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If there is a large number of extraterrestrial intelligent life in the universe, then why haven't these extraterrestrial civilizations contacted us until now? Why have extraterrestrial civilizations been slow to make contact with human civilization?
This question is called the Fermi paradox, that is, the theory that alien civilizations may not exist, but now there are people who continue to claim that they have come into contact with the existence of extraterrestrial civilizations, is this true or false?
Extraterrestrial civilizations have not shown up so far, do extraterrestrial civilizations really not exist?
Recently, Dr. Kevin Tong of Princeton University in the United States considered the existence of extraterrestrial civilizations and came to a research conclusion: human beings may be the first intelligent life in the universe.
In his argument, there are indeed a large number of rocky planets and habitable planets in the universe, and if conditions permit, there may be multiple civilizations with advanced intelligence, but we have not yet found other intelligent life, which may be due to the speed of light and the age of the universe.
1. How many habitable planets there are.
The question of extraterrestrial civilizations naturally starts with the Earth, which is the only planet in the universe that is suitable for human existence.
The habitability of the earth is just one of the nobles in the endless stars of the universe, and the earth can give birth to intelligent life not only because of the earth's unique environment, but also because the earth is lucky.
And extraterrestrial civilizations were born on Earth, which makes people full of expectations and curiosity about extraterrestrial life, but so far Earth is the only planet that can prove the existence of intelligent life in the universe.
So is the Earth the only intelligent life form in the universe?
This is obviously impossible, but no one can explain the problem, and there are doubts about the existence of extraterrestrial civilizations.
This problem is the Fermi paradox, that is: there are many extraterrestrial civilizations in the universe, but we have not found any evidence of extraterrestrial civilizations so far, and extraterrestrial civilizations in the universe probably do not exist.
This question was raised by Fermi, who also thought about the existence of extraterrestrial civilizations, but ultimately believed that extraterrestrial civilizations did not exist, which is also the source of Fermi's paradox.
So according to our existing science and technology and cosmological calculations, how many planets are suitable for the birth of life in the universe?
At the 2013 meeting of the Royal Astronomical Society, a scientific research team led by astronomers from the Massachusetts Institute of Technology in the United States made a mountain-like number of habitable planets, according to their survey, even if only a few star systems in the universe can support life, then in the observable universe can find 1 billion planets that can support life in star systems.
In fact, this number does not exceed the number of known stars in the universe, and if there are more stars in the universe than known, then there will be at least a billion stars in the universe suitable for life.
This means that there may be at least 1 billion stars in the universe that are suitable for life, and at the same time, small stars such as the Sun have a relatively long period of stellar activity, which is conducive to the birth of life.
The number of sun-like stars in the universe is 2 billion, which means that the number of stars in the universe suitable for life is likely to be 10 billion.
If you want to accurately calculate the number of habitable planets, you can consider the two major elements of the universe, stars and planets, the number of stars in the universe is about 700 billion, of which the number of stars suitable for life is about 10 billion, that is, the number of stars like the sun.
About 30% of the planets born from sun-like stars are able to create conditions suitable for human existence.
Out of a total of 700 billion stars in the universe, there are about 210 billion planets that can create suitable conditions for human habitation, and it can be seen from this data alone that there are a large number of planets suitable for human habitation in the universe.
So if we continue to calculate, there are at least 350 million planets suitable for human habitation out of the additional 700 billion planets, and if we estimate the number of planets suitable for life that can be created by 10 billion stars, then there are at least 400 trillion trillion planets.
So, the number of planets with intelligent life is about 3.6 billion out of 700 billion planets, and if the total number of planets is calculated at 350 million billion, then the number of planets with intelligent life is 2.1 billion.
Although this number is not very certain, it shows us that the number of planets with intelligent life in the universe is still very large, and the existence of these intelligent life forms also makes extraterrestrial civilizations more real.
However, intelligent life here can only be judged based on the development of life on the earth, because the environment and conditions for the birth of life on the earth are similar, so the existence of intelligent life in the universe is also due to the similar environment and conditions for birth.
Therefore, the intelligent civilization here only refers to the intelligent life of human beings similar to the earth, and there are many planets similar to the earth in the universe, and the life development of these planets is also different, so there must be many more planets with intelligent life.
2. The age of the universe and the speed of light limit.
According to the age of the Big Bang, it is about 13.8 billion years, which also means that the universe has existed for 138 billion years, and the time of life on Earth in the universe can only be very short.
It is very difficult for intelligent life to be discovered and contacted by us in this short period of time, and the speed of light in the universe will also hinder the development of civilization, the speed of light travels at a speed of 300,000 kilometers per second, and the distance between the Earth and other stars is light-class distance.
If you use a human spaceship to sail to other stars, not only the time is very long, but also the number of years away from the earth is also very large, so faster-than-light propagation is the speed at which information can be transmitted to any location in the universe in an instant, but at present, human beings have not yet invented the technology of faster-than-light propagation.
For advanced intelligent life, it also needs the baptism of time in the universe, and then gradually arises in the long years, and the generation of life in the universe also needs conditions, and the generation conditions of life cannot break the limit of the speed of light, and requires a large number of cosmic materials, but on the other hand, this also means that human beings are also the earliest existence in the universe to produce advanced intelligent life.
According to cosmology, if we exclude the problem of extraterrestrial civilizations, human beings are the first to produce advanced intelligent life in the universe, then human beings are the number one people in the universe.
If human beings are not the first batch of intelligent beings in the universe to produce advanced intelligent life, then the intelligence of other life forms may not be as advanced as human beings, but in terms of the age of the universe, they are about the same as human beings, all of which are their conjectures and inferences.
3. The birth of intelligent life in the universe and the possibility of faster-than-light propagation.
According to their conjecture, life in the universe was born later, but it may be much ahead of humans in terms of intelligence, and the way they designed to propagate faster than the speed of light is also speculated by using curved space-time.
Scholars believe that if human beings want to explore the stars of other galaxies, one is to spend a long time, and the other is to consume huge energy, the propagation of curved space-time can well solve the two major problems of human beings in space exploration, and the propagation of curved space-time can greatly shorten the time of space exploration, and can save a lot of energy.
There is also a possibility that they do not want to come into contact with us primitive intelligent beings at all, and their consciousness may have reached a certain level, not only in terms of technological development, but also in terms of moral evolution, and they may not want to break the peace in the universe.
Human beings may be just a new creature in their eyes, and they may not have contact with other intelligent life, they may have an impact on the environment, so they do not want to come into contact with human intelligent life, and human values and culture may not be accepted and understood by them, just like the contact and cooperation between different civilizations on the earth, there will be different challenges of civilization exchange and cooperation.
The existence of higher intelligent life in the universe is still a mystery, we cannot judge and explain, and no evidence has been found that there is higher intelligent life in the universe.
However, the development of modern science and technology can allow us to make further breakthroughs in space exploration and research, which may be a further understanding of extraterrestrial civilizations, but for human beings, the distance and time barriers between civilizations may stimulate human exploration in technology and morality, and promote the progress of human civilization.
And in terms of material conditions, moral truths, and religious spirits, we cannot ignore one of them, because in these conditions there may also be things that will change intelligent life and the universe.
epilogue
The birth of intelligent life in the universe requires conditions, and whether the birth of life adapts to the conditions of the universe cannot be explained by human beings, but this also shows that there is a possibility of intelligent life in the universe.
Human exploration and research in outer space may enable us to understand and cherish our own lives and the earth, and stimulate our enthusiasm for scientific research.