For several decades, humanity has been trying to find other civilizations using the most advanced technologies. Nevertheless, this work has not yet yielded results, and earthlings are officially considered the only intelligent creatures in the entire visible Universe. The employee of the American space agency Ellen Stofan named five reasons why people still have not met with representatives of other worlds.
The first reason is simple, and if it turns out to be true, it will be a big disappointment for those who are looking forward to contact with aliens. We are probably truly alone in the universe, and no aliens exist. With these facts you just have to come to terms and live on.
The second reason is not much better than the first: aliens, perhaps, are ordinary microbes or organisms such as algae that do not have intelligence, and, accordingly, no contact in this case will work either.
Third: there is an extraterrestrial intelligent life, and it is quite diverse and numerous. The only problem is that these superintelligent creatures have no interest in the Earth and its inhabitants in practice, on this basis they don’t make contact. Stefan calls it the zoo theory, according to which aliens simply observe people, but nothing more.