18#,Xly: Thumbs up, the theory of parallel universes does solve the problem of space-time paradox, but in fact, it is not an exaggeration to say that this theory is "sophistry". It is the result of human imagination. Think about it, simply using an illusory theory has successfully solved the problem that has troubled supporters of space-time theory for a long time. Isn't this great?

But the parallel universe theory has a fatal loophole! In the parallel universe theory, the large universe has infinitely multiple parallel universes, which means that no matter how small the chance of an event is, as long as it complies with the rules of the universe, it is possible to happen in one of the parallel universes.

Suppose we set a scale for the development level of science and technology and make the most developed civilization in the Milky Way "top level", then the possibility of a civilization developing to the top level is one trillionth of a trillionth of a civilization, and the possibility of this top civilization mastering the technology that travels through different universes is one trillionth of a trillionth of a trillionth of a civilization that travels through the universe happens to be even smaller in front of your computer. Although the probability is extremely small, in general it is still possible.

Since there are countless parallel universes, there will always be one universe that will produce civilizations with this kind of technology and appear in front of you.

But in fact, we have not seen any civilization coming out of the computer. From this we can prove that the parallel universe does not exist, and even if it exists, it must not be infinite. Or, the technology that travels through the parallel universe itself violates the rules of the universe and should not exist.

To sum up, the possibility that the poster comes from a parallel universe is theoretically almost zero.

19#, Big Thumb: A crooked theory! A crooked theory!!

20#, a glance at ten thousand years: I don’t know if the poster comes from a parallel universe. Maybe as Xly said on the 18th floor, the possibility is almost none. But I know. The poster will definitely not come from the future!

21#, Thumbs: Why is the 20th floor so sure? Ask for advice! Ask for advice!!

22#, a glance of ten thousand years: The reason is very simple, because entropy increases!

23#. Thumbs: It seems to make sense.

24#, a glance at a thousand years: The first law of thermodynamics is the law of conservation of energy, which tells us that all energy is conserved in the process of transmission and transformation; while the second law of thermodynamics tells us that heat cannot be transferred from low-temperature objects to high-temperature objects without causing other changes. In other words, in a system, the system always develops in the direction of entropy increase, which is an irreversible process!

...

Entropy refers to the state function of a system, which indicates the degree of chaos in the system.

The second law of thermodynamics says that the entropy value of an isolated system will only increase but not decrease. In other words, this system will only develop in an increasingly complex and increasingly chaotic direction. It is like a ball of flour thrown into a closed room. Once thrown out, it will only become disordered. This is a process of entropy increase. You cannot let the flour that has been thrown out and becomes chaotic back into your hands, which means that the entropy reduction cannot be achieved.

Any object in the world has entropy value. A cup has entropy value, and a broken cup has entropy value. If you break a complete cup, the entropy value of the broken cup will be larger than before it was broken. This is because a broken cup is more chaotic than a broken cup.

Similarly, since the entropy value of an isolated system will only increase and not decrease, it is impossible for the cup to spontaneously return to the complete state from the broken state. The law of entropy increase clarifies the directionality of time from the perspective of the time axis. It has irreversible characteristics.

Of course, one thing to note here is that the law of entropy increases refers to an isolated system. If you artificially glue the broken cup back, then extra energy is provided outside the system. Although the phenomenon of entropy reduction is achieved locally, it is still a process of entropy increase in a larger range.

32#, One glance at ten thousand years: The poster said that he came from 2030, which means that the entire universe has flowed back, which means that countless stars and particles in the entire universe have entered the process of entropy reduction. This is simply incredible. If the entire universe is an isolated system, then where can I get such a huge amount of energy if I want it to reduce entropy?

Local entropy reduction will inevitably require a larger range of entropy increase! A problem arises here: Our universe is too big, so where does the greater energy come from?

...

After a thousand years of words, the entire forum seemed to be digesting his views and was silent for a moment.

Su Yuan was also in deep thought, yes, if the entropy value of this world will only increase as Wannian said at one glance, then the moment when he traveled through time and in the world, wouldn’t it be a substantial process of entropy reduction from even more chaotic to relatively chaotic?

As we all know, refrigerators can be refrigerated, and some low-temperature refrigerators can even reduce the internal temperature to minus 80 degrees below zero or even lower. If the temperature is compared to entropy, the entropy value inside the refrigerator will undoubtedly decrease. But it should also be noted that during the cooling process, the heat does not actually dissipate, but is discharged from the inside to the outside. At the same time, during the discharge process, electrical energy is also required to urge the compressor to do work. In a larger system, the heat is not reduced, but because the electric energy is converted into heat energy, the total heat energy increases.

So Su Yuan was also thinking that whether he was using [retrogression] or a time machine to turn back time, it was actually a process of local entropy reduction. According to the law of entropy increase, greater "chaos" must appear in the overall system.

The problem is that the world line is jumping, and the world line value is a mathematical quantity that represents the entire world and the entire universe, that is, the backflow of time covers the entire universe.

So what force drives the entropy reduction of the universe? At least in the face of this force, even the entire universe is just a relatively small isolated system.

What a magnificent and great existence this should be!

For several days, the posts in this technology forum have remained silent. There are occasionally more interesting speeches every day, but it always makes Su Yuan feel as difficult as squeezing toothpaste. On the other forums, some buildings have been flooded with hundreds of floors, nearly a thousand floors.

But no matter how popular it is, Su Yuan is not very interested. She urgently needs answers and fishes out the owner of the diary. As for whether the floor is popular or not, it is really not a place she is interested in.

This situation lasted for several days. Until the morning of December 24, a post appeared:

68#, Rootless duckweed: Is it difficult to understand local entropy reduction? The jumping of the world line means that the entire universe has become a "local" isolated system of local entropy reduction. Although it is huge enough, you should know that the universe is finite and boundless. The meaning of this sentence is to tell us that although our universe has no boundaries, it is actually a finite individual.

The universe is not a simple three-dimensional space, it is a more complex "curved world". If a person walks along a straight line, it will never reach the edge of the universe. On the contrary, it will inexplicably come to its starting point from the opposite direction. Because from a three-dimensional perspective, you think you are walking in a straight line, but in fact you are bending along with the space.

So, we don't know how big our universe is in.

So, why can't it become a local isolated system in entropy reduction? As long as there is a larger system that provides energy to it, entropy reduction can be generated!

With the sudden speech of the rootless duckweed, the entire forum suddenly became active. Who doesn’t know the truth? The question is, how can it provide the tremendous energy that drives the entire universe back? It’s an incredible thing to think about it.

Su Yuan looked at Su Caiwei with interest and said, "Mom, there is a prerequisite for the statement of rootless duckweed, that is, the system to achieve entropy reduction must be an isolated system, and it must not have material communication with the outside world during the time span of time rewinding..."

Take the Milky Way as an example. If the Milky Way and other extrarias have no material exchange between galaxies in 100 million years, then theoretically, as long as you have the technology of turning back time and enough energy, the isolated system of the Milky Way can be reversed for 100 million years.

But if the Milky Way is always communicating with other galaxies. For example, the powerful gravity of the Milky Way has been swallowing up a certain satellite galaxy around it, or there are always wandering stars in the Milky Way breaking free from its constraints and running towards the depths of the universe, then the Milky Way cannot turn back time.

Because you can't let things that are already inside or outside the system disappear or pull them back for no reason.

Su Caiwei nodded with clarity, "Listen to his tone, it seems like she is sure that the universe is a closed individual."

78#.Big White Rabbit: So what kind of existence is providing energy to drive the entire universe backflow?

Su Yuan asked with the help of Alaya's power.

Rootless duckweed quickly answered, and his answer was only four words.

79#, Rootless duckweed: a long river of time!

"Time is long, what does this mean?" Su Yuan looked at the computer screen in confusion, and was about to typing on the keyboard to ask about the confusion in his heart, someone had asked this question earlier than her.

80#, Thumbs up: What's the long journey?

81#, a glance at it: Yes, what is the long river of time?

82#, Rootless duckweed: The long river of time is an endless past and an endless future, and the river of time formed by the present being interpreted. In the long river of time, space, matter, and energy are all things that are "light specific gravity". They can exist in the long river of time, but they will never become the protagonist, or even an insignificant existence!

The long river of time is always a large collection of timelines. Whether complete or disordered, countless timelines can exist in the long river of time. The space fragments, material fragments, and energy fragments that depend on the timeline exist, so there is a reason for existence in the long river of time.

Rootless duckweed: The long river of time is so mysterious. Where to choose a universe of time, it is a real universe. In other words, if a part of the energy can be divided from the long river of time and applied it to the universe where we are, what's the difficulty of causing it to decrease entropy?

If we want our universe to flow back one day, we only need to draw a one-day timeline. If we flow back one year, we will draw a one-year timeline. As long as we find the correct way to borrow energy from the long river of time, the whole process is as easy as drawing a wire.
Chapter completed!