From the day human beings were born, we began to look forward to and awe at the stars in the sky, wanting to understand what the stars and so on in the sky are. In ancient times, due to the lack of scientific guidance, people were unable to explain many natural phenomena, and finally put a god label behind these mysterious natural phenomena.
Compared with the mystery of nature, the universe is even taller. For modern humans, our feelings for the universe are vast and mysterious, and we want to uncover these mysteries. For humans in ancient times, their feelings for the universe are more fearful, and they cannot understand: Why does a fireball of terrible destruction fall from the sky? In fact, we all know these fireballs now that they are meteorites.
It wasn’t until mankind embarked on the path of scientific development hundreds of years ago that Galileo’s astronomical telescope allowed us to see the starry sky beyond the earth at close range for the first time. At this time, people’s fear of the universe is gradually disappearing, from fear to curiosity and longing for the universe.
With the continuous evolution of human technology, in 1957, mankind’s first artificial satellite was finally successfully launched. This was the first step for mankind to go out of the earth to explore the universe. Subsequently, human probes continued to fly out of the earth and began to explore the moon, Venus, Mars and even the distant edge of the solar system.
Through continuous exploration and research, we have discovered that we now have a lot of knowledge about the universe and put forward the theory of the Big Bang, which believes that the universe originated from the Singularity Big Bang 13.8 billion years ago. Knowing that the universe has been expanding rapidly since its birth, the current observable universe of mankind has reached 93 billion light-years.
In addition to cognition of the vastness of the universe, we also know that the Milky Way is 100,000 light-years in diameter, and hundreds of billions of stars exist in it. The solar system is only a small member of it. The more we know about the vastness of the universe, the more we will think of a mystery we want to solve, that is, the mystery of alien civilization.
In the eyes of many scientists, the universe is so vast that we cannot imagine that there are at least trillions of galaxies like the Milky Way. On such a scale, there should be a large number of alien civilizations in the universe, but why do we see the universe? Lonely?
In the 1950s, the nuclear physicist Enrico Fermi proposed the famous “Fermi Paradox”. This view holds that from the time and scale of the Milky Way galaxy, if there is an extraterrestrial civilization that is much more advanced than human beings, Then they should have explored and colonized the entire galaxy early, but why have we not found any so far?
The exploration of extraterrestrial civilization started from the moment human beings walked out of the earth. Scientists launch Voyager 1 and Voyager 2, both of which carry CDs that record information about the earth and human beings, heading out of the solar system, hoping to be captured by alien civilizations one day, and know the existence of the earth, and then come The solar system is in contact with humans.
In addition to launching probes, scientists also actively send wireless pulse signals to the deep space of the universe, hoping to get a response from alien civilizations. Scientists even used the world’s powerful radio telescopes to continuously scan the entire starry sky, searching for signals of possible alien civilizations.
With so much effort, have we achieved real results? The answer is no. So far, we have not found any traces related to alien civilizations, nor have we received any “calls” from alien civilizations. How is this going? In theory, there should be many alien civilizations in the Milky Way, but why can’t we find any traces?
For this doubt, scientists have also put forward a lot of conjectures, such as the laboratory theory, that the starry sky where humans are located is only a laboratory of alien civilizations, in which there is only a living planet on the earth, and only human civilization. Some scientists also put forward the theory of virtual universe, believing that the world we live in is a virtual world of advanced civilization.
In addition to these conjectures that scare us, there is another conjecture that has been supported by many scientists, and that is the von Neumann probe conjecture. This conjecture believes that there should be many extraterrestrial civilizations in the galaxy that are far stronger than human beings. After they have the ability to cross the interstellar, they will inevitably explore and search the entire galaxy to see how many life planets and intelligent civilizations exist.
To explore the entire galaxy, even if it is an alien civilization with interstellar navigation, it cannot be done in a short time. And the life span of life is limited, and coupled with the loneliness brought about by the long travel in interstellar space, it is unlikely that alien life bodies will personally pilot the spacecraft for long interstellar exploration.
At this time, the alien civilization may choose artificial intelligence to complete this exploration task. It is necessary to know that artificial intelligence is so powerful that it is actually no different from intelligent life, and they have a long life span, hundreds of thousands of years, millions of years for humans. It is not difficult to be smart.
Therefore, the alien civilization has built a large number of artificial intelligence interstellar probes, which are launched in all directions of the Milky Way. The function of the probes equipped with artificial intelligence is very powerful. It is hoped that a comprehensive exploration of the entire galaxy will be completed in 500,000 years. Seeing this, some people will raise the question: If advanced civilizations launch a large number of probes around the galaxy, then the solar system should not fall.
If a probe comes to the solar system, such an obvious alien vehicle, we shouldn’t be unable to find it, but why haven’t we seen it? Please don’t worry, we will get to the point below. It may seem to many people that interstellar detectors should be very huge and very obvious targets, but have we considered such a situation: that is, the interstellar detectors of alien civilizations are very small, so small that we can’t see them. ?
Astrophysicist Zaza Osmanov concluded through research that von Neumann detectors do not need to be too large at all. They only need about 1 nanometer to be enough, and only a micro detector of about one nanometer. Can we see it? Naturally it is invisible.
But can such miniature detectors really exist? I believe many friends also know that humans have also begun research and exploration of nanotechnology, and nano robots will also be realized in the future to serve humans. Since humans can make nanorobots, advanced civilizations that are much more advanced than humans can naturally make more powerful nanodetectors.
Another advantage of nanodetectors is that they can replicate themselves. Due to their small size, they can obtain extremely small hydrogen atoms from the ubiquitous interstellar dust, making themselves complex, and the replication time will be very fast. . Computer simulations show that if there are 100 von Neumann detectors, they will spread into a space of 1 parsec (3.3 light years), and the number will reach an astonishing 1X10^33.
If this conjecture is correct, it means that nano-detectors may exist in various locations in the space of the Milky Way, and the existence of the earth and humans may no longer be a secret. One reason why alien civilizations have not yet come to Earth is that the distance may be very far away, and they don’t want to spend too long to come to Earth.
Another reason may be that the resources of the solar system are too scarce. Extraterrestrial civilizations cannot get enough benefits and benefits from the solar system. In addition, human civilization is only a low-level civilization of less than one level. Alien civilization is not very interested, so we can’t find any traces of the existence of alien civilization.
Of course, these are just conjectures. To prove them, humans need to continue to work hard to develop science and technology. Only when the scientific and technological strength is strong enough can we find the answer. Otherwise, human beings may never be contacted by alien civilizations.