Article URL: https://en.wikipedia.org/wiki/Fermi_paradox Comments URL: https://news.ycombinator.com/item?id=49137419 Points: 6 # Comments: 1

The Fermi paradox is the apparent inconsistency between the lack of conclusive evidence of extraterrestrial civilizations and the apparently high likelihood of their existence.[1][2][3] In simple terms, the Fermi paradox asks why, given the vast number of stars and potentially habitable planets in our observable universe, there is no clear evidence of extraterrestrial civilizations. The paradox is named after physicist Enrico Fermi who blurted out the question—remembered by Emil Konopinski as "But where is everybody?"—during lunchtime after the conversation had already moved on to other topics. This happened at Los Alamos in 1950 with colleagues Konopinski, Edward Teller, and Herbert York. The paradox first appeared in print in a 1963 paper by Carl Sagan, and the paradox has since been fully described by scientists. Early formulations of the paradox have also been identified in writings by Bernard Le Bovier de Fontenelle (1686) and Jules Verne (1865), and by Soviet rocket scientist Konstantin Tsiolkovsky (1933). There have been many attempts to resolve the Fermi paradox,[4][5] such as suggesting that intelligent extraterrestrial beings are extremely rare, that the lifetime of such civilizations is short, or that they exist but (for various reasons) humans see no evidence. Some of the facts and hypotheses that together serve to highlight the apparent contradiction: Enrico Fermi was a Nobel Prize-winning physicist who predicted the existence of neutrinos and helped create the first artificial nuclear reactor, an early feat of the Manhattan Project.[14] He was known to pose simple but seemingly unanswerable questions—termed "Fermi questions"—to his colleagues and students, like "How many atoms of Caesar's last breath do you inhale with each lungful of air?"[15] In 1950,[note 1] Fermi visited Los Alamos National Laboratory in New Mexico and, while walking to the Fuller Lodge for lunch, conversed with fellow physicists Emil Konopinski, Edward Teller, and Herbert York about reports of flying saucers and the feasibility of faster-than-light travel.[18] When the conversation shifted to unrelated topics at the lodge, Fermi blurted a question variously recalled as: "Where is everybody?" (Teller), "Don't you ever wonder where everybody is?" (York), or "But where is everybody?" (Konopinski).[19] According to Teller, "The result of his question was general laughter because of the strange fact that, in spite of Fermi's question coming out of the blue, everybody around the table seemed to understand at once that he was talking about extraterrestrial life."[20] According to York, Fermi "followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of such calculations that we ought to have been visited long ago and many times over."[21] However, Teller recalled that Fermi did not elaborate on his question beyond "perhaps a statement that the distances to the next location of living beings may be very great and that, indeed, as far as our galaxy is concerned, we are living somewhere in the sticks, far removed from the metropolitan area of the galactic center."[20][note 2]