With the birth of mankind, the earth has also been upgraded from an ordinary planet of life to a planet of intelligent life. After human beings entered the civilized stage, the earth once again upgraded and became a civilized planet. With the birth of human civilization, the speed of human development is also accelerating, especially after entering the era of science and technology hundreds of years ago, mankind has ushered in rapid development.
With the help of science and technology, we soon realized our dream of flying to the sky, and we were able to step out of the earth and explore the universe. The moment we saw the vast universe, a huge doubt appeared in front of us, is that human beings alone in the universe? Is there a civilization of wisdom like human beings?
If it were in the earth age, many people might doubt the existence of extraterrestrial civilization, but when we really walked out of the earth and saw the vast universe, this doubt was basically gone. Most people believe that alien civilization exists. Why do people think that alien civilization exists? Mainly because the universe is so big that we can’t imagine it.
Let’s not talk about the entire universe. Take the dusty galaxy of the universe as an example. The Milky Way with a diameter of 100,000 light-years has hundreds of billions of stars. Among them, the number of terrestrial planets in the habitable zone may not be less than one trillion. With such a huge number, even if there is a very small probability of living planets and civilized planets, there is a high probability that there will be many intelligent civilizations in the Milky Way.
And the entire vast universe, there may be as many as trillions of large galaxies like the Milky Way, do you think there are alien civilizations? The existence of alien civilization in the universe is normal. If it does not exist, then the abnormality appears very abnormal and gives us a sense of fear.
Scientists naturally believe in the existence of alien civilizations, because from a numerical point of view, no matter how harsh the conditions for the birth of life are, there should be many living planets and many alien civilizations in the universe. Someone might say, since alien civilization exists in the universe, why can’t human beings find it?
In fact, the main reason is that the scientific and technological strength of human beings is still very weak. We are not yet an interstellar civilization and cannot go out of the solar system to explore various galaxies. Naturally, it is difficult to actively search for alien civilizations. Since mankind is still unable to actively search for alien civilizations, can it be discovered through passive means? The so-called passive approach is that alien civilizations take the initiative to come to earth to make contact with humans.
In theory, this possibility should exist, but the reality is that no advanced civilization has come to visit the earth until now? So some people have this question again: Why didn’t the advanced civilization visit the earth? Regardless of the scale of the universe or the age of the universe, there should be advanced civilizations that are much stronger than humans in the vast universe.
Let’s take the age of the universe as an example of 13.8 billion years. In such a long time, the time when the planet of life was born is naturally different. Some planets of life may have been born before the earth, so long as such a planet of life If normal development continues, the possibility of a civilization will be born in the future. If alien civilization was born tens of millions of years earlier than human beings, then the scientific and technological strength of alien civilization is far beyond our imagination.
In the eyes of mankind, a few light years, thousands of light years or even hundreds of millions of light years is a distance that cannot be crossed, but for a powerful advanced civilization, this distance is nothing at all, especially when it has developed to the top. Alien civilizations, the universe may already be their back garden. It is not difficult to discover the existence of the earth and humans naturally.
If the existence of the earth and human beings is not a secret to advanced civilizations, why did they not visit the earth? In fact, there may be two reasons. One reason is that advanced civilizations feel that the level of human civilization is too low, and there is no place for communication between the two. This is like, in the eyes of humans, ants are small and low-level creatures. It is naturally impossible for us to communicate with ants, because the gap between the two is really too big.
Although human beings are also intelligent civilizations, their strength is still very weak due to the short development time of human beings. We are still at a very primitive stage of technology, and advanced civilizations have mastered the most essential things of the universe, such as super-light flight, space jump, time shuttle, etc. And these technologies are completely impossible in the current human physical system. Take the speed of objects as an example. In the human physical system, the speed of light is the limit of speed. In the eyes of advanced civilizations, the speed of light may only be the most basic and slowest speed in the universe.
It is precisely because the civilization levels of the two are so different that advanced civilizations do not want to have contact with humans. The two have no common language at all. Advanced civilizations are more willing to communicate with civilizations of the same level, because this can promote the development and promotion of civilizations.
Another reason may be that there is nothing in the earth or the solar system that can attract advanced civilizations. The development of any civilization is inseparable from resources, even advanced civilizations are the same, but the resources needed by advanced civilizations may be completely different from the resources we need. In the eyes of mankind, all kinds of metals, fossil energy or nuclear fusion energy are what we need, but in the eyes of high-energy civilizations, these resources are too low-level, and advanced civilizations may no longer be used.
It is possible that in the eyes of alien civilizations, black hole energy, dark matter energy and other powerful energy sources of the universe are what they need. The more advanced the civilization, the higher the energy intensity requirements, so they will continue to search for powerful energy sources in the universe for mining. And our solar system and the earth do not have any particularly powerful energy sources. The most powerful energy source is probably the controllable nuclear fusion that has not yet been realized.
It may be that the solar system and the earth do not attract advanced civilizations, so even if people have already discovered the existence of the earth and human beings, they are unwilling to visit the earth. Perhaps only when humans continue to work hard and truly become interstellar civilization in the future can they be integrated into the circle of cosmic civilization. At that time, whether we are actively searching for various galaxies or passively having alien civilizations will contact us, it will become a lot easier.