The exploration and research of alien civilization has always been a hot topic in the scientific community. As early as the last century, just after mankind stepped out of the earth, we started the extraterrestrial civilization search program.
There are three ways for scientists to search for extraterrestrial civilization. One is to launch Voyager 1 and Voyager 2 interstellar probes, both of which carry a gold CD-ROM recording the earth’s coordinates and human information. Even after a billion years, this disc can be read normally.
Scientists hope that when Voyager comes out of the solar system, it will be intercepted by alien civilization, and then come to the solar system to communicate with human beings through the earth coordinates left on the CD. The second way is that we take the initiative to send the wireless signal of human civilization to the universe, knowing that the propagation speed of the wireless signal has reached the speed of light.
If there are alien civilizations near the solar system, then human wireless signals may be received. So as to let the alien civilization know that there are earth and human beings in the direction of the solar system of the galaxy. The third way is to search for possible extraterrestrial civilization signals in the universe through radio telescopes.
The universe has a long history of 13.8 billion years. In this long historical process, the universe has never stopped expanding. We don’t know how big the universe is now. At least the observable range of human beings has reached 93 billion light-years. In such a vast area, there are countless earth like planets.
The earth can give birth to life and civilization, so those planets with similar ecological environment of the earth also have great possibility of giving birth to life. Even in the universe, there may be advanced civilizations that were born earlier than human beings. They may have already developed into interstellar civilization, with more powerful signal detection ability and technology of crossing interstellar navigation.
Searching for possible signals of alien civilization in the universe is a reliable way for human science and technology to search for alien civilization. We should know that the distance between galaxies in the universe is at least a few light years. If the spacecraft does not have at least the speed of sub light, we will not be able to get out of the solar system and reach nearby galaxies. Therefore, Voyager 1’s hope of finding an alien civilization is very slim. It can’t get out of the Oort cloud at its speed for 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 galaxies of the solar system have the existence of alien civilization and have entered the era of science and technology, then the signal sent from the earth will only take more than four years to arrive, which is hopeful to be received by the neighboring civilizations.
In the same way, if there are alien civilizations in the galaxies near the solar system, as long as we enter the era of science and technology or are more advanced than human science and technology, then we can easily observe the special features of the solar system and the earth through the observation equipment. Of course, the observation equipment can only roughly observe that the earth may be an ecological planet, but the existence of life and civilization is unknown to alien civilizations.
At this time, alien civilizations speculate that there may be intelligent civilizations on the earth, so they need to make a trial. How can they make a trial? That’s to send civilization signals. At the speed of radio waves, it won’t be long before they arrive in the solar system. Human radio telescopes are likely to receive such mysterious signals. Naturally, the signals of civilization are very different from those of celestial bodies. As long as they are received, it is easy for us to think that there are alien civilizations “calling” human beings.
When we receive a civilization signal to greet human beings, contradictions among scientists will appear. Some people think that after searching for more than half a century of alien civilization, mankind has finally made a major discovery and has taken the initiative to say hello to mankind. Then we should also reply to each other and let each other know the existence of earth civilization.
Some people think that it’s not clear whether the alien civilization is friendly or evil. We can’t actively respond to such a signal. Silence is the best choice. So which one is better? If alien civilizations take the initiative to “call” mankind, should we reply?
In fact, Hawking has given the answer to this question. Someone once asked hawking the same question, and Hawking’s answer was no reply. Hawking believes that as long as wisdom and civilization are not stupid, the interests of civilization are above everything else. There is no real peace and stability within human beings, let alone alien races completely different from human beings.
Although the history of human civilization is only about 6000 years, it is a period of constant wars. In the past 6000 years or so, there have been many wars among human beings. In modern times, there have been two world wars. Even now in the age of peace, 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 friendly contact between alien civilizations and human beings? In fact, it is very difficult. The premise of peace and friendship is that the two civilizations have the same strength and no one dares to rush into conflict. Otherwise, both civilizations may be on the road to the end.
However, if there is a huge gap between the two civilizations in terms of strength, and if one civilization has a totally crushing attitude towards the other, it will be difficult to achieve true peace and friendship. The development of human civilization is inseparable from science and technology and resources. The earth’s resources are widely used by us and are facing the risk of exhaustion.
Without resources, the development of human civilization will stagnate, even regress step by step, and finally come to an end. When human beings walk out of the earth, the future direction of our resources acquisition is the various planets in the universe, and among the numerous planets, the resources of ecological planets are undoubtedly the most abundant. Therefore, every living planet is a treasure land of resources.
When human beings discover a low civilization planet, the first thing we think of is colonizing the planet, and then the resources here will be used by us. Similarly, once advanced civilizations discover the earth, they will also think of the earth’s resources and want to take them for themselves. If our strength is not as good as that of alien civilization, we can imagine the consequences.
Therefore, we can not respond to the signals sent by alien civilizations to human beings. It may be that the advanced civilization of the universe is actively casting its net. We should know that the universe is vast and vast, and even the advanced civilization can not explore every place. At this time, the use of radio broadcast in the form of casting the net is undoubtedly a very good choice.
If a civilization replies to this signal, then the advanced civilization will know where the other party’s coordinates are and what the strength of civilization is based on this signal. The strength of the signal can often represent the strength of a civilization. The stronger the civilization is, the stronger the wireless signal technology will be. This is easy to judge from the signal strength.
Some people may say that the speed of a radio signal is only the speed of light. Even if we search for such a signal to reply, the alien civilization may be very far away from us, and the signal will not arrive in a short time. When the signal is received by the alien civilization, it may be thousands of years or even tens of thousands of years later. At that time, human civilization may have become an interstellar civilization, not afraid of the unfriendliness of aliens.
If you think so, it’s a big mistake. Who has determined that the transmission of wireless signal must be the speed of light and can’t surpass it? At present, the speed of human wireless signal is indeed the speed of light, but our science and technology has begun the exploration and research of quantum mechanics. There is a kind of quantum entanglement in quantum mechanics, and its speed is far beyond the speed of light.
If the wireless signal of advanced civilization is based on quantum entanglement technology, then the speed is far faster than the speed of light. Even if the alien civilization is tens of thousands of light-years away from us, it may take only a few years or even less for the signal to reach the earth. There’s no need to walk on the road for tens of thousands of years or more.
On the contrary, the speed of human’s return signal is only the speed of light, which normally takes tens of thousands of years to return to the target galaxy. But there is no absolute. If the ability of advanced civilization to search for cosmic signals is far beyond our imagination, then the signals sent by human beings do not need to reach the galaxies of alien civilization, and they may be received at a farther location.
Therefore, we should not measure the technology of alien civilization by human technology. We have only been on the road of technology for hundreds of years. The advanced civilization may have gone for tens of thousands of years or even more. In the face of absolute strength, human beings have no ability to resist. Therefore, we should keep enough caution on the road of searching for alien civilization. We’d better hide ourselves completely, and don’t wave everywhere before we become an interstellar civilization.