The exploration and research of alien civilizations has always been one of the hottest topics in the scientific community. As early as the last century, after human beings walked out of the earth, we started the search for extraterrestrial civilization.
Scientists search for extraterrestrial civilizations mainly through three methods. One is to launch Voyager 1 and Voyager 2 interstellar probes, both of which carry a golden compact disc that records the coordinates of the earth and human information. This disc can be read normally even after one billion years.
Scientists expect that when Voyager leaves the solar system, it can be intercepted by alien civilizations, and then come to the solar system to communicate with humans through the earth coordinates left on the disc. The second way is that we actively send wireless signals of human civilization to the universe, knowing that the propagation speed of wireless signals has reached the speed of light.
If there are extraterrestrial civilizations near the solar system, then human wireless signals may be received. In this way, alien civilizations know that the direction of the solar system of the Milky Way has the presence of earth and human beings. The third way is to search for signals of possible alien civilizations in the universe through radio telescopes.
The universe has a long history of 13.8 billion years. During this long history, the universe has not stopped its pace of expansion. We don’t know how big the universe is now. At least the observable range of human beings currently reaches 93 billion light-years. Within such a vast range, there are countless terrestrial planets.
The earth can breed life and give birth to civilization, so there is a great possibility that life will be born on those planets that are similar to the earth’s ecological environment. Even in the universe, there may be advanced civilizations that were born earlier than human beings. They may have developed into interstellar civilizations, possessing more powerful signal detection capabilities and technology for crossing interstellar navigation.
Searching for signals of alien civilizations that may exist in the universe is a relatively reliable way for human technology to search for alien civilizations. We must know that the distance between galaxies in the universe is at least a few light-years or more. If the spacecraft does not have a speed of at least the sub-light speed, we will not be able to get out of the solar system to reach nearby galaxies at all. Therefore, the hope of Voyager 1 to find an alien civilization is basically very slim. It will be impossible to get out of the Oort Cloud at its speed in tens of thousands of years.
In the current human cognition, the speed of light is the limit of speed, and only photons and radio waves can reach this speed. If the neighboring galaxy of the solar system has an extraterrestrial civilization and has entered the age of technology, then the signal from the earth will be able to arrive in more than 4 years, and it will hopefully be received by the neighboring star civilization.
In the same way, if there are extraterrestrial civilizations in galaxies near the solar system, as long as they enter the technological era or are more advanced than human technology, then it is easy to observe the special features of the solar system and the earth through observation equipment. Of course, the observation equipment can only roughly observe that the earth may be an ecological planet, but whether there is life and civilization exists, alien civilization is also unknown.
At this time, extraterrestrial civilization guesses that there may be an intelligent civilization on the earth, and it needs to be tested. How to test it? That is to launch a civilization signal. At the speed of radio waves, it will not take long to reach the solar system. Human radio telescopes are likely to receive such mysterious signals. The signals of civilization are naturally very different from those sent by celestial bodies. As long as they are received, it is easy for us to think that there is an alien civilization for humans.” Call”.
When we receive a civilized signal that actively greets humans, contradictions among scientists will also appear. Some people think that humans have searched for more than half a century of alien civilizations, and finally made major discoveries, and they took the initiative to say hello to humans, then we should also reply to the other side and let the other side know about the existence of earth civilization.
There are also people who think that whether an alien civilization is friendly or evil, we still don’t know. It is not possible to actively respond to such signals. Keeping silent is the best choice. So which one is better? If an alien civilization takes the initiative to “call” humans, should we reply?
In fact, Hawking has already given the answer to this question. Someone once asked Hawking about this question, and Hawking’s answer was not to reply. Hawking believes that as long as it is a wise civilization, it is not stupid and sweet. The interests of civilization are above all else. There is no real peace and stability within human beings, let alone alien races that are completely different from humans.
Although mankind has only about 6000 years of civilization history, this is a period of constant wars. During the 6,000 years or so, there have been many wars within human beings, and there have been two world wars in modern times. Even now in the peaceful age, there will still be small-scale conflicts and wars in some areas.
There is no real peace and stability within human beings. Can we expect alien civilizations to have friendly contact with humans? It’s actually very difficult. The prerequisite for peace and friendliness is that the strengths of the two civilizations are similar, and no one dares to rush into conflict, otherwise it may be that both civilizations are on the road to end.
But if the power gap between the two civilizations is very large, and one civilization is completely crushing the other civilization, true peace and friendliness will be difficult to achieve. The development of human civilization is inseparable from science and technology and resources. The earth’s resources are used by us in large quantities and face the risk of exhaustion.
Without resources, the development of human civilization will stagnate or even regress step by step, and finally come to an end. When mankind leaves the earth, the future direction of our resource acquisition will be the various planets in the universe, and among the many planets, the resources of the ecological planet are undoubtedly the most abundant. Therefore, every planet of life is a treasure land of resources.
When mankind discovers a low-level civilization planet, our first thought is to colonize the planet, and then overlord the resources here for our use. Once the same advanced civilization discovers the earth, it will also think of the earth’s resources and want to take it for itself. If our strength is not as good as the alien civilization, the consequences can be imagined.
Therefore, we cannot respond to the signals sent by alien civilizations to mankind. This may be because the advanced civilizations of the universe are actively casting a net. You must know that the universe is vast and vast, and even advanced civilizations cannot explore every place. At this time, it is undoubtedly a very good choice to use the form of radio broadcasting to cast the net.
If a civilization responds to this signal, then the advanced civilization will know where the opponent’s coordinates are and how strong the civilization is based on this signal. The strength of the signal can often represent the strength of a civilization. The stronger the civilization, the stronger the wireless signal technology. This is easy to judge from the signal strength.
Some people may say that the speed of radio signals is only the speed of light. Even if we search for such signals to reply, it is possible that the alien civilization is very far away from us, and the signal will not reach it in a short time. When the signal is received by an alien civilization, it may be thousands or even tens of thousands of years later. At that time, human civilization may also become an interstellar civilization, and there is no fear of aliens being unfriendly.
If you think this way, you are quite wrong. Who has determined that the transmission of wireless signals must be the speed of light, can’t it be surpassed? At present, the speed of human wireless signals is indeed the speed of light, but our science and technology have begun the exploration and research of quantum mechanics. There is a kind of quantum entanglement in quantum mechanics, and its speed far exceeds the speed of light.
If the wireless signal of advanced civilization is researched on the basis of quantum entanglement technology, then the speed will far exceed the speed of light. Even if the alien civilization is tens of thousands of light-years away from us, it may only take a few years or less for the signal to reach the earth. There is no need to walk on the road for tens of thousands of years or more.
On the contrary, the human response signal speed is only the speed of light, and it takes tens of thousands of years to return to the target galaxy under normal circumstances. But there is no absoluteness. If the ability of advanced civilizations to search for cosmic signals is far beyond our imagination, then the signals sent by humans do not need to reach the galaxies of alien civilizations, and they may be received at a farther position.
Therefore, we should not use human technology to measure the technology of extraterrestrial civilization. We have only been on the road of science and technology for hundreds of years. High-level civilizations may have been around for tens of thousands of years or even longer. In the face of absolute strength, humans have no ability to resist. Therefore, we must be cautious enough on the road to search for alien civilizations, it is best to hide ourselves completely, and do not wander around before becoming an interstellar civilization.