From the point of view of entropy, the second law of thermodynamics can be described as follows: in an irreversible thermal process, the micro-increment of entropy is always greater than zero. Ｘ

So...... The question is, what exactly is entropy?

In a statistical sense, entropy measures the disorder of a system, that is, the more disorganized the system, the greater its entropy.

In short, the heat flows from a hot place to a cold place, and after enough time, all the heat will be equalized. These are all obvious properties, and there is no mystery about them: boiling water cools, ice melts. To reverse these processes, you have to use additional energy.

But it's such a simple law, it's so annoying that it makes people desperate for the world.

Scientists would rather not have discovered it, and someone even committed suicide because of it.

In its broadest sense, the second law of thermodynamics holds that the "entropy" of the universe is increasing day by day.

For example, the mainspring of a mechanical watch is always getting looser; You can tighten it, but it takes a little bit of energy. This energy comes from the loaf of bread you eat, the wheat that makes bread, and needs to absorb the energy of sunlight as it grows;

In order for the sun to provide this energy, it needs to consume its hydrogen for nuclear reactions.

In short, every decrease in entropy in every part of the universe must come at the cost of an increase in entropy elsewhere.

"In a closed system, the entropy always increases, until it can't be greater. At this point, the system reaches a state of completely uniform thermodynamic equilibrium, and no further changes occur unless the outside world supplies the system with new energy. ”

But for the universe, there is no "outside world". Therefore, once the universe reaches a state of thermodynamic equilibrium, it dies completely, and this end result is simply called "heat death".

At that time, the stars go out, the black hole dies, and all the atoms are almost evenly distributed in space, all of which are the same temperature.

In the era of heat death, micro-scale quantum events become the ultimate dominant.

"Heat death" is a major conjecture of human beings about the outcome of the universe.

It will take at least 10^1000 years for the entire universe to reach heat death, and this ending is still too far away for human beings.

So, let's go back to a smaller perspective to describe the "entropy increase theory".

A house, if left uncleaned, is bound to be covered with dust over time. At this time, we can think that the degree of disorder in the room increases, that is, it represents a spontaneous increase in the entropy of the whole room.

If someone enters the room to clean and the room becomes clean, does the entropy of the room decrease?

Yes, the local entropy decreased, but the entropy of "people + rooms" did not.

The process of cleaning consumes physical energy, which leads to a decrease in the entropy of the isolated system of the "room". Since the energy conversion process will inevitably produce heat energy that cannot do work, this increment is greater than the decrease in disorder caused by "the room is cleaned".

Overall, the entropy of the "person + room" system has increased.

Scientists are very unhappy with this entropy increase conclusion, which means that the degree of disorder in the world has been increasing, and the future is not good.

In order to find a stronger counterexample, attempts have been made to create perpetual motion machines or other ways to circumvent entropy increase.

In 1871, the British physicist Maxwell conceived an experiment in which a chest was split in two by a plate with a trap door, guarded by an elf caught from Mount Hyjal to work as a coolie.

The elf can measure the speed of gas molecules, and for the molecule on the right, if it is fast, he will open the door and let it pass, and if it is slow, he will close the door and not let it pass.

For the molecule coming from the left, the slow one will let it pass, and the fast one will not let it pass.

Over time, the molecules on the left side of the box will be fast and the right side will be slow.

This means that the crate is less disordered and the entropy is reduced.

The witty Maxwell also assumed that the trap had neither mass nor friction, so the elf did not do any work in the process, and this was not a violation of the second law of thermodynamics?

It was not until 60 years later that this problem was satisfactorily resolved.

The Hungarian physicist Silard proposed that it was the "intelligence" of the elves that did the work.

He believed that the process of obtaining information (how fast or slow the elf judges the molecule) requires energy and inevitably causes an increase in entropy by a quantity that is no less than the entropy that decreases as the molecule becomes ordered.

In this way, the whole system, consisting of boxes, molecules, and pixies, still obeys the second law of thermodynamics.

Looking back now, it is logical that obtaining information requires additional work, but at the end of the 19th century, wise Maxwell did not see the effect of the elves' "observation ability" on the chest-molecule-goblin system.

It was not until the 20th century that physicists realized the important role of the "observer" in quantum mechanics that the relationship between information and physics was understood.

Then some people will ask: since all the processes in nature eventually tend to be disordered, why is there such a high order as life?

In his book "What is Life" written in the forties of the last century, Schrödinger proposed that life extracts "order" from the environment to maintain its own "order".

Eating and drinking is the process of ingesting "orderly", and the order of food is reduced through digestion, and finally the "disorder" is discharged back into the environment in the form of lazing.

In addition, organisms emit residual entropy from physiological processes into the environment by dissipating heat. The higher body temperature of warm-blooded animals is conducive to the more efficient removal of entropy, and thus the more intense life processes can be generated.)

In general, the entropy of emissions is greater than the negative entropy of uptake, so the principle of entropy increase is satisfied.

In this sense, the emergence of life, especially intelligent life, has accelerated the distribution of energy and greatly promoted the process of disorder in the universe!

"We guess that the universe is too slow to die and create life, isn't that so?"

For example, the act of burning coal, oil, and natural gas releases the energy originally stored in fossil fuels, so that it is distributed into the environment more quickly in the form of radiation and heat transfer, and the use of nuclear energy even gives life the ability to release the energy inside the atoms.

If the process of entropy increase is likened to demolition, then intelligent beings are like chengguan invited by the universe.

The higher the level of civilization, the more it can help the universe return to heat death.

In this way, does the purpose of the universe not seem like a well-planned suicide with a magnificent plot?

But why did the universe commit suicide? Why do you want to return to heat death?

Why does entropy increase spontaneously and not decrease spontaneously?

Why do you have such a rule?

Unfortunately, this is a philosophical question at the cosmic level, and we don't know the answer.

The above part is the [theory of entropy increase in thermodynamics].

We can generalize the concept of "entropy" to everything else and find it ubiquitous.

For example, if a glass of water is dropped into a drop of ink, it will slowly diffuse due to the thermal movement between the molecules until the ink is evenly distributed. The ink went from orderly to disordered, and it became extremely difficult to restore it to its original appearance.

This is a process of increasing entropy.

A pile of sand, which takes a lot of effort to form a cone, will slowly collapse...... This is also the process of entropy increase.

The universe is decaying, and so is everything in the human world.

Life, this highly ordered being, is a low-entropy body. However, life is not eternal, and individual beings can also get sick and age.

From the moment a person is born, the entropy is constantly changing, until the moment of death, the entropy representing his individual increases to the maximum.

This kind of entropy can be vaguely quantified, it is concrete, and we can simply replace it with [physical health indicators], [lifespan], etc.

If, due to a reasonable lifestyle, or some technology, it is equivalent to ingesting a negative entropy flow for living organisms, its entropy will increase more slowly, or even decrease.

But in general, the entropy of an individual is still measured by a slow increase until the individual dies.

Then, let's talk about civilization.

Nothing in the universe is eternal, and we assume that civilization also has its own [entropy], but the entropy of civilization is more abstract.

It is difficult to intuitively calculate how big the entropy of civilization really is. It is constantly changing from moment to moment and can only be simply estimated based on a few performances.

In the age of the earth, there are many reasons for the change of dynasties and regimes, but in the end, can the degree of order be measured by entropy?

There are many factors that affect the entropy of civilization, including but not limited to the external environment, technology, social system, population number, population quality, etc.

In particular, the factor of science and technology is a significant negative entropy flow, and as long as science can continue to progress, civilization can easily remain strong......

If the [Civilization Entropy Increase Hypothesis] is true, we must be careful, because entropy will always increase spontaneously, and we must find ways to control its entropy increase, whether it is social factors or technological factors.

Otherwise, the demise of civilization will become an inevitable event.

From this point of view, tomorrow is not good...... According to the theory of entropy increase, tomorrow will only naturally get worse, not automatically better.

This is also a hypothesis on the philosophical tree of the universe.