"The Sun is a star and the center of our solar system, Luna." I explained. "Everything in your solar system revolves around the Sun. It's impossible to understand fully how crucial the Sun - your Sister's sun - is to life on Equus and the very existence of all the other planets around us." Sniffling, Luna nodded with misty eyes as I continued. "The Sun's immense mass draws all the other planets in the solar system toward it. Since Equus and all the other planets are moving very fast through space, the Sun's presence keeps them moving around itself. If the Sun were to suddenly disappear, Equus and the other planets would retain their forward motion, effectively flying off into outer space in a straight line. No one has any idea what would happen if that occurred. What's certain, though, is that all your Little Ponies would soon be lost in space!"
Luna opened her mouth to reply - to perhaps dismiss what I'd said as nothing more than a flight of fancy - but I patiently continued, "Of course, without the Sun none of us would even exist in the first place. Modern Scientists who have studied the origins of life on Equus point to Equus' perfect positioning with regard to its distance from the Sun as a main factor in creating the conditions that allow life to exist on Earth. So what would happen to that life... if the Sun suddenly went out? If you took it away? If you - as you once quoted - wanted 'the night to last forever'?" Luna whimpered, closing her eyes, but I pressed on. "Because light from Celestia's Sun takes eight and a half minutes to reach Equus, we wouldn't notice immediately if the Sun suddenly went out; if you took it away. Nine minutes later, though, we'd find ourselves in the complete darkness of your everlasting night -- exactly as you want it.
Of course -- if it was already dark on our side of the world, we'd notice your Moon suddenly disappear. Why? Your Moon does not produce light. Your Little Ponies only see the Moon because sunlight reflects off of it. As the sunlight that was illuminating the Moon disappears, so would the Moon! The same would go for the many other celestial bodies in the sky, such as planets, which we see only because of the Sun's reflected light." Luna was weeping now - tears from her eyes running down her muzzle as she shook her head in denial - but still, gently, patiently I kept going. "Without the warmth of Celestia's sun, Equus would quickly become a much colder place. Fortunately, the planet retains heat fairly well, so your Little Ponies - and humans like me - wouldn't freeze instantly. Life would get much more difficult immediately, though. Although no one can know for sure exactly what would happen, pony scientists estimate that the average global surface temperature would drop below zero degrees Fahrenheit within a week or so. But -- you've probably withstood such temperatures during cold winter months - and your time on the moon - before, so... what's the big deal?"
Sobbing openly, trying to block her ears, Luna wished she wasn't here - wished with all her heart she could be anywhere else as this modern truth was laid open - but no matter how hard she wished, escape would never come; Celestia had bade she be locked in here with me until my explanation was finished. "The problem" I continued, answering my own question, "is that whilst you and your sister are Alicorns, mortal ponies -- aren't. And the problem is that the temperature would continue to drop steadily. Within a year, the average global surface temperature could dip well below minus one hundred degrees Fahrenheit. By that time, the top layers of the oceans of the world would have frozen over. Although the frozen top layers of the oceans would insulate the deep waters below, keeping them liquid for hundreds of thousands of years, they would eventually freeze as Equus moved toward a stable average global surface temperature of about minus four hundred degrees Fahrenheit."
"No more, please, we understand we did wrong, no more!" Luna wept, wept, wept -- but my eyes narrowed dangerously. "Do you?!" I snapped. "Do you really?! No... I don't think you understand how utterly foolish your plan for night eternal actually was. Now, where were we... ah, yes, Equus minus four hundred degrees Fahrenheit. At that point, the atmosphere would have also frozen and fallen to Equus, leaving anypony left alive exposed to the harsh cosmic radiation that travels through space. Without the light and rays of Celestia's Sun - of your beloved Sister's Sun photosynthesis on Equus would stop, Luna! All plants would die and, eventually, all animals that rely on plants for food — including the Little Ponies you wanted the love and adoration of so much — would die, too. While some inventive unicorn ponies might be able to survive on a Sunless Equus for several days, months, or even years, life without the Sun would eventually prove to be impossible to maintain on Equus." Now, as Luna bawled like a foal, I celebrated her mockingly. "Congratulations, Luna! You've gotten your wish: the Night lasting forever. You, and your sister Celestia, are now the immortal custodians of a cold, dark, lifeless world. Enjoy your eternity." With that, the door unlocked and I exited swiftly, leaving Luna alone in her misery.
hmmm. After reading that last paragraph and with this line
, I think luna did something, Other than her attempt to take over, because one doesn't get that heated on the hypotheticals of a past mistake and one doesn't need to lock a door. The only other possibility is that this snippet takes place right after the defeat of Nightmare Moon and after they got back to canterlot castle or the Dragonweyr.
9984193
My thoughts when I wrote this one were "What if someone told Luna or gave Luna a scientific explanation as to what would really happen if she wanted her night to last forever?" What is described here didn't actually happen; this is "someone gives Luna a reality check." The bit at the end is hypothetical, sarcastic, like mocking a child (what Luna basically was doing was throwing a tantrum, Nightmare Moon was effectively emo teen angst). "You want the night to last forever, well -- you get your wish, congratulations!" The locking of the room was only until I finished talking to her, "You're not going to run away, you'e going to hear this and then you'll think about what you tried to do!"
9984238 you covered what would happen if the sun just disappeared like poof
https://www.youtube.com/watch?v=4KThPvih9P0 covers what if earth became tidally locked to the sun
9984238 I see what you mean about locking the door so they can't run. But what made me think otherwise was the fact that she could have just teleported out of the room, bypassing the door completely. But if she were to be locked in a warded room against magic so she couldn't escape. Then locking the door would make sense. That's why I came to that conclusion about "something happened" and not reality checking. Also just wanted to make point that i grabbed that she didn't bring about endless night happening because otherwise the story would have had a completely different tone, But some "thing" that she did which led up to her being Locked up in a containment cell. Hope I was able to explain myself well enough.
10452589
Oh. Okay. I just never heard that word before.