres vary in the amount of sunlight they get over the year in very predictable ways. This is exactly what determines the seasons. On December 21st, the north pole is pointing as far as it can away from the sun, while on June 21st, it is pointing as near to the sun as it can.

Here's a handy video illustrating the basics.

6073385
Indeed, that is all true, and thanks for the well wishes. Though I should point out that for my particular project, I've made every effort to make the AU as close to MLP canon as possible without becoming either (a) self-contradictory, or (b) irrational.

In other words, those visual gags we're discussing would certainly not be a canon mechanic in my AU because a rational universe must maintain physical laws. Even one where prolific use of magic is a regular thing. If ponies are effectively made of rubber, how can we form a consistent damage model if they are wounded? That's just one of a multitude of examples.

Aside from the visual gags, there must also be things like consistency in exactly how magic works, or the power levels of alicorns, which was always a conundrum for me until I found a way to resolve it. MLP is terribly inconsistent in that regard. Overall, my AU is definitely meant for fans of canon MLP, and I never take license with major alterations unless it's unavoidable. Almost every important historical event or person given in the show is included and explained.

There's also a whole lot of expansion outside the scope of the show. Everything from origins to eventual spacefaring civilization is covered, but that is mostly a framework for the purpose of writing potential stories.

In case you're interested, you can view the basic notes on the universe structure and metaphysics here. I think you'll find them ridiculously comprehensive. I'm also working on a full verbose lore document which I'll release as a blog series eventually, but that's on hold until I'm finished writing a story chapter that is my current priority.

6073437
I've been meaning to respond to this for a while! Thanks for the info, I learned something new and I can see that my earlier belief was wrong. It's hard to admit that and it's especially hard to admit that online! Thanks for taking the time to educate me and write on my friend, write on!

6101231

Thanks for the encouragement!

Hello is this thread still active?