Beneath Deep Space

From the perspective of entropy, the second law of thermodynamics can be described as: In an irreversible thermal process, the slight increase in entropy is always greater than zero.

So...the question is, what exactly is [entropy]?

In a statistical sense, entropy measures the disorder of a system, that is to say, the more disordered the system, the greater its entropy value.

Simply put, heat flows from a hot place to a cold place, and after enough time, all the heat is averaged out. These are obvious properties, no mystery at all: boiling water becomes colder, ice cubes melt. To reverse these processes requires additional expenditure of energy.

But such a simple law is so annoying and makes people full of despair about the world.

Scientists would rather not discover it, and some people even commit suicide because of it.

In its broadest sense, the second law of thermodynamics states that the "entropy" of the universe increases with each passing day.

For example, a mechanical watch's spring is always getting looser; you can wind it up, but that takes a bit of energy. This energy comes from the piece of bread you eat. The wheat used to make the bread needs to absorb the energy of sunlight during its growth;

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

In short, every local decrease in entropy in the universe must be at the expense of an increase in entropy elsewhere.

"In a closed system, entropy always increases until it cannot be larger. At this time, the system reaches a completely uniform state of thermal equilibrium, and no changes will occur unless the outside world Provide new energy to the system.”

But for the universe, there is no "outside world". Therefore, once the universe reaches a state of thermal equilibrium, it will completely die. This final result is simply called "heat death."

By that time, stars are extinguished, black holes die, all atoms are almost evenly distributed in the universe, and all spaces have the same temperature.

By the time of heat death, quantum events at tiny scales have finally become dominant.

"Heat death" is one of mankind's major conjectures about the ending of the universe.

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

So, let’s go back to a smaller perspective and describe the “increase entropy theory”.

If no one cleans a house, it will become dusty over time. At this time, we can think that the degree of disorder in the room has increased, which means that the entropy of the entire room has spontaneously increased.

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

Yes, the local entropy decreases, but the entropy of "person + room" does not decrease.

People consume physical energy in the process of cleaning, 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 perform work, this increment is greater than the reduction in disorder caused by "the room is cleaned".

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

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

In order to find a more powerful counterexample, people try to create perpetual motion machines or other methods to avoid entropy increase.

In 1871, the British physicist Maxwell imagined such an experiment: a box was divided into two parts by a board with a trap door guarded by an elf captured from Mount Hyjal as a coolie.

The elf can measure the speed of gas molecules. For molecules coming from the right, if the speed is fast, he will open the door to let it pass. If the speed is slow, he will close the door to prevent it from passing.

For the molecules coming from the left, the slow ones will be allowed to pass, and the fast ones will not be allowed to pass.

After a while, the molecules on the left side of the box will be very fast and the molecules on the right side will be very slow.

This means that the disorder of the box is reduced and the entropy is reduced.

The clever Maxwell also assumed that the valve has neither mass nor friction, so the elf did not do any work in this process. Doesn't this violate the second law of thermodynamics?

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

Hungarian physicist Szilard proposed that it is the "intelligence" of the elf that does the work.

He believed that the observational process of obtaining information (the elf judging the speed of molecules) requires energy and will inevitably cause an increase in entropy no less than the decrease in entropy due to the molecules becoming orderly.

In this way, the entire system composed of boxes, molecules and elves still obeys the second law of thermodynamics.

Looking back now, it is logical that extra work is required to obtain information. However, at the end of the 19th century, a wise person like Maxwell did not see the impact of the elf's "observation ability" on the box-molecule-evil system.

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

Then someone may ask: Since all processes in nature eventually tend to be disordered, why does there exist such a highly ordered existence as life?

In thinking about this philosophical issue, Schrödinger proposed in the book "What is Life" written in the 1940s that life extracts "order" from the environment to maintain its own "order".

Eating and drinking is a process of ingesting "orderliness". The orderliness of food is reduced through digestion, and the "disorder" is eventually discharged back to the environment in the form of diarrhea.

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

Generally speaking, the entropy of emission is greater than the negative entropy of intake, so the principle of entropy increase is satisfied.

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

"We speculate that the universe rejected the entire heat death process as being too slow and created life. Is that right?"

For example, the act of burning coal, oil, and natural gas releases the energy originally stored inside fossil fuels, allowing it to be distributed more quickly into the environment in the form of radiation, heat transfer, etc. The use of nuclear energy even makes life possible. The ability to release energy within atoms.

If the entropy increase process is compared to demolition, then intelligent creatures are like city management personnel invited by the universe.

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

From this point of view, does the purpose of the universe seem like a well-planned suicide with a magnificent plot?

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

Why does entropy increase spontaneously but not decrease spontaneously?

Why set such rules?

Unfortunately, this is a cosmic philosophical question for which we don’t know the answer.

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

We can extend the concept of "entropy" to other aspects and find that it is everywhere.

For example, if a drop of ink is dropped into a glass of water, it will slowly spread due to the thermal motion between the molecules until the ink is evenly distributed. The ink changes from order to disorder, and it becomes extremely difficult to restore it to its original state.

This is a process of entropy increase.

A pile of sand is piled into a cone with great effort, and it will slowly collapse... This is also the process of entropy increase.

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

Life, this highly ordered existence, is a low-entropy body. However, living bodies are not eternal, and individual lives will also get sick and age.

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

This kind of entropy can be fuzzy and quantified, and it is specific. We can simply replace it with [physical health indicators], [life span], etc.

If due to a reasonable lifestyle or certain technologies, it is equivalent to ingesting negative entropy flow into the living body, its entropy increase will become slower, or even decrease.

But in general, measuring the entropy of an individual is still a process of slowly increasing until the individual dies.

Then, let’s talk about civilization.

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

It is difficult to intuitively calculate how much entropy a civilization has. It changes from moment to moment and can only be estimated simply based on some performances.

In the age of the earth, there are many reasons for changes in dynasties and regimes, but in the end, can entropy be used to measure the degree of order?

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

In particular, the technological factor is a very significant negative entropy flow. As long as science can continue to progress, civilization can easily remain strong...

If the [civilization entropy increase hypothesis] is true, we should 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 inevitable.

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

This is also a hypothesis on the tree of cosmology.

——Professor Heigl, a sociologist of the universe.