Astrophysicist Jill Tarter of the SETI (Search for Extraterrestrial Intelligence) project named two main reasons why, in her opinion, humanity has not yet established contact with alien civilizations. The Daily Mail reports.
The first reason is the enormous size of the universe. Humanity, according to Tarter, has so far explored only a small part of it. The astrophysicist compared the scale of the studied spaces with water in a glass poured from the World Ocean of the Earth.
The second reason lies in the technological stagnation, the onset of which the scientist saw in the 21st century. Tarter believes that mankind has probably not yet discovered (or has not noticed) the forms of communication necessary for communicating with alien intelligence.
According to Tarter, if aliens visit Earth, they will "become the ones who set the rules", which will be associated with their higher level of technological development. A similar point of view is shared by the British theoretical physicist Stephen Hawking. The scientist suggests that the aliens may well turn out to be militant nomads who will try to conquer and colonize the planet.
The search for extraterrestrial civilizations is carried out mainly within the framework of the SETI project, to which the Russian billionaire donated one hundred million dollars in 2015. Hawking supported the entrepreneur's initiative. Humanity searches for alien civilizations exclusively in the electromagnetic range.
Some scholars disagree with this point of view. For example, British mathematical physicist Roger Penrose does not exclude that ancient civilizations could use gravitational waves resulting from collisions of black holes for contacts with other intelligent beings.
In addition, as a means of communication with alien worlds, it is possible to use neutrinos, which interact extremely weakly with matter. The level of human development at the present time does not allow the use of gravity or neutrinos for communications.