The theoretical physicist Michio Kaku assures that it will be already in this century when humanity will be able to establish contact with extraterrestrials.
The scientist responded to a question from a user on the Reddit website about possible contact with alien civilizations.
During an online interview Kaku said that, in his opinion, humans will discover extraterrestrial life by listening to radio signals.
It will be necessary to "decipher their language" to determine what kind of civilization the alleged interlocutors belong to. However, this will not be an easy task, since the representatives of another civilization will live a few decades of light from Earth, as the physicist theorizes.
The scientist of Japanese origin is not the only one with ambitious ideas about the supposed contact with the aliens. Thus, the well-known American astrophysicist Seth Shostak assures that humanity will not take more than two decades to contact the aliens.
Meanwhile, the famous British astrophysicist Stephen Hawking warns that humans should not attend to the presumed signals coming from space, since aliens could represent a danger to humanity.
US investigators Michael Hippke and John Learned also try to draw attention to the alleged threat of "contaminated messages." As they speculate, aliens could send them to Earth, harming human media.
As for the types of extraterrestrial civilizations, in 1964 the Soviet astrophysicist Nikolai Kardashov offered a scale - known as the Kardashov scale - to measure the degree of technological evolution of a stellar civilization.
The scale is based on the amount of energy that civilization possesses and, also, on the degree of possible colonization of space. In general terms, a Type I civilization has mastered the resources of its home planet, Type II, its planetary system, and Type III, of its entire galaxy.