Scientists have estimated that there are least 36 intelligent alien civilizations within the Milky Way, the same galaxy as Earth and the solar system, but warn that they are likely so far away that contact will be impossible in the foreseeable future.
The team behind the study at the University of Nottingham developed a new hypothesis for assuming the time and environment required for intelligent, communicative life to develop based on the one example they had to use – Earth.
On Earth, the scientists noted, intelligent life took around five billion years to develop in a metal-rich environment.
Using this assumption, the researchers found that under a strong scenario, in which life forms between 4.5 and 5.5 billion years, as on Earth, there must be at least 36 intelligent civilizations with the Milky Way.
“This is a lower limit, based on the assumption that the average lifetime of a communicating civilization is 100 yr [sic] (since we know that our own civilization has had radio communications for this time),” the scientists wrote in the study’s abstract that was published in peer-reviewed scientific journal The Astrophysical Journal.
“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,” Professor of Astrophysics at the University of Nottingham, Christopher Conselice who led the research, said in a statement.
Should these civilizations be spread evenly across the galaxy, it would suggest the nearest intelligent, communicating alien species is a mere 17,000 light years, or 160 quadrillion kilometers, away.
The sheer distance involved is “likely far surpassing our ability to detect it for the foreseeable future, and making interstellar communication impossible,” the researchers wrote.
“Furthermore, the likelihood that the host stars for this life are solar-type stars is extremely small … which may not be stable enough to host life over long timescales,” they added.
The search for extraterrestrial life continues, but Conselice warned that no news would not necessarily be good news.
“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. By searching for extraterrestrial intelligent life – even if we find nothing – we are discovering our own future and fate,” he said.
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