How many civilizations exist in our galaxy?

‘There should be at least a few dozen,’ researcher says

Are we alone in the universe? Is there anyone else out there?

A new study published this week aims to answer these ageold questions. The research calculates there could be more than 30 intelligent civilizations throughout our Milky Way galaxy.

“There should be at least a few dozen active civilizations in our galaxy under the assumption that it takes five billion years for intelligent life to form on other planets, as on Earth,” University of Nottingham astrophysicist Christopher Conselice, who co-authored the research, said in a statement.

This estimate assumes that intelligent life forms on other planets in a similar way as it does on Earth.

As a point of reference, there are an estimated 250 billion stars in our galaxy and roughly one planet per star, Forbes reported.

Study lead author Tom Westby, also of the University of Nottingham, explained: “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.

“Our new study simplifies these assumptions using new data,” Westby said, “giving us a solid estimate of the number of civilizations in our galaxy.”

These civilizations, however, would be about 17,000 light-years away on average, making finding and speaking with them practically impossible with today’s technology.

A light-year is roughly six trillion miles.

The new research also suggests that searches for extraterrestrial intelligent civilizations not only reveal how life forms but also give us clues for how long our own civilization will last.

The study said the number of civilizations depends on how long they are sending out signals of their existence into space, such as radio transmissions from satellites and television.

If other technological civilizations last as long as ours, which is 100 years old, then there would be as many as 36 intelligent technical civilizations throughout the galaxy.

“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 said.

“By searching for extraterrestrial intelligent life — even if we find nothing — we are discovering our own future and fate.”

The study was published in the peer-reviewed Astrophysical Journal.