If you've ever looked up to the stars and wondered if there's anyone else out there looking back at us, a new study has found that there could be a minimum of 36 active, communicating intelligent civilizations in the Milky Way galaxy.
Unfortunately, due to the vast distances and time involved to travel between the stars, we may never know for sure if they exist. And without a direct messages from any little green men who might be hanging out in our celestial neighborhood, scientists don't actually know for sure if there's actually any life out in the great beyond. But, in the study published Monday in The Astrophysical Journal, scientists used math, statistics and what we do know about our universe to determine that there's a pretty good chance of intelligent life out there.
In 1961, astronomer and astrophysicist Frank Drake came up with a formula that looked at the probability of another active, communicating,extraterrestrial intelligence (ETIs) evolving in the Milky Way galaxy. The equation was not meant to be taken as a serious prediction of how many civilizations existed in the galaxy, but rather give people an idea or approximation on how many might exist. Drake's equation looked at a number of factors that might lead to another civilization evolving - including the rate of star formation, the fraction of those stars that have habitable planets, a fraction of those that go one to develop intelligent life, and a fraction of those that have intelligent life begin transmitting signals into space (radio, or otherwise) and how long that civilization might last.
Because the Drake equation was never meant to be taken seriously, but rather as a primer on the number of ETI civilizations that exist, scientists at the University of Nottingham developed their own approach.
"Drake developed an equation which in principle can be used to calculate how many Communicating Extra-Terrestrial Intelligent (CETI) civilizations there may be in the Galaxy," the authors wrote in their study. "However, many of its terms are unknowable and other methods must be used to calculate the likely number of communicating civilizations."
"The key difference between our calculation and previous ones based on the Drake equation is that we make very simple assumptions about how life developed," study coauthor Christopher Conselice, a professor of astrophysics at the University of Nottingham, told CNN.
"One of them is that life forms in a scientific way — that is if the right conditions are met then life will form. This avoids impossible to answer questions such as 'what fraction of planets in a habitable zone of a star will form life?' and 'what fraction of life will evolve into intelligent life?' as these are not answerable until we actually detect life, which we have not yet done."
"Our calculation involves Galactic star formation histories, metallicity distributions, and the likelihood of stars hosting Earth-like planets in their habitable zones, under specific assumptions which we describe as the Astrobiological Copernican Weak and Strong conditions," the study's authors wrote. "These assumptions are based on the one situation in which intelligent, communicative life is known to exist—on our own planet."
While we haven't officially heard from anyone in our galactic neighborhood, there have been a number of strange, unexplained sightings of UFOs, including three videos released by the Pentagon this year that showed US Navy pilots encountering what appear to be unidentified flying objects in 2005, 2007 and 2015.
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