Chapter 42 The Penrose-Yang Limit

At half-past six, the operations office closed for the day, and the various departments and units within 151 entered shift-change time. Shang Lu followed the others out of the cavernous storage depot and returned to his dormitory.

"What's wrong, young chief engineer?" Chen Yu was already back. Sitting on the edge of his bed with a book in hand, he looked up at Shang Lu, who had just come off work. "You don't look so good."

"Had a bit of intimate contact with the driver comrade," Shang Lu rolled his eyes, tossed his hard hat onto the bedside table, bent down to take off his shoes, and pulled a washbasin out from under the bed.

The bending motion pulled on his sore abdominal muscles, and Shang Lu winced, drawing in a sharp breath.

"Is that sister really that fierce?" Chen Yu asked.

Shang Lu draped a towel over his shoulder, his features twisting as he nodded, baring his teeth to say, "Fierce as hell."

He carried his washbasin out the door and walked downstairs to the courtyard water trough to fetch water. This was the peak hour for faucet congestion; out of six faucets lined up along a long concrete trough, five were already occupied by tanned, robust men who had stripped off their sweat-soaked white undershirts and were bent over washing their hair. Muddy water mixed with the white foam of shampoo, converging into a meandering little stream at the bottom of the trough.

Shang Lu tossed his washbasin onto the last vacant spot at the water trough and turned on the tap, sending a gushing white stream of water cascading down.

"Engineer Shang, off work?" The logistics department cadre right next to him glanced over from beneath the faucet and shifted aside a bit.

"Off work."

Shang Lu bent down, took off his stinky socks, balled them up, and stuffed them into his pockets. Barefoot in plastic slippers, he thrust both hands under the faucet to rinse off.

Chongqing in October was still as hot as a steamer, and the dormitories were practically ovens. In an era before air conditioning was manufactured, the only thing Shang Lu and Chen Yu could rely on was that dilapidated oscillating electric fan. Chen Yu had nicknamed it Louis XVI—a nod to the fan's severe spinal issues, as everyone lived in fear that its head might suddenly snap off mid-oscillation.

Shang Lu splashed some water on his face at the trough, then picked up his basin and sat down on the steps.

The setting sun dyed the lush woods and the clouds overhead a brilliant crimson, like a roaring fire spreading from the ground up into the sky. Even before the sun had completely set, the moon had already climbed into view. Shang Lu gazed distantly at the moon and submerged both feet into the basin. The moon still hung there faintly, as though nothing had changed—Moon Angel 003 was not always visible. It was a massive, smooth, and flexible ring, so thin it practically lacked thickness, yet over four thousand kilometers in diameter, revolving around the moon at high speeds like a planetary halo. At first glance, it strongly resembled a planetary ring, but the crucial difference was that it was not composed of pulverized ice and rock; it was a single continuous entity.

Moon Angel 003 reflected light toward Earth only when the angle was just right, an occurrence that happened maybe a few times a month, and the timing was often fleeting.

Some people regarded seeing the Moon Angel as a symbol of good luck because it was one of the few Angels completely harmless to human society, and moreover, it was beautiful, reflecting a dazzling diamond-like radiance. Yet no one dared to guarantee what kind of face was hidden beneath its mask. The Moon Angel could not harm humanity only because it was trapped in the moon's gravity well, three hundred and eighty thousand kilometers away from Earth. Clearly, Angels had descended upon other celestial bodies besides the moon; the gravity of massive celestial bodies was the primary factor influencing their activities, and the largest gravitational source within the solar system was the sun.

People hypothesized that the sun actually attracted the greatest number of Angels.

What would happen if an Angel were pulled to the sun's surface by gravity? Predictably, it would rapidly pass through the sun's outer atmosphere, convection zone, and radiation zone, ultimately plunging into the dense core and carving out a tiny low-temperature space within the tens of millions of degrees Celsius of high-temperature plasma. Due to the properties of four-dimensional space, thermal radiation could hardly conduct into the interior of the Angel; it was the most powerful thermal insulator in the universe. With just a membrane so thin it lacked thickness, fifty million degrees Celsius could exist on one side while the other approached 0K.

If the Angel expanded sufficiently, it could easily extinguish the sun—though long before that, it would first collapse into a black hole due to excessive spatial curvature.

Just as stars collapsing into black holes have the Schwarzschild radius and the Oppenheimer limit, Angels likewise possessed a limiting size when expanding—the universe did not allow them to expand without restriction. This limit was called the "Penrose-Yang Limit." Angels of different measures had varying Penrose-Yang limits; once this threshold was exceeded, the Angel would inwardly close into a black hole due to excessive surface spatial curvature—which was precisely the reverse of the situation for stars in three-dimensional space. In our universe, celestial bodies formed black holes through collapse, but Angels formed black holes through expansion.

Shang Lu soaked his feet in the icy water. The tap water pipelines of 151 ran down from the mountain interior, sparing the water from being baked by the sun, and it carried a refreshing, invigorating chill. Though undrinkable, it was just right for cooling off.

The cadres living in the courtyard had finished bathing and sat in small groups under the corners of the walls, waving fans to enjoy the cool air.

"Damn... shift over a bit, shift over a bit."

"Smack!"

"Damn it, why are there still mosquitoes?"

Sporadic voices drifted over, indistinct. Shang Lu stared blankly at the rocking, rippling reflection in his washbasin, lost in thought. Every day at this hour, he would review all the work done that day, formulate plans—arrange the operations office's tasks—debug the MEG system—conduct adaptive training for Shen Jiang. As he thought, his mind drifted far away, and memories sealed away in a corner floated back to the surface. That old projector clicked and whirled in his mind, playing blurry, yellowed old photographs.

——"Of course, BCI is a miraculous technology. Its success relies entirely on me, you know."

"We don't have much time, Shang Lu. You have a higher talent than I do. You're still young, but you need to grow up fast."

"20190827!"

"Remember this string of numbers."

"Both BCI and the Angels will lead humanity to its end."

"Doesn't it look good?"

The projector froze. That truly was a gentle, smiling face.

Shang Lu slowly exhaled, covering his face with his hands.

Can you please tell me... is everything I'm doing actually right?

· · ·

"Right!"

Shen Jiang let out a breath, marking two large red crosses on the form with a deep crimson marker. The crossed-out items were Pot Angel 013 and Pillar Angel 016, respectively.

"That jerk is out of his mind. Damn it, was he hired as a plant by Wang Feng?"

"I told you long ago," 1047 said in her earpiece. "The people in the operations office are unequal to the task. Don't I know the background of Wang Feng and the others? They can't accomplish anything. Hanging out with them will only waste your time."

"But Director Ji has unconditional trust in them. What can I do?" Shen Jiang frowned. "I don't know what kind of spell that kid cast. I admit he has some skill, but all his talent is used to torture me. Solving math problems and singing—what kind of training is that? The training schedule is so intense, yet I have to waste half my time on such an absurd thing..."

"The next Angel could descend at any moment," 1047 said. "We need to seize the time and improve efficiency."

Shen Jiang tapped her forehead and said, "1047, think of a way for me to get out of this ridiculous situation. I don't want to sit in a chair anymore, foolishly doing math problems and singing."

1047 paused for a moment. "This is something you'd better negotiate yourself."

"No, no, that guy and I are incompatible; he's my natural nemesis," the girl shook her head rapidly. "Help me think of a way."

1047 pondered for a moment. "Since this is a test approved by superiors, I suggest you cooperate for now, but to negate their plan, you still have to start from the ultimate outcome."

"Speak."

"As long as we prove that their hypothesis is sheer nonsense and all their work will ultimately be in vain, this farce can be called off in time."

"But by the time they get results, all the time will have been wasted!" Shen Jiang said. "One thousand hours! That could drag on until next year."

"It won't take that long. I've also carefully studied the MEG-BCI system during this time. Based on my years of experience, I believe it falls behind the iEEG-BCI system by a country mile even in the most basic motor imagery segment. In other words, it can't even pass the limb control hurdle," 1047 said with absolute confidence. "A BCI that can't even achieve precise limb control has no business discussing the Rabin-Shang value, let alone numerical relativistic calculations. It could never serve as the operating system for a colossal mecha from the very beginning."

Shen Jiang felt a flicker of doubt upon hearing this. Could the supervisor be that stupid?

Would he invest so much effort into a system incapable of even precise limb control?

"We can find a time to initiate an internal competition between the operations office and the accounting office, competing purely on the most basic limb control precision," 1047 said. "If the MEG system can match the level of the iEEG system, then I'll concede defeat and admit the possibility of their success. If the MEG level falls far short of the iEEG, then we'll have ample grounds to persuade Director Ji and the higher-ups to cancel the operations office's completely immature project. What do you think?"

Shen Jiang thought about it, then slapped her thigh. "Good, let's go with your idea."