New Study Reevaluates the Likelihood of Extraterrestrial Intelligence in Our Galaxy

Among the most critical, long-standing questions that humankind has asked in its entire history is if intelligent life other than on our planet exists in our Milky Way Galaxy. It has so far been very challenging to come up with a reasonable estimate of how many extraterrestrial intelligent life and civilizations are out there.

New research recently published in The Astrophysical Journal applied an innovative approach to providing the solution. Researchers led this study from the University of Nottingham. The study limited its parameters with the assumption that the extraterrestrial life and civilizations will have developed similarly to life here on Earth. With this limitation, the researchers came up with an estimated number of Milky Way Galaxy life forms that are intelligently communicating and are sentient. They revealed that more than 30 intelligent and communicating civilizations are present within our own Milky Way.

Christopher Conselice, University of Nottingham Astrophysics professor and study author, explained that when we assume that five billion years are needed before intelligent life can be formed on a planet, then there should be more than 30 extraterrestrial intelligent civilizations now existing in the Milky Way Galaxy. He explained that it is a way of seeing evolution at the cosmic scale. This calculation is known as the Astrobiological Copernican Limit.

Tom Westby, the first author of the study, says that traditionally, the way to estimate how many intelligent civilizations exist out there is based on guessing the values as they relate to life. This type of guesswork only creates many varied opinions and sparks intense debate on the subject. Their new study, he says, simplifies the assumptions with the use of new data and provides a reliable estimate for the number in question.

There are two Astrobiological Copernican limits. The first says that intelligent life takes less than five billion years to form, while the second says that it forms just after five billion years. On Earth, an intelligent communicating civilization was formed after four and a half billion years.

Considering the criteria, where the required metal content equals what our Sun has (because our Sun is relatively rich in metal content), it can be calculated that there must roughly be 36 intelligent, active communicating civilizations in the Milky Way.

This study also considers the calculation in relation to how strongly these civilizations actively send out signals into space regarding their existence. One good method of doing this is through the use of radio transmissions using television, satellites, and similar means. The study arrived at its conclusion based on the assumption that these technological civilizations have survived as long as we have. Our civilization is currently a hundred years old.

Our distance from these civilizations is roughly 17,000 light-years, which makes detection, much less communication, quite difficult considering our current technology. One possibility says that only one civilization in our Galaxy exists - that is, ours - unless other extraterrestrial civilizations have prolonged survival times, just like we do.

According to Conselice, their research suggests that the search for these intelligent civilizations will reveal how life in our Galaxy forms, as well as provide hints on how long Earth's civilization can last. By doing this search, regardless if we find any, we also discover our own fate and future.