Where is the alien? Have they been to Earth?
Although there are countless incidents about "seeing aliens or alien spacecraft", there is basically no clear evidence. But whether there are aliens visiting the earth or not, most people firmly believe that aliens must exist.
The reason is very simple. There is no evidence that the universe is designed for humans. The universe is so big. The diameter of the observable universe reaches 93 billion light years, with hundreds of billions of galaxies, and each galaxy has hundreds of billions of stars and planets. There are more stars in the universe than the sum of all the sand on Earth.
The history of mankind is only one million years, while the history of modern civilization only lasts a few hundred years. From a probabilistic analysis, it will be destined to appear in the universe with a history of civilization of millions or even tens of millions of years. It is hard for us to imagine how high a cosmic civilization that has developed for tens of millions of years will reach.
If there were such a developed cosmic civilization, they should have been traveling around every corner of the universe at will. Why can't we see their traces?
We all know that there is a speed limit in the universe, that is, the speed of light. If you want to travel around the vast universe at will, it is inevitable to break the limit on the speed of light.
According to Einstein's theory of relativity, the absolute speed of anything cannot exceed the speed of light. If you want to fly in the universe, you can only control space and space and use the plasticity of space and time to indirectly complete superlight speed flight.
For example, the warp engine and wormhole technology that often appear in science fiction novels use this characteristic of time and space to complete superluminal flight.
Advanced alien civilizations may have had the ability to control time and space for a long time, but why did they not visit the earth?
This is also the core problem of " Fermi Paradox ". There may be many reasons, such as the universe is too big. Even for a highly developed alien civilization, it is difficult for them to accurately discover the earth in the vast universe. Because the earth is so small in the universe!
There is another possibility that alien civilizations have long been here on Earth, but humans have not yet appeared at that time, and they left after that. It is possible that they will visit the earth again one day in the future. According to their technological level, they should be able to predict the future evolution direction of life on Earth.
There is still this possibility. Aliens have long discovered humans and the earth, but in their eyes, human civilization is too backward, and it is not even a civilization. Human beings are as small as ants. There is no idea of communicating with human civilization in their subconscious mind.
Just imagine, will you make any connection with local ants when you travel thousands of miles away?
The development height of alien civilizations may exceed human civilization for a million years or even longer. In the eyes of human beings, they are like gods!
