Extraterrestrial civilizations

Extraterrestrial civilizations – if we consider all civilizations other than those that exist on our planet, they are called extraterrestrial civilizations.
Calculating the order of the number of civilizations in the Universe can be done in several ways, which include the product of several factors: the number of stars in the Universe, the fraction of galaxies that have giant planets, the fraction of planetary systems where life has been detected, and the fraction of biospheres that have reached the level of civilization. In fact, the uncertainty of the result is a consequence of the uncertainties in the values of the factors. If one wishes to estimate the number of civilizations with which contact can be attempted, three other factors must be considered: the fraction of civilizations that have reached a high technical level; the fraction of those that wish to make contact with other civilizations; and the ratio of the time of existence of a technologically advanced civilization to the time of existence of second-generation stars containing the chemical elements formed in their first generation. Because the values of these factors are uncertain, it is not yet possible to estimate the probable number of extraterrestrial civilizations. Therefore, we should not expect one in the foreseeable future.
Indicators of the external manifestations of civilizations depend on the level of development of science and technology, which affects the amount of energy that is used for the benefit of communities. It has become possible to make a simple classification of the level of development of civilizations based on the amount of energy they use. These levels have three levels: the first level is 1013 watts, which means the level of consumption that has been achieved on Earth; the second level is 4*1017 watts, which means that all the energy of its central star is used; the third level is 4*1030 watts, which means that all the energy of the galaxy is used.
There are all possible civilizations which have no desire to communicate with their own kind. However, at their high degree of development, they must emit powerful electromagnetic waves in the infrared and radio range. Their registration is quite probable with the help of methods of astrophysics. As an example, thanks to radio and television stations, the radiation emitted by the Earth is now comparable in power to that of the Sun, and the emission of infrared radiation is inevitably associated with the use of any kind of energy for any kind of activity. However, despite this, all attempts to detect manifestations of technological activity of extraterrestrial civilizations have not yet been successful.
It should be borne in mind that even at the moment the age of the Earth’s highly developed civilization has not reached 150 years. At this time, internal combustion engine machines, steam engines and water propulsion engines, and electricity began to be widely used. This period of time, during which it can be visible to extraterrestrial observers by being a comparable source of radio emission to the Sun, is only 50 years. This time radiation from terrestrial radio and television stations has been concentrated to only one thousandth of the radius of our galaxy. Consequently, it is possible that our civilization has not yet been detected by representatives of other civilizations for the same reasons that we ourselves have: because of the lack of visible manifestations of the activities of our brethren in reason.
There is no doubt that the emergence of mind is one of the natural stages of the development of matter. If we take this hypothesis into account, we can assume the existence of extraterrestrial civilizations in the future.