Using the assumption that intelligent life forms on other planets are similar to those on Earth, researchers from the University of Nottingham were able to estimate the number of intelligent interacting civilizations within the Milky Way. According to the authors, in our own galaxy there can be more than 30 active communicating intelligent civilizations. The study is published in The Astrophysical Journal.
“In our Galaxy, there must be at least several dozen active civilizations, if we assume that it takes five billion years to form intelligent life on other planets, like on Earth. This assumption is related to the rate of evolution. We called this calculation method the astrobiological limits of Copernicus, ”says Christopher Conselice, professor of astrophysics at the University of Nottingham, one of the researchers.
The study shows that the number of civilizations greatly depends on how long they actively send signals about their existence into space, such as radio broadcasts from satellites, television and so on. If other technological civilizations will last as long as ours, which is now 100 years old (according to researchers, the countdown must begin with the invention of radio), then in our Galaxy there will be about 36 intelligent technical civilizations that are capable of communication.
Nevertheless, the average distance to these civilizations will be 17 thousand light-years, which makes their detection and communication with them very difficult using current technologies. It is also possible that we are the only civilization in our galaxy.
The authors in their work presented the concept of two astrobiological limits of Copernicus. According to them, intelligent life forms form in less than five billion years, or in about five billion years. On Earth, for example, a civilization capable of communication took shape in 4.5 billion years. Among other things, astrophysicists took into account that for the formation of civilizations similar to ours, a star must have certain parameters of metal concentration and luminosity, and also have a rocky planet with an atmosphere in the habitable zone. A preliminary calculation gave an estimate of 36 possible civilizations.
“Our new studies show that the search for extraterrestrial intelligent civilizations not only allows us to approach the discovery of other forms of life, but also gives us an understanding of how long our own civilization will last. If we find that intelligent life is a common occurrence, it will show that our civilization can exist for much longer than several hundred years. If we find the opposite, it will be a bad sign for our own long-term existence. In search of an extraterrestrial intelligent life – even if we do not find anything – we discover our own future and destiny, ”concludes Conselice.