SETI
Are there civilizations in the universe that are technologically more advanced than ours? This fascinating question is the basis of the SETI (Search for ExTraterrestrial Intelligence) project, which observes the sky in search of possible traces of these civilizations.
We now know that the majority of stars in our Galaxy have their own planetary systems, and that there must be tens of billions of potentially habitable planets in the Milky Way. We also know that life appeared relatively early in the history of the Earth, and that it is able to adapt to extremely difficult conditions (temperature, pressure, acidity, radiation, etc.). Finally, the numerous examples of evolutionary convergence known on Earth as well as the apparently important evolutionary advantage of a high level of intelligence suggest that technological intelligence is one of a finite number of evolutionary "solutions" that could be selected in any biosphere rich in complex multicellular organisms. Considering that our Galaxy is 13 billion years old and that our species only appeared there about 200,000 years ago, the hypothesis that other technologically advanced species appeared there before us is not ridiculous. Moreover, considering the ultra-fast development of our technology during the last two centuries and our current understanding of the laws of nature, it seems quite possible that a technological civilization predating ours by millions or even billions of years could have acquired the capacity for interstellar travel. Such a civilization could have sent exploration probes around all the stars of the Galaxy well before the appearance of Sapiens. This hypothesis is reinforced by the possibility of self-replicating probes. Indeed, it has been shown that with such interstellar probes capable of making copies of themselves, the exploration of all the stars of the Galaxy could be done in a few million years "only", even if these probes could only travel at a few percent of the speed of light.
These considerations lead us to the hypothesis that the best place to look for traces of technologically advanced extraterrestrial life could be ... our solar system. This is one of the hypotheses currently studied by SETI. Michaël Gillon has modestly contributed to the study of this hypothesis, based on the principle that if extraterrestrial probes are around every star in the Galaxy, they must necessarily communicate with each other, and it might be possible to detect these communications.
