After that message, no further transmissions came from the Trolor Civilization. That was the end of their communication.
The message sent a chill through Xiao Yu.
“Ten years… only ten years? Entropy increase… heat death?” Xiao Yu’s mind began racing, those terms flashing rapidly through his thoughts.
Xiao Yu understood clearly what the principle of entropy increase meant, and he also understood its massive implications for the universe. One could say that it is precisely because of the existence of this principle that time doesn’t flow backward, and the universe has taken the shape it has today.
Entropy is a measure of the level of disorder in the distribution of matter within a system. It originates from the Second Law of Thermodynamics. The concept of entropy can be explained with a simple example. Everything in the universe has its own entropy value, a teacup has its entropy, a pen has its entropy, even a computer or a human has its entropy.
Entropy comes in degrees. A newly built house has very low entropy because it’s orderly and tidy. A dilapidated, long-abandoned house filled with dust has a higher entropy value than the new one.
That’s what entropy is. A shattered cup has a higher entropy than an intact one. A broken computer has more entropy than a new one. A decaying corpse has higher entropy than a living person. In general, the more broken and chaotic something is, the higher its entropy.
And in an isolated system, entropy can only increase, never decrease. That’s why a broken cup won’t mend itself, a damaged computer won’t revert to factory condition, a dead person won’t come back to life, and time cannot flow backward.
Of course, a broken cup can be repaired, a malfunctioning computer can be restored to near-new condition, and with cloning technology, a living body could even be replicated from a corpse. But there’s one crucial point, the concept of entropy applies to isolated systems. Once external forces intervene, it is no longer isolated.
From the principle of entropy increase, it follows that if you don’t clean a room, it will only get dirtier over time. There’s no scenario where you leave a room untouched, and it becomes cleaner by itself. If we consider a house as an isolated system, without gravity, external energy, living beings, or any external interference, then over time, that house can only grow increasingly chaotic. The plaster on the walls will flake off, the structure will collapse, and ultimately, the matter that once formed the house will spread evenly throughout the system. At that point, its entropy will have reached its maximum.This is the essence of the principle of entropy increase. For example, our universe is an isolated system. Thus, its ultimate fate will inevitably be heat death. In countless years, there will be no stars, no planets, no comets, no white dwarfs, no neutron stars, not even black holes. All will vanish. The universe will be filled only with an endless sea of leptons and photons.
This is the inevitable end for an isolated system.
“Entropy increase? This small universe… will it dissipate?” A sense of unease stirred in Xiao Yu’s heart.
“According to the Trolor Civilization, this small universe will undergo heat death in ten years… all matter within it will vanish. Could it be that the rate of entropy increase is related to the size of the universe? A larger universe, due to its vastness, sees entropy increase more slowly, while this smaller, unstable small universe sees entropy rise so rapidly that it reaches maximum entropy within just ten years?”
A new worry began to surface in Xiao Yu’s mind, because he realized another possible factor.
That factor… was time.
“I don’t know whether time in this small universe flows at the same rate as in the greater universe. I’ve already been here for nearly a year, but I have no idea how much time has passed in the real universe. If the entropy in this small universe increases rapidly, does that also mean that time flows faster here than it does in the larger universe? If I’ve spent one year here, and a million years have passed in the greater universe, then that would be a disaster. A million years would be enough time for the Sweepers to recover their strength, and enough time for the Guardian Civilization to repair their flagships. Who knows what state the galaxy would be in by then. I hope… such a thing doesn’t happen…” Xiao Yu silently prayed in his heart.
His concern over this issue even momentarily outweighed his curiosity about the spatial weapon.
“I have to hurry.” Xiao Yu thought to himself, quickly pulling up the spatial weapon technology passed down by the Trolor Civilization into his mind and beginning to review it.
He had finally acquired the most important part of the Trolor Civilization’s legacy, but instead of excitement, Xiao Yu felt none. You need to survive to use a weapon, but you also need to survive to enjoy it. Xiao Yu didn’t believe that his current level of technology was enough to resist entropy and heat death.
“From the history of the Trolor Civilization, this small universe has existed for at least five hundred thousand years. It makes no sense for it to suddenly undergo heat death within just ten years after being stable for so long. There’s only one explanation, during the past five hundred thousand years, the program left by the Trolor Civilization must have continuously drawn energy from the greater universe, using external forces to maintain and stabilize this small universe system and delay its decay.”
“If that’s the case, perhaps it also explains why the star system at the entrance to this small universe was so empty. All the material in that system, except for the central star, which was probably too massive to handle, was likely transported by the Trolor Civilization into this small universe and converted into energy.” Xiao Yu silently speculated.
“If that’s true…” a new thought suddenly emerged in Xiao Yu’s mind.
According to the laws of physics, time is not actually irreversible. Time is just a conceptual tool, a metric for measuring motion. If a person walks from their front door to a school and takes five minutes, and then walks back to the front door, returning to the original position, could it be said that time has flowed backward by five minutes?
That example isn’t entirely precise, of course, because our world contains more than just one person, there are winds, moving cars, and countless other variables. So let’s simplify it further: suppose the universe contains only one fundamental particle. Assume this particle doesn’t undergo any internal change. There’s nothing else in the universe. If the particle moves from point A to point B, taking five minutes, and then returns from point B to point A, restoring the original state, has time not reversed?
Some might argue that time still flowed forward. But if the particle returns to its initial condition, and the universe is identical to what it was five minutes earlier, why can’t we say time has reversed?
It’s an extreme example, such a situation could never truly exist in reality. However, even in our real universe, there may still be ways to reverse time. Right now, Xiao Yu had just thought of such a possibility. Of course, whether it could be realized was another matter entirely.
The principle of entropy increase holds that time cannot flow backward in an isolated system, but who’s to say that our universe is the only one? Perhaps there really are other universes. And perhaps, in those universes, vast amounts of matter and energy also exist. If, one day, it becomes possible to extract energy from another universe and inject it into our own, then the entropy of our universe could be reduced. And once entropy decreases, time could theoretically flow in reverse, just like human effort can restore a filthy room to cleanliness, or repair a shattered cup to perfection.
“Any civilization capable of doing such a thing would surely be godlike in nature. There’s no need to even consider Level 6 civilizations, this would be far beyond them. If… and this is a big if… if one day I could reach that level, to the point of restoring order to the greater universe, returning everything to its origin, and restoring Earth to the human era, then perhaps it’s not entirely impossible.” Xiao Yu mused. “That kind of power… must belong to Level 7, or even higher civilizations. Reversing time… Logic Weapons… I really wonder, what kind of secrets do Level 7 civilizations hold?”
Time reversal and Logic Weapons, these were two capabilities Xiao Yu speculated might belong to Level 7 or even higher civilizations.
He shook his head slightly, brushing aside the chaos in his mind, and continued carefully studying the material.
The result left Xiao Yu somewhat disappointed. Originally, he had hoped that this technical document would allow him to glimpse some of the spatial technology of a Level 6 civilization, paving the way for his own advancement. But now, he realized that such hopes were futile.
Because the technical document was the same in nature as the Specter Detector he had once obtained, it only detailed how to construct and use the device. It included nothing about its underlying principles, technical mechanics, or theoretical foundations. In other words, with this document, Xiao Yu could build a spatial weapon and use it, but he had no way of modifying it, not even the slightest bit, because he didn’t understand the underlying theory behind its construction.
“Well, one shouldn’t be too greedy. Having access to this kind of weapon is already enough. As for its inner workings… I’ll study them carefully another time.” Xiao Yu thought to himself, setting aside his momentary frustration and beginning, following the instructions in the document, to construct his first Level 6 civilization weapon, Fractured Space.