Milky Way May Hold at Least 36 Intelligent Civilizations

Photo credit: ESO/Y. Beletsky

(CN) — The quest to uncover other intelligent life in the Milky Way reached a new milestone Monday as researchers said they’ve charted out the number of civilizations in our galaxy that may be home to intelligent beings.

The search for other intelligent life in our galaxy — and the larger mystery surrounding whether humans are alone in the universe — has both inspired and tormented astronomers and other stargazers for decades.

In order to aid our species’ journey into the unknown, University of Nottingham researchers set out to plot the number of possible extraterrestrial civilizations in our 13.6 billion-year-old galaxy.

Scientists operated their study using modeling that assumed other intelligent life in the galaxy would develop the same way it does on Earth.

Under the theory, researchers estimate there are over thirty “active communicating intelligent civilizations” in the Milky Way, according to the study published Monday in The Astrophysical Journal.

Christopher Conselice, astrophysics professor at the University of Nottingham, said in a statement researchers developed the estimate by looking at evolution on a cosmic scale.

“There should be at least a few dozen active civilizations in our galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth,” said Conselice, who led researchers in the study. “We call this calculation the astrobiological Copernican limit.”

The astrobiological Copernican calculation contains two limits: that intelligent life forms in less than 5 billion years, or that it forms after 5 billion years — similar to on Earth where a communicating civilization formed after 4.5 billion years, the study said.

Study lead author Tom Westby said in a statement researchers using the calculation believe up to 36 active civilizations may exist in the Milky Way.

“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,” Westby said. “In the strong criteria, whereby a metal content equal to that of the sun is needed — the sun is relatively speaking quite metal rich — we calculate that there should be around 36 active civilizations in our galaxy.”

The estimate hinges on determining the method that active civilizations are using to send out into space any relevant clues of their existence, such as radio transmissions from satellites.

A major issue researchers identified is that the average distance to any of these 36 civilizations would be 17,000 light years.

With our present technology — which has been developed within a 100 year span of global technological innovation — detection and communication would be difficult, the study said.

Conselice said the study findings may signal what lies ahead for our own civilization on Earth.

“Our 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,” Conselice said.

“If we find that intelligent life is common, 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.”

Researchers did not immediately respond to a request for comment.

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