Where is Everybody?

Imagine you’re sitting with a group of friends, discussing the vastness of the universe and the possibility of extraterrestrial life. Suddenly, one of your friends asks,

“If there are so many stars and planets out there,

Where is everybody?”

– one of those friends.

This simple question, posed by physicist Enrico Fermi in 1950, has since become known as the Fermi Paradox.

The Fermi Paradox is the apparent contradiction between the high probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations. Given the vast size of the universe and the many stars and planets, it seems logical that there should be many other civilizations out there.

Yet, despite decades of searching, we have not found any definitive evidence of extraterrestrial life.

So, what’s going on? There are many possible explanations for the Fermi Paradox, including the idea that extraterrestrial civilizations are too far away to detect, that they are avoiding us, or that they simply don’t exist. However, there is also the possibility that we simply haven’t found them yet, and that with further research and exploration, we will eventually uncover the mysteries of the universe.

One of the most intriguing explanations for the Fermi Paradox is the idea of the “Great Filter.” This theory suggests that there are many obstacles that civilizations must overcome in order to develop and become detectable by other civilizations. These obstacles could include things like natural disasters, disease, or war. If this is the case, it could mean that we are alone in the universe, or that other civilizations are too far away or too different from us to detect.

In conclusion, the Fermi Paradox continues to be one of the most intriguing mysteries in the search for extraterrestrial life. While we may never know the answer for certain, the search for extraterrestrial life is an important and exciting field of research, as we continue to explore the vastness of the universe and uncover its many secrets. Whether we find evidence of extraterrestrial life or not, the journey will be full of discovery and wonder.

But the above conclusion is generated by Chat GPT which does not know about this new research paper published on 22.12.2022:


A new solution to the Fermi Paradox is presented: probes or visits from putative alien civilizations have a very low probability until a civilization reaches a certain age (called the “Contact Era”) after the onset of radio communications. If biotic planets are common, putative advanced civilizations may send probes not to any planet showing biosignatures, but rather to planets with technosignatures, such as radio broadcasts. The contact probability is defined as the chance to find a nearby civilization located close enough so that it could have detected the earliest radio emissions (the “radiosphere”) and sent a probe that would reach the solar system at present. It is found that the current contact probability for Earth is very low unless civilizations are extremely abundant. Since the radiosphere expands with time, so does the contact probability. The Contact Era is defined as the time (since the onset of radio transmissions) at which the contact probability becomes of order unity. At that time alien probes (or messages) become more likely. Unless civilizations are highly abundant, the Contact Era is shown to be of the order of a few hundred to a few thousand years and may be applied not only to physical probes but also to transmissions (i.e., search for extraterrestrial intelligence). Consequently, it is shown that civilizations are unlikely to be able to intercommunicate unless their communicative lifetime is at least a few thousand years.

The Fermi Paradox Revisited: Technosignatures and the Contact Era

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