Chapter One: Welcome to 1960

If life could be chosen over again, Lin Ran would never have chosen to spend the last day of 2019 stargazing at Cherry Springs National Park.

He had merely been looking for a discreet spot around his neatly pitched tent to relieve himself, when he stumbled upon a peculiar, luminous portal. His curiosity got the better of him, and he drew closer to see what it was.

And then? Then there was nothing.

When consciousness returned, all he could see was utter darkness.

Lin Ran did not wonder if he had gone blind, for more terrifying than the loss of sight was the disappearance of hearing, touch, taste, and smell.

No matter how he tried to open his eyes, he could not feel their presence.

All around him was an empty void—darkness, silence, and emptiness gradually surfaced in his mind.

No! There was light—Lin Ran could sense a flame-like glow in the distance, devouring the blackness.

He didn't know what that light was, but his intuition screamed that once it had consumed all the darkness, his consciousness would be swallowed as well.

Countless thoughts sped through his mind. "I came to watch the stars, but are the stars now watching me? Have I been abducted by aliens?"

Regret flooded Lin Ran. Had he known things would turn out this way, he would have gladly spent the last day of the decade bored in his rented room or reading in the library—anything would be better than this.

If consciousness faded, at best he'd become a vegetable, at worst, he'd die.

At first, his mind was full of distractions, but as time slipped by, those thoughts vanished, leaving only endless pain and torment. Lin Ran now fully understood why solitary confinement was the ultimate torture.

Both the environment and the threat of losing his very consciousness pushed him to the brink of collapse.

"No! I can't just die here. If I'm gone, my mother won't survive either." As the only child of a single-parent family, Lin Ran knew exactly what he meant to his mother.

But no—sheer willpower couldn't stop the flames from spreading.

Thinking wouldn't help either.

So what could he do to halt the fire's advance?

Panic gripped him. He didn't need to wait for the fire to consume his consciousness—his own negative emotions were enough to devour him.

"No, I need to find something to occupy myself with, or I'll go mad." Lin Ran resolved.

As a top graduate of Jiaotong University's School of Aeronautics and Astronautics, now a PhD student in computer science at Stony Brook University, Lin Ran's idea of "something to do" was to review the knowledge stored in his mind.

"Applying Graph AI to various problems, including partial differential equations, bioinformatics, quantum physics, materials science..." Computer science is a vast field, and Graph AI is one of its newest branches.

Lin Ran had always had a strong passion for aerospace, but he hadn't chosen that path because, as a Chinese national, he could never get into an American aerospace program—let alone with a scholarship.

So, for the sake of his future, he gave up his dreams of distant horizons. A doctorate in computer science would open far better prospects, whether he stayed in the US or returned to China, than working in aerospace in China.

But he hadn't anticipated that Graph AI would be such a quagmire.

"Design and Manufacturing, Principles of Automatic Control, Aerodynamics, Engineering Thermodynamics, Comprehensive Russian, Aircraft Design..." These were all his core subjects.

Yes, Russian too—even more than English, which was only taught in the first year, while Russian was a compulsory course from freshman to junior year.

Textbooks, lectures, and exercises he'd once completed flashed through his mind. Compared to his current research, the aerospace material calmed him, offsetting the dread brought on by the blackness.

"Functions, limits, derivatives, integrals, multivariable calculus..."

"Mechanics, thermodynamics, electromagnetism, optics, modern physics..."

"History of Aviation and Aerospace, Types of Aircraft, Principles of Aerospace Technology..."

Course after course unfolded in his consciousness, recalling details he'd nearly forgotten. If he'd been this diligent before, his GPA would have been first in his class, not just in the top five.

Even the once tedious Russian lessons now seemed fascinating. He'd even gladly sit in the front row and endure the professor's spittle.

"I can only hope this will be for the best, as the Russian saying goes: 'Every misfortune brings a blessing.'"

That saying means: "A blessing in disguise."

After thoroughly dismantling and reviewing all his university courses, Lin Ran began to notice strange changes within himself.

Details he'd long forgotten, fragments barely noticed in class, were coming back to him—his brain's computational power was growing ever stronger.

As the flames devoured the darkness, it was as if his mind was being forged in the process.

Yet the fire's relentless spread continued, and he could now feel its heat—proof of just how close it was.

"If life really ends like this, perishing in a sea of knowledge doesn't sound so bad."

If his brain had once been an ordinary x86 computer, it was now a supercomputer. High-level determinants, large systems of linear equations, parameterized equations—problems that required massive computation in linear algebra, he could now solve quickly in his head.

Time cycled endlessly between pain, reflection, and memory.

Lin Ran found not only his mental abilities vastly improved, but his focus—once eroded by smartphones—had undergone a qualitative leap. He could now concentrate longer and enter a state of flow more easily.

"If I ever return to the real world, I'd be an absolute genius!" he thought—if only he could return.

After reorganizing his memories, Lin Ran turned his attention to his current research: "Using AI to solve the Navier-Stokes equations."

He had said before that Graph AI was a pit, because the field was so new—so open-ended that it felt like nothing concrete could be done.

In 2017, Professor Samuel's team at Washington University published a paper titled "Data-driven discovery of partial differential equations," bringing AI-driven equation solving into the public eye.

It was then that Lin Ran jumped into this field.

Samuel's research focused on AI solving partial differential equations; so did Lin Ran's, except he was tackling the Navier-Stokes equations—the pinnacle of the field.

The Navier-Stokes equations are among the greatest unsolved problems in mathematics, on par with the Riemann Hypothesis and Goldbach's Conjecture.

A general analytical solution to the Navier-Stokes equations would revolutionize aircraft design, optimize wind power, make wind energy as viable as solar or nuclear, and allow cars to achieve the best possible aerodynamic efficiency...

In short, finding a general solution would provide an optimal answer for every real-world problem involving air, liquid, or solid flow.

Even if the Nobel or Fields Prize failed to recognize such an achievement, the scientific community would protest en masse.

This was one of the rare problems whose solution would have the most direct and profound impact on the real world.

But Lin Ran's work, despite sounding grand—using AI to solve the Navier-Stokes equations—was not about finding a general solution, but rather specific solutions under certain conditions. The difficulty was like searching for a needle in a cup instead of the ocean.

"But right now, I only have my mind—no computer," he thought.

Using his limited advanced math, Lin Ran began deriving formulas in computational fluid dynamics.

From textbook finite difference methods, he derived higher-order, compact, and adaptive finite difference methods.

From finite element methods, he derived mixed, discontinuous, and isogeometric analysis finite element methods.

The moment he reached a result, he sensed the flames slowing their advance. "Is it possible that expanding the boundaries of knowledge can hold back the fire? What is required to extinguish it entirely? Must I really solve the Navier-Stokes equations?"

From finite volume methods, he moved on to higher-order, unstructured, and dual-time-step finite volume methods.

With his senses gone, mathematics became his only source of beauty.

Bit by bit, he drew closer to the Navier-Stokes equations:

"If I assume ideal flow in a two-dimensional plane, then by adding certain boundary conditions, I can obtain exact solutions for velocity and pressure fields..."

"For viscous laminar flow between circular pipes or parallel plates, I can derive exact solutions showing parabolic velocity distributions..."

The flames steadily receded.

From planar Couette flow to Poiseuille flow, from Hagen–Poiseuille flow in circular pipes to Taylor flow between rotating concentric cylinders...

Sudden starts of flat plates or pipes, oscillating plates, or flows near rotating disks—two-dimensional or axisymmetric stagnation flows impinging on plates...

When inertial forces vastly exceed viscous forces, the Navier-Stokes equations can be split into two regions for solution: uniform flow in the outer region, and in the inner region, neglecting the horizontal derivative of the viscous term, yielding a similarity solution...

The mathematical edifice built by predecessors was a marvel Lin Ran had only glimpsed before; now, not only could he see the whole, he perceived insights others had missed. He realized he might truly add a new level to the mathematical tower—one named Navier-Stokes.

Step by step, Lin Ran approached the general solution.

"How much time has passed? I think I've found the general analytical solution to the Navier-Stokes equations!"

He tested his general solution against various forms. It seemed he had truly succeeded—solving Navier-Stokes with only his knowledge of fluid mechanics. This was more miraculous than cultivating immortality in a martial arts novel, Lin Ran mused.

Though there were no experts to verify his work, no crowds to witness it, no world to cheer, no Nobel honors to crown him—he knew that by wrestling with the ultimate question and persevering through endless ages, he had not lost his mind, nor his reason. His soul cheered for him; his spirit applauded.

"If my advanced calculus teacher, Old Wang, knew this, he'd feel his life was complete—having taught a student who solved the Navier-Stokes problem."

Before he could celebrate, the encroaching flames were swallowed by darkness. The blackness began to crack, and a world of dazzling color slowly revealed itself.

"What on earth has happened to me?"

The roaring vehicles on the street, the attire of the passersby, and most strikingly, the large crystal globe with “1960” emblazoned on it—all provided Lin Ran with a precise message: Welcome to 1960.

“The neon globe marked ‘1960’ is 46.2 meters from me. The air temperature is about fifteen percent higher than at Cherry Springs. From the angle of sunlight, the approximate time of day, and the environment, I’m probably still somewhere in New York State...”

The red, classic structure behind him and the word "TELEPHONE" told him he was standing next to a phone booth.

Every license plate of the passing vehicles, moving in slow motion, was etched into his mind.

Lin Ran felt that if a bullet were to fly toward him at that moment, he could track its trajectory and dodge it.

Countless pieces of information exploded in his mind like fireworks. His brain and body’s evolution was impressive, but his greatest realization was: “The Door.”

“To be precise, I can now travel through every door I’ve ever passed. Every door is an anchor point, and that glowing white ring created a door to a parallel world in 1960—this phone booth behind me.

Right now, in 1960, I have only one door; in 2020, I have countless doors.”

Every door he’d ever crossed in his life appeared in his memory.

Standing in the New York cold, Lin Ran gritted his teeth and lingered by a newsstand, reading the day’s New York Times for free, trying to get his bearings.

“In 1957, the Soviet Union successfully launched the world’s first artificial satellite, Sputnik 1, marking humanity’s entry into the space age...”

“On January 1, 1958, the European Economic Community and the European Atomic Energy Community were officially established...”

“In 1958, Jack Kilby at Texas Instruments invented the integrated circuit...”

“Sir, ten cents for a New York Times New Year’s special edition.”

He set down the newspaper and remained by the newsstand, standing on the dirty snow. On a nearby billboard, a blonde woman smoked beneath the slogan “Camel cigarettes, the doctor’s choice!”—half obscured by snow.

In the phone booth behind him, a young man in a tweed suit shouted into the receiver, “Those hicks in Houston don’t understand orbital correction at all!”

Lin Ran glanced back, spotting the NASA silver badge on the young man’s chest, the glass fogged with condensation.

Before he knew it, Lin Ran found himself in the lobby of a nearby café, a cup of hot water on the table. The blonde, blue-eyed waitress behind the bar gave him a friendly smile, while across from him sat the same young man from the phone booth.

“Sir, you mentioned orbital correction just now. I believe I might be able to offer you some assistance.”