A New Dawn
Applejack guffawed. "Sure, Twi, when there's a Summer Sunraising Festival we pretend like Princess Celestia is raisin' the sun, but we don't really BELIEVE it."
Twilight stared at her friend.
"Twilight? You ok?"
Twilight answered, "I'm fine. I think I just...misheard you, somehow. I thought you said Celestia doesn't raise the sun."
"That's right."
Twilight gasped. "You said it again!"
"Ah sure did."
Twilight's powerful magical glow grabbed onto Applejack, and dragged the earth pony behind Twilight, towards Ponyville Library. "AJ, let me PROVE it to you!"
***
Ten minutes later, Twilight ran from shelf to shelf inside the library, grabbing books, speed-searching through them, and leaving them open on a table.
"I can't believe these science books ALL have the same mistake!" Twilight wailed. "Who decided to put these defective books in the library, anyway?"
Applejack chuckled. "This last book is brand new, Twilie. Ah reckon maybe YOU ordered it."
"No!" Twilight screamed towards the sky. "This can't be happening! It must be...some kind of coverup. Maybe it's a trick, to distract evil villains from trying to ponynap Celestia and ruin the sky's proper cycle of day and night!"
Applejack shook her head. "What Ah told you is just basic science. The world orbits around the sun, and spins on its axis, and the spin is what gives us day and night."
"That's a lie!"
"It's the truth. Celestia ain't got nothin' to do with it. Ah'm just tellin' you what everypony learns in school as a foal."
"That's a lie too!" Twilight pointed an accusing forehoof at her friend.
"Which part is a lie too?"
"That everypony learns your crazy superstition in school as a foal!"
Applejack carefully adjusted her hat again. "Ah see. So you...know somepony who didn't?"
"That would be me!" Twilight said proudly.
Applejack put one hoof over her mouth, trying to stifle more giggles. After a minute, she said, "Ah see. So where DID you go to school?"
Twilight straightened up with pride. "The best school in Equestria! Celestia's School for Gifted Unicorns, in Canterlot!"
"Ah see." The earth pony's mouth twisted up into a half-suppressed smirk. "And...who would happen to run this school you went to?"
"Princess Celestia herself! The smartest pony in the world! So that PROVES it!"
AJ took a deep breath. "Ah see. So the smartest pony in the world...or the pony who CONVINCED you she's the smartest pony in the world, anyway...runs a school that just HAPPENS to tell you the sun literally shines out of her cutie mark."
"That's not what I said at all!"
"My apologies." AJ took another breath. "Twilight...Ah understand that a really strong unicorn, like yourself, can lift a whole pony. But the sun is a lot bigger than a pony. Ain't nopony can lift the whole sun."
"Celestia can!"
"And if Celestia CAN lift the sun...what keeps the sun from fallin' back down again, as soon as she gets distracted? If somepony sneaked up behind Celestia and yelled 'boo!' would the sun plummet? Or what if Celestia didn't get enough sleep the night before, and she takes a little nap without meanin' to? Would the sun fall straight down and crush everypony?"
Twilight shook her head. "I'm going to find some ponies who aren't as crazy as you, and make you see reason!" She ran out of the library.
Applejack wiped her forehead with one foreleg. "It's sad," she said, "to find out one of your best friends has been brainwashed by some cult. Ah shore hope she can get over it."
***
Twilight knocked on the door of a cottage. "Fluttershy?" she said. "Something terrible has happened!"
A moment later, the door opened. "Hello, Twilight. What's wrong?" asked a butter-yellow pegasus.
"Applejack thinks Princess Celestia doesn't raise the sun! How can anypony be so ignorant!"
Fluttershy looked at her friend, blinking a few times.
"And what's worse...somepony tampered with all the library's science books! Now those books say the world revolves around the sun, not the other way around! And something about the whole world spinning like a top, too!"
Fluttershy blinked a few more times, saying nothing.
"Fluttershy! How can this be happening?"
Fluttershy thought for a minute. Finally, she said very softly, "Twilight...I understand your religious beliefs are very important to you. I would never disrespect them."
Fluttershy nodded, turned around, and went back into her cottage. She called back over her shoulder, "But if you'll excuse me, I have to clean about a hundred and fifty litter trays now."
***
Twilight shouted up at a cloud. "RAINBOW DASH!"
She shouted again.
A minute later, a pale blue pegasus landed on the ground in front of Twilight. "'Sup?"
"Rainbow Dash! I can hardly believe what our friend Applejack said to me!"
Rainbow's head tilted quizzically.
"Applejack said, Princess Celestia does NOT raise and lower the sun every day. Can you BELIEVE such a thing?"
Rainbow pursed her lips. "Yup."
"'Yup' what?"
"I can believe Celestia doesn't move the sun. I mean, I didn't get all A's in school, but I did learn the basics. You can't be a good weatherpony if you don't know any science."
"What."
Rainbow snickered. "Wait...are you trying to tell me, you really believe Celestia raises and lowers the sun and moon, all on her own?"
"Well...not ALL on her own. Now that her sister's back from the moon, Luna helps too. At least with the moon."
Rainbow laughed raucously. "This is HILARIOUS. The straight A student doesn't know what causes day and night." Rainbow laughed so hard she toppled over sideways, rolling around in a patch of daisies.
"But EVERYPONY knows Celestia raises and lowers the sun!"
"Sure!" Rainbow guffawed again. "Everyfoal under the age of three 'knows that,' I guess."
"But it's TRUE! Celestia moves the sun herself, every morning and evening! None of this 'orbit' nonsense!"
"Sorry, Twi. I think you've been misinformed. Celestia has nothing to do with it."
"Oh yeah? When Nightmare Moon ponynapped Celestia, the sun DIDN'T RISE! Explain THAT, you dumb skeptic!"
Rainbow climbed back onto her feet. She gave Twilight a serious look.
"Twilight...when we were 'fighting' Nightmare Moon...you noticed she was very good at magically turning into a cloud of vapor and sneaking around, right?"
"Well, yes..."
"Before we fought her, she sneaked all over town and turned all the clocks ahead. Like daylight savings time, but even farther ahead. She just made it LOOK like the sun wasn't rising on schedule. The REAL reason the sun didn't rise was, it was still the middle of the night."
"Oh yeah? If it was just a dumb clock trick, then WHY did we have to rescue Princess Celestia from her?"
"'Rescuing Celestia' was just a game, like the other scavenger hunts Pinkie organizes. Like when foals search for eggs on Bunny Egg Day...except this game was for grownups. Especially for one bookworm student who needed to go out and touch some grass."
"HOW DARE YOU SAY I NEED TO TOUCH SOME--!" Twilight charged at Rainbow, who leaped up into the air and hovered out of reach.
"Twilight? I think you need to...calm down?"
"A moment ago, you said PINKIE organizes this kind of so-called game!" Twilight screamed. "Of COURSE! It's PINKIE'S fault!" She ran back towards town, her ears literally venting steam.
"Huh." Rainbow shrugged. "I guess Twilight doesn't appreciate the little prank we played on her, when we let her think Celestia getting ponynapped was real."
***
Twilight's magic ripped the front door of Sugarcube Corner from its hinges. "Pinkie! You get out here right now!"
Unlike her usual bouncing gait, Pinkie walked cautiously through the doorway. "Twilight? Is something wrong?"
Twilight sank onto her haunches, putting her forehooves over her face. "I don't even know anymore."
Pinkie stepped closer, and gingerly hugged her friend. "Oh, dear."
Twilight's tears dripped onto Pinkie's shoulder. "I can't believe it. Either way, ponies have lied to me, and tricked me, and...it's just awful."
"What...oh. This must be about the sun, isn't it?"
"Yes." Twilight bared her teeth in something like a snarl. "It's about the sun."
"I'm so sorry," Pinkie said. "Did somepony tell you?"
"Yes." Twilight sniffled. "It was Applejack."
Pinkie patted Twilight's shoulder. "She never could lie worth a breezie's fart. No wonder you found out the truth."
"How could everypony lie to me, about something so important?" Twilight said. "How could they do this to me?"
Off to one side, Rarity approached. "Yes," she remarked. "How COULD ponies do this to you?" She shook her head. "I'm so sorry I let somepony talk me into going along with it. I think I know somepony else who you should talk to...the ringleader of this entire charade. Somepony who most of all deserves a good TALKING TO, if you know what I mean."
Twilight sniffled again. "Who?"
"The pony who could have told you the truth years ago, before you even met us...but who instead let you believe the lie. Princess Celestia."
***
In Canterlot Palace, a small purple unicorn walked into the throne room, her shoulders slumped, her face wet with tears and tense with anger. She looked up sternly at her throned mentor.
Celestia looked down at her student. "Oh, my," she said. "I'll be handling this in my private rooms. Raven Inkwell, cancel my four o'clock. This is more important."
"Yes, your highness," the bureaucrat replied.
***
In Celestia's parlor, Twilight stomped one hoof. "Tell me the truth! Tell me whether you really raise and lower the sun yourself! Which ponies have really been lying to me? Everypony in Canterlot, or every pony and library book in Ponyville?" Twilight sighed. "Because...if I really think about it, Applejack's logic makes a lot of sense. And so did some of the things Rainbow Dash told me, and the science books I've read today."
The unicorn grimaced. "Either way, why did you cooperate with such a horrible game, all played at my expense? Why did you make such a complete and utter fool of me?"
Celestia poured two fresh cups of tea: one for her visitor, and one for herself. She took a sip. "My most faithful student, the explanation is simple. You would NEVER be fit for even the lowest position in government, unless you first learned to be less gullible. Rescuing me from Nightmare Moon was a test...but not quite the kind of test you thought it was.
"Your true lesson these last few months...started with sending you to make friends outside of Canterlot. Getting you away from Canterlot ponies who are constantly flattering me, ponies who say even the sun rises only on my say-so. You needed to learn the good sense to be skeptical, to see even ME as less than perfect, and the courage to confront even your biggest hero, your highest idol, if you think she might be wrong. THESE are the first steps on your new journey."
Twilight sniffled. "So...Applejack and Rainbow and all those science books in Ponyville were right. You don't raise and lower the sun. You never did."
"You have found the truth, my faithful student." A single tear trickled from Celestia's eye. "I can only beg you to forgive me."
Twilight growled, "Maybe."
Celestia nodded, a serious expression on her face. "Well...that's a start."
Addendum
Inspired in part by elyonblade's artwork: https://www.deviantart.com/elyonblade/art/Gravity-Versus-Equestria-408851642
If you want to read a REBUTTAL of sorts, you could try https://www.fimfiction.net/story/500717/twilight-loses-her-innocence-anything-to-save-the-world