[[[cp|w:210|h:140|a:c|u:/chapters/201510/8/36218716357989630430]]]Preface In the seventies of the last century, the United States produced a president who was very obsessed with extraterrestrial creatures - Jimmy Carter. He not only personally revealed the fact of his UFO sightings to the UFO Research Association, but also invested a lot www.biquge.info of manpower and material resources to explore alien civilizations. It was under the chairmanship of Jimmy Carter that on August 20, 1977. The Voyager 2 space probe left the Earth with mankind's best wishes for extraterrestrial civilization, and half a month later, Voyager 1 broke into space at a faster speed and flew into the depths of the universe.

In the vast universe, is human civilization really alone? Why are scientific Americans obsessed with the exploration of extraterrestrial civilizations? If the existence of extraterrestrial intelligent life is really discovered, what will it bring to the people of the earth? This series of question marks haunts the scientific community and appeals to the imaginative public. Many scientists have the opposite attitude towards humanity's enthusiasm for extraterrestrial life.

The famous British astrophysicist Stephen Hawking once warned mankind that aliens are almost certain to exist, but we humans should not try to find aliens, and should try to avoid contact with them, otherwise it may bring catastrophe to mankind. Hawking believes that in many other parts of the universe, aliens must exist, not only on the surface of planets, but also in the centers of stars, and possibly even floating in interstellar space.

There are 100 billion galaxies in the universe, each containing hundreds of millions of stars, and Earth cannot be the only planet with life. If aliens do invade, humans will be powerless compared to aliens who can travel through the stars. Even if alien space-time follows the same laws of physics as ours, and we are discovered when we enter the solar system, we don't have much time to prepare for war with aliens. Since it is unlikely that aliens will land on Earth in a spaceship traveling at the speed of light, they will inevitably slow down after entering the solar system. When Pluto's orbit is four rays from Earth, when the alien spacecraft enters Pluto's orbit at one-tenth of the speed of light, our fighter jets only have 40 hours to lift off, and the chances of the earthlings winning in such a hasty battle are slim to none, and this is not taking into account the fact that the aliens have a more convenient way to transport warships.

The Italian-born physicist Enrique Fermi famously proposed the Fermi paradox as to whether aliens exist or not: if aliens do exist, where are they? Fermi doesn't believe in the existence of aliens, and his paradoxes do have lethal power. Although there have been reveries about aliens in ancient and modern times, so far humans have not been able to detect their existence. For a long time, many people have claimed to have witnessed alien visits to Earth and even contact with humans, but the mainstream view is that it is nothing more than a psychological effect of human beings.

Fermi's paradox is very convincing, if aliens exist, there are only two situations, one is that aliens are on distant unknown planets, and there is no way to get in touch with humans until now, and even in the lifetime of human beings, the significance of the existence of such aliens can be ignored. Our Milky Way galaxy is 10 billion years old and about 100,000 light-years in diameter. At present, the fastest known speed is the speed of light in a vacuum, and it is impossible for physical particles to reach the speed of light, even if an alien spacecraft flies through the galaxy at a speed close to the speed of light, it will take 100,000 years, and also take into account the supply during the journey and the lifespan of alien creatures, which cannot be done according to the laws of physics currently known by human beings. However, where there is life, there will be miracles, and we humans are living examples, since Copernicus proposed the heliocentric theory has only been more than 500 years now, human beings have landed on the moon, and the people of Copernicus' time will definitely think that landing on the moon is unthinkable. If extraterrestrial civilizations had been on their way to Earth just 500 years before we did, they might have solved these problems.

The second explanation of Fermi's paradox is the so-called zoo effect, where aliens have arrived, even around us, but their technology is higher than that of humans, they can see humans, but humans can't monitor them, just like we go to zoos to see animals. Where are aliens? Is it really all around us?

On any planet, life will create miracles only if the needs of life for information, energy, and materials are satisfied! If aliens do ever visit Earth, then a series of unsolved mysteries on Earth - Atlantis, the pyramids, the 30 degrees north latitude, the Bermuda Triangle, crop circles, and those vampire monsters (Jersey Devil, Chupacabra, Swan Man) will be solved.