NOTE : This is a THEORY. It is not confirmed, and you are free to have your own theories or just stick with what the show says. This post is just an idea I had which I wanted to show because I thought it was interesting. I am aware that MLP is a cartoon, and thus has cartoon physics, but it's fun to speculate! Also, I'm not doing this because I hate Celestia. I love the Alicorns, don't worry.
Throughout the show, it has been established that Celestia raises the Sun, and Luna raises the Moon, in order to create a day and a night on Equestria.
As a kinda scientific person, I always doubted it, but My Little Pony is a show involving talking ponies and magic, so the laws of physics could be very different and the Sun could very well be very tiny and orbit Eques (I'll call the planet Eques, because I believe Equestria isn't the whole planet). Or Eques could be flat, having the Sun and the Moon around it and moved by the Alicorns.
First, let's be clear, Eques is not flat. Why am I so sure of that? Look at that picture from Secret of My Excess :
A spherical globe of the planet. Thus, Eques isn't flat. (Also, judging from the continents, maybe Eques is an post-apocalyptic Earth, in the distant future? Hard to tell, as they seem unclear and change quite a bit in when a globe is shown, so I'll not expand on that)
So, with the flat theory out of the question, it is still possible that the Sun and the Moon are somehow moved around the planet by the Alicorns.
But, as I was watching the premiere of the sixth season, inside Sunburst's house, I saw this :
A...solar system model? With the Sun in the middle? Oh. My. God. This changes EVERYTHING!
And, it's not a random background element, it's in the middle of the screen for a few seconds, so it's meant to be seen.
There is a planet with a moon in the front. We can assume it's Eques and the Moon, orbiting around a big Sun with several other planets (I want a space episode now).
This model clearly shows Eques orbits the Sun, and the Sun doesn't orbit Eques...and Celestia moving such a large star around Eques would use waaaay too much energy and potentiality cause chaos in the solar system, sending planets colliding with each other.
But wait! It's impossible to say that Celestia is faking the whole thing, as in the finale of Season 4, we see Twilight trying to raise the Sun, but having some trouble with it, so something is happening.
So, if the alicorns aren't moving the Sun, and they aren't faking it, it can only mean that they are actually spinning the planet around it's axis! I made a diagram to explain it.
(Get ready for horrible, not to scale MS Paint drawings)
In this diagram, Equestria, the dark green continent, is in the dark. It's nighttime, everypony is sleeping.
Celestia decides to "Raise the Sun", so she uses her very strong magic to rotate the planet around the axis.
The planet spins around the axis, the sun appears to move in the sky, as if Celestia was raising it, and ta-daa! It's day! Everypony thinks she raised the sun, even though she didn't!
How about Luna? Well, she also does some work, as she spins the planet around again. HOWEVER, she is ALSO moving the Moon. Luna is constantly holding the Moon in the same position, and moving it along Eques' orbit around the Sun, because if she didn't, the Moon would show up during daytime, and confuse everypony. But, wait, there is more. This Moon could also be a bit magical. While it was being moved around by Luna, it stored some magic. If the Moon ever passes in front of the day side of the planet, the magic will cause it to absorb the light coming from the sun, bathing the day side in night. This explains how Nightmare Moon, in the very first episode, could cause a perpetual night :
It also explains the split sky in Season 4 :
The Moon is simply overlapping a little with the day side, but not enough for the planet to be entirely dark.
And now, let's answer a few questions this theory creates :
-How did the planet spin before ponies evolved?
I think the planet did spin before ponies evolved, but it was very slow and kinda erratic, due to the proximity of the Moon and the tidal forces. The ponies helped it stabilize.
-Couldn't Celestia just give the planet a push and let it spin, without her having to do anything?
She could, but her status wouldn't be as glorious. Moving the sun is a glorious accomplishment.
-Why doesn't everypony knows about it?
Simple. To preserve their "godlike status", the alicorns set a strict rule. Anypony discovering about the secret and revealing it would be arrested, and the memory of the ponies erased using magic. Sunburst seems to know about it, and anyone studying magic and astronomy probably would.
-What happened when Twilight had trouble raising the sun in Season 4?
I guess she just trying to spin the planet but ended up moving the axis, thus causing that weird erratic sun movement.
-Since the ponies have to manually change the seasons, does it means the planet has no axial tilt?
Yes!
-If then, why can't the princesses change the tilt to get seasons?
The changing of seasons is an old tradition in pony history. Why would they change it? It's mostly viewed as a fun activity.
-Wouldn't everyone be flung away when Twilight rotated the planet really fast?
I guess she knew about the whole thing and protected the ponies with some kind of "anti-flung" spell?
-How did Discord switch day and night so fast in The Return of Harmony Part 2, without destroying the planet because of tidal forces?
That one is really hard to answer. He moved the Moon really fast, in such a way it eclipsed the Sun. As he brought the Moon close to the day side, the light from the Sun got "sucked" into the Moon, thus making it look like the Sun is being dragged down. Smart Discord. Smart Discord.
So, this concludes my theory! Basically, the alicorns spins the planet around the axis, and the Moon has the power to absorb light, but it's usually kept behind the planet, to avoid confusion and darkness. (I might be overthinking it a little bit, but I like to overthink things!)
END NOTE : I'm not trying to discredit Celestia. Moving the planet is still an accomplishment, but it just makes more sense than moving the sun physics-wise. Some could even argue that it's better, because if she did move the Sun, it would have to be very small in order to orbit around Eques, and she would have to move a much smaller mass.
Tell me what you think of it!
I would classify them, from worst childhood to best childhood, like that (Before they got their cutie mark, of course) : Applejack - Pinkie Pie - Rarity - Fluttershy - Rainbow Dash - Twilight Applejack : Her parents died when she was very young, and she was raised by her grandmother. I'm not sure this was such an happy childhood. Pinkie Pie : She had a gloomy family and did a tiring and boring job. Rarity : Probably had very strict parents and rules. Fluttershy : Okay, she couldn't fly very well, but at least she could fly. The bad thing is the bullies. Rainbow Dash : Same as Fluttershy, except she could fly better and maybe was less affected by the bullies. Twilight : Maybe she had no friends, but she had quite a loving family and good life conditions.
I find baby ponies to be very cute. I especially like the big heads and cute eyes. However, just like the user above me, I think that even if they are cute, they can be really annoying sometimes...
But how could this become canon? I'm not sure the writers even check the forums, plus it would be a pain to introduce into the show, wouldn't it be? I also had a mini overthinked overthinking an overthinked thing : That solar system model is placed just in front of the camera. As my theory states, it could reveal an hidden truth...can this actually hints to a big reveal later in the season? Okay I'm overthinking it too much now. And also...I was wondering...do we have any actual solid proof she isn't lying about that sun-raising thing only to get her godlike status? I might have missed something though. I'm not that kind of guy who gets ALL the details.