From childhood to adulthood, we always have such a question in our minds - are humans the only ones in the universe? Where will the aliens be?
There is no shortage of depictions of extraterrestrial life in film and television, Super Saiyans, ET, Aliens, Predators, Avatars... So many extraterrestrial beings are "active" on the screen. Is there any extraterrestrial life in the real universe?
In the 1960s, the American astronomer Frank Drake proposed a complex formula, the Drake formula (pictured). This formula is used to extrapolate the number of alien civilizations that may have come into contact with humans. A series of estimated parameters are substituted for the number of stars in the galaxy, the proportion of stars with planets, the probability of evolving intelligent life, the probability of communication of civilizations, and so on. The American astronomer and popular science writer Carlsagan estimates that according to Drake's equation, the number of planets with extraterrestrial intelligent life should be about 1 million; the American science fiction writer Asimov believes that there should be 670,000 such planets; and Frank Drake himself is more conservatively estimated to be 100,000.
According to Drake's formula, there may be so many intelligent life in the Milky Way alone, and there are hundreds of millions of galaxies like the Milky Way in the vast universe, and there should be many extraterrestrial civilizations in the entire universe. Maybe there are as many real lives as "Ganges sand". So why don't we see aliens? The Fermi paradox is a scientific paradox about aliens, interstellar travel.
In 1959, Nature published an article titled "The Quest for Interstellar Communication," in which two astronomers, Koccone and Morrison, proposed the idea that microwave radiation could be used to probe other civilizations in the Milky Way. Later, astronomer Frank Drake proposed two equation solutions known as the Drake equation (also known as the Drake equation).
公式1为：N=Ng×Fp×Ne×Fl×Fi×Fc×FL
公式2为:N=R*×Fp×Ne×Fl×Fi×Fc×L
Where: N: the number of civilizations in the Galaxy that may communicate with us;
Ng: The number of stars in the Milky Way;
fp: the proportion of stars with planets;
ne: the number of terrestrial planets in each planetary system;
fl: Proportion of habitable planets with life evolved;
fi: the probability of evolving highly intelligent creatures;
fc: the probability that a highly intelligent being can communicate;
fL: The proportion of the duration of technological civilization in the life cycle of the planet;
R*: The average rate at which stars form in the Milky Way;
L: The life of scientific and technological civilization;
The difference between Equation 2 and Equation 1 is that R* replaces Ng and L replaces fL.
The Drake formula, used to estimate the number of extraterrestrial planets in the Galaxy, is seen as the first formal theoretical response to the Fermi paradox.
In the 2002 book "Where Are Extraterrestrial Civilizations?" published by physicist Stephen Weber? In the book, 50 solutions to the Fermi paradox are listed, which can be mainly summarized into the following three aspects
First, there is no other civilization in the universe.
In 1975, Hart published a paper in the Royal Journal of Astronomical Sociology, "An Explanation for the Absence of Extraterrestrial Civilizations on Earth", and after discussing them one by one, Hart came to the backward conclusion that extraterrestrial civilizations did not exist at all.
Alien civilizations exist (or have existed), but they have so far been unable to contact us.
There is such a story recorded in the scriptures, which makes people wonder - Sariputta asked Shakyamuni: "Worldly Venerables, other Buddha's lands are solemn and beautiful, why is it that the Buddha's land (the world of The Buddhas) where you live is full of thorns, gravel, hills, etc., and the environment is filthy and smelly?" Shakyamuni replied, "Because the karmic force of all beings in this world is like this, the evil is more than good, and it is in the same level state, so the world in your eyes will appear as you see it." With that, Shakyamuni pressed his toes to the ground, and Sariputta's eyes immediately turned into a pure and solemn environment, a rare treasure, and everyone was sitting on a lotus flower. Shakyamuni said, "Sariputta, my Buddha's land is actually like this, and only the world seen by those who have a pure heart and a certain degree of merit sees this way.", so the same river, the heavenly people see the light, the human beings see the water, and the hungry ghosts see the fiery and fierce flames. Because of the different physiological structures, people and different animals see the world completely differently, and what different animals see will also be different colors.
Alien civilizations have come to Earth, but we don't know.
Japanese scholar Yukishi Shida is a professor in the Department of Physics at Waseda University in Japan. Once, in an interview with reporters, he said that through in-depth study of Buddhist texts. He argues that Buddha Shakyamuni had communicated with aliens, which confirms why many of the profound and mysterious descriptions in the sutras are similar to high-energy and quantum physical phenomena.
He gave an example. For example, there is a passage in the Lotus Sutra (translated into the vernacular): On the side of the celestial body, there is a pure light and solemn country, and the leader is "Jinghua Su Wang Zhi Rulai". He ruled over many "people who lived long and possessed a noble spirit". Among these people was a great man named Myoyin Bodhisattva, who had countless virtues, learned the truths of the universe, and acquired valuable "thoughts": such as the idea of knowing all living languages (i.e., telepathy), the free way to travel to and from any place in the universe (teleportation), and the idea of knowing the changes in the universe according to the movement of the moon and the sun.
One day, Myo yin bodhisattva suddenly received a telepathic technique transmitted by the great master Shakyamuni from the earth world. The Bodhisattva Miaoyin then reported to King Zhirulai of The Pure Flower And asked to come to the world of Pasa (the earth) to see Shakyamuni and many practitioners. King Zhiru of Jinghuasu agreed, but told Miaoyin Bodhisattva that falling from a high-altitude celestial body to a low-dimensional (i.e., dimensional) object cannot still use the natural frequency, but must match the frequency of the low-degree celestial body. In other words, it is "customary entry": when visiting the earth, you must reduce your own frequency to a frequency suitable for the earth's nature.
Curiously, when The Bodhisattva began to meditate, near the place where Shakyamuni spoke, 84,000 "lotus constellations" appeared, all of which were golden stems, silver leaves, and diamond petals (in Buddhist texts, it is customary to use the lotus flower of Ruixiang to indicate an incredible phenomenon. We think that this "lotus constellation" may point out a different brilliance of the flying saucer).
Coincidentally, "The Three-Body Problem" mentioned the hypothesis that advanced alien civilizations are deliberately hiding themselves, and they are afraid of being exposed to the eyes of other civilizations in the universe. The famous scientist Hawking is very supportive of this view,
The Fermi paradox is an open-ended question for both the astronomical and science fiction communities. Everyone can come up with their own answer, and no one knows the right answer to this question until they are actually officially exposed to aliens. However, from the mathematical probability and logical analysis, in the vast universe, there should be many earth-like planets suitable for life.