In the legends of various civilizations, day foreign visitors are very common , and all outsiders have magical technical capabilities without exception.
Therefore, many people believe that not only exist in the universe, but they also came to Earth and had contact with humans a long time ago. However, because human technology was too backward at that time, could not produce two-way communication , so aliens slowly passed on as aliens, and finally integrated with the myths of various civilizations.
However, no matter how realistic the legend of this ancient alien is, it will not be accepted by the scientific community because there is no practical evidence to support it. Therefore, if you want to truly solve all the unsolved mysteries related to aliens, there is only one way, , that is, to actually find traces of aliens or aliens in the universe.
Astronomers have always actively sought out the loyal surroundings of aliens. From the Arecibo telescope and Arecibo information in the last century, to Voyager 1 and 2 probes, are all projects promoted by the astronomy community to find alien civilizations in the universe. However, now Arecibo has collapsed. Voyager 1 and 2 have almost run out of power for more than 40 years. It has not yet flew out of the solar system. It is even more distant to find aliens.
Some more rational astronomers and cosmologists believe that with the current aerospace speed of human civilization and the relatively remote location of the sun in Milky Way , it is almost impossible to find aliens by actively launching probes. Even if alien spacecraft really passes through the outside of the solar system, humans will not be able to find them , and they will not be able to find human probes, because even the planets are extremely small in the vast space, let alone the probes.
Based on the above facts, it is impossible for humans to find aliens in a short period of time. They can only hope that human civilization will be discovered and visited by alien civilizations.
So is it possible for human civilization on earth to be discovered?
The answer is that it is possible
. Regardless of the spread of information caused by electromagnetic waves communication that humans have used for more than 100 years, only increases from the carbon dioxide emissions caused by industrial production in recent centuries, may cause human civilization on earth to expose its existence, because the spectrum of any planet will contain the atmospheric components and proportions of the planet, and the spectrum is a basic planet data that is easily observed and collected from a distance.
In this case, if an alien civilization scans the spectral data of the earth through large-scale sky patrols and compares it with other Earth-like planets, will find that the carbon dioxide content in the earth's atmosphere has a period of rapid increase in , which can infer that there is a smart civilization on the earth and has developed industries.
Although the above spectral measurement method is only applicable to intelligent civilizations within a range of hundreds of light years from the earth, over time, this spectral feature of the earth will become more and more obvious, and it will become more and more likely to be discovered by other alien civilizations in the universe.
When humans discover alien civilizations or alien civilizations discover humans, the primary problem they face is how to deal with their relationship with alien civilizations.
Hawking During his lifetime, he repeatedly called on humans not to actively contact aliens, and did not reply when contacted, because humans could not tell whether the alien civilization in the depths of space was friendly or evil. rashly establishing a connection is too risky . If it really attracts the three-body person, it will be done.
Of course, this is for the situation where aliens are at a higher level than humans. If human civilization discovers an alien civilization with a technical level not as good as humans in the future, the situation may be similar to Columbus discovers the New World , that is, plunder and destroy. movie " Avatar " is a portrayal of this situation . The aliens on the Pandora planet have resources but their technology is not as good as humans, and can only be plundered by developed human civilizations.
Considering that the on the earth, Columbus and Native Americans can plunder when they belong to humans, it is not difficult to imagine what will happen to after humans arrive in a planet with rich resources and intelligent civilizations and different races from humans in the future.
Overall,
Alien civilization has always been the biggest variable in the future development of human civilization. It is possible that humans will still not find alien civilizations in the next few hundred thousand years, and may also appear around the earth in the next second.
