Milky Way could be home to 36 intelligent alien civilisations

There could be more than 30 civilisations of intelligent aliens in our own galaxy, new research has suggested.

According to a study by the University of Nottingham, there should be “at least a few dozen” active alien worlds in the Milky Way if intelligent life forms elsewhere in a similar way as it does on Earth.

However, the average distance to these civilizations would be 17,000 light-years, making close encounters of any kind very difficult with our present technology.

Professor of Astrophysics at the University of Nottingham, Christopher Conselice led the research.

He said: “There should be at least a few dozen active civilisations in our Galaxy under the assumption that it takes five billion years for intelligent life to form on other planets, as on Earth.”

The research shows that the number of civilisations depends on how long they are actively sending out signals into space, such as radio transmissions from satellites and television.

Signals have been sent from the Earth for 100 years. Credit: PA

If other technological civilisations last as long as ours, which is 100 years old, then there will be about 36 ongoing intelligent technical civilisations throughout our galaxy.

The idea is looking at evolution and applying it on a cosmic scale, Professor Conselice explains, a calculation called the Astrobiological Copernican Limit.

The two Astrobiological Copernican limits are that intelligent life forms in less than five billion years, or after about five billion years.

On Earth, a communicating civilisation formed after 4.5 billion years.

First author Tom Westby explains: “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.”

Discovering the scale – if any – of intelligent life could offer a glimpse into the chances of our own long-term survival.

If intelligent life is common then this would reveal our civilisation could exist for much longer than a few hundred years, the university states.

Alternatively, if we find that there are no active civilisations in our galaxy then it is a bad sign for our own long-term existence.

Professor Christopher Conselice added: “By searching for extraterrestrial intelligent life - even if we find nothing - we are discovering our own future and fate.”