Chapter Text
The force of gravity—though it is the first force with which we are acquainted, and though it is always with us, and though it is the one with a strength we most thoroughly appreciate—is by far the weakest known force in nature. It is first and rearmost.
Isaac Asimov (Asimov on Physics, 1976)
There's a smile that Essek Thelyss makes only when he thinks no one is looking.
It starts at the left-hand corner of his mouth, the side that dimples fractionally deeper, before curving up into an asymmetric slant just wide enough to bare the pointed hint of an eyetooth. Sometimes, if Essek's really taken with something, the tooth will escape to worry along his lip, a flash of white gleaming against plum skin.
It's taken Caleb multiple weeks since their rendezvous in Eiselcross to fully discern this phenomenon, caught only in glimpses when the other wizard's impeccable sight is highly preoccupied. Four times it's occurred in relation to research, occasions where one of them has uncovered some ancient tome or document or dashed-off note that strays particularly near to recognizable dunamantic theory. Thrice it's happened when what they've thought to be a nondescript ice shelf spills over into a massive overlook of a preserved Aeorian ward, rows of buildings nearing an eon in age deposited a mile underground and left nearly pristine. And once it has happened as if through no cause at all during a quiet evening in the Tower's salon, Caleb's periphery catching the tilt of Essek's head as he'd emerged from reading to smile almost imperceptibly into the fireplace.
The exact emotion it’s meant to convey remains an enigma, perhaps drifting somewhere in the murky waters between distant thought and wistfulness. But then, of course, it’s intended for no one but Essek himself.
That inscrutable expression surfaces once again among the frozen debris of the long-abandoned study where they now sit, surrounded by a haphazard nest of pilfered logbooks and research documents like a pair of very strange birds. Caleb’s skimming the initial pages of a yellowed treatise on spatial transmutation when he catches a rustle of movement as Essek’s posture abruptly shifts, straightening with enhanced focus. The smile’s there when he looks up, lefthand canine working overtime at the edge of the mouth. Something very interesting, then.
“Anything good?”
Essek’s eyes don’t waver from the black book in his hands when he replies, continuing to drill violet holes into the page before him.
“That is a word for it, I suppose.”
The smile vanished when Essek spoke but a certain intensity remains about him, one gloved ring-finger tapping staccato against the book’s back cover. That’s a development too, Caleb thinks, for a man who has lived so much of his life perfecting an impenetrable facade.
A brief thought flits through his mind that perhaps he should leave Essek to finish reading, but this is immediately quashed by overbearing curiosity. He cranes his neck forward in an attempt to make out the marred title between the other wizard’s fingers.
“Care to share, or- ?”
Essek tilts the cover up towards him, where his eyes are able to make out the looping, unintelligible script of old Elvish. Caleb’s face falls minutely.
“Ah, I see.”
One long, jewelried ear flicks as Essek seems to catch the hint of disappointment in his tone, and after a moment he lays the book down gingerly in front of himself, gaze lingering on the pages.
“I can attempt to summarize, if you’d like.”
“Please, if you’re so inclined.”
Essek’s eyes drag up from the book to meet Caleb’s, speculative.
"First, a question. How much do you know about theoretical physics?"
There is a beat in which Caleb chews the inside of his lip.
"The fundamentals, I suppose. Matter cannot be created or destroyed. Work cannot be done without energy. Heat always travels to the coolest location. Nothing moves faster than light. The like."
He ducks his head when Essek’s expression remains unmoved, more than a little abashed. There are few things Caleb hates more than the sensation of not knowing.
"I realize that’s very limited- my methods of study have always skewed more towards the experimental."
Essek nods.
"Understandable, with your basis in transmutation. I am the opposite- the majority of dunamantic study deals in abstractions."
The response is so thoroughly academic that Caleb has to bite back a sudden reflexive grin.
"Is that to say you're more cerebral than I am, Herr Thelyss?"
He's rewarded with a look and a delicate snort.
"Perhaps on a matter of principle. But no matter- here, I’ll provide a brief lesson."
Caleb scoots forward on the stone flooring as Essek sifts out a single sheet of parchment from the debris around them.
"You’re already accomplished enough in your study of graviturgy to have developed an approximate of the Gravity Sinkhole spell, but have you deduced the full theory behind it?"
Caleb's brows furrow.
"I believe that it's intended to function by increasing pressure within a limited area, if that’s what you mean. In my case, at least, I achieve that by massively densifying a section of air near the target."
Essek cocks his head at that, considering, and something plays at the edge of his mouth.
"Interesting. That is certainly a very- transmutative approach, but I'll demonstrate something more concise. Consider this."
He produces a single pearl from somewhere within the inscrutable folds of his cloak, placing it delicately onto the elevated parchment where it dips and settles.
"What this parchment represents is the concept of spacetime, which is a theoretical unification of the three physical dimensions along with the singular time dimension. In this case, moving along the top of the page constitutes a shift with respect to space, while curvature into the page means a shift with respect to gravity."
To illustrate his point, Essek tilts the parchment, allowing the pearl to roll along the surface.
"As you can see, the presence of mass inherently alters the shape of spacetime. Something very light, such as a pearl, has a limited gravitational field and affects it only slightly. However, introducing something heavier-" Essek replaces the pearl with a small chunk of onyx, which Caleb hadn't seen him retrieve- "creates more appreciable warping."
Now he drops the pearl back onto the parchment, where it promptly rolls into the indentation alongside the onyx.
"In addition, as heavier bodies create such significant curvature, the spatial placements of lighter bodies are inherently drawn to them. This is why moons orbit planets, planets orbit stars, and so on."
Caleb nods slowly, gazing at the parchment.
"I see. The same rationale as to why we don't all fall off the face of Exandria, if only on a more abstract scale."
Essek does grin a little at that terrible joke.
"Indeed. Now, one more caveat."
Setting aside the onyx, Essek rolls the pearl into the center of the parchment, where he stops it with one slender finger.
"You’ve seen that greater mass creates a greater curvature with respect to spacetime. However, in my previous example the onyx was also larger geometrically, which distributed its footprint over a wider area. The key is density."
He presses the pearl firmly into the page, creating a significant depression.
"If I were to have an object the same size as this pearl but as dense as the onyx, it would create a much steeper degree of curvature. In terms of spacetime, this slope is indicative of relative gravitational intensity."
Caleb considers the pearl, along with the finger. It’s long and slender, as if somehow designed for the exact purpose of forming arcane somatics; the nail is a perfect oval and impossibly manicured despite their many days of arduous travel. He remembers that he’s supposed to be thinking about something else.
"The greater an object's density, the more strongly other objects are drawn towards it."
Essek's focus is concentrated on the parchment, but when he speaks there’s a little lilt in his voice that means he is pleased.
"Precisely. Which, in turn, means that it requires a greater amount of energy- and is therefore much more difficult- for something to escape its gravitational field."
Caleb rolls this around in his head for a moment as he makes a connection.
"So that’s why my Gravity Sinkhole worked. I created a small, highly dense pocket of matter in a local area, and it drew surrounding objects in forcefully."
He pauses. Another connection.
"But then- as such a point pulls in additional mass, would it not become even stronger gravitationally?"
Violet eyes flick up to fix him with a razor-keen gleam, which inspires a brief but pleasant thrill in his belly. Essek had released a few Dancing Lights earlier when they’d determined that this room was worth investigating, and the white-purple glow lends his dark sclera a silvery sheen.
“Right again. This is why even relatively simple graviturgy can be so dangerous in the hands of an experienced mage- if the effects can be maintained, it’s exponentially powerful.”
“Interesting. Keeping control of that must also put a massive amount of strain on the caster.”
“Indeed, which is why, to my knowledge, almost every mage who has ever cast such a spell has only managed to hold it for a matter of seconds. But I’ll return to my original point- your version of Gravity Sinkhole isn’t wrong, per se, but it can be streamlined.”
The pearl vanishes back into whatever pocket had materialized it within Essek’s cloak, and the parchment is laid on the floor next to the book. Caleb watches as Essek turns and rummages amongst the mulch scattered about them before ultimately returning to the parchment with a rather desiccated piece of charcoal.
In impeccable handwriting, he prints a short, solitary equation in the center of the page, which he turns to face opposite himself with a flick of his hand. Caleb stares at it, brow furrowing, as he is presented with a brief expression simply reading E = mc2. He is silent for several moments.
“I- don’t understand.”
He feels his ears and the back of his neck heat as an innate rush of embarrassment accompanies the admission, especially since he’s becoming increasingly aware of how pleasant it feels to be correct in front of Essek- but either the other wizard is undaunted by this or tactful enough to pay it no mind. Instead, his mouth merely turns up in the hint of a smile as if he’d been expecting the lack of comprehension, which does something funny to Caleb’s brain that ends up sending all of the warmth plummeting down into his chest.
“This is another fundamental difference between dunamancy and the other schools of magic, I believe. What we’ve discussed so far is referred to as general relativity, gravitational concepts which largely build off of the classical physics you already know. This, however, has to do with what is known as special relativity.”
He proceeds to hand the charcoal over to Caleb, which just serves to confuse him further. Again, Essek seems cognizant of this, and he taps the parchment between them.
“Just define the terms within this equation, if you would.”
Acutely hoping that physics notation between the Empire and Kryn Dynasty has remained consistent, Caleb scrawls energy and mass below the respective variables. His writing looks comically harsh beneath Essek’s own elegant hand.
He hesitates at the c variable, momentarily unsure. Heat capacity or viscosity would make little sense here, he decides, and so with a surreptitious glance up at Essek Caleb writes speed of light.
Essek returns his gaze, head dipping in satisfaction.
“Exactly right. Indeed, energy is equal to a given amount of mass times the square of the speed of light. What is the significance of this, you think?”
Caleb turns his eyes back to the page, partly to reconsider the equation but mostly because actually watching Essek while he praises him makes his neurons feel a bit like they’re swimming in molasses.
“Energy and mass are directly interchangable,” he says, because it sounds pretty good. And then, a beat later: “and therefore densifying energy would be proportionally equivalent to densifying matter.”
Essek does not immediately reply and so Caleb hazards a glance back up to gauge his reaction, which turns out to be a spectacular mistake because the other wizard is beaming at him like the full moon. The warmth that had settled in his chest runs down the length of his spine to pool thick in his stomach.
“Excellent as always, Caleb Widogast,” Essek says, and his teeth are incredibly white when he smiles so plainly; the canines are long and sharp. “Most early dunamancy students take weeks to digest that.”
Caleb’s brain processes this superficially, still stuck on the teeth.
“Is that so?”
“Oh, yes. Even Ludinus Da’leth was not convinced of the veracity when first presented.”
Essek’s demeanor dulls a bit at that and the smile fades, which is sufficient to shake Caleb out of whatever strange reverie he’d created while staring at his mouth. He recollects himself, considering the chipped flagstone below his left knee.
“The Assembly knows of these concepts, then.”
“This much I attempted to impart, yes,” Essek replies sardonically, “and little else. But then the Martinet is not half the student you are, and far more self-absorbed.”
The other wizard’s tone is wry and clipped, but Caleb still has to squash a bizarre, subconscious urge to preen at the words. He clears his throat instead, gesturing back to the parchment.
“The Gravity Sinkhole spell, then. It can be performed differently?”
"Ah- yes," Essek says quickly, seizing back upon the topic. “Using this equivalence as its basis. I assume you’ve already deduced that since mass and energy can be equated, concentrated energy can also be a source of gravity.”
“Ja, I followed as much.”
“Then you essentially understand the difference between our spells. You use arcane energy to densify matter, which subsequently creates an increased field of gravity. In contrast, I generate condensed energy directly to produce the same effect. This may not sound like a very significant change, but by eliminating that one extraneous step, your casting becomes much more efficient.”
Caleb shuts his eyes, picturing the two scenarios in a side-by-side schematic.
“So this approach is more akin to evocation than transmutation,” he says. “Rather than manipulating matter, I’d instead produce a sort of energy burst.”
“Indeed. The casting process is far smoother, but I should warn that it will likely feel highly volatile.”
A series of vicious and incredibly familiar flame evocations flash like snapshots along the back of Caleb’s brain.
"I’m aware,” he replies, and his voice sounds far drier than he intends.
Essek’s responding grimace lasts for a fraction of a second before being abruptly cut through by a deep, muffled groan- the sound of metal straining against itself somewhere nearby- followed by a dull rumble in the floor that rattles Caleb’s chest. A few of the books left in the study’s crumbling shelves fall to the ground with an unceremonius series of thuds.
Blue and violet eyes flash up to meet each other and then Essek is on his feet in an instant, the dunamancy book simultaneously vanishing into his Wristpocket with a flash of purple light. His gaze flicks back down to Caleb where he is scrabbling together two additional books and a handful of loose notes.
“Come- I’m afraid we may be due for unwelcome visitors.”
The notes suddenly levitate five feet off of the floor, where they promptly sort themselves before settling in Essek’s hands. Caleb stands, tucking a book under each arm.
“Danke. Let’s go, then; I’d rather not waste spells just to have this place’s refraction turn me into another fucking farm animal.”
Generally it’s safer to be outside of Aeor’s ruins than in when avoiding the worst of its dangers, so Caleb carefully trails Essek out of the study and back along a series of outwardly-winding corridors that ultimately deposit them a few hundred feet below the ice shelf where they’d made last night’s camp. He starts rifling through his component pouch upon exiting before pausing to glance up.
“If you’re satisfied, I wouldn’t mind calling it a day. The creatures in this ward seem more active towards evening, and it’s already seventeen minutes to five.”
Essek nods slowly, rubbing at his chin.
“Fine by my account. I’d appreciate a quieter setting to review that text.”
After a moment of additional rummaging, Caleb manages to retrieve his raven’s feather, and with a pair of muttered conjurations two sets of arcane wings burst open in a downward sweep to launch both wizards up and onto the shelf above.
Essek habitually moves to wait at the far edge upon landing, allowing Caleb ample space for casting. There’s a flash of purple light in Caleb’s periphery as he goes to retrieve the Tower’s components and he glances over with a degree of amusement to see that the black dunamantic book has reappeared in Essek’s hands.
“Impatient?”
“Your Tower takes ten minutes to cast,” the other wizard replies without looking up. “I may as well, unless you need me for something?”
“No, nothing.”
Caleb’s hands lay out glass and stone of their own accord, the spell at this point deeply entrenched in muscle memory. A question materializes gradually in his mind as he sets out the final cat statue and flexes his wrists, preparing to concentrate.
“You said before that the effects of graviturgy spells were self-feeding,” he muses, “but also that no mage had ever maintained one for longer than a few seconds. If that’s the case, how can you be certain that it really occurs? As you said, it does seem virtually impossible to control.”
“Firstly, because the mathematics prove it to be so,” Essek responds evenly. “And secondly, I said almost no mages had done it, not no mage at all.”
That piques Caleb’s interest enough to divert his attention away from casting and back to Essek, who continues to read. The book in front of him does not, however, completely camouflage the familiar, melancholic shadow-smile that has bled across his mouth.
“And you’re sure of the veracity of this person's work?” Caleb presses.
There’s a beat in which his chest squirms with immediate regret as the other wizard’s expression deepens into something grey and rueful.
“Yes,” Essek replies after a moment, gaze still swallowed in the pages of the book. “You're looking at him.”