The industrial age has opened a new chapter in human civilization, allowing us to achieve leaps in science and technology in a short period of hundreds of years. Powerful technology not only makes people’s quality of life higher and higher, but also enables mankind to realize the dream of flying to the sky, to get out of the earth to explore the secrets of the universe.
Facing the vast space of the universe, whether it is the earth or human beings, it is too small, and the universe is not completely dark and cold. Behind the dark and cold lies a dazzling and magnificent starry sky. Through the naked eye, we can see less beautiful scenery of the universe, but through an astronomical telescope, we can see a beautiful and wonderful universe.
The beautiful and dazzling universe brought us infinite shock. When we calmed down in this turbulent mood, we discovered an unusual event, that is, the universe was too quiet. This quietness of the universe is unreasonable. According to the observations of scientists, there are about 100-400 billion stars in the entire Milky Way.
In a system of hundreds of billions of stars, even if there is only a one-thousandth probability of a planet suitable for the birth of life, the number of living planets and civilizations in the entire galaxy is also a very large number. If so, then the Milky Way should be more lively, not as quiet as it is now.
In order to find alien civilizations in the vast universe, human beings have resorted to all their abilities to search for traces of the existence of alien civilizations through various methods. Mankind mainly uses three methods to search for alien civilizations. One is to launch interstellar probes out of the solar system, such as Voyager 1 and Voyager 2, both of which carry a golden disc that records the earth and human beings, and move towards the outside of the solar system. go ahead.
The second method is to search for wireless signals from alien civilizations that may exist in the universe. If an alien civilization also embarks on the road of science and technology, it will inevitably be inseparable from the use of wireless communication, and the stronger the civilization, the stronger the wireless communication technology. Therefore, unintentional or intentional technological civilization will have wireless signals spread in the universe. As long as we can receive such mysterious signals, we can determine the existence of alien civilizations.
The third method is that humans actively send their own civilization signals to the depths of the universe, hoping to be received by alien civilizations and get their response. It’s just that scientists believe that the possibility of success is relatively small. The reason is that humans’ scientific and technological strength is still very weak, and the emitted signal will continue to weaken as the distance increases. It may not reach the galaxy where the alien civilization is located. Has weakened to the point of indistinguishable.
Searching through the above three methods, more than half a century has passed, except for a few specious signals, nothing was found at all. This result makes us feel frustrated. Is it possible that humans exist alone in such a large universe?
Scientists naturally do not think that human beings are lonely in the universe. In order to better search for alien civilizations, scientists have modified their search ideas and methods in recent years. At present, we mainly use two methods to search for alien civilizations. One is to search for possible technical signs of alien civilizations, such as Dyson balls, interstellar probes, etc.
If the strength of the alien civilization has reached the interstellar, then it is inevitable to build some particularly large and conspicuous man-made objects. The Dyson Sphere is a giant building that wraps around the stars after reaching the second stage of civilization to make full use of the energy of stars. .
If a star is surrounded by a Dyson sphere, then the light and dark changes of the star will be very conspicuous, and we can see at a glance that there are unusual things around the star. If we can observe such stars, we can speculate that there may be extraterrestrial civilizations here, and through this method, scientists have indeed discovered some stars with particularly obvious changes in light and darkness. They are the celestial bodies that scientists focus on observing and tracking.
Another way is to find terrestrial planets that are very similar to the earth in accordance with the standards of the earth’s ecology. The earth can become an excellent planet of life and can also give birth to human beings, which means that the earth’s ecosystem meets the conditions for the birth and evolution of life. Then, in the universe, terrestrial planets that are very similar to the earth’s ecology will have a high probability of giving birth to life. , And even evolved intelligent life.
Therefore, in recent years, scientists have accelerated the detection of terrestrial planets, and the results have been good. So far, scientists have discovered hundreds of terrestrial planets in the starry sky within 1000 light-years from the ground, some of which are similar to the Earth. The similarity is very high. Scientists speculate that they may all be living planets, and some may have evolved intelligent life or even more advanced interstellar civilizations have emerged.
However, most of the habitable planets are located 100 light-years away from the earth, and the closest habitable planet to the earth discovered by current observations is in the Tigaden star system located 12.5 light-years away. Tigaden Star is a red dwarf star located in Aries, with a mass of one-tenth that of the sun and a surface temperature of only 2700 degrees Celsius.
In recent years, scientists have discovered two terrestrial planets in the habitable zone of this red dwarf star, both of which have a mass larger than that of the earth, and there is a high probability of liquid water on the surface. These two habitable planets are almost in the same habitable zone as the inner planets of the solar system, and the surface temperature also allows the existence of liquid water.
Of course, this star system may not have only two planets, there may be other planets in locations that we cannot observe. This shows that there is no shortage of habitable planets that are very similar to the Earth in the Milky Way, and it is possible that the actual number is far greater than we thought.
If there are so many habitable planets in the Milky Way, there is a high probability that there will be so many intelligent civilizations, but why have we not found any of them? In fact, it is mainly related to distance. We must know that the distance scale of the vast universe is very exaggerated, and the basic unit of distance is also light-years. Under the exaggerated scale, even the claimed fastest speed of light can only be regarded as a turtle speed.
The technological strength of alien civilizations may be much stronger than that of humans. We can discover habitable planets through observations. Then alien civilizations can naturally discover the existence of the earth, and even the traces of human existence. It’s just that alien civilizations also have no way to deal with the exaggerated cosmic distance. Before they can break the speed of light, it is difficult for civilizations to really contact each other.
After all, the life span of life is very limited. Even if human beings determine that there is an alien civilization in the planetary galaxy, we cannot travel by spacecraft. Alien civilizations are also unable to truly come to the solar system to come into contact with humans. Such news is undoubtedly good news for humans. This shows that the strengths of cosmic civilizations are not much different, and they have not truly broken the speed of light to become interstellar civilizations.
There are competitions, wars, and all kinds of darkness within human beings, so it is bound to be impossible for the cosmic civilizations to live in real harmony. When two civilizations meet, the stronger one may colonize the weaker. This is the law of survival of cosmic civilization.
Therefore, it is very reasonable for Hawking to warn humans not to actively seek out alien civilizations on many occasions. An inadvertent response from humans may bring disaster to the earth. We search for alien civilizations by searching for signals from the universe, so alien civilizations may also be looking for signals from other civilizations everywhere.
Once this civilization has the capability of interstellar navigation, it will go to learn about the location of the intelligent civilization discovered through the signal. The alien civilization spends a huge price to go to a certain wisdom literary star department, I believe it will not be to go sightseeing, the high probability is to colonize and plunder.