Hundreds of years ago, after continuous efforts and development, human civilization finally entered the road of technological development. With the help of science and technology, mankind soon realized the dream of flying out of the earth and began to explore the universe.
When we walk out of the earth and see the vast universe, people will think of the same question: Does alien intelligent life exist? Maybe in the time when mankind just walked out of the earth, many people still had some doubts about the existence of extraterrestrial civilization. However, with the continuous development of human science and technology and the continuous improvement of the cognition of the universe, more and more people continue to affirm the existence of extraterrestrial civilization, including many cosmologists.
Hawking said he was a well-known cosmologist, and he had no doubts about the existence of extraterrestrial civilization. In fact, in the cognition of most scientists, there is basically no doubt about the existence of extraterrestrial intelligent life, so soon after human beings left the earth, they began the search for extraterrestrial civilization. Although this project has not found any evidence of the existence of extraterrestrial civilization until now, people still affirm the existence of extraterrestrial civilization.
It may be said that for anything to become a reality, there needs to be sufficient and valuable evidence. Now that we have not found any valuable evidence for the existence of alien civilizations, why can we be sure of the existence of alien civilizations? So is the probability of the existence of alien civilization in the universe zero? In fact, the existence of human beings has already told us the answer.
To unravel this mystery, we must first have a general understanding of the origin of life on earth and mankind. Many people may know that mankind originated from ancient apes millions of years ago, but if time is pushed forward until the time when life on earth originated, then mankind is actually from the initial simple primitive life, through several years. It has evolved step by step in one billion years.
So how did the most primitive life on earth come from? In this regard, scientists have not yet completely solved this mystery. On the issue of the origin of life on earth, scientists have put forward two hypotheses. One hypothesis is that the most primitive life on the earth is naturally formed by inorganic substances on the earth under certain conditions in the ocean hotbed.
Another hypothesis is that the original life of the earth comes from outside the sky, which is brought about by small celestial bodies such as comets hitting the earth. For these two viewpoints, the scientific community generally recognizes the first one, that is, the earliest primitive life on the earth was born from the inorganic matter of the earth itself. From this point of view, we can understand that life actually originates from inorganic matter.
You should know that the early earth environment was also very harsh. Later, with liquid water resources and a thick atmosphere, the earth’s ecological environment continued to form, and then there was a suitable environment for the birth of life. At the beginning, the surface of the earth did not have the conditions for the birth of life. Only the hot springs in the depths of the ocean that are in contact with the geothermal heat are the hotbeds for the birth of life.
Modern scientists have been able to prove this point through continuous observational experiments. Everything in the world is made up of basic material elements. The same is true for the early primitive life. Organic matter evolved and gave birth to primitive life under the suitable environment of the hotbed. However, primitive life has undergone continuous evolutionary evolution, and life forms have become more and more complex. Finally, there are terrestrial organisms, mammals, and human beings.
So is this birth form of life on earth unique to the earth? Believe not, any terrestrial planet similar to the earth can give birth to its own life in a similar pattern. As long as life is born, it will have the attributes of evolution. As long as there is no catastrophic disaster in the environment of the planet, it may eventually evolve into intelligent life and develop into an intelligent civilization.
Of course, not all terrestrial planets can give birth to life, and this requires a probability. Many things in this world and the universe are probabilistic events. The birth of human beings on the earth is actually a random probability, and the birth of life on earth is also a random probability event.
Of course, this probability is much lower than the 50% probability of flipping a coin, and the probability of terrestrial planets being able to give birth to life must be very low. Although this concept is very low, as long as the probability is not zero, then the existence of alien civilization is an inevitable event. Because the existence of human beings is actually the best evidence.
If humans do not exist and life on earth does not exist, then the probability of the existence of alien civilizations may be zero. However, the existence of the planet of life and the existence of human beings have told us that the probability of alien life is not zero, and the probability of alien civilization is not zero. There may be some friends who don’t understand this very well, and think that when the probability is very low, it is no different from zero. For example, in terms of the probability of quantum mechanics, the probability of humans passing through a wall is not zero, but we are successful. The probability is basically zero because the probability is too low and too low.
With such a small probability, will there be other life planets in the universe, and will other intelligent civilizations exist? The answer is yes. If you know how many terrestrial planets there are in the universe, you will understand. Our solar system is just a small star system with three terrestrial planets, and the solar system is only one of the hundreds of billions of stars in the Milky Way.
The number of terrestrial planets in the Milky Way may reach more than 1 billion. If the probability is very low, there will be no second intelligent civilization in the Milky Way. Then we go out of the Milky Way and look at the entire universe. At this time, the number of terrestrial planets is too large for us to count. From the perspective of the universe, we count the large galaxies like the Milky Way, the number may be in the trillions.
In a galaxy like the Milky Way, the number of terrestrial planets has reached billions. Multiply this number by tens of trillions, what a huge number. But let us not forget that the universe currently observable by mankind may be just the tip of the iceberg of the vast universe. Therefore, when we talk about the universe now, we often use the observable universe to describe it.
The observable universe is only the tip of the iceberg of the entire universe. Beyond the observable universe, there is a vaster world. We cannot understand how many galaxies and terrestrial planets still exist there. Therefore, from the perspective of the entire universe, even if the probability of the existence of an alien civilization is as low as the probability of humans passing through a wall, there will also be an alien civilization.
Of course, the probability of existence of living planets is much higher than the probability of humans passing through walls. It is important to know that there are too many terrestrial planets like the earth in the universe, and the organic matter of the earth can be formed under certain circumstances. Early primitive life, then other terrestrial planets will naturally have a high probability of forming primitive life.
Therefore, scientists predict that the existence of life in the universe may be a universal phenomenon, and even the solar system may have a lot of extraterrestrial life. It’s just that if the life planet finally wants to evolve and grow into a civilized planet like the earth, the probability is very low. To know the evolution of primitive life to intelligent life, it takes billions of long years.
In such a long time, as long as a huge catastrophic event occurs on this planet, it is possible to end the evolutionary process of life. For example, the Earth’s neighbor Mars, through a lot of observations, scientists believe that Mars was also a beautiful planet of life in its early days, and it may be born at the same time as the early life on Earth.
It’s just that, after a huge disaster occurred on Mars, life ended, and life on Earth continued to evolve, and finally humans were born. It can be seen that there may be too many living planets in the universe, but it is estimated that there will not be too many intelligent civilization planets. It seems that it is also very difficult for humans to find alien civilizations, unless we have the ability of interstellar navigation and can quickly reach various galaxies for exploration.