New research suggests that searches for extraterrestrial intelligent civilizations not only reveals the existence of how life forms, but also gives us clues for how long our own civilization will last, according to astrophysicist Christopher Conselice, based on the hypothesis that it takes 5 billion years for intelligent life to form on exoplanets, as it did on Earth.
“If we find that intelligent life is common,” Conselice says, looking at evolution a cosmic scale called the Astrobiological Copernican Limit, “then this would reveal that our civilization could exist for much longer than a few hundred years, alternatively if we find that there are no active civilizations in our Galaxy it is a bad sign for our own long-term existence. By searching for extraterrestrial intelligent life—even if we find nothing—we are discovering our own future and fate.”
Astrobiological Copernican Limits
Reinforcing the Fermi Paradox, the average distance to these civilizations would be 17,000 light-years away, making detection and communication very difficult with our present technology. It is also possible that we are the only civilization within our Galaxy unless the survival times of civilizations are long and that they survive there own Anthropocene Epochs.
The two Astrobiological Copernican limits are that intelligent life forms in less than 5 billion years, or after about 5 billion years—similar to on Earth where a communicating civilization formed after 4.5 billion years. In the strong criteria, whereby a metal content equal to that of the Sun is needed (the Sun is relatively speaking quite metal rich), the new research calculates that there should be around 36 active civilizations in our Galaxy.
The new study led by the University of Nottingham and published today in The Astrophysical Journal has taken this new approach to this problem. “There should be at least a few dozen active civilizations in our Galaxy,” says Google Scholar, Conselice.
“The classic method for estimating the number of intelligent civilizations relies on making guesses of values relating to life, whereby opinions about such matters vary quite substantially,” says first author Tom Westby. “Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our Galaxy.”
The research shows that the number of civilizations depends strongly on how long they are actively sending out signals of their existence into space, such as radio transmissions from satellites, television. If other technological civilizations last as long as ours which is currently 100 years old, then there will be about 36 ongoing intelligent technical civilizations throughout our Galaxy.
The Daily Galaxy, Sam Cabot via University of Nottingham