The adrenaline, the wind in her mane, the heat coursing through her as she tears through the sound barrier with relative ease. There was no high like it. The faster she went, the greater she felt.
Today she was going to do it. Do something that everypony said was impossible. She was going to hit the speed of light. No matter how skeptical others were, no matter how much everypony told her she wouldn't survive it if she could, rules were meant to be broken.
Rainbow Dash stood, wings unfurled at the edge of a granite cliff. Through her deep magenta eyes was the most spectacular and inspiring view. A majestic, misty waterfall, as wide as Cloudsdale itself cascaded around the the narrow cliff peak she stood on. As far as she good look left or right, she saw nothing but millions of gallons of ice cold water pouring down into a seemingly bottomless well of white, cool vapor.
Drops of cool dew collecting on her muzzle and brow as she raised her head up into the overcast sky. "What a perfect last sight to behold if I don't make it back", she thought albeit in less eloquent words.
She took a few short breathes as the waterfall roared. Licked her lips and arched her back in preparation. "Here goes nothing"
With a quick kick of her legs she jet off towards the waterfall. Drops of water hit her face like cool wet bullets (slightly painful but par for the course for her speed). As she closed in on the waterfall her heart raced with initially fear. She dove with with a splash drowned out by the bellowing of the falls.
The waters weight pushed her downwards, ruining her momentum. Rainbow Dash new if she had no resistance initially, she would never achieve her goal. Her wings desperately flapped as the wall of water was thrashing her delicate wings around, weakening their hollow bones and causing Rainbow to lose important feathers.
"Aagh!" she screamed as she felt her right wing bend unnaturally by the force of the water. Her eyes geared up as she grit her teeth, look of determination in her eyes. She took off like a jet, ripping up the falls living a wake in her stead. As she flew the waterfall was being cut by a turquoise knife and as she reached the falls peak she launched out of the water in took off like a rocket into the sky. By the time she had done this, the one massive waterfall and become two very large ones.
Whizzing into the stratosphere with a satisfied look of determination on her face, the water that still clung to her literally boiled off as was about to her trademark "Sonic Rainboom"
She ripped through clouds, wind howling in her ears as a cone of sound grew around her. Her wing throbbing, she agonizingly forced herself foreword. She groaned loudly as she took off, spend tenfold as a rippling cascade of spectrum color tore through the sky.
Before she new it she was hove the clouds, where the air is ice cold and borders on space itself. She kept flying. The intensity of her speed kept her burning hot regardless of where she was.
Faster, faster, faster she flew as the air grew colder, colder, colder.
The sky began to grow dark, with a clear line separating the blue sky from the void of space. Icicles began to grow on her hooves, only for her to boost forward another mach to burn them off.
Then, as the blueness beneath her sank, she passed out of her worlds atmosphere in to the chilling silence of space. Only a being of her determination, or drive can fly her. It is where only the few most daring Pegasi have ever laid eyes upon.
She had no time to take in the beauty of the twinkling stars, colorful nebulae and heavenly bodies drift. She had to keep flying. Fly or freeze solid. There is no turning back once you reach this state. You stop to turn around you are a pony popsicle in a second.
She kept flying. Faster, faster faster she flew, sparkly debris and dust glittering across her. She flew across the moon, leaving a massive rainbow-lit canyon for all of the Earth Ponies to see in the sky. She jettisoned off the moon with no intention to slow down.
She ripped through the asteroid belt, chunks of rock reduced to dust and pebbles as the cyan blur tore through them with ease.
She was approaching a massive, pink gas giant planet, free of rings but surrounded by glittering gems. Rainbow Dash dove head first send the gems drifted out in every direction as she flew through them. When she hit the gas giant itself a pink wind tunnel opened up as she blindly soared through the beautiful whirling funnel of creamy pink clouds.
She couldn't see it's majesty. Her eyes were cemented shut. RD was now aware it was unlikely she would see her friends again. She new she was being selfish, but this was something she lived to do.
Hours of contemplation went by while she flew in a trance. Planet after planet she whizzed by.. None had her friends. She wanted to be the first pegasus who would hit the speed of light. But who would no of her deed, who would care about some crazy mare drifting frozen through space years from now? This was a mistake. If only she could control her ego, and not do stupid things like this. She couldn't fly forever. She would have to stop sometime, and she's too far away she'd stop before she could come back. "Why did I have to-".
Rainbow Dash was somewhere she didn't recognize. A disorienting colorful void. Like all of creation was bombarding her senses, then a second later somehow more than all of creation was bombarding her senses. Was she dead? No, she could see space out of her peripheral vision. She was in this universe. Could she have reached the speed of light? Has all of existance bended to her?
She didn't know the science and didn't care to ask Twilight lest she give away her intend to do this. All she knew is that her eyes, her mind couldn't process all she was witnessing. She panicked but never stopped flying. Her wings flapped very slowly despite the cosmos around her zipping by faster than her simple brain can analyze.
She kept going faster. Faster than the speed of light? She knew Twilight yammered on about that being impossible. She didn't care. She kept flying. Soon the colors of creation around her began to recede. A white, empty well of light appeared in front of her. She flew into it. The universe became smaller and smaller behind her till the white consumed she could see.
With a loud pop Rainbow Dash fell into an empty white void. She floated there with a confused and tired look on her face. The slow clip-clop sound of hooves grew louder and louder.
Princess Celestia walked into the void with an angered look on her face. Rainbow Dash still derp-eyed and sweaty didn't know what to think.
Princess Celestia sighed. "You broke the laws of the universe and flew faster than speed of light right?". Rainbow Dash breathing heavily just puffed out. "..yeah."
The princess rolled her eyes. "Not again. Do know how long it will take me to recreate all that?"