外星文明存在的可能性（The possibility of extraterrestrial civilization）.doc

外星文明存在的可能性（The possibility of extraterrestrial civilization） The possibility of extraterrestrial civilization Types of civilization In the vast universe, the civilization of the human race on earth is insignificant. Because the earth is so short, humans began to create civilization for just a few million years, the development of science and technology but for hundreds of years, but decades of exploration of space technology, and compared the age of the earth for 4 billion 600 million years, the Milky Way, aged 10 billion to 15 billion years, is a drop in the bucket in. Cada Xue J, a former Soviet astrophysicist, proposed that civilization be divided into three categories: Type 1 Civilization: it can master all the resources of the planet. Just as earth civilization, it can mobilize cosmic energy that is equivalent to the total output power of the earth at present, and its energy is 1016 watts. Now we can circle our earth within a day, learn about events on earth, and leave the earth for lightning access on the moon. Type II Civilization: it can control the material and energy resources of its central star and planetary system, and its energy is about 1026 watts. Type III Civilization: it can hold all the resources of its own star system, and its energy is about 1036 watts. American astronomer Karl Sagan suggested that three types of civilization can be divided into 10 sub scales according to energy scale, that is, 1016 watts for type 1, 1017 watts for type 1.1, 1018 watt for type 1.2, and so on. Our earth civilization is a civilization of type 0.7. These three types of civilizations are not beyond, but because they are qualitatively different, it can be imagined that this process will be very long and difficult. Extraterrestrial civilization equation How many civilized planets exist in the galaxy? In 1960, Frank Drake, an astronomer at the University of California, proposed a possible way to search for extraterrestrial civilizations. Such a formula is N=R * Fp * Ne