Are we alone in the universe?
We have been looking deep into space with telescopes for decades. And yet we haven’t discovered any extraterrestrials. Maybe we will probably never find aliens but that is no reason to doubt their existence.
The answer to the question of whether there are aliens is very likely to be: Yes!
The universe is unimaginable, maybe even infinitely large. Therefore, the probability is very high that not only life but also intelligent life exists outside of the Earth.
Our galaxy, the Milky Way, has between 100 and 400 billion stars. And it is only one of the billions of galaxies in the observable universe — the part of the universe where light has reached since the Big Bang. It would be astonishing if intelligent life only existed on Earth, a rock planet in an elliptical orbit around a star called the Sun.
Nevertheless, we have not yet made contact — or have not yet found anyone to contact. Why?
Fermi paradox asks the same: where are aliens?
The physicist Enrico Fermi asked himself this question in the middle of the 20th century. The so-called Fermi paradox was named after him, which states — In our Milky Way, there are so many stars and planets that one would expect to find numerous intelligent civilizations, and yet we have not discovered any.
There are several approaches to solving this paradox, i.e., the contradiction between expectation and observation.
For example, it could be due to technology.
So the question would be: Why have we not yet found any intelligent aliens in our area of the Milky Way using our technical means?
Because our current means, that is, our telescopes, which search the sky for sources of electromagnetic radiation of different wavelengths — i.e., visible light, UV, infrared, radio waves, and so on — only enable us to search for extraterrestrials in our neighborhood. More precisely, in a part of our Milky Way within a radius of up to a few thousand light-years. Overall, the Milky Way has a diameter of more than 100,000 light-years.
So we may not have found any intelligent aliens because there simply aren’t any in our area of the Milky Way. We would simply be unlucky or maybe lucky, because the aliens could be hostile to us because humans are the technically superior species in our area of the galaxy.
Check out this video by SETI Senior Astronomer Seth Shostak about a short rundown of what the Fermi Paradox has to do with the search for ET.