Study suggests possibility of dozens of intelligent civilisations in our galaxy

A new study has calculated that there could be more than 30 intelligent civilizations throughout the milky way galaxy.

This is an enormous advance over previous estimates which spanned from zero to billions.

One of the biggest and longest-standing questions in the history of human thought is whether there are other intelligent lifeforms within our universe. Obtaining good estimates of the number of possible extraterrestrial civilizations has however been very challenging.

The study led by the University of Nottingham is published in the Astrophysical Journal.

Using the assumption that intelligent life forms on other planets in a similar way as it does on Earth these researchers have obtained an estimate for the number of intelligent communicating civilizations within our own galaxy, the Milky Way. They calculate that there could be over 30 active communicating intelligent civilizations in our home galaxy.

"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. The idea is looking at evolution, but on a cosmic scale. We call this calculation the Astrobiological Copernican Limit," said Professor of Astrophysics at the University of Nottingham, Christopher Conselice who also led the research.

"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, giving us a solid estimate of the number of civilizations in our galaxy," said the first author of the study Tom Westby.

"The two Astrobiological Copernican limits are that intelligent life forms in less than 5 billion years or anytime after about 5 billion years -- similar to on Earth where communicating civilizations formed after 4.5 billion years. 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," added Westby.

The research shows that the number of civilizations depends strongly on how long they are actively sending out signals of their existence into space, such as radio transmissions from satellites, television, etc. If other technological civilizations last as long as ours which is currently 100 years old, then there will be about 36 ongoing intelligent technical civilizations throughout our galaxy.

However, the average distance to these civilizations would be 17,000 light-years away, making detection and communication very difficult with our present technology. It is also possible that we are the only civilization within our galaxy unless the survival times of civilizations like our own are long.

"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. 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," Said Professor Conselice.

Conselice sums this up as he says "By searching for extraterrestrial intelligent life -- even if we find nothing -- we are discovering our own future and fate."

( With inputs from ANI )