Chapter Text
It was the third year of the clone war, and Ahsoka Tano had just returned with the five younglings in her care from an unexpectedly exciting Gathering mission to the safety of Obi-wan's cruiser, when a small oversight by a programmer from nearly 4000 years prior changed the course of the galaxy forever.
The oversight came when this programmer, whose name has long since been forgotten, was writing a piece of code to convert noisy raw sensor data into intelligible scientific measurements. The holoscanners for which the code was intended were used to measure the stress and strain in varying materials, to judge the structural stability and safety of old buildings, damaged starships, or even hills and mountains that could be at risk of landslide or avalanche. To convert the 3-dimensional raw data outputted by the scanner into a more useful form, various mathematical transforms and such are applied - a rather complex process requiring much knowledge and training to do correctly.
And it was here that the programmer slipped up. You see, they had been trying to work out an improved algorithm - one that was able to convert more data using less processing power - and they thought they had succeeded. By rearranging and swapping out some of the transforms for others, the new algorithm achieved the same results on the test datasets as the old had, in a fraction of the time. Pleased with this result, the programmer sent their algorithm to the lab which they worked for, who tested it on new data from several different holoscanners. The results all looked good, and the programmer received a moderate bonus payment for their work. Some years later, the programmer retired, and then some years after that, died, never realizing that their work had one hidden flaw.
As it turned out, though no one ever noticed this, the algorithm the programmer had created failed when the data samples it was transforming were taken at certain frequencies. Such algorithms work, you see, by taking the data from multiple samples and transforming it based on the values of the surrounding samples and the time between samples. In the case of this algorithm, a particular quirk of the interplay between the multiple mathematical transforms the programmer used resulted in exponentially building errors as the sampling rate approached a few very specific frequencies. This caused the resulting calculated values to deviate from what they should be, misrepresenting the data that was gathered. This flaw was never discovered by the lab, or by any of the many companies and people who licensed (or copied) the algorithm, because none of their holoscanners happened to operate at these frequencies. In this regard, you might say that the algorithm was actually not flawed at all - when used for the products it had been tested on and developed for.
There was, however, one man who licensed this algorithm and used it in a rather eccentric personal invention that it had not been tested on. This man's name was Fez Burba. His invention, the Burba Seismic Activity Reader, used a custom built holoscanner to check the cores of planets for any damage that could be dangerous to those living on them. And, as fate would have it, that holoscanner happened to operate on exactly one of the frequencies which caused the algorithm to fail.
It was at this point, many decades after the death of the unnamed programmer, that Fez Burba held the title of Scientist Notary and Planetary Consult to the Galactic Senate. Eager to test his new invention, he developed an outlandish theory: That the orbital bombardment of Coruscant by the Sith Empire could have damaged the planet's core. Fez Burba was a man who held his own mind in quite high regard, and this fact did not do much to endear his colleges (or the senate committee) to his theories. Nevertheless, his theories did turn out to be correct more often than one might think (unless one happened to be Fez Burba himself, of course), and he was quite surprised when his new invention showed no evidence of dangerous damage to the core of Coruscant. Here, unfortunately, his ego may well have sealed the fate of trillions of people in the far future; while there was a part of Fez which wanted to investigate more (surely he couldn't have been wrong after all?), he was very conscious of the fact that the more he investigated, the more eyes would be on him if and when he ended up proving his theory incorrect again. And so, he quietly submitted a report to the senate committee with the results of the initial scan, and turned to work on his next theory (though he did relocate to another planet just to be sure.) The next decades passed without any reported seismic activity on Coruscant, and Fez Burba died believing that to be one of his few incorrect theories.
Time, however, would vindicate him in the end (though long after both his name and theory had passed beyond all record). The damage to the planet that he had predicted was actually there. If his probe had functioned as intended, it would have reported a terrifying picture: the stresses in the core of the planet were almost at their breaking point. The pressures of the magma, the plates of the crust, long bound into a fixed position by the cities atop them, it all balanced right at the edge of a catastrophe so violent as to make the destruction of Taris seem benign. One can only imagine what kind of panic and chaos would have followed such a report - an evacuation of the most populous planet in the galaxy, and the capital of the Republic, would have been a refugee crisis the scale of which has never been seen. Perhaps such a blow would even have weakened the Republic enough that the Sith Empire may have won the war, changing the course of the future back in that time. As it turned out, though, this danger was left to slumber. For millennia the people of Coruscant went about their lives unaware, giving little, if any, thought to the rock and magma far below their city.
And it was now, as the younglings put away their sabers after the ritual presentation, as Palpatine sat in his office reading battle reports, his mind focused far away on the events of his grand plan, that the balance broke.
The first thing Palpatine noticed was a slight rumbling. He might have connected it with a groundquake, had he experienced one before, but as is, his first thought was an equipment malfunction in the senate office building or a ship passing too close. That illusion was shattered when he was thrown from his chair by a violent movement, his ears suddenly deafened by a clamor of noise. A sense of dread prompted him to abandon secrecy and draw on the force to pull himself up and steady his footing against the constant movement all around him, at which point he found that the floor was slanted. He turned to the window and froze in shock, not believing what his eyes were showing him.
The entire visible city, as far as the horizon, was tilting up towards the sky, now almost at a 45 degree angle. As he watched, the great plate of metal and buildings split in two a long distance away, the upper part falling away from him. A second later, a torrential blast of molten rock rose above the horizon and began to fall. Then another. He was sliding, he realized suddenly, the whole section of city was sliding backwards, downwards, as it tilted even farther.
And then a shockwave of even greater magnitude hit Palpatine, breaking his concentration and knocking him off his feet. He fell backwards, landing in a heap on the back wall of his office, looking up at the shattered window now above him. He was in time to see the sky darken, the sun blocked out by... the city. Another section of city, upside down buildings clinging and falling from the crumbling plate, had been flipped by the blast, and came crashing down from above.
Admiral Yularen, standing on the bridge of his cruiser in orbit above Coruscant, looked agape out the window. After several seconds, he turned shakily and ran to the back of the bridge, shouting as he opened the door.
"General, General, come immediately, I-"
But General Anakin Skywalker was already aware, even though the communications room didn't have windows. He was leaning on the holotable in front of him, overwhelmed by the wave of death in the force, barely aware of his own surroundings.
Far away, Ahsoka felt it too. She locked eyes with Obi-wan, the horror and panic mirrored in each other's faces, struggling to stay standing. The younglings, less attuned, looked up at them with confusion and alarm, some of them feeling something that was wrong but not the full extent.
On Serreno, Count Dooku felt the wave of death and examined it curiously. It resembled, perhaps, what he hoped to feel when Darth Sidious sprang the trap and destroyed the Jedi order, but surely that could not have happened yet. He had just reached towards his comm to inquire for news when reports started flooding in from his generals and agents. The first few, he didn't believe. But then came more, and some with images.
Dread rose rapidly, then mixed with another, curious, feeling inside him. Darth Sidious was dead. The plan, that he had given his life to, was gone. And yet, there was an unfamiliar lightness to his feelings that he struggled to place. What could... of course. Darth Sidious was dead. What he felt was freedom.
And so, in the end, the damage sown by the old Sith Empire, in an age long forgotten, was the undoing of the Banite Sith and their grand plan in the present day. Darth Bane's defeated enemies may have considered it revenge - the old ways destroying the rule of two and crippling the Republic simultaneously. The Jedi, had they known the full picture of what happened, may have said that it was fitting - the dark side sabotaging its own efforts in its blind attempts to destroy the light.
But none of this was known. All evidence of the bombardment damage to the core of the planet was erased in its violent collapse. The sudden destruction of Coruscant remained a terrifying mystery to the people of the galaxy, studied and theorized over without consensus for ages to come.