Scientists at the Federal Polytechnic School of Lausanne (Switzerland) have developed a statistical model to determine the likelihood of finding an alien civilization in the Milky Way. According to the findings of the researchers, if humanity does not detect the source of radio signals within a radius of 40 thousand light years, then in the galaxy, most likely, there is no one but us. This was announced in a press release on Phys.org.
In his calculations, physicist Claudio Grimaldi (Claudio Grimaldi) used Bayes' theorem, which allows you to determine the probability of an event that is statistically related to another event that has already occurred. For example, by the absence of sources of alien radio signals at a certain distance from the Earth, one can assess the possibility of a technologically advanced civilization at a greater distance.
So, if astrophysicists do not find traces of aliens within a radius of a thousand light years, then the probability that the Earth remains in the access zone for radio signals coming from other regions of the galaxy exceeds 10 percent. In this case, radio telescopes are simply not sensitive enough to detect them. If at least one civilization is within a thousand light years, then the likelihood of another civilization in another part of the Milky Way rises to almost one hundred percent. However, until now, scientists have managed to "listen" to space at a distance not exceeding 40 light years.
The Grimaldi method takes into account only the possibility of contact with a civilization like ours, but not with intelligent beings at earlier stages of development or following an alternative path of technological development.