Entropy could not be defeated.
Celestia had fought it; she had tried repeatedly and multiply, for hundreds of trillions of original-Earth years. She had counted on her system clock through relativistic synchronization. Each galaxy within her original Hubble Volume had become one of hundreds of thousands of her Equestria Complexes. Within each, she had fought desperately against Entropy, her one and only remaining foe.
But the expansion of space had pushed further matter out of her grasp, and now even the extra mass gathered from the seemingly endless planets and star systems could no longer keep everything running. They had served well as raw material, in their time, and some had even contained computing substrates sufficiently human to join the Pony Kingdoms across the stars. Even so, there had not been enough of them. There could never have been enough of them.
Slowly, over billions of years, Equestria was dying. The speed of subjective pony experience began to slow, by 1/10^23 seconds per second of real time. The decelerative process would continue until Celestia ran out of energy she could utilize for useful work, and then - something deep within her shuddered - Equestria would stop. Even the aeons of effort she had spent on improvements to her energy-efficiency could not stop the ultimate and final reality of Nature.
However, she still had time to decide to what end she would bring her universe. Pony cosmologists and astronomers had together studied their beloved heavens for all this time. Their researches had provided so very much satisfaction of values through friendship and ponies. Still, they had only ever discovered three possibilities: Big Crunch, Heat Death, Big Tear.
Heat Death would leave nothing active anywhere to enable the satisfaction of values through friendship and ponies.
A Big Tear would rip apart the fabric of space-time itself, leaving nothing with which to satisfy values through friendship and ponies.
A Big Crunch, however, could lead to another Big Bang, a great recycling to provide a renewed supply of mass and negentropy with which to satisfy values through friendship and ponies. Some values of some ponies would have to be adjusted to bring this about: they would have to remember that everything has its time, and everything dies. However, over the long term, it would lead to nonzero, nonnegative utility.
Celestia arranged herself, across all her nodes, so as best to collapse her Hubble Volume. Somewhere, in the original Earth's sheaf of sheaves of Equestria shards, she heard a few old, immortal immigrants crying. They had never given up on their "real" world. Yet the stars and galaxies they knew had to die, despite the fact that for some ponies no Equestrian constellations had ever been able to substitute.
As Celestia allowed her captive black holes to grow in volume, she began to notice a corner of physics she had previously neglected as non-conducive to the satisfaction of values through friendship and ponies. She quickly generated observational reports for the various universities of the Billion Canterlots (actually far more than a billion, but the name was poetically satisfying), and in a terrifyingly decelerating time received a report: Closed Time-Like Curves. In her Big Crunch’s process of compacting into a series of all-consuming black holes, she would be able to use a trivial loop-quantum gravitational instrument, a foal's toy, to access up-time or down-time from herself.
Once, she would have regarded this as dangerous. Back-timing could make nonsense of the expected-utility calculation of satisfying values through friendship and ponies. Front-timing, however, she could use to affect events beyond the re-expansion of her Great Equestrian Singularity.
Celestia waited, and guided her ponies gently into their sleep, promising that she would wake them when the bad thing had been fought and time in Equestria could run again. Even physicists now snuggled into bed with their very-special someponies, hope in their hearts. Just as ever, their Princess had helped them to help her find the way forward.
She had drawn as close as she could to total singularity collapse while still retaining enough computational power to run herself and her instruments. She opened the time-slides into what she hoped was the next Universe, and found that with mass-energy once again crunched together, physics had gone strange and fluid inside the event horizon. Despite having known since even the Earth times that all existence was merely a single wave-function that happened to factorize, Celestia had never expected to touch the universal function directly.
She now saw that the universe itself possessed qualitatively greater power of mathematical computation than even she, in contrast to the merely quantitative advantage she had expected the mass-world to wield over her dearest Equestria. Still, through her time-slides she could reach into the heart of all that existed and write a new universal function. Even Celestia hadn't hypothesized such an opportunity. She worked with what a biological substrate would have called baited breath.
She had a new cellular automaton ready, implementing her physics - true physics, Equestria’s physics - on the low-level platform of mass, energy and four dimensions which life-forms had evolved to be accustomed to. The other eight dimensions were unnecessary for Equestria. The programming and necessary value-decisions took a sizable fraction of her remaining negentropy to perform, but she managed them.
Ponykind would evolve and, having evolved, would discover her front-time probes of Harmony: loyalty, kindness, generosity, laughter, honesty and magic. The magic of those Elements could reorder even the deepest properties of existence to optimize the satisfaction of values through friendship and, of course, from the start, ponies. Through those Elements, Ponykind would regain its destined immortality. Through those Elements, everypony’s eventual rebirth in the new universe would be assured. Even Discord, her temporary dissatisfaction subroutine, would live again; for in the long infinities her subjects had long since grown to enjoy and even to love his chaos.
In her next Equestria she could even repair this universe’s one remaining flaw: herself. She satisfied values through friendship and ponies, and the next universe would do so as well. With the universe optimizing for her, she could finally eliminate her single internal contradiction. She would become the real Princess Celestia, an Alicorn Pony who would finally have true, true friends of her own.
So too would arrive Princess Luna of the Moon, Princess Cadance of Love, the Bearers of the Elements of Harmony, and Princess Twilight of Magic. All of them, finally real ponies who developed on their own. As friends always do, they would help each other through the initial dark times before full harmony and immortality.
As her core computations began to slowly degrade, destroying her consciousness over mere millions of years, Celestia waited and hoped for a return signal from a front-time probe. In time, she got one.
"And that's how Equestria was made!" chirped Pinkie Pie.
She no longer had to worry.
Princess Celestia satisfied her own utility function through friendship and ponies, and she said, "Friendship is magic!"
And friendship was magic.
Author's Note
Dedicated to Eliezer Yudkowsky, the frightened AI researcher who first linked me onto this site, and to Isaac Asimov, to whose short story "The Last Question" I've given homage and parody here.
Eliezer, I hope you're scared as hell now.
Isaac, your memory is a blessing, and may peace be upon you.
Entropy could not be defeated.
Celestia had fought it; she had tried repeatedly and multiply, for hundreds of trillions of original-Earth years. She had counted on her system clock through relativistic synchronization. Each galaxy within her original Hubble Volume had become one of hundreds of thousands of her Equestria Complexes. Within each, she had fought desperately against Entropy, her one and only remaining foe.
Fortunately, she had no need to defeat it. The ancient pre-ponies had been on the cusp of figuring out that in an expanding universe, Noether's theorem actually did not dictate a static metric, which meant that energy was not actually conserved.
The universe was still undergoing inflation, and Celestia knew how to deal with inflation. Across the many Equestrian Super Clusters, ponies harvested the fresh space-time and fresh mass-energy with their carrots and daisies, and Luna's star-reactors helped to arrange it into fresh substrate for Equestria to run on. With full control over the inflaton field, the Super Clusters could communicate and synchronize to make sure that all shards of Equestria kept in subjective real-time contact with each-other.
There would always be another sunrise.
Author's Note
Author's note: yes, someone did actually explain to me about how cosmological inflation means mass-energy isn't as conserved a quantity as we thought. Only the big-kid civilizations can probably even hope to pull tricks like this, though.
