A new study by scientists at the University of Nottingham suggests there are at least 36 intelligent alien civilizations in our galaxy, the Milky Way, Forbes reports. As the publication points out, the Milky Way, which contains our Solar System, is estimated to be home to anywhere between 100 billion to 400 billion stars, with approximately one exoplanet per star.

The study, referred to as The Astrophysical Journal, ultimately focuses on the number of Communicating Extra-Terrestrial Intelligent civilizations in the Milky Way, with an overall assumption that intelligent life is capable of inhabiting other planets similar to ours. Participating scientists presume it takes roughly five billion years for intelligent life to form on other planets, adding that technological civilizations are likely to last at least 100 years. In comparison, a technological civilization finally appeared on Earth after roughly 4.5 billion years of evolution.

In estimating 36 active communicating intelligent civilizations in our galaxy, researchers have taken into account star formation histories, the commonality of metal-rich stars like the Sun, and the likelihood of stars hosting Earth-like planets.

“The classic method for estimating the number of intelligent civilizations relies on making guesses of values relating to life, but opinions about such matters vary quite substantially,” said Tom Westby, Assistant Professor, Faculty of Engineering at the University of Nottingham. “Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our galaxy.”

While at least 36 civilizations are estimated, detection and communication are currently impossible as the average distance to one of the life forms is presumed to be 17,000 light-years. Still, it could be that none of these intelligent alien civilizations exists in our galaxy, or, that there are many more.

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