Where are the extraterrestrials? Gathered in Paris by METI (Messaging Extraterrestrial Intelligence), scientists looked at the Cité des Sciences in Paris on this issue which, although it feeds the fantasies of neophytes, is nonetheless serious and "extremely debated" .
"When we try to better understand the universe, the question of whether we are alone is unavoidable," says Florence Raulin-Cerceau, doctor of astronomy and lecturer at the National Museum of Natural History.
Even if we are "in search of something we do not know if it exists," recognizes Douglas Vakoch, president of METI International, a San Francisco-based organization dedicated to sending messages to other planets. we have to debate it.
In 1950, the physicist and Nobel Prize winner Enrico Fermi exclaimed: "where are they?" while he debated at the canteen of the national laboratory of Los Alamos of the possibility of a life elsewhere, judging astonishing that we have not yet crossed of extraterrestrials, seen the vastness of the Universe and the old age of the Galaxy. A question known as the "Fermi Paradox".
Since then, numerous contact attempts have been made, such as the Breakthrough Listen program, which is run by physicists from the very serious Royal Society Science Academy in London, or research by the SETI (Search for Extraterrestrial Intelligence) Institute in California.
The universe is scrutinized, on the lookout for an intelligent activity (radio frequency, laser beam ...) or artificial objects in orbit in front of stars (like spheres of Dyson).
But it is about "recent ultra searches", relativizes Florence Raulin-Cerceau, reminding that it will be necessary several generations to have elements of answer.
"The formation of the Earth is 4.65 billion years, extraterrestrial research is 40 years," adds Cyril Birnbaum, responsible for the planetarium of the City of Science and Industry, which prepares a film on the paradox for the end of 2020.
- Christopher Columbus effect -
But if the search for extraterrestrial life has not borne fruit, our knowledge of the Universe has totally changed: in 2014, astronomers discovered Kepler-186f, first cousin of the Earth located in the "habitable zone" of its star, where the temperature allows the presence of water in the liquid state, essential for life.
Since then, the catalog continues to thicken, confirming that the Earth is not a galactic exception.
"The intelligence has appeared several times on Earth independently in different groups", explains Jean-Pierre Rospars, research director INRA, citing crows, cetaceans, primates ...
"This shows that the appearance of intelligence in evolution is not an accident specific to the Earth but a kind of rule," he adds.
An idea that is not unanimous, some thinking rather than the appearance of intelligence is a combination of circumstances that is not ready to reproduce.
"There is no reason to think that humans have reached the highest cognitive level possible, higher levels could evolve on Earth in the future and already be reached elsewhere," he adds.
This may be why we have not been able to get in touch, communication between populations of different cognitive levels being complicated.
The extraterrestrials may also have preferred to remain silent, given the risks of destabilization that would provoke such a meeting.
"If the extraterrestrials visit us one day, I think the result will be similar to what happened when Christopher Columbus landed in America, a result not really positive for the Indians," said British physicist and cosmologist Stephen Hawking in 2010.
Another possible explanation for the "great silence": in view of the great age of the Universe, "it may well be that thousands of civilizations could have hatched, live for tens of thousands of years, while remaining alone", explains Nicolas Prantzos, astrophysicist of the CNRS.
"Being alone in the galaxy does not mean being the first or the only one in the history of the galaxy," he adds.
For the researcher, these civilizations could be too far away: "suppose that there are 1,000 civilizations but that they are 100,000 light years from us, it is possible that we can never contact them".
One thing is certain, "if you find an extraterrestrial life, even bacterial, it would be a huge step for science and reflection on the place of the living in the universe," enthuses Florence Raulin-Cerceau.
"When we try to better understand the universe, the question of whether we are alone is unavoidable," says Florence Raulin-Cerceau, doctor of astronomy and lecturer at the National Museum of Natural History.
Even if we are "in search of something we do not know if it exists," recognizes Douglas Vakoch, president of METI International, a San Francisco-based organization dedicated to sending messages to other planets. we have to debate it.
In 1950, the physicist and Nobel Prize winner Enrico Fermi exclaimed: "where are they?" while he debated at the canteen of the national laboratory of Los Alamos of the possibility of a life elsewhere, judging astonishing that we have not yet crossed of extraterrestrials, seen the vastness of the Universe and the old age of the Galaxy. A question known as the "Fermi Paradox".
Since then, numerous contact attempts have been made, such as the Breakthrough Listen program, which is run by physicists from the very serious Royal Society Science Academy in London, or research by the SETI (Search for Extraterrestrial Intelligence) Institute in California.
The universe is scrutinized, on the lookout for an intelligent activity (radio frequency, laser beam ...) or artificial objects in orbit in front of stars (like spheres of Dyson).
But it is about "recent ultra searches", relativizes Florence Raulin-Cerceau, reminding that it will be necessary several generations to have elements of answer.
"The formation of the Earth is 4.65 billion years, extraterrestrial research is 40 years," adds Cyril Birnbaum, responsible for the planetarium of the City of Science and Industry, which prepares a film on the paradox for the end of 2020.
- Christopher Columbus effect -
But if the search for extraterrestrial life has not borne fruit, our knowledge of the Universe has totally changed: in 2014, astronomers discovered Kepler-186f, first cousin of the Earth located in the "habitable zone" of its star, where the temperature allows the presence of water in the liquid state, essential for life.
Since then, the catalog continues to thicken, confirming that the Earth is not a galactic exception.
"The intelligence has appeared several times on Earth independently in different groups", explains Jean-Pierre Rospars, research director INRA, citing crows, cetaceans, primates ...
"This shows that the appearance of intelligence in evolution is not an accident specific to the Earth but a kind of rule," he adds.
An idea that is not unanimous, some thinking rather than the appearance of intelligence is a combination of circumstances that is not ready to reproduce.
"There is no reason to think that humans have reached the highest cognitive level possible, higher levels could evolve on Earth in the future and already be reached elsewhere," he adds.
This may be why we have not been able to get in touch, communication between populations of different cognitive levels being complicated.
The extraterrestrials may also have preferred to remain silent, given the risks of destabilization that would provoke such a meeting.
"If the extraterrestrials visit us one day, I think the result will be similar to what happened when Christopher Columbus landed in America, a result not really positive for the Indians," said British physicist and cosmologist Stephen Hawking in 2010.
Another possible explanation for the "great silence": in view of the great age of the Universe, "it may well be that thousands of civilizations could have hatched, live for tens of thousands of years, while remaining alone", explains Nicolas Prantzos, astrophysicist of the CNRS.
"Being alone in the galaxy does not mean being the first or the only one in the history of the galaxy," he adds.
For the researcher, these civilizations could be too far away: "suppose that there are 1,000 civilizations but that they are 100,000 light years from us, it is possible that we can never contact them".
One thing is certain, "if you find an extraterrestrial life, even bacterial, it would be a huge step for science and reflection on the place of the living in the universe," enthuses Florence Raulin-Cerceau.
