The researchers also took into account such a factor as the self-destruction of intelligent beings. This is reported in an article published on the arXiv.org preprint repository.
To assess the prevalence and age of alien civilizations, experts used a galactic simulation model that takes into account the probability of abiogenesis (the origin of life from nonliving matter), the rate of evolutionary changes and the probability of the death of a civilization. It turned out that the last parameter most of all affects the number of intelligent civilizations and their age.
According to the simulation results, the largest number of possible alien civilizations inhabits the ring region located four thousand parsecs (one parsec equals 3.2 light years) from the center of the Milky Way. The distance from the center of the galaxy to the Sun is 8.5 thousand parsecs.
At the same time, more and more civilizations disappear over time, but the inner regions of the Milky Way remain the most densely populated. In addition, most intelligent life forms of the Milky Way are young, making them difficult to detect.