According to researchers: There may be more than 30 civilizations in our galaxy alone.
Communication is difficult because of the distance.
In our home galaxy, according to one estimate, there could be about 36 intelligent civilizations under very specific assumptions. Discovery of and communication with these aliens is very difficult with current technology, because the average distance between these civilizations is about 17,000 light years, emphasize Tom Westby and Christopher Conselice of the University of Nottingham.
Researchers believe intelligent life is likely
The scientists presented their assessment in “The Astrophysical Journal”.
The two researchers had wondered how many communicating extraterrestrial intelligences (CETI) could exist in the Milky Way that could in principle be tracked down by their radio signals.
“The idea is to look at evolution on a cosmic scale,” explained Conselice. “Assuming that, as on Earth, it takes about five billion years for intelligent life to develop on other planets, there should be at least a few dozen active civilisations in our galaxy.”
Alien life may be a preview of life on its own
For their estimate, the scientists looked at the proportion of Sun-like stars in the Milky Way with Earth-like planets in their habitable temperature zone. They also assumed an average life span of 100 years for a communicating civilization, as long as radio communication exists on Earth.
“We calculate that there should be about 36 active civilizations in our galaxy,” Westby said.
The search for the aliens in our wider cosmic environment could also provide us with clues about the fate of our own civilization, the researchers believe.
“If we find that intelligent life is common, it would show that our civilization can exist for much longer than a few centuries,” explained Conselice. “Otherwise, if we discover that there are no active civilizations in our galaxy, it is a bad sign for our own permanent existence.”
