Astrophysicist Dr. 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 first reason is the huge size of the universe. Mankind, 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 Earth’s oceans.
The second reason is the technological stagnation. Tarter believes that humanity probably has not yet discovered (or noticed) the forms of communication necessary for communication with alien intelligence.
According to Tarter, if aliens visit Earth, they “become the ones who set the rules”, which will be due to their higher level of technological development.
A similar point of view was shared by the British theoretical physicist Stephen Hawking. The scientist suggested that the aliens may well turn out to be militant nomads who will try to conquer and colonize the planet.
The search for alien civilizations by mankind is carried out exclusively in the electromagnetic range. Some scholars disagree with this view. For example, the British mathematical physicist Roger Penrose does not exclude that ancient civilizations could use gravitational waves resulting from the collision of black holes to contact other intelligent beings.
In addition, it is possible to use neutrinos, which interact extremely weakly with matter, as a means of communication with alien worlds.
The level of development of mankind currently does not allow the use of gravity or neutrinos for communications.