The universe is so big, why can't we find alien civilizations? They may have collapsed before interstellar expansion

The universe we live in is a space that is so vast that it is incomprehensible. Since the universe is so large, why have we not found any traces of the existence of alien civilizations so far?

Does the universe being so large mean that there must be alien civilizations? This is indeed the case. Our solar system is a star system with a radius of 1 light year, which contains 1 star, 8 planets, numerous asteroids and other celestial bodies, and this is just one of the hundreds of billions of star systems in the Milky Way. There are countless galaxies like the Milky Way in the universe. You can try to imagine how small the probability of the existence of alien civilizations is, but as long as you substitute this tiny number into the huge base number of the universe, the final result will show that the probability of the existence of alien civilizations is very large.

Astronomer Drake combined eight variables to calculate the number of alien civilizations in the universe that could communicate with us.

These eight variables include the number of civilizations in the Milky Way that may communicate with us, the number of stars in the Milky Way, the proportion of stars with planets, the number of Earth-like planets in each star system, the proportion of planets with life evolution and habitability, the probability of evolving higher intelligent life, the probability of higher intelligent life being able to communicate, and the proportion of technological civilization duration in the life cycle of the planet. Obviously, most of the variables in Drake's equation are uncertain, but Drake still came up with a calculation result through estimation. The result shows that the number of civilizations in the Milky Way that can communicate with us should be between 1,000 and 100 million. Even if the minimum value of 1,000 is taken, it is already more than enough, but we have not received any information from any civilization. Why is this?

There have always been many explanations for this problem, and one of them is called the "Great Filter" hypothesis.

The "Great Filter Hypothesis" was proposed by Robin Hanson. He believes that in the birth of intelligent civilization, the difficulty of some key links has been seriously underestimated by us, and most civilizations cannot cross this key link. This key link acts as a filter, and most civilizations are filtered out by it. We know that life did not exist on the earth from the beginning. Intelligent life on the earth needs to go through 9 stages from scratch: 1. Have a suitable planetary system; 2. Self-replicating molecules; 3. Simple single-cell life; 4. Complex single-cell life; 5. Sexual reproduction; 6. Multicellular life; 7. Have enough brain capacity and learn to use tools; 8. The stage we are currently in; 9. Have the ability to expand interstellar.

In our opinion, these nine stages are logical, at least the first eight stages, but this is most likely a misunderstanding caused by "survivor bias".

In fact, among these nine stages, one or several stages are extremely difficult, and the probability of being able to cross them is extremely small, and most of the civilizations in the universe are filtered out at this stage. If this hypothesis is true, then a new question arises, that is, where exactly is this extremely difficult stage? If it is in the first eight, we don’t have to worry, but if the ninth stage is extremely difficult, then the future of human civilization will also be worrying.

In fact, many scholars believe that the Great Filter is located exactly in the ninth stage, and there is relevant research to support this.

Is it so difficult to have the ability of interstellar travel and interstellar expansion? In fact, the key to the problem is not this, but if this hypothesis is true, it means that most civilizations will collapse before they have the ability of interstellar expansion. According to a research result published in the Journal of the Royal Society Interface, the cause of civilization collapse is likely to be population explosion. The growth rate of population is closely related to the development of civilization. A deduction result shows that since 3 million years ago, a total of about 79 billion people have been born in the world, and the current world population is close to 7.9 billion, which means that the total number of people in the world is only 10 times the current population.

The rapid population growth probably began after the Industrial Revolution. It can be seen that the development of civilization, especially the improvement of productivity, has a strong driving force on the increase in population speed.

It can be seen that if the world population continues to grow explosively, it will inevitably lead to the collapse of civilization. After all, resources are limited, and the ecological carrying capacity is also limited. Maybe you think this is not a problem, isn't it enough to just control the population growth? The problem is not that simple. Everything is determined by objective laws. Artificial restrictions cannot change objective laws. It is like if the potato production increases exponentially year by year, but it is impossible to stipulate that the potato is 10 million per potato. Of course, this does not mean that there is no way to change all this. If the speed of technological innovation can exceed the speed of population explosion, then civilization will not collapse due to the rapid growth of the population.

For more information, please follow the official account: sunmonarch