Title: "Life's Equations"
Author: Kristen999
Genre: Gen
Spoilers: None
Words: 4,500-
Summary: This is the story of John Sheppard and mathematics.

Author's Notes: All math and science mistakes are my own.

Many thanks towildcat88 for her swift beta and suggestions. And to sharpes_hussy for answering my questions.

The roll spins between his fingers, the length of string growing longer as the bundle shrinks. His short legs trip over a hole in the lawn, but he keeps running.

"Careful, honey!" Mom shouts. "Watch where you're going."

John's too revved up to slow down, eyes to the sky, watching the red diamond kite climb above the house. It took two hours for them to construct the wooden rods, ensuring all the parts were identical in length, sewing the cloth to the frame.

And it soars, whistling in the wind. John's only six, but he knows the kite's heavier than air; something invisible is lifting it far, far away, toward the clouds. "You see it, Mom?"

"I do, sweetie!"

The tail flaps and twirls in the wind, and the spindle runs out of string, so he ties the end in a knot around his wrist. The book from the library said kites flew like airplanes, using things called arrowdienamics. The pictures had been easier to figure out than the words, and when he turns seven, he'll be smart enough to build one that'll go higher than Tommy Foster's.

The stewardess reeks of perfume, the heavy odor of flowers wafting over as she places a cola into the drink holder. "You like flying with your dad, sugar?"

John's nose is pressed against the window, staring at the rushing clouds. "Yeah."

His father crisscrossed the globe on business when Mom used to be around, coming home on the weekends. After Mom was gone, his father appeared on Sundays at the dinner table, and then, after a while, it was anyone's guess.

John turned ten today and there's a vital meeting in Tokyo, but Rita, their housekeeper, did the thing where she placed her hands on her hips and yelled something in Spanish at Dad, and before he knew it, John got to come along on the flight.

"Can I visit the captain?" he asks.

"Don't bother the crew; they're busy," his father snaps, never looking up from the reports strewn across the plush leather seat.

The stewardess places a finger to her red-caked lips and takes John's arm, escorting him up front, Patrick Sheppard completely oblivious.

The cockpit is a mini Disneyland, with instrument panels of flashing lights, gauges, and buttons. John freezes, eyes scanning various readouts, resisting the urge to touch things, hands behind his back like he does at museums.

"You can come closer if you like," the pilot says.

John hesitates, but the flight attendant nods, and he takes two steps, eyes wide as saucers.

"Wanna watch me navigate?"

"Yeah!" Then John adds, "Yes, sir."

"I'm Captain Styles."

"John Sheppard," he replies properly, watching the captain adjust their heading.

"Ever wonder what makes the plane fly?"

Never answer unless you're a hundred percent certain. "Thrust?" John says hesitantly.

Captain Styles glances back at him and John stares at the metal wings on his cap, waiting for the correction.

"You're right."

That's all it takes and John beams, stepping closer to the console. "Yeah, it moves the plane through the air with propulsion."

"Where'd you hear that?"

"Read about it," John replies, fascinated by their speed and heading. "Gas accelerates in the engine and the plane goes the other direction."

"That's impressive."

"I'm going to be a pilot one day so I have to study early. I know forces pull and push the plane," he says, picturing where the winds and air hit the craft. "They control how it moves." John looks up. "That's torque, right?"

"For the most part," the captain chuckles. "Tell you what. If you sit really still in the other seat, I'll show you all about acceleration. Deal?"

This is the best birthday present ever. "Deal!"

Numbers are natural parts of his life, like breathing or walking but once those are learned, there's nothing left. Math always evolves, building on itself. From counting to calculation to measurement. With those three principles, it moves to the study of shapes and motion on objects.

Algebra's easy even if he's taking it early in the eighth grade, but he gobbles up the basic foundations in preparation for the next puzzle.

John builds a rocket in industrial arts class while the other students cut cars out of blocks of wood. They all have speed on the brain; so does he. Except they're focused only on velocity and distance, thinking only in two dimensions.

He's stumbled upon the arithmetic of triangles and functions. The angles of X and the values of Y, W, and Z. These are the key forces on model rockets during flight.

Trigonometry is the mathematics of propulsion. For most people, sine, cosine, and tangent are useless buttons on a calculator; for him, they'll predict how high his rocket will reach.

Families have been invited to cheer during the big car race inside the gym and some of them gather outside to watch John's test flight. Everyone congregates together; parents, jocks, geeks, punk rockers, and some of the cheerleaders.

There's one person missing from the cliques and random onlookers and when Apollo One breaks 1500 feet, John's not as excited about it as he thought he'd be.

He chews the end of his pencil, studying the overhead display of the Cessna, perplexed by what he hears.

It's Friday and like clockwork, Dr. Shaw lectures in the same plaid suit snacked on by moths, hand automatically pushing back thick-rimmed glasses that slide down his nose. He drones on without breathing, lesson memorized, more bored than half his slumbering students. "Longer Path Theory states that airfoils are shaped when the upper surface is longer than the bottom."

He points robotically at the little red balls around the tiny plane barely glancing up at those not paying attention. "These air molecules have farther to travel over the top of the airfoil than along the bottom. In order to meet up at the trailing edge, the molecules going over the top of the wing must travel faster than the molecules moving under the wing."

But that's not right. What about the net force around the entire surface?

"Doctor Shaw?"

Shaw's clearly not used to pupils speaking and interrupting his well-oiled routine. "Yes?"

Those not drooling on their books suddenly have something new and exciting to stare at. John nearly loses his nerve, but starts imagining a Falcon 10 in mid-flight. "Um…don't airfoils produce lift because of the turning, not the distance?"

"Air molecules travel faster over the top to meet the molecules moving underneath at the trailing edge," Shaw sighs, repeating some book verbatim.

"Then how do planes fly upside down?" John asks.

Stacey Kiddington smacks her gum loudly, blowing a sugary pink bubble. If he waits two minutes longer, class will end, and he'll duck out. After the weekend, no one will remember his question.

"The difference in pressure across the airfoil produces the lift. So--"

"But when the plane is inverted, the longer surface is at the bottom," John blurts, unable to stop himself.

Doctor Shaw shuffles his papers, searching for answers, the 2-D model Cessna with its dots and incorrect use of force staring back. Then the bell rings and everyone bolts, ready for the football game or pep rally or whatever.

John picks up his books, stuffs them in his backpack, and hurries out, the last student to leave.

John's SAT scores are reflective of his motivations. Equal effort for equal gain. The questions are easy – a couple take contemplation – but it doesn't hold his attention. His mind tends to wander-- about the upcoming playoffs, whether Linda Rozzie will call him back this week, or if he should go see Return of the JedI for the sixth time.

Maybe he didn't dissect the vocab part into their Latin origins like he should, or care about the endless lists of synonyms and antonyms. John will score what's needed to get into any Ivy League school (the ones Dad insists he attend), but he's not going to sweat over the results.

The university invites pile up, but the only piece of mail that counts arrives on a Monday. His hands tremble while ripping open the envelope, eyes scanning the results of his Air Force Officer Qualifying Test, his ticket into the ROTC program.

Dad doesn't know about his ACT and ASAB scores from his sophomore year or his interviews with the service academies. Relief nearly knocks him off his feet, followed by shock that he didn't screw this up. He's been accepted, scoring in the highest percentile. Then again, he actually gave a damn about every question and answer.

He balances earning an engineering degree at Stanford and drives to San Jose State for his Aerospace Studies and Leadership Labs. In the meantime he's improved running a mile from ten minutes to six, and seventy push-ups and sit-ups don't wear him out anymore.

The only thing left is to reduce his waist size to a thirty-two, but he's only off by a belt hole.

"Mr. Sheppard, do you have a moment?"

Doctor Abass is the research king of the Math department, bringing in the cash with every journal article and teaching only two classes a semester. John's rarely seen him outside his hidey-hole of an office and is surprised when the little man catches him in the hall. "I wanted to speak to you," he says, in the same voice used in lectures.

"Yes, sir?"

Abass is short of breath, taking a second to recover from chasing John down the hall. "You never got back to me about accepting graduate studies. I've worked with the reserve program before and I know the Air Force supports officers in pursuit of masters or doctorial work."

He continues with the pitch for the scholarly high road, but John stops him short. "In two weeks I'll be starting flight school."

"But you show such aptitude for proofs and theorems. Why don't you make an appointment with me later in the week? Then we can sit down to discuss--"

"Doctor Abass, I'm just not interested in research," John says the word like it's vinegar.

The good professor looks aghast, like John's just told him that the Law of Relativity is a sham. "Mr. Sheppard, this isn't something to be taken likely."

"I'm not," John replies a bit tersely. "I've known this all my life."

G force expresses acceleration relative to gravity's pull. Four Gs translates to four times the force of gravity -- which means it feels like John weighs seven hundred pounds right now. And that's only the beginning.

Both Serb MiGs are chasing him over the no-fly zone, and yeah, he crossed it first, sniffing around at mysterious troop movements and by the time his alarms blared, they'd dived out of the sky.

Damn – not good, not good.

He's still on the wrong side of the map, banking right then going into a huge climb, reaching five Gs, lodging his heart into his lower colon. His pressure suit inflates, forcing the blood back into his extremities. His F-14's more maneuverable and it's the only thing saving his ass.

That's until the first MiG gets a missile lock on him. He accelerates from five-ninety to six-twenty, tightening his stomach, thigh, and leg muscles-- combating his body's resistance to pumping blood back to his brain.

He's crossed into seven Gs; the pressure crushes him in three dimensions – front, left, and up. Over twelve hundred pounds of force squeezes the air from his lungs and shoves his eyeballs into the back of his skull.

Tunnel vision closes in, going from gray to white, and the MiGs are still tracking him.

G-ratings are composed of negative and positive peaks and the three axes of acceleration. John goes from straight up, to straight down, braking hard and rolling into a dive.

It's not all about speed, but a change in direction, and he's reached eight Gs and is blacking out, should actually be unconscious, but John fights it. The pressure's reversing, fusing his spine to his seat, all the blood going into his head.

Then his helmet bounces off the side of the canopy and he realizes a couple of seconds are missing and his F-14 is spinning out of control. John yanks back on the stick, regaining control and panting into his oxygen mask. The bogies have lost him; dropping thirty-thousand feet in ten seconds must've confused the hell out of them.

In three minutes he'll be over friendly territory with enough intel to authorize air strikes that'll never make it on the evening news.

The last Taliban stronghold is obscured by black plumes of thick smoke two kilometers wide. This is Afghanistan in a nutshell: endless mountains surrounded by sweeping desert sands, all their missions reduced to attacking caves and tunnels. Someone got lucky, striking a hidden cache of enemy munitions, setting off multiple explosions, and forcing all Al Qaeda forces to flee and scatter.

John guides his Copra within weapon's range, eyes darting from his mobile mapping computer to his targeting systems.

His screen shows no friendly positions on the ground; his tactile fire sensors detect and classify the dozens of moving targets below. He plots the information, prioritizing the most dangerous ones and shapes the battlefield to his own in under thirty seconds.

Ten little green lights representing ten separate objectives stop blinking within seconds of each other, the combatants now part of the craters left behind. John doesn't celebrate, analyzing the data from his computer and syncing up the next targets with his navigation system.

There are two other stationary targets and an enemy convoy retreating east over a kilometer away. The new long-range algorithms he installed earlier work beyond expectations.

"We going after them, Major?" Lieutenant Avery, his eager crewmate, inquires over the headset.

Major. After four weeks it still sounds odd, like it should be someone else. His team wants payback for the latest roadside bombs planted outside Bagram Airfield. The two unmoving dots on his LCD screen could be setting up more surprises for the 5th Marine Battalion, scheduled to pursue resistance.

Day after day they pound enemy forces using the most sophisticated computers and the most advanced aerial fighting vehicles in the world--and body bags continue to pile up because of explosives made with fertilizer and scrap parts. He flips the safety release off with his thumb and squeezes the trigger; the hellfire missiles will do the rest.

He excels at reading rows of displays and crunching graphics updates and changes, taking out blips and evading anti-aircraft rocket launchers.

Tomorrow John's transferring to a Pave Hawk unit, where the priorities are extractions and rescue operations. He'll remain in medium threat environments, sweating and tasting aviation fuel.

But he'll still be in the air.

The Zonk are children playing with their gods' leftover toys. Except the 'toys' are Ancient tech and those they worshipped forgot to leave any great books for morally acceptable behavior. Like all those with power and the megalomania to seek more, the Zonk shot first and asked questions later.

Waking up trussed up to a chair with a splitting headache is nothing new. Leather bindings dig into raw wrists and his numb legs are strapped to the wooden legs by his ankles. Panic bubbles up from his gut, because this is eerily similar to a certain Genii torture chamber. His racing heart increases the blood flow, clearing the layer of thick cotton over his brain--and it hits him. John knows the reason why the room is spinning and the overhead lightning burns holes through his eyes.

"You ready, Colonel?"

John flinches as a hand grips his shoulder from behind and the cold metal tip of an instrument against his left temple sends icy knives into his brain.

"Tell me the gate codes."

John's skin sizzles with electricity and the interrogator's words rip into his head like thousands of voices of Wraith Queens.

"Tell. Me. The. Codes."

Each syllable is an amped up tuning fork vibrating and tearing down his mental defenses, yanking answers out of their heavily guarded barriers.

John retaliates with roadblocks. Diagrams of roller coasters, windmills, and football plays. Words don't work, neither do colors or memories, but that doesn't stop his mind from filling with harmless information.

"Don't fight it."

The device retracts data, ripping apart neurons and transmitting information back into his interrogator's mind. John gleans snapshots of tyranny and violence, of burning towns, and plundered worlds from the mutual connection.

"Show me how you dial the gate address."

The first two codes are extracted in seconds; John's not sure if he's screaming out loud, but he squeezes his eyes close, releasing a flood of overwhelming data.

Abstract facts and ideas act as speed bumps against the invasion of his mind and John focuses on natural integers. He delves into properties of number theory and unsolved problems of twin prime conjectures and Fermat's last theorem.

"This won't slow me down. I'll find what I'll need."

But the voice falters, caught up in the concept of infinity and John pushes onward. To space and geometry. Topology and fractals. McKay's image pops into his head, challenging John's fray into chaos theory. It's a crack in the door and the interrogator shoves his foot in and tries to kick it open.

Rodney isn't here; he's on Atlantis, and images of the sea and city are seized upon.

"That's it. Don't you want to go home? Tell me the activation sequence."

John resists the drilling and clawing and bellowing commands. His skull feels like it's been cracked open, the steel instrument burrowing through bone and gray matter.

"No!" he screams, thinking of differential equations.

The burning slows, his host confused and bewildered by vector calculus, expanding into discrete mathematics.

And by information theory of computers and data.

John unloads the hard drive of his mind, of things he doesn't ponder or care about but that sit inside his brain to be accessed in times of crisis.

Things like random trivia of compression and entropy, and one of the Millennium Problems.

The interrogator growls and curses, then screams.

John's mind reels from thunderous aftershocks and the collective desires and plans of a ruthless soul. Then his body slumps over, shaking and sweating when the mental link is suddenly severed.

"Sheppard?"

He leans into the hands holding him up, while two other sets cut away his bonds. John grips Ronon's leather coat, smells the coffee Rodney drank earlier.

"John, are you alright? We came as quickly as we could," Teyla soothes.

"I know you did," he whispers back, shivering in relief at holding out long enough for his team to find him.

Smoke irritates his eyes and lungs while blood drips down the side of his head, staining his shirt collar. John battles double vision, wondering how hard he hit his head during the explosion. Damaged equipment burns and cables dangle from the ceiling, but the only thing that matters is keeping a deranged uber geek in his sights.

The daily toils and tribulations of Pegasus have cracked their newest astrophysicist's grip on reality, causing John to curse the SOP he created for training civilians on how to a fire a weapon.

"Stand back or I'll blow his brains out!" Doctor Richter shouts, a .45 digging into the side of Rodney's head.

John steps closer and Rodney can't help himself. "What words did you not understand, Sheppard?"

"Can it, McKay," John snaps, because shouting doesn't help his headache. "Let's talk about this," he says, in a very calming tone.

"Not another step!" Richter screams, finger curling around the trigger.

"Alight, alright," John concedes. If there weren't two McKays in front of him, he'd taken the shot by now. His memory of the last hour is hazy at best, flashes of yelling and alarms, followed by BOOM. "Wanna tell me what this is about?"

Richter is in his late thirties with a mass of prematurely graying hair and clothes that haven't been ironed in days. His whole body trembles and John's nervous as hell that a twitchy finger might jerk on accident. Rodney's pale with cuts on his arms and face, but maybe being held hostage over a dozen times has taught him to be somewhat calm versus ranting and raving.

"He's going to rip holes in the universe," Richter stammers. "I…I have to stop him."

"I am not going to destroy the universe, you idiot!" Rodney snarls.

John glares at Rodney to keep quiet and seeks the deranged man's attention. "What makes you say that, Doc?"

Richter is all kinds of skittish, flinching at streams of flying blue sparks from a near-by console, but his grip on the gun is white-knuckled tight. "I uncovered his secret experiments and failed test runs! The first one wasn't powerful enough. Only took out a solar system!" Richter rants, shaking Rodney's shoulder. "The next one almost tore apart space and time!"

"It wasn't an entire solar system and in the last one I was looking for a new power source!" Rodney barks.

Richter presses the barrel into Rodney's skull even harder. "But you almost destroyed a parallel dimension!"

"Well, yes! But--"

"Exactly! You don't deny it!" Richter shouts, voice shrill, verging on hysterics.

"No, wait…yes, I did those things on accident, but I'm not some evil genius hell bent on killing every living being in existence!" McKay's really scared now; it's in his eyes, and they're begging John to do something. Please! Right now!

John's arm and hand are steady, pointing straight away while sweat pools at his brow. But he has to talk this out since his vision swimming. "You have any proof?"

Richter smacks his lips, excited to share his findings. "He's creating phantom energy that's overcoming all other forces in the universe. In fact…it's expanding this very minute," he says, staring at the air in front of him, eyes going wide. "Tearing apart all gravitational boundaries and ripping apart atoms."

Okay, this is beyond bat shit insane. Talk him down, John. "McKay's got a few screws loose, but he's not trying to destroy the universe."

"Shut up! Shut up! Shut up!" Richter screams, hiccupping. "You have no idea what you're talking about!"

"You're the one going on about phantom energy and I think with all the crap we've dealt with, I'd know a little about it," John counters.

"Phantom energy's the reason the universe is expanding and Dr McKay's creating it when we're not looking." Richter moves the muzzle to under Rodney's chin. "But you're not going to release doomsday. I won't let you."

"Yeah, how's that? By blowing up the freaking lab? Don't you think if I had a pocket of dark matter hidden under my lab coat, it might have caught on fire during the explosion you set off!" Rodney rants, spittle flying.

Control. Find control. "Wouldn't gravity affect things?" John asks. "You know, keep the acceleration in check?" It works. Richter's attention is on him. "And how could he destroy the universe if there are hundreds, even millions of them left over? Even I know about string theory."

"But…but our universe would be destroyed," Richter babbles.

"By the increase in dark matter. That's what you're talking about, right?" John asks but doesn't wait for a reply. "And what about vacuums in space? Wouldn't they counterbalance the expansion from the Big Bang?"

Richter looks at John like he's grown three heads, which wouldn't be that far from the truth the way his brain is imploding. There's a third Rodney and Richter merging into each other, screwing his ability to hit the right target. So, he thinks about all those science magazines he's read at the Midway station or all the brushing up he constantly does to keep in the loop with all the geek talk.

"And what about potential energy? And the resulting proportions?" John keeps his weapon steady while the room tilts. "The freaking law of thermodynamics?"

Richter's gun hand shakes, complexion paling. "How do you know about any of that? You can't."

John smiles. "Why not?"

Richter spasms, his body blasted by a familiar red burst of energy and he collapses in a heap. Rodney nearly trips over the guy's limbs in his scramble to get away, the room bursting with noise and running footsteps of a squad of Marines.

"Took you long enough," John drawls.

Ronon holsters his blaster, hand clapping each of them on the shoulder. "You guys okay?"

John thinks the floor looks like a fantastic place to take a nap, but Rodney's in his face, equal parts relieved and bewildered. "Are you secretly earning a PhD when I'm not looking? I mean most of your plans are from life and death bits of brilliance, but you talked like you actually understood what you were saying. And don't give me the 'could have been MENSA' crap."

There's no need to hold up his weapon and John allows his arms to fall, standing down. "Does it matter?"

"Yes, um...no." Rodney's expression says otherwise. "I mean, why hide your intelligence behind a gun? Not that there's room for someone else to argue my theories. Besides, you have a job that you're already good at."

Despite the dizzying image of his friends thanks to the concussion and the added ringing in his ears, John manages a heartfelt. "Thanks."

He's surrounded by a gaggle of Athosian children who are still eager to play despite dozens of games of hide and go seek and fight the Wraith. Sitting under the enormous oak-looking tree and snacking on his apple sounds more appealing to his exhausted body. John volunteered to take Teyla to New Athos so he could sneak in a little R&R after thirty-three straight days of hell, but he admits this afternoon with the kids has been fun.

Someone tugs on his sleeve and he looks down at Lela, a little girl with diamond blue eyes and amazingly thick red hair. "Can I take a ride in your jumper, Colonel Sheppard?" she asks.

"Yes, could we?"

"Me, too. I want to come."

If he takes one child up, he'll have to take them all. "I'm not sure if that's a good idea," John says, hands out fending off the enthusiasm.

"But we want to fly!" one of the older boys insists.

There's no remembering all their names and they're all talking at once. "Hold on, hold on." John thinks for a second and snaps his fingers. "We could fly some other way."

"How?" Lela pipes up.

"With pieces of wood and string from the jumper," John pauses, searching the settlement. "And if we ask some of your parents nicely for some cloth. We could build a kite."

"That stuff can't make something fly," one of the younger boys laughs.

"Oh, really?" John challenges, kneeling on one knee, pulling out his knife and drawing wind-lines in the dirt. "I tell you what. If all of you help me make it, I'll show you how things called drag and lift can make a kite soar."

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