(Thanks for the votes, Late Sunset⊙Gui Lai!)
Only a few seconds later, Chuanhe opened his eyes and looked down at Hui.
"I can't explain what comes next to you directly like this. We need a higher level of security. Hui, you're going to feel very uncomfortable in a moment, so make sure you keep your chakra under control. This is extremely important," Chuanhe said sternly.
"Yes, Father." Hui took a deep breath and nodded solemnly.
Chuanhe closed his eyes. Hui sensed his father's chakra gradually drawing inward until it became completely undetectable. Then, slowly, a bone-chilling feeling began to emanate from him. Hui felt as though his chakra had a will of its own, actively fleeing from that presence.
Chuanhe slowly reached out and moved to touch Hui's head. Hui recognized the familiar hand, yet instinctively leaned back.
Hui gritted his teeth, forcing himself to sit still as he struggled to keep his chakra under control.
The hand moved so slowly, yet at that moment, Hui's awareness seemed to stretch endlessly.
The world before him was like the sun setting. Its vibrant colors slowly faded into a darkness devoid of everything. There was no light, and yet Hui could see both himself and his father.
His own figure? Why could he see himself?
"All right. In this illusion, there's almost no chance of anything leaking."
There was no sound. Instead, the information appeared in Hui's mind directly, like a memory. To understand it, he had to recall the past.
One strange experience after another made Hui instinctively try to move away from his father. But no matter how hard he tried, the figure he saw remained motionless.
"Hui, this world is false. This is an illusory world. But because its principles are so unusual, it feels terrible to be in. At least information conveyed this way is almost impossible to leak. Even having your memories read wouldn't work—though, of course, that assumes it's done through chakra extraction."
"What I'm about to tell you is so shocking to this world that there can't be the slightest mistake."
"Just bear with it for now. You probably can't speak, so listen patiently while I explain."
"What you observed wasn't wrong. The gap between this theory and what you know is simply too great, so I'll explain it directly. The knowledge you've learned so far can't explain it."
"I started out just like you, but there was one difference: I believed more firmly in the conservation of mass and energy. So I was puzzled by how Water Release and Earth Release could so clearly violate the conservation of mass."
"Then I encountered Ōnoki on the battlefield. That destructive beam of his erased every bit of matter it touched. Only afterward did I realize that Ōnoki's Dust Release seemed to violate the conservation of mass too."
"Ōnoki claimed that Dust Release reduced matter to atoms. Ha! That's utter nonsense—ignorant and foolish. Even if matter is reduced to atoms, it's still matter. It still exists in this world."
Chuanhe raised a hand slightly. An iron sphere appeared before Hui, then crumbled into a pile of iron dust.
"As you can see, when a piece of iron becomes iron atoms, it still exists."
"It's just like I told you before: chakra is matter, not energy. What other people or textbooks say is their business. Whether the conclusion is true or false is something you have to judge for yourself, Hui. Don't believe everything you're told."
"Ninjas care too much about their own strength. Apart from a small number of medical ninjas, hardly anyone puts much effort into studying this."
"Clearly, Dust Release is like Water Release and Earth Release. They all seem to cause an obvious violation of the conservation of mass in this world."
"You came up with a good design for your second little experiment, too. But you haven't encountered many jutsu, so unfortunately, you were still wrong. That's not your fault."
"This phenomenon isn't absolute. Senju Hashirama, the First of Konoha, had Wood Release, which could leave a lasting impact on this world. The trees he created lived far longer than ordinary plants."
"Your conclusion was exactly the opposite: not all creations made with ninjutsu chakra disappear from the world."
"All these anomalies caused me a great deal of trouble. As I said earlier, I believed firmly in the conservation of mass and energy. So I started trying to explain these phenomena while still assuming those laws held true."
"Dust Release gave me a great deal of insight. Unlike the other jutsu I just mentioned, it caused an obvious loss of mass."
Hui saw Ōnoki use Dust Release. Unlike the destructive beam his father had described, what appeared before him was Dust Release: Atomic Dismantling Jutsu.
He saw a glowing white cube, like an eraser for this "world." Whatever it touched vanished completely.
The memory abruptly ended.
Then Hui saw a huge sheet of "paper" appear on the ground.
"To make this easier to understand, we'll use this to explain it."
"I call this way of thinking dimensional reduction. Most people can't understand things by thinking directly in three dimensions, but it's much easier if you compare them to two dimensions."
Hui saw a square "blank" suddenly appear on the huge sheet of paper. The paper was still the same, but Hui clearly understood that something seemed to be missing from that spot.
"That was the phenomenon. At the time, though, I didn't understand it."
"Back then, I was researching Space-Time Ninjutsu. This was after I left the Uchiha Clan."
"I had a very hard time in the clan. It was Yuki who gave me the Summoning Technique and storage scrolls I wanted."
Hui had been deep in thought, but this interrupted him. It was the first time his father had mentioned his mother to him. Hui felt conflicted.
"I'd come up with a brilliant 'idea' and was trying to create negative mass."
"I mentioned negative mass and the conservation of mass and energy earlier."
"At the time, I wondered what would happen if matter touched the boundary of space. Would it simply disappear? That didn't seem to obey the conservation of mass and energy."
"But disappearance seemed like the most reasonable explanation. The usual way to solve a physics problem was to use conservation of momentum and conservation of mass and energy. If matter simply disappeared, it would violate both laws."
"The phenomenon and the theory contradicted each other. That wouldn't have been a problem in the world I came from, but Space-Time Ninjutsu really exists in this world."
"Even when two spaceships traveling in opposite directions at the speed of light observe each other, they can only measure the speed of light. So why should matter be able to violate both laws when it touches the boundary of space?"
"So I started wondering: if matter touched the boundary of space while obeying both laws, what would happen?"
"That question stumped me for a long time. Every result I predicted obeyed only one of the two laws."
"That was when I first thought of the concept of negative mass. As if possessed, I came up with the following hypothesis."
"An ordinary object undergoing an elastic collision behaves like this (K). But what if, after matter touched the boundary of space, all its mass became negative and it returned along the same path (divination)? Then momentum would certainly be conserved, while mass and energy would simply have an extra negative sign."
Hui was struggling to follow, but a question came to mind. Wouldn't that still violate the conservation of mass and energy?
The darkness before him changed, and Hui saw himself standing by the sea with his father.
Looking at the waves, Chuanhe explained:
"Hui, if you were measuring the waves, would you count only the crests? Matter is like these waves. They just curve space-time in completely opposite directions, but to the same degree."
"Everything turns into its opposite at the extreme. The conservation of mass and energy was derived from reasoning about ordinary matter. Before this, the concept of negative mass didn't even exist. Who says that when mass turns negative, mass and energy are no longer conserved?"
"Besides, there's one point that matters most: mass and energy are scalars. They have magnitude, but no direction. Momentum is a vector. It has both magnitude and direction."
"Isn't the kinetic energy carried by negative mass still kinetic energy? The negative sign doesn't matter when it comes to the magnitude of kinetic energy. On the contrary, that negative sign matters a great deal for momentum. And in the process I'm hypothesizing, momentum is conserved."
"Of course, I knew you'd scoff at this explanation too. I had serious doubts about it myself and wanted to abandon the hypothesis outright."
"But then I thought of something else, and it changed my mind."
"Hui, did you know there's a mysterious celestial body in the universe called a black hole? It's like the planet beneath your feet, but its mass is so immense that even light can't escape. That's why I wanted to explain light to you first."
"As I said earlier, light is also a kind of matter. When mass reaches a certain point, even light can't escape."
"Around massive celestial bodies like black holes, another strange phenomenon occurs: time dilation. From the perspective of someone near a black hole, time outside seems to pass faster. Conversely, to an observer outside, time near the black hole seems to slow down."
(If you can't understand this, you can refer to Interstellar.)
"That's what happens with positive mass. So what if the mass is negative—"
"That's right. From the outside, time near negative mass would speed up."
(There are equations that can verify this. Search for them if you're interested.)
"Time speeding up, combined with the boundary of space, made me think of the boundary of the universe."
"Without a doubt, the boundary of the universe is also the boundary of space. If this really holds true, wouldn't it explain why the universe is expanding faster than the speed of light? It could also explain why the expansion is accelerating."
"I was incredibly excited at the time. I tested it over and over with storage scrolls, but got nothing. I couldn't produce even a single electron's worth of negative mass. After thinking it over repeatedly, I finally realized where the problem lay."
"In this world, space and energy aren't the same things as the space and energy I knew. They may have the same names, but they aren't the same things."
"That meant the storage scroll in my hands wasn't the boundary of space. The conclusion still hadn't been disproven."
"But by then, it didn't matter whether it was true or false. I'd opened the door to a whole new world. That was the first lesson I taught you: I began to ask myself what chakra really was. Was it matter or energy?"
Chuanhe sighed. His mistaken approach had given him insight and helped him see the world anew.
Failure was the mother of success. That saying was true.
Hui was dazed by the flood of memories. He even unconsciously overlooked the meaning of "planet." At that moment, he wasn't paying attention to such details. He was completely absorbed in following his father's train of thought.
Before you continue