The Fermi paradox raises one of the most famous questions in the field of space exploration: If there is life outside our planet, how is it possible that it has not manifested itself yet?
Our galaxy has billions of stars. Since we have no reason to think that our solar system has anything special, it is logical to conclude that there must be very many planets with conditions more or less similar to ours.
Therefore, if our planet has life and, what is more, intelligent life, it is possible (or even probable) that this life could have develop on other planets not too far from ours. In astronomical terms, of course.
The fact that we have not yet heard of the existence of intelligent life (or life in a broader sense) outside our planet intrigues many. Including Enrico Fermi himself, who gave his name to this famous paradox.
There are many theories that attempt to explain this apparent discrepancy. One of the latest, the one postulated by the astrophysicist Amri Wandel in an article in The Astrophysical Journal. The hypothesis that Wandel postulates is based on the idea that, if the planets that have life outside our solar system are common, an extraterrestrial civilization wanting to explore and learn about other forms of life it would limit itself to seeking contact only with planets where they had verified the existence of intelligent life.
Matter of time.
The other key is found in the natural limitation of the speed at which light travels. The main evidence that the aliens could take as a reference to meet an intelligent civilization.
The human being began to “emit” these waves at the end of the 19th century, which implies that they could only have reached the star systems located in a “small” bubble a little over 250 light years in diameter. A tiny volume if we compare it with the Milky Way and its disk of 100,000 light years in diameter.
Furthermore, even if we assume the existence of life in this bubble around us, any answer would take the same time to reach our planet. If we limited our bubble to the places where our signals could have been picked up in time to send us a response, the circle narrows even more.
Wendel estimates based on this that it is “first contact” It would take between 400 and 50,000 years to reach. This is the time it would take for our first signals to cover a significant part of our galaxy in order to give them time to reach another planet and its inhabitants time to reply to us.
There is a third issue that can be related to Wendel’s approach, and it is the possibility that this hypothetical extraterrestrial civilization could detect our signal and discard it, considering that we are in a sufficiently advanced state. In that case the aliens could be waiting for our signals to transmit messages more typical of intelligent creatures.
Since the Fermi paradox gained popularity, a multitude of answers have been raised to explain it. The possibility that we are simply uninteresting to aliens is one of them. This idea is similar to the one that another old acquaintance of the search for extraterrestrial life, Avi Loeb, proposed to downplay the idea of an alien invasion.
Among the many other answers to this question, time is key for several. Either because we could be one of the first intelligent civilizations in our galaxy or because we could be one of the few survivors of our time. There are also those who believe that aliens may have noticed our planet before humans could understand and record the visit.
Whatever the case, the search continues. We may even be able to detect life before it detects us.
Image | Mario Roberto Durán Ortiz, CC BY-SA 4.0
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