At the command, the small ship activated its warp drive. The space around it began to bend, and the distant starry sky twisted and warped in their field of vision. The ship did not travel through the greater universe as it usually did. The moment the warp drive activated, it mysteriously vanished from the space of the greater universe.
"Academician, is this four-dimensional space?" Hu Yu asked.
"I think it should be," Academician Zeng replied.
Though they had imagined the scene before them many times, it still far exceeded everyone's expectations. Everything inside the ship had changed appearance. This was an entirely new, bizarre world, one that transcended time, space, and human imagination.
The scenery was constantly changing. Since humans were three-dimensional beings with three-dimensional vision, they could not perceive all four spatial dimensions at once. Instead, their perception shifted among any three of the four dimensions. Through the fourth dimension, they could see things they had never been able to see before, such as the contents of sealed boxes and the various wires hidden inside the ship's walls. They could also see past obstacles to whatever lay behind them.
But the human brain could only perceive three dimensions at once, so when the fourth dimension appeared, all objects lost their sense of depth, leaving only length, width, and the fourth dimension. It was like looking at a cross-sectional view in an engineering drawing, with every internal structure clearly visible, including human organs. Fortunately, there were no female crew members aboard the ship, or the situation would have been extremely awkward.
"Academician, Academician, are you all right?" Hu Yu called, worried that everyone might feel unwell in this kind of space.
"We're fine, don't worry. Multidimensional space won't have a substantial effect on objects, but no one should move around. Stay where you are. We need to slowly figure out how to survive in this space," Academician Zeng replied. To Hu Yu, the nerves in Academician Zeng's face were moving constantly along with his mouth, while his internal organs were also slowly wriggling.
"Good. Is everyone else all right too?"
"Don't worry, General. We're all fine."
"Whatever you do, don't touch anything out of curiosity, or some very bad things will happen when we return to the space of the greater universe," Academician Zeng warned. "For example, if you put your hand through my body via the fourth dimension, you could easily damage my body. And if you move around carelessly and cause something to enter our bodies through the fourth dimension, we won't feel anything in this space. But when we return to the greater universe, we'll discover something extra inside our bodies. It might be a cup, a pen, or even a chair leg. Anything could happen."
"All we need to do now is observe this world with our eyes," Academician Zeng continued. "The instruments will record all kinds of data from here for us. We'll study it when we return to the three-dimensional greater universe and find the rules for survival in this space."
"By the way, Academician, how do we get out of this space?"
"It's easy. We just need to turn off the warp drive. Right now, we're like ants flying in the sky. Once we lose our energy, we'll fall back to the ground. Four-dimensional space is a high-energy space, and low-energy objects will be expelled directly. That's about enough. All the data has been collected, so let's return to the greater universe."
Amid a flicker of intermingling light and shadow, everything before them finally returned to normal. Even these experienced scientists felt far more stimulated than if they had attended a huge, explosive concert. After all, this was humanity's first true entry into four-dimensional space.
Four-dimensional space played an irreplaceably important role in both ordinary applications and warfare, especially wars between civilizations. Mastering dimensional technology meant holding the power of life and death over one's opponent. On the battlefield, entering the fourth dimension at will to strike at three-dimensional space was as easy as crushing ants underfoot. Moreover, the applications of dimensions went far beyond simple teleportation and evasion. There were enormous energy differences between dimensions, so the dimensions themselves could be called a terrifying weapon. If a piece of four-dimensional space were cut out and forcibly stripped of its fourth dimension, turning it into three-dimensional space, the lost dimension would release enormous energy.
For now, however, the fleet's spatial technology had not reached that level. Even entering the fourth dimension required relying on the remnants of the space bubble left behind by the swarm that had been delivered.
Hu Yu immediately ordered the Deep Blue Fleet and the 300,000 Hunter-Killers nearby to approach. The other 300,000 Hunter-Killers, tens to over a hundred light-years away, also received the message to return, but not one of them did.
"General, we won't return. Coming back now would be no different from telling the enemy where the Deep Blue is hiding. We're holding the enemy warships up on the perimeter, so the Deep Blue should hide as quickly as possible. But don't worry, General. Although the enemy is pursuing us, the fleet is widely dispersed, and our losses aren't too great. Once the Deep Blue is hidden, we'll scatter and take detours to continue on to Alpha Centauri, where we'll wait for you. Take care, General," fleet commanders Yang Fan and Chen Peng both replied.
"All right. We've fought together for many years, and you've never let me down. For the sake of the people, your decision is the right one. I'll send two engineering ships to take detours to Alpha Centauri as well. They can also reach twenty times the speed of light. Stay in contact, and good luck."
Yang Fan and Chen Peng had been Hu Yu's subordinates back in the Earth era. Like Hu Yu, they had been lucky enough to survive countless wars. Both were now commanders of the Hunter-Killer Fleet. Hu Yu hardly ever needed to concern himself with the warships' affairs; the leaders could keep every detail of the massive fleet in perfect order. They knew that Hu Yu had only given the order to return because his feelings had compelled him to do so. The best course was still for them to lead the fleet away themselves, relieving Hu Yu of enormous pressure.
Although the Hunter-Killers on the perimeter were being pursued, the enemy had only five warships. Even if they were more than ten times faster than the human ships, hunting down 300,000 tiny Hunter-Killers across an area a hundred light-years in radius was easier said than done. Even if the Hunter-Killers did not flee into the distance, five warships alone could not wipe out all 300,000 of them without spending several decades.
Most of these warships had a chance to evade the enemy pursuit, and they had ample time to hide in the four-dimensional space bubble. But if they did, the trajectories of a large number of warships would all point to a single location. Any civilized being with a sound mind would know what that location meant. To ensure the Deep Blue's absolute safety, the best course was to leave it alone and have everyone scatter and flee. The enemy would be unable to pursue them all or learn the fleet's intentions.
Wars in the interstellar age were often measured in years. A war lasting eight or ten years was nothing unusual; even hundreds or thousands of years were possible. Warships therefore needed sufficient supplies. Although the Hunter-Killers did not carry enough for a thousand years, they had no trouble sustaining their two crew members for fifty. This was also a precaution for when they were scattered during a war or needed to break through separately. Only with sufficient supplies could the crew travel long distances to another star system and survive.
The four-dimensional space bubble was less than one light-day from the Deep Blue's original docking area. The Deep Blue would need only a few hours to reach its vicinity. According to the satellites, the five alien warships were still busy in a region eighty light-years away. The large number of Hunter-Killers in the outer reaches had succeeded in drawing their attention, and they had not resumed searching farther ahead.
Academician Zeng was leading a group of spatial physicists in an intense effort to interpret the various data from the space bubble. If they could not interpret the relevant information in time, the Deep Blue would be unable to remain in the four-dimensional space bubble for long. Humans needed to move, eat, and work. These activities, utterly ordinary in the three-dimensional greater universe, became extraordinarily difficult in four-dimensional space. To escape the alien civilization's pursuit, they would very likely need to stay in the bubble for a long time. Humans could not simply sit there without eating or drinking. Without a reasonable solution, when they returned to the greater universe, they might discover that someone's heart had been twisted outside their body, someone's hand had appeared in another ship, or two people had grown together into conjoined twins.
Eighty light-years away, five enormous warships, each dozens of times the size of a Hunter-Killer, gathered together.
"Number One, there isn't much time left for the mission. There's no way we can destroy all these human warships. They're too scattered."
"Number Two, I've already reported the situation here to our superiors. Other warships will be here to support us soon."
"Number One, our main mission is to follow that old human man. Is it necessary to destroy every one of these ordinary warships?"
"I don't know either. The supreme head of state gave the order for this mission personally. I don't know what that old human man did to get the head of state to issue the order himself."
"Number One, haven't you noticed that our head of state has changed a lot in recent years?"
"I haven't noticed. What's changed?" Number One asked.
"In the past, every directive the head of state issued was for the development of our civilization. But lately, he's given a lot of attack orders, both against targets within our civilization and outside it. Our civilization used to develop peacefully and rarely came into conflict with other civilizations. Look at how our fleet has multiplied in size over the past few years. It's bigger than ever before."
"I suppose so. But those things aren't for us to figure out. The head of state must have his reasons. He's doing it for our civilization too."
"And do you remember the previous minister of industry?"
"Of course. The previous minister of industry was such an admirable man. He made many contributions to the development of our civilization. Unfortunately, he later rebelled and led a fleet to attack the homeworld. In the end, they were all wiped out."
"That's not what happened, Number One. I have a friend who works at a base on the homeworld. His position isn't high, but he knows a lot of inside information. Once, while we were chatting, he told me that the minister of industry never rebelled at all. He merely opposed the head of state's massive fleet expansion because it was causing imbalanced development in other areas. So he and a group of others were accused of rebellion and executed. The most innocent victims were the fleet stationed on the minister's planet. They didn't know anything at all before a fleet of our own kind launched a surprise attack and destroyed them. Luckily I wasn't there, or I couldn't have borne it, whether I was attacking or being attacked."
"I've heard about that too," Number Five said. "Number One, the story has already spread privately across the homeworld. The head of state's faction has suppressed it, though, so it hasn't spread outside, and no one dares talk about it openly. We've been working in the fleet all this time, so we've heard very little about these things."
"That's not all. Haven't you noticed? Several of our civilization's top officials have been replaced. The veteran officials were removed one by one for all sorts of reasons," Number Four, who had remained silent until now, said.
"That can't be true. Even opposition to the head of state's orders is perfectly normal. Things like that are bound to happen. People can talk out their differences. Everyone's doing it for the civilization; the head of state wouldn't go that far," Number Three interjected.
"That's what I thought too, but my friend swore it was absolutely true. He also said he knew some extremely confidential things, but they were so important, and he was too insignificant, so he didn't dare bring them out. Sigh, forget it. Let's not talk about this anymore. It would be bad if we were found out. Things like this aren't for small fry like us to get involved in. We should just look after ourselves. By the way, Number One, where exactly did that old human man come from?"
"I'm not very clear on that myself. All I know is that he's a member of this human civilization. He arrived in our civilization's territory a few years ago and was even received by the leader. But it's strange. How could a being from a civilization that hasn't even reached the middle stellar level be received by the leader in person? All right, enough talk. Let's get back to the mission. We still haven't found the main body of their civilization. It's really strange. Their warships are all in this area, but no matter what we do, we can't find the main body of their civilization. Could the members of their civilization be scattered among these warships?"
"Sigh, let's carry on. At this rate, we won't be going home for a long time."
Aboard the science ship, Academician Zeng and several top spatial physicists were deep in discussion. Their final conclusion was that a small number of people might be able to live in four-dimensional space after rigorous training. But they were not dealing with a few people; they had hundreds of millions. Among them were children who loved to run and jump, as well as workers busy with all kinds of jobs. The Deep Blue was a bustling place, and there were also all kinds of animals. None of these factors could be controlled precisely. To survive in four-dimensional space, they had to separate out the fourth dimension, leaving only three.
Three dimensions could exist within four, but removing the fourth dimension was a difficult problem. Finally, a spatial physicist named Liu Bo proposed an idea. Since the fourth dimension was difficult to eliminate, they could stabilize a region of space in the greater universe and drag it into the space bubble. If they kept it from merging with the space inside, they might be able to create a region of three-dimensional space for the Deep Blue Fleet.
But this idea already fell into the realm of cutting space. Humanity had not even found a way to survive in four-dimensional space, let alone cut space. Dr. Liu Bo explained, however, that this was not cutting space; it could only be called pulling space. It was like an ant on a piece of paper flying into the sky while remaining firmly stuck to the paper. If the force lifting the ant was strong enough, it would pull the paper out of shape along with it. The paper bulging upward would also mean that that part of it had entered three-dimensional space. Academician Liu Bo also proposed a concrete plan for pulling three-dimensional space from the greater universe into the four-dimensional space bubble.