Physicists have been searching for the most basic laws of the universe over the years, hoping to solve all the mysteries. However, in the process, people have put forward many conjectures based on existing discoveries. Although these conjectures It has not been confirmed, but it has also caused everyone to doubt the "world authenticity" of and , such as the Boltzmann Brain we are going to talk about today.
And if the Boltzmann brain is real, then there may be at least 7.5 trillion trillion trillion trillion trillions of consciousnesses floating in the universe. So, what exactly is a Boltzmann brain?
Boltzmann brain
What is Boltzmann brain?
When many people see Boltzmann's brain for the first time, they will think that it is very similar to Einstein's brain, and that it is a scientist's brain that was used for research.
But in fact, the Boltzmann brain is not a real thing. It is a hypothetical proposed by Austrian physicist Ludwig Boltzmann.
Boltzmann
Perhaps some people will think about the reality of the world when they have insomnia late at night.
If you happen to have heard of the "brain in a vat" experiment, then you will feel that in fact, our various feelings are transmitted to the brain through the senses and then obtained , and what if the senses can be simulated ? Does that mean that everyone, including the universe, is actually and false ?
Brain in a Vat
Boltzmann believes that the formation of the universe comes from the fluctuation of entropy. During this fluctuation process, things that are originally ordered will become chaotic and disordered according to the law of entropy increase.
When reaching a certain critical point, the entropy increase of and will stop, followed by the process of entropy decrease . This process will turn the disordered things in into orderly . However, the probability of is very low and it also takes a long time.
In the evolution process of universe fluctuations , there will be many self-awareness maintained in a low-entropy state. They are like lonely brains or consciousness bodies. These brains are called glasses. elzman brain .
If this hypothesis comes true, then during the tens of billions of years of fluctuations in the universe, at least 7.5 trillion trillions of consciousness bodies have been produced, and they are all floating in the universe.
The cosmic microwave background radiation map reveals fluctuations
It can be seen that Boltzmann's brain itself is closely related to entropy, so next we will take a look at what entropy is and what the fluctuations of the universe are.
"Entropy" and the ups and downs of the universe
If you like to watch some science fiction-themed movies and novels, you should be familiar with entropy . It is a very important concept in physics, and it is also a concept that has not been obtained. A comprehensive understanding of the concept.
This means that humans currently do not have a thorough understanding of entropy , but this does not prevent us from treating it as a "scale" , just like length and weight, entropy is used to express system chaos to the extent.
What is entropy?
Entropy was originally proposed by German physicist Clausius in 1865. It appears in the second law of thermodynamics and is a thermodynamic state function.
The second law of thermodynamics can also be called "entropy increase theorem" . It believes that when an object is somewhere, it will always change from the current order to disorder , and this is the death of life.
Clausius and the law of entropy increase
On the basis of Clausius, Boltzmann extended it and . He not only proposed the concept of microstates based on probability theory, but also concluded The famous Boltzmann entropy relation is derived.
This relationship is different from Clausius's entropy, which is only meaningful for equilibrium states. It is not only applicable to thermodynamic isolated systems, but can also be extended to non- thermodynamics systems, and is known as "generalized entropy".
This relationship quantitatively gives the statistical and microscopic significance of entropy, and specifies the physical connotation of entropy: entropy is proportional to the logarithm of the system's microstate number, that is, "entropy is a measure of the disorder of the system."
Boltzmann's formula was engraved on his tombstone
The reason why entropy is related to the universe must also mention the highly recognized Big Bang theory. According to the situation that the universe originated from the explosion of ordered singularity , the current universe should be in a high-entropy environment .
However, according to current observations, the current status of universe is contrary to our expectations. It is in low-entropy state .
The difference between low entropy and high entropy
Because only in the process of entropy reduction can everything in the universe move from disorder to order. Although from our perspective, the universe is still disordered, the formation of many celestial bodies and galaxies, including the formation of life and the brain , are all products of 's low entropy.
The brain is a product of low entropy
In this way, the universe has actually produced many low-entropy products during countless fluctuations. If we take the Boltzmann brain as an example, its number can reach tens of trillions.
And in this process, some consciousnesses of are that have existed for a long time, and some may disappear as soon as they appear. If those who disappear are included, the number will double again.
In fact, Boltzmann brain does not refer to "a certain kind of brain", it is more like a broad concept. The core of is that as long as time is long enough, any low-probability event in will occur , because the fluctuations of the universe are uncertain. When entropy reduction occurs and reaches a certain limit, will become chaotic and disorderly. can become disorderly.
For example, if dinosaurs were given some more time, then maybe they could develop civilization.
Dinosaurs
So, the laws and civilization we see now, including various things that have appeared in the long evolution, may be Boltzmann brains, but compared to those floating in the universe, ours The brain appears more advanced.
But by the same token, since higher-level low-entropy products have been born, from a probability perspective, lower-level "Boltzmann brains" may have already filled the universe.
Boltzmann’s brain may have spread all over the universe
After all, according to the formula, the probability that the universe fluctuates out of our world is e-10^100, and the probability that the universe fluctuates out of Boltzmann’s brain is e-10^ 28, once compared, we are more like and .
We can imagine further based on this. Since the probability of of Boltzmann brain producing is so high, but we have not found it, does that mean that may actually be "Boltzmann brain" ?
After all, as we mentioned above, in fact, we perceive our own existence through consciousness generated through the senses. If those Boltzmann brains in the fluctuation process can also simulate similar self-awareness with continuity, then maybe we are not so special after all.
Sensory simulation of the brain in a vat
To sum up, combined with the experiment of the brain in a vat, it will produce a feeling of "doubting life" . It’s no wonder that scientists always doubt themselves and the world in the process of research.
But it should be noted that the Boltzmann brain is only a hypothetical so far, so you must not take it as the truth and then trap yourself in it.
It is worth mentioning that although the Boltzmann brain has not yet been confirmed, entropy has been identified as existing, and it has penetrated into many fields during its development. is both related to the death of old things, It is also related to the germination of new things. Einstein even said, "The theory of entropy is the first law for the entire science."
Einstein
The application of "entropy" in the real world
As we mentioned above, before entering In the process of low entropy , the world moves from disorder to order. For an open system, the entry of negative entropy flow will offset its own entropy increase , allowing the system to maintain a stable and orderly dissipative structural state.
Dissipative structure refers to: "An open system far from equilibrium, through constant exchange of matter and energy with the outside world, may transform from the original chaotic and disordered state into a state of time, space or function. ordered state, thereby forming a new ordered structure far from equilibrium."
Dissipative structure
Therefore, when we regard the earth as a system, the earth system will move in the direction of increasing entropy , and in this process the earth system will exchange energy with the outside world , so it is Given the negative entropy flow, it eventually reaches a certain threshold, and the increase and decrease of tends to balance , thus keeping the system stable.
Entropy maintains a balanced state
In this process, humans may plunder natural resources due to profit or other motivations. In this case, such as industrial activities, this will increase the entropy of , resulting in a reduction in the orderliness of the system.
When the system gradually becomes chaotic , various extreme weather will appear. Therefore, in order to maintain orderliness and the dissipative system of the natural environment in , various human actions should take into account the changes in entropy.
Industrial activities will increase entropy.
Entropy theory is a century-old concept. Although it was born from thermodynamics, it is also closely related to life sciences, chemistry, biology, etc. It is no wonder that Einstein believed that It's the basic rule. Judging from the current situation, this is really the case.
