Milky Way galaxy could be home to 36 active, intelligent civilisations besides humans, study suggests

If technological civilizations last as long as they do on Earth, it is estimated that there could be 36 ongoing intelligent civilizations in the galaxy.


Humans have always been intrigued to know whether there are other intelligent life forms in the universe. Scientists, however, have never doubted it.

Now, a new study led by the University of Nottingham and published in The Astrophysical Journal has come up with an educated guess for the number of intelligent civilizations in our Milky Way galaxy. They have calculated the possibility of over 30 active, communicating, intelligent civilizations in the galaxy.

Speaking about their research, lead scientist and Professor of Astrophysics at the University of Nottingham, Christopher Conselice said, "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.”

Conselice went on to explain that the idea was to look at "evolution, on a cosmic scale." The calculation, he said, is called the Astrobiological Copernican Limit.

Research suggests we might be sharing the galaxy with 36 civilisations of intelligent life, Image: Pixabay

Research suggests we might be sharing the galaxy with 36 civilisations of intelligent life, Image: Pixabay

The Astrobiological Copernican limits come in two forms. One is a "weak" limit that suggests intelligent life forms on a planet any time after 5 billion years of its formation, but no sooner. The second is a "strong" limit is where life formed between 4.5 billion and 5.5 billion years ago, as it did on Earth.

Researchers made use of the latter in their calculations, under the assumption that life on other planets develops similarly to how it develops on Earth, and matching that to planets that could be home to similar evolution. It also assumed that the new species would need to develop in a metal-rich environment, since humans (the only intelligent life we are currently familiar with) developed near the Sun, which is rich in minerals.

Detecting the presence of civilizations in the galaxy is largely dependent on how well we can pick up signals that are being sent into space in the form of radio transmissions, the authors told The Independent. If these technological civilizations last as long as that on Earth, it is estimated that there could be 36 ongoing intelligent civilizations.

However, with the average distance between these civilizations being 17,000 light-years away, it would make detection and communication "very difficult" with the present technology available on Earth. Researchers say that it is also possible that ours is the only civilization in our galaxy unless the survival times of civilizations like ours are long.

Conselice stated that the new research suggests the search for alien life not only reveals how life forms, but also provides clues for how long our own civilization will last.

"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," Conselice stated.


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