"It might be a little hard to understand for a three-dimensional world, but it's much easier to explain when it's two-dimensional." The instructor said: "The 'sphere' in front of me is just a simple sphere, and its interior and exterior can be understood as non-existent, or in other words, for the two-dimensional creatures living in the 'sphere', these three-dimensional spaces themselves cannot be perceived. ”

"At this time, let the black villain walk around again."

After that, the black figure on the "sphere" began to move again, but this time, no matter which direction the black figure moved, it would never be able to find the boundary of this world.

"The surface area of the spherical world is finite, but the black man can never reach the boundary, because as a sphere, there is no boundary in itself." The instructor said slowly: "And this is the so-called 'limited and unbounded'. ”

"In fact, we can move much slower than this little black man, and if the spherical world is still expanding like a balloon...... the white sphere in front of the instructor really began to expand gradually: "Then it may be difficult for a person to go from one end to the other for the rest of his life." ”

"It's actually much easier to understand the finite and unbounded two-dimensional world, and then compare it to the three-dimensional world."

Yan Xiuze scratched his head and said with a smile: "Don't mention anything else, instructor, your teaching level is still as high as ever...... Can you explain an abstract concept so plainly......"

"Hey, don't rush to slap the ass just yet." The instructor glanced at Yan Xiuze and snorted coldly: "It stands to reason that this should only be very rudimentary knowledge for you, why did you suddenly ask me such a question?" ”

"It's a bit complicated to explain why." Yan Xiuze said seriously: "Instructor, you should know that the leader of the Black Star Society, Black Star has left the earth with that alien, right?" ”

"Huh? I don't really know that. The instructor sighed: "Since that incident ten years ago...... The Black Star had completely disappeared from public view, and at first I thought he was just hiding from the world, and I didn't think he had left the earth......"

"Actually, that's not the point, the point is, before he left, he left me a sentence......" Yan Xiuze snapped his fingers at this time, and a white point of light suddenly appeared at his fingertips, and with a "boom", the point of light exploded......

The instructor saw that the surrounding scene had turned into an endless grassland, and above his head was a long galaxy composed of bright stars, and the black star turned his back to them from afar, and quietly said a sentence that Yan Xiuze had heard many times: "Yan Xiuze, I am waiting for you at the boundary of the universe." ”

Wow –

The scene faded, and it turned back into a point of light on Yan Xiuze's fingertips again.

"That's it." Yan Xiuze put away the light spot and said, "Before Black Star left, he left me such a sentence. ”

"Actually, when I first heard it, I felt a little strange."

"Because according to the current mainstream view of 'finite and unbounded', the universe should have no boundaries."

"So in that case, what exactly does this 'boundary' in Black Star's words refer to?"

While the instructor frowned and pondered, he subconsciously touched the red rope tied to the tail of the horse on the back of his head, and after a long time, he said slowly: "I said, Xiu Ze...... I mention a possibility here, is there a possibility that the physical literacy of Blackstar itself is not high? ”

"You mean, what he said was actually fundamentally wrong?" Yan Xiuze asked rhetorically.

"Isn't that possible?"

"No, I don't think Blackstar would make such a low-level mistake, and besides, it's not too much knowledge with too high a threshold, right?" Yan Xiuze shook his head: "Besides, don't forget, there is a real alien by his side, even if he doesn't know 'finite and unbounded', the alien Shank, who has been traveling outside all year round, will not know?" ”

"So, I'm actually more inclined to see if it's the mainstream view in physics today...... Wrong? ”

Yan Xiuze frowned and said, "The universe is actually ...... Is there a boundary? ”

"There are other hypotheses...... the instructor shook his head, "but do you know which one is true?" This black star...... I can't explain it clearly, and I didn't forget to leave a puzzle when I left. ”

"One more thing...... Yan Xiuze hurriedly said, "I ...... last night Isn't it a hangover? ”

"When I was asleep, I actually had a rare dream."

"Dreaming?" The instructor wondered, "I thought the superpowers would no longer dream. ”

"The dream was real, and I still remember it clearly." Yan Xiuze said to himself: "At the beginning, it should have been when I was still an ordinary person, when I went to the hospital to check my blood abnormality, and I happened to listen to the follow-up news about the meteorite falling from the sky in the Northern Hemisphere. ”

"Eh, are you talking about the largest meteor shower swarm of the century?" The instructor frowned and said, "Since the meteorite landed, Howell's syndrome has appeared suddenly...... Over the years, I don't know how many experts have studied the correlation between the two, but after all, there is no clue. ”

"But the timing of the two is too coincidental, the meteorite on the front foot has just landed, and the back foot is ...... The guy named 'Howell' in the United States entered the incubation period of Howell's syndrome, and a few years later he was also the first to detect the existence of this condition, so much so that he simply named it after him. ”

"You also know the rest of the matter, blessings and misfortunes depend on each other, who would have thought that side by side with death would be a great opportunity to become a superpower."

"Well, that's right." Yan Xiuze nodded: "Therefore, although the direct causal relationship has not yet been determined, at least, that meteorite that fell from the sky does have a strong correlation with the appearance of the superpowerhouse later." ”

"And then, my dream was abruptly connected to the words left by the Black Star ...... before."

"It is said that there are thoughts and dreams at night...... A person's dream is a kind of embodiment of his subconscious......" Yan Xiuze said slowly: "Since this is the case, it shows that in my potential consciousness, the two things of 'Superpower Origin' and 'Black Star Departure' are connected. ”

"So, I'm wondering, could the two really be connected?"

Or to put it more bluntly...... As a supernatural who awakened before me, could Blackstar actually know a part of the inside story about the origin of superpowers? Or is his departure actually to pursue the truth about the appearance of the superpower? ”