Scientists have analyzed the properties of already discovered planets outside the solar system and came to the conclusion that the number of inhabited worlds in the Milky Way will amount to several tens of thousands, if astronomers discover at least one such planet in the coming decades. The results of their calculations were published in the scientific journal Proceedings of the National Academy of Sciences.
вЂњOne of the main tasks of astronomy in the coming decades is to discover traces of life on the surface of exoplanets. Our calculations show that if we discover even one planet with possible traces of life, this will mean that with a probability of 95% there are tens of thousands of inhabited worlds in the Milky Way, вЂќ the researchers write.
Half a century ago, the American astronomer Frank Drake came up with a formula that can be used to calculate how many extraterrestrial civilizations in our Galaxy with which contact is possible, and also estimate the chances of this. Drake's calculations showed that there must be a lot of such planets and that humanity must definitely meet its inhabitants.
However, in the years following the publication of the equation, not a single contact with aliens occurred. Scientists of the time, including Enrico Fermi, began to question the truth of Drake's assumptions. As a result, the Italian formulated the so-called вЂњFermi paradoxвЂќ: if intelligent aliens exist, why hasn't humanity discovered any traces of them before?
Scientists still cannot resolve this paradox. Previously, they assumed that humanity has not yet met with extraterrestrial civilizations due to the fact that unique conditions have developed on our planet, which is necessary for the formation of intelligent life. Now, this hypothesis seems unlikely because astronomers have discovered thousands of Earth-like planets around the stars closest to us.
Professor of the University of Rome Tor Vergata (Italy) Amedeo Balbi and researcher at the Swiss Federal Polytechnic School Claudio Grimaldi tried to solve a simpler problem вЂ” to count the number of potentially habitable planets.
In their calculations, the scientists took into account what we now know about the conditions on other planets and how progress in astronomy and the construction of new telescopes will affect the вЂњhorizonвЂќ of mankind in the coming decades. In addition, they were not interested in the total number of civilizations that have ever existed in the Milky Way, but in the number that we could detect right now.