To date, we have no evidence of the existence of intelligence and extraterrestrial life, although the existence of the latter is certainly more probable than intelligent life. We observed in Chap. 9 the existence of evolutionary convergences, that is, the tendency of various species living in the same environment to develop, under the pressure of natural selection, certain structures that cause them to resemble each other. We also provide some examples of evolutionary convergences. A question without a certain answer is whether intelligence can be a further convergent character, that is, whether its appearance is only a question of time. In the discussion in the previous chapter, we observed that some scientists believe that intelligence tends to grow over time from simpler to more complex species and that, given enough time, we would reach levels of intelligence similar to those of humans. Others, however, think in a completely different way, such as Ernst Mayr, for whom only one of the 50 billion species that lived on Earth was able to generate civilization and electronic technology. Additionally, for Stephen Jay, the appearance of the human species is due to a succession of contingencies. Some simple estimates conclude that an advanced species could conquer a galaxy in a few tens of millions of years. It is also estimated that habitable earths and super-Earths have existed for at least 9 billion years. Therefore, the question that Fermi posed to his colleagues in 1950 arose spontaneously: where is everybody? Although the possibility of real contact between our system and other civilizations may be unlikely, contact via electromagnetic wave transmissions is simpler, which makes great silence rather anomalous. This silence could be due to several reasons: the scarcity of technological life in the Universe or life in general, the great distances of these civilizations, a short life of advanced civilizations that could self-destruct or disappear owing to natural causes. In the latter case, as Aditya Chopra says, the great silence would be because the extraterrestrials are all dead. Another possibility is the lack of interest of advanced civilizations in communicating or that they communicate, but we are not able to recognize such signals because they are sent with technologies we do not know. This discussion leads us to conclude that since we are not certain about the points listed above, we can only try to scan the sky in search of signals or send our own in the hope that some civilizations will receive them and respond to us.

The Great Silence (Searching for ET)

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发表日期：

2025年

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Antonino Del Popolo

摘要

To date, we have no evidence of the existence of intelligence and extraterrestrial life, although the existence of the latter is certainly more probable than intelligent life. We observed in Chap. 9 the existence of evolutionary convergences, that is, the tendency of various species living in the same environment to develop, under the pressure of natural selection, certain structures that cause them to resemble each other. We also provide some examples of evolutionary convergences. A question without a certain answer is whether intelligence can be a further convergent character, that is, whether its appearance is only a question of time. In the discussion in the previous chapter, we observed that some scientists believe that intelligence tends to grow over time from simpler to more complex species and that, given enough time, we would reach levels of intelligence similar to those of humans. Others, however, think in a completely different way, such as Ernst Mayr, for whom only one of the 50 billion species that lived on Earth was able to generate civilization and electronic technology. Additionally, for Stephen Jay, the appearance of the human species is due to a succession of contingencies. Some simple estimates conclude that an advanced species could conquer a galaxy in a few tens of millions of years. It is also estimated that habitable earths and super-Earths have existed for at least 9 billion years. Therefore, the question that Fermi posed to his colleagues in 1950 arose spontaneously: where is everybody? Although the possibility of real contact between our system and other civilizations may be unlikely, contact via electromagnetic wave transmissions is simpler, which makes great silence rather anomalous. This silence could be due to several reasons: the scarcity of technological life in the Universe or life in general, the great distances of these civilizations, a short life of advanced civilizations that could self-destruct or disappear owing to natural causes. In the latter case, as Aditya Chopra says, the great silence would be because the extraterrestrials are all dead. Another possibility is the lack of interest of advanced civilizations in communicating or that they communicate, but we are not able to recognize such signals because they are sent with technologies we do not know. This discussion leads us to conclude that since we are not certain about the points listed above, we can only try to scan the sky in search of signals or send our own in the hope that some civilizations will receive them and respond to us.