US astronomers have calculated different scenarios regarding the existence of alien civilizations and have come to the conclusion that they are likely extremely rare, but capable of establishing contact with human beings on Earth, an article published on the electronic portal arXiv.org says.
Intelligent alien civilizations could really exist in our galaxy, Jorge Soriano from the City University of New York and his colleagues argue in one of their publications released on arXiv.org.
Soriano’s team has been trying to answer the Fermi paradox: the discrepancy between the strong likelihood of the existence of intelligent alien life and the absence of any visible proof of it.
The scientists’ calculations show that the percentage of intelligent extraterrestrial civilizations among the total possible number of aliens would be extremely small — about 0.5 percent. This, according to the scientists, explains why we do not observe them today.
At the same time, Soriano argues, these civilizations could have existed for about 300,000 years. Theoretically, they should have been able to establish contact with human beings on Earth if they know about its existence.
The search for their tracks will be possible only in the future, when a greater number of Earth “twins” are discovered by NASA’s advanced space telescopes, Soriano believes.
According to the latest research NASA has identified 10 planets orbiting in their star’s habitable zone, meaning they could be capable of supporting alien life.
The potentially habitable space rocks, which have not yet been verified, are among 219 new planet candidates spotted by NASA’s Kepler space telescope in the Cygnus constellation.
The habitable zone is the range of distances from a star where liquid water – one of the building blocks of life – could pool on the surface of a rocky planet.
Some experts are confident that the emergence of intelligent aliens is closely related to unique living conditions, which have been found only on Earth. Other astronomers believe that we can’t communicate with aliens because galactic civilizations either disappear too fast to be noticed or because they actively hide the fact of their existence from humanity.