Simulation explains the question ``Why do not you meet even though there should be advanced civilizations other than the earth?''

The question, ``Considering the size of the universe, there should be extraterrestrial civilizations, but for some reason no evidence of contact has been found,'' is called ``

Fermi's paradox ,'' after the physicist Enrico Fermi, who proposed it. and has been the subject of vigorous debate. One of the hypotheses that explains this reason is the `` dark forest hypothesis '' that `` civilizations are destroying other civilizations for survival strategies '', which can be tested in simulations.

EvangelosSciFi - DarkForestSim

There must be a highly developed civilization like human beings in the vast universe. The idea that it exists is held by many. However, since mankind has never found such evidence, this problem is called 'Fermi's paradox' and is discussed.

One of the opinions on this problem is the 'Dark Forest Hypothesis'. The Dark Forest Hypothesis has two premises. One is that ``even if one civilization learns of the existence of another civilization one-sidedly, there is a deep physical and cultural distance from the other civilization. We cannot understand and trust each other because we can think of each other.” One of the premises is that even if both civilizations are well-meaning civilizations, unnecessary conflicts and anxieties will arise under circumstances where communication is difficult, and a ``chain of suspicion'' will occur.

The other is that ``no matter how inferior the opponent is technically, there is a possibility that it will develop dramatically in the future, so someday you may notice our existence.'' Even if you choose to 'find a civilization but hide without contact', there is a possibility that it will be discovered by the other party eventually, so the first problem will emerge again.

Under this premise, a civilization that has become aware of another civilization cannot hide or communicate. The safest course of action for the survival of civilization is to 'keep in the shadows, never reveal your existence, and wipe out other civilizations as soon as you find them.' As a result, the Black Forest Hypothesis is that no evidence of contact between civilizations can be found. This theory quickly became a hot topic after it appeared in the science fiction novel ' Three Bodies II: Dark Forest .'

By the way, Mr. Aristotle Evangelos, a science fiction writer, made it possible to execute such a dark forest hypothesis by simulation. A part of the screen of the simulation created by Mr. Evangelos looks like this. Each colored circle you see on the screen represents one civilization.

Each civilization has four attributes, ``power'', ``visibility'', ``detection threshold'', and ``reach'', and each time (tick), the value of each attribute increases or decreases by 1 depending on the probability. If the reach (radius) increases and touches another circle, the 'comparison' step begins.

The comparison step compares power, visibility, and detection thresholds between the two civilizations. Here, if one civilization can see the other civilization unilaterally, that is, if the detection threshold is higher than the other's visibility, and if it has stronger power than the other, destroy the other civilization. increase.

The color of the circle indicates each attribute, red for power, green for visibility, and blue for detection threshold. The color of each circle indicates the characteristics of each civilization. For example, the red circle at the bottom is strong, has little green component, so it is low visibility (difficult to find), and has almost no blue color, so it can be detected. It shows that the threshold is low (easy to find others), and you can see that it is a fairly powerful civilization.

If a true green circle is formed, the civilization is easy to find, hard to find others, and weak in power. Purple, which has high red and blue components, has a strong power, but it has a weak ability to find others.

The simulation works roughly like this. When Mr. Evangelos prepared 1000 civilizations and conducted an experiment, only five civilizations remained after a while. It is unlikely that these remaining civilizations will come into contact with each other, and there is a good chance that the simulation will continue in this state.

In addition, the simulation also displays a graph showing the 'difference in average attributes between the destroying side and the destroyed side' as a moving average, which is interesting. The red line (force) greatly exceeds the baseline gray line, indicating that the value of the destroying side was much higher than the value of the destroyed side. Conversely, green (visibility) and blue (detection threshold) are below the baseline, meaning that the destroyer value was lower than the destroyer value.

Due to the mechanism that strong civilizations can destroy weaker civilizations, the remaining civilizations will uniformly become stronger over time. Furthermore, the destroyers tended to have lower detection thresholds than the destroyed, in other words, they were better at finding others.

However, there is some variation in visibility, and in some comparison steps it seems that 'a civilization with low visibility is destroyed by a civilization with high visibility'. In other words, no matter how easy it is for others to find you, it doesn't matter as long as your strength and ability to find others is high. Evangelos evaluated that the visibility attribute was always neutral in the simulation.

In summary, Evangelos said, ``Although the universe was teeming with civilizations billions of years ago, we are living in the late stages of the simulation, making it less likely that we will encounter other civilizations. On the other hand, it's quite possible that we're in the early stages of the simulation, just in the void left by a destroyed civilization, in which case we'll just have to wait for the next comparison. But this will probably take millions of years.'

Mr. Evangelos has released the simulation file , and anyone with the development environment ' NetLogo ' can play.

in Software, Posted by log1p_kr