But intelligent life is an entirely different matter. We do not know the precisely required conditions, but during hundreds of millions years of terrestrial animal existence it happened only once, and quite recently.
Is there any connection between having a huge moon to evolution of intelligent life? Maybe, but in this I am purely speculating. The moon enables tide, potentially creating drying niches where animals may be trapped and forced to develop terrestrial enabling mechanisms. The moon is also a light origin at night, thus may provide some advantage to an intelligent creature. Again, this is mere speculation.
Is the a connection between evolution of intelligence and our peripheral location in the galaxy? If dinosaur extinction is typical to the dangers that big animals face, probably yes. In the center of the galaxy, celestial bodies collide much more frequently, leaving less time to evolve. Eventually, any civilization has to acquire the means to eliminate the danger of falling meteorites. We have not acquired this technology yet, even though we evolve where such collisions are less frequent, a privilege that is specific to the edge of the galaxy.
Our hardships in conquering outer space are not over yet. What are the chances of inventing writing? I do not know. But 99.8% of the length of human existence it managed without writing, which first appeared about 5,500 years ago.
We also know that Man has produced artificial radio signals only for about 120 years, a tiny fraction of Earth’s history. The first signals were very weak. But even if we assume that the first signals traveled through space and somebody actually listens to them, there is still a huge distance to cross. The distance to the closest stars spans dozens of light years, a non-traversable limit, we know.
There are many reports of encounters with aliens, human abductions by aliens, high speed unidentified flying objects and so on, all nourishing theories of encounters with aliens allegedly covered by governments. Naturally, some science fictions stories also deal with it, without pretending to describe actual events. It is noticeable that no reports existed before such science-fiction stories were published.
Science fiction stories have been around for centuries at least, even more if one considers ancient texts like Epic of Gilgamesh and Ezekiel’s chariot vision. But apparently the first known story of a hostile encounter between humans and aliens was in 1898, Herbert George Wells’ “The War of the Worlds”. The story is told about aliens from Mars invading Earth to conquer the planet, and deploying terror and destruction along the way.
Other stories of the same genre have been published. The best (and most frightening) in my opinion is from 1951, Robert Heinlein’s “The Puppet Masters”. In this book aliens obtain mind control over the humans they contact.
The first reports of UFOs appear in 1947. The first abduction report is probably Antônio Vilas-Boas’, a Brazilian farmer, in 1957, who was not just abducted. Although the abductor was a male alien, on the spaceship there was a female alien that had sexual intercourse with the captive. From 1961 abduction reports multiplied. Usually the captives were from English speaking countries, mostly the USA.
In 1997, the director-general of Israel’s Ministry of Science, the late Zvi Yanai, addressed the subject: “One of the characteristics of pseudo-science is that time does not increase understanding of the phenomenon. Indeed, after 50 years of alleged encounters with UFOs and aliens, we know no more about them today than we did fifty years ago. Such is the case with Loch-Ness dinosaur, astrology, parapsychology, chirology and other similar beliefs.”
Nowadays nearly everyone has a photo-capable smart-phone and still no reliable documentation of a human-alien encounter. It seems that we will have to keep solving our problems ourselves.