We will not learn about the existence of living beings from alien stars, even if someone lives there. And there is a strong proof of that.
We have not yet found traces of aliens for the reason that intelligent life occurs extremely rarely in the universe. She must disappear very quickly or hide from the rest. But such explanations, which are given by some scientists, have a very strange and often unrealistic character.
Astronomical odds
More than half a century ago, American astronomer Frank Drake developed a formula for calculating the number of civilizations in the galaxy with which contact is possible, trying to assess the chances of detecting extraterrestrial intelligence and life.
Physicist Enrico Fermi, in response to a fairly high assessment of the chances of interplanetary contact according to the Drake formula, formulated a thesis that is now known as the Fermi paradox: if there are so many alien civilizations, then why does humanity not observe any traces of them?
Scientists have tried to solve this paradox in many ways, the most popular of which was the hypothesis of a “unique Earth”. It boils down to the fact that for the appearance of intelligent beings, unique conditions are necessary — an exact copy of our planet.
Other astronomers believe that we cannot contact extraterrestrials for the reason that galactic civilizations either disappear too quickly for us to notice them, or because they actively hide the fact of their existence from humanity.
There is another explanation of the Fermi paradox, which is based on the variation in values for the initial parameters used in the Drake equation when calculating the number of intelligent beings.
The mathematics of life
Many scientists, estimating the number of civilizations in the Milky Way and in the Universe, simply ignore the probabilistic and inaccurate quantities used, whose values can sometimes differ by 7-8 orders of magnitude. As a result, they do not receive a very wide range of answers, but quite a “specific” figure that does not correspond to reality, but is close to the expected one.
And if we calculate the Drake equation taking into account all possible errors and variations in his arguments? These include, for example, such things as the rate of formation of stars in the Galaxy, the proportion of luminaries with planets, the number of Earth-like planets and the typical lifespan of civilizations.
Combining the results of these calculations with the help of statistics, it can be found that the Galaxy is completely devoid of intelligent life in 30% of cases, although with some combinations of parameters, the number of extraterrestrial civilizations is very high.
Such results suggest that the Fermi paradox does not make sense — the absence of life in the observable universe can be explained using the Drake equation. Most likely, humanity really remains the only intelligent group of beings in the galaxy, although other civilizations may have existed in the future or in the past.
But this does not make the SETI (Institute for the Search for Extraterrestrial Civilizations) projects and the Breakthrough Listen initiative meaningless. Such observations are extremely important in order to narrow the spread in the values of the parameters of the Drake equation and to find a real answer to one of the main questions of The universe.