Quantum Pony

How does the Equestria Solar System look like?

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I created my own headcanon for the Equestrian system not too long ago. I made it similar to our system, but with some notable differences. The first 6 planets are mostly based on the ones in the image that @Scar posted, with a couple of changes. I then added 6 other planets that are more distant and were not known to the ancient Equestrians, for a total of 12 planets.

They're in the spoiler below if you're interested. :)


The Sun

A yellow G4V star, similar in size to our Sun. Princess Celestia does not raise it, that is just illusionary magic.


Inner (Terrestrial) Planets:


1. Ultus

A small, scorched Mercury-like planet orbiting extremely close to the Sun.

Moons: none


2. Jalis

Another Mercury-like planet close to the sun. It is slightly larger than Ultus.

Moons: none


3. Kovestum

A hot and heavily cratered planet, similar in size to Mars.

Moons: 2


4. Renaia

The Earth-like world where Equestria is located. It is the only planet in this system to support life. Princess Luna does not raise its moon, that is just illusionary magic.

Moons: 1


5. Wistrol

A large rocky planet, about twice the size of Renaia, with a hazy atmosphere and a prominent ring system.

Moons: 5


Outer (Giant) Planets:


6. Doukall

A massive super-Jovian gas giant that is four times as massive as all other planets in the system combined. It was the most distant planet known to the ancient Equestrians.

Moons: 57


7. Merlanos

An acid green gas giant, slightly smaller than Saturn, with a highly prominent ring system.

Moons: 39



8. Ferlatta

A white ice giant with a faint ring system, the most distant planet visible to the naked eye from Renaia.

Moons: 17


9. Olyria

A bright blue ice giant with a highly prominent ring system. It is the largest of the ice giants.

Moons: 23


10. Seforia

A deep purple ice giant with no visible ring system. It is the smallest of the ice giants.

Moons: 14


Distant Planets:


11. Axtum

A frozen Mars-sized planet three times as far from the sun as Seforia, traveling in a highly eccentric elliptical orbit.

Moons: 2


12. Zylonda

A dark ice giant orbiting at the furthest edge of the system. Its gravitational effects distort Axtum’s orbit.

Number of moons unknown


Edited by LyraLover 💚

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23 hours ago, Quantum Pony said:

Hi @Dreamstar Moonlight Thank you so much for the detailed comment!!! I am really glad you liked it! :pinkie:

Yes! You are absolutely right! By classifying magic as a fundamental force of nature, it is very likely that the values of certain fundamental constants of the Equestria universe will be different than ours. And since whether or not a fusion reaction occurs heavily depends on these constants, it is not impossible to happen with a much lighter star. 

This is absolutely beautiful! This scene settles the question of flat vs spherical earth once and for all!

So, in a the Hearth's Warming eve episode, Pinkie (Chancellor Puddinghead) remarked that the world is round, but that didn't really settle the question as Equestria can be disk shaped or spherical. But the video you linked shows the image of (what seems like) Saturn's ring going around it. So indeed! it looks like Equestria IS spherical (which makes the computations above much easier to perform). 


Ohh I see, indeed then the tides will follow similar pattern as Earth's tides. So far I am constraining myself to the MLP universe from the episodes, but including the IDW comics will be really interesting and enriches what we can say about the structure of the universe. There are some very interesting things in IDW comics from parallel universes to time traveling Observers that one can explore.


So here I'd argue that  just like how Earth's moon have different phases despite being tidally locked, Equestria's moon can have different phases too. However, since we do not see the 'dark side of the Equestria moon' I would argue they are tidally locked. This would in fact lead to a situation where Equestria experiences all the different phases from waning crescent to waning gibbons in a single day :) .

Ahh! This looks very interesting. I will take a closer look at this and perhaps it will give me a different view on how tidal locking works in Equestria. Thanks for the link!! 


So based on the model here I'd say it is geocentric. Although now that I think about it, it is possible that whenever Celestia 'moves' the sun, one can imagine the Sun being the massive object in the centre of the solar system and Celestia uses it as a pivot to move the Earth around it. But this would mean Celestia wasnt really upfront with 'moving the sun' bit for the last thousand moons ;) . 

This is a very interesting question!

Following the model here one might be eager to say that a 'moon' is a single day. However, that clearly contradicts many evidences in the show. For example, a thousand moons would then only be a few years. If that is true,  Twilight and her friends would have seen the reign of the two sisters when they were younger... So this puts a lower boundary (of a day) on what a moon can be. 

On the other hand, a moon can't be too long either, since Equestria portal opens once every 30 moons, so its probably not on the same scale as a year. This puts your predictions of 7 to 29 days nicely within the boundary. It is likely that 'a moon' and 'a year' is not trivially defined by the orbit of Sun and Moon around Earth.  I will need to do some more thorough research on this before getting back to you :secret:.                       

   Having a chronology of events that includes all MLP related material is an enormous and amazing task! It requires an abundant knowledge of the show's material and from your responses above I'd say you definitely have such knowledge! :) I would love to see it when it's completed! :) 

(p.s: Would the timeline also cover events happening in parallel universes too? It will probably be just a branch off the main timeline, but some of them (like the opposite/mirror universe) does deviate from the main timeline quite early in Equestria history :ooh:. )

Thank you for your detailed response! I will think about the length of a moon some more and get back to you :) !


@Quantum Pony

Thank you for your comment!

And I'm so happy that you agreed to most of my points! As for the Equestrian moon going through all of the phases in a single day – I don’t think that particular fact would really affect my chronology in any particular way, so I’d be happy to agree with you on that point.

Here's another thing I think I can clarify for you.  The Equestrian solar system is indeed geocentric, and this image from Part 2 of the season 4 premiere proves it!


(I only found this image after I posted my original comment – barely a couple of days ago). So that’s another point we can both agree on.

Going to the subject of ‘moons’ (the unit of time) – that’s a very tiresome topic because it can be anything from (approximately)  3 days to a week or even 27-29 days (but less than a month), depending on the story. Jayson Thiessen went on record saying that a ‘moon’ has ‘no human equivalent’ [source: https://mlp.fandom.com/wiki/Moons ], so I don’t think it would be possible to pin down an exact value. However, if you do manage to come up with a plausible theory (however far-fetched it may seem to you) that can explain how ponies define a ‘moon’ (preferably 1 moon = 3.42 days or 7 days – I’ll explain the reason in my final project), I would be delighted to hear it!

As for your question,

“Would the timeline also cover events happening in parallel universes too? It will probably be just a branch off the main timeline, but some of them (like the opposite/mirror universe) does deviate from the main timeline quite early in Equestria history.”

The answer is ‘Yes!”. And although at first glance, it may seem that the mirror universe deviates from the main timeline continuity; in actuality, it does not!

You may be surprised, but if you probe deeper into the storylines, you’d notice that there’s a lot of ‘ambiguity’ involved, and my friends and I, with the help of other fans have come up with explanations that tie together everything as well as can be expected, while staying as closely as possible to the canon material. I apologise if I sound vague, but attempting to explain all of this would take me another couple of pages! You’ll see what I mean when I finally post our notes on the mlpforums site and my DeviantArt page. I’ve already completed up till season 5, and and made rough outlines covering seasons 6-8. Season 9 doesn’t need much re-arranging, so I’ve kept it for the last. Hopefully, if everything goes as planned, our work will be complete by the end of this year, or the first week of January, 2021. And naturally, your work will be credited!

Thank you again for taking the time off to reply to my comment! If you have any more updates on your model, I’d love to check them out.

Have a great day!

- Dreamstar Moonlight


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Hey @Quantum Pony!

I thought I’d share with you my theories about how long a ‘moon’ is in the equestrian calendar, since these may help you come up with an answer based on your model. So, without further ado, let me present the possible answers to the most headscratching, annoyingly tiresome question:

"How long is a moon?"

This topic has been speculated for so long that now there are now several varying answers to this question. The commonest answers are:

1) 1 moon = 1 lunar cycle; approximately 27-29 days (but less than a month)

2) 1 moon = 3.42 days (average length of each phase of the moon)

3) 1 moon = approximately a week

4) "Many moons" is an arbitrary term to mean a very long period of time. Kinda like how we say "it's been ages since we last met".

Theory (1): 1 moon = 1 lunar cycle: 27-29 days

This theory is most widely accepted, and it does explain why Twilight freaked out when Luna told her the portal to the Equestria Girls world would close in 3 days, and Twilight won't be able to return to Equestria for another 30 moons (approximately 3 years). It also makes sense for Twilight and her friends to meet "once a moon" (once every 27-29 days) when she establishes the Council of Friendship.

But this concept throws a hammer in the works if you consider Granny Smith was speaking facts when she mentioned that the Apple Family Reunion takes place every 100 moons. That means the Apples hold a reunion every 8 years or so. But seeing that there was a reunion in the pilot episode and another in season 3, and the fact that seasons 1-3 take place within a single year, it makes much more sense if 1 moon = 3.42 days so that 100 moons = 342 days, thus placing Apple Family Reunion 23 days before Summer Sun Celebration (June 21) in season 4.

Also, if according to your hypothesis, the moon goes through all of its phases during a single day, then this theory goes down the drain. Also, if you assume that 1 moon equals 1 day, well, that theory wouldn’t hold water one bit. I doubt the Apples will hold reunions every 3 months if we go by the logic. And the Council of Friendship would have to meet every single day. We know that's not the case.

Theory (2): 1 moon = approximately 3 – 3.42 days

Going by this theory, when 100 moons have passed, that means it's been 342 days since the first reunion we saw in the pilot episode when Twilight first came to Ponyville. Assuming that an Equestrian year has 365 days, the Apple Family Reunion we saw in season 3 takes place around 28th of May  (23 days before the Summer Sun Celebration on June 21).

When Twilight suggested that she and her friends meet once a moon' (The Last Problem), and Rainbow's comment to Luster Dawn that they meet "this time, every moon) .....Do you think it's plausible that they meet every 4 days (the closest approximation to 3.42)? Or does it seem to be too short a period?  Granted, meeting once a month makes sense considering they all have jobs and are trying to schedule a meeting with the ruler of the land, but....


Also, another user gave a plausible explanation to this theory; their reason being (and I quote):


.......Assuming the portal works once every 90 days (~1 season on Earth): There would be an astronomical reason for the portal to be opened on each of the equinoxes and solstices: the combination of the inclination of the planet, the elliptical shape of its orbit and its rotation will provide the exact same predetermined alignment with a distant star (if it was programmed to recognized it through typical parameters like "ascension" and "declination"; then establish a connection). This is a "brute force" safe mechanism. If the system had an ansible to look for [like the book] as a reference to draw 3 spatial coordinates (using 3 known points visible from both planets used as "zero" for reference) and the point of origin [the statue itself]; then it will work just like a Stargate. The occultation of that star by the local moon of the planet interrupts the connection [probably a safety mechanism prevents its use since the matter/energy transmission could be affected by its local gravity well ]; then when Pony! Twilight overrides this, she risks having a "telefrag" if she uses it at the night when the moon is high [both in Rainbow Rocks and The Friendship Games, the portal was used (or tried to be accesed) always during the day; maybe because she has figured this problem].”

Theory 3) 1 moon = approximately a week

Honestly, I haven’t found anything to support this theory. So I’ll just leave it like that for the time being.

Anyway, hope you find this useful!

As always, I’d love to hear which theory you support based on your model of the solar system!

Have a fantastic day!

-          Dreamstar Moonlight

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