Instruct: Given a question, retrieve documents that answer the question.
Query: When was the Fermi paradox created?
Although Fermi's name is most commonly associated with the paradox, he was not the first to ask the question. An earlier implicit mention was by Konstantin Tsiolkovsky in an unpublished manuscript from 1933.[23] He noted "people deny the presence of intelligent beings on the planets of the universe" because "(i) if such beings exist they would have visited Earth, and (ii) if such civilizations existed then they would have given us some sign of their existence." This was not a paradox for others, who took this to imply the absence of ETs, but it was for him, since he himself was a strong believer in extraterrestrial life and the possibility of space travel. Therefore, he proposed what is now known as the zoo hypothesis and speculated that mankind is not yet ready for higher beings to contact us.[24] That Tsiolkovsky himself may not have been the first to discover the paradox is suggested by his above-mentioned reference to other people's reasons for denying the existence of extraterrestrial civilizations.
Michael H. Hart published in 1975 a detailed examination of the paradox,[9] which has since become a theoretical reference point for much of the research into what is now sometimes known as the Fermi–Hart paradox.[25] Geoffrey A. Landis prefers that name on the grounds that "while Fermi is credited with first asking the question, Hart was the first to do a rigorous analysis showing that the problem is not trivial, and also the first to publish his results".[26] Robert H. Gray argues that the term Fermi paradox is a misnomer, since in his view it is neither a paradox nor due to Fermi; he instead prefers the name Hart–Tipler argument, acknowledging Michael Hart as its originator, but also the substantial contribution of Frank J. Tipler in extending Hart's arguments.[27]
A related idea to the zoo hypothesis is that, beyond a certain distance, the perceived universe is a simulated reality. The planetarium hypothesis[117] speculates that beings may have created this simulation so that the universe appears to be empty of other life.
If we consider this possibility of a PBC in our galaxy we are still faced with Fermi's paradox. However many of the proposed solutions for Fermi's paradox also hold true for a PBC. In terms of the search for extraterrestrial life and astrobiology because of the almost infinite possible forms a PBC could take and our lack of understanding of these we would effectively be blind in this search. For this reason even though there is a logical argument for the existence of PBCs our best hopes remain with looking for biological life.
Fermi Linux is the generic name for Linux distributions that are created and used at Fermi National Accelerator Laboratory (Fermilab). These releases have gone through different names: "Fermi Linux", "Fermi Linux LTS", "LTS", "Fermi Linux STS", "STS", "Scientific Linux Fermi", "SLF". For the purposes of this entry they can be used interchangeably to designate a version of Linux specific to Fermilab.
Anthropic principle– Philosophical consideration that observations of the universe must be compatible with the observers Astrobiology– Science concerned with life in the universe Extraterrestrial hypothesis Fermi problem Interstellar travel Olbers' paradox Rare Earth hypothesis– Hypothesis that complex extraterrestrial life is a very improbable phenomenon and likely to be extremely rare Time travel § Absence of time travelers from the future– Concept of moving between different points in time Wow! signal– 1977 narrowband radio signal from SETI
Fermi Paradox is the 2002 (see 2002 in music) album by the band Tub Ring named after Enrico Fermi's Fermi Paradox.
Hart published in 1975 a detailed examination of the Fermi paradox: the contrast between the extreme likelihood of extraterrestrial life somewhere in the universe and the total absence of any evidence for this. Hart’s work has since become a theoretical reference point for much of the research into what is now sometimes known as the "Fermi-Hart paradox". Concerning Hart's contributions to the study of the paradox, Geoffrey A. Landis writes: "A more proper name for [the paradox] would be the Fermi-Hart paradox, since while Fermi is credited with first asking the question, Hart was the first to do a rigorous analysis showing that the problem is not trivial, and also the first to publish his results". Robert H. Gray argues that the term "Fermi paradox" is a misnomer; he argues that it is not the work of Fermi, nor is it an actual paradox (rather an argument). He views Hart as the proper originator of this argument, in his 1975 paper. Gray therefore proposes, that instead of the (standard, but in his view incorrect) name "Fermi paradox", it should be known as the "Hart-Tipler argument"–acknowledging Hart's priority as the argument's originator, but also acknowledging Frank J. Tipler's substantial extension of Hart's arguments in his 1980 paper "Extraterrestrial intelligent beings do not exist".
A famous example of a Fermi-problem-like estimate is the Drake equation, which seeks to estimate the number of intelligent civilizations in the galaxy. The basic question of why, if there were a significant number of such civilizations, ours has never encountered any others is called the Fermi paradox.
It is illegal to outright invade one of the seeded civilizations, and the progenitor aliens must wait for them to drive themselves into extinction without outside interference. The progenitor-aliens do not manipulate the seeded civilization in any way, nor were they genetically designed with a predisposition to kill each other: the progenitors simply discovered that (according to the Fermi Paradox) most industrial civilizations will drive themselves into extinction before developing interstellar spaceflight. The percentage of civilizations that survive to an interstellar stage is actually so astronomically low that out of billions of planets to choose from, a single survey ship might never encounter one. 
Perhaps the Fermi paradox itself—or the alien equivalent of it—is the reason for any civilization to avoid contact with other civilizations, even if no other obstacles existed. From any one civilization's point of view, it would be unlikely for them to be the first ones to make first contact. Therefore, according to this reasoning, it is likely that previous civilizations faced fatal problems with first contact and doing so should be avoided. So perhaps every civilization keeps quiet because of the possibility that there is a real reason for others to do so.[28]
The Fermi paradox is a conflict between the argument that scale and probability seem to favor intelligent life being common in the universe, and a total lack of evidence of intelligent life having ever arisen anywhere other than on the Earth.
Fermi wrote a paper "On the Origin of Cosmic Radiation" in which he proposed that cosmic rays arose through material being accelerated by magnetic fields in interstellar space, which led to a difference of opinion with Teller. Fermi examined the issues surrounding magnetic fields in the arms of a spiral galaxy. He mused about what is now referred to as the "Fermi paradox": the contradiction between the presumed probability of the existence of extraterrestrial life and the fact that contact has not been made.
Toward the end of his life, Fermi questioned his faith in society at large to make wise choices about nuclear technology. He said:
(Film about Fermi’s Paradox, climate change, capitalism, and collapse.)
The first aspect of the Fermi paradox is a function of the scale or the large numbers involved: there are an estimated 200–400 billion stars in the Milky Way[14] (2–4 × 1011) and 70 sextillion (7×1022) in the observable universe.[15] Even if intelligent life occurs on only a minuscule percentage of planets around these stars, there might still be a great number of extant civilizations, and if the percentage were high enough it would produce a significant number of extant civilizations in the Milky Way. This assumes the mediocrity principle, by which the Earth is a typical planet.
The Great Filter, in the context of the Fermi paradox, is whatever prevents "dead matter" from giving rise, in time, to expanding, lasting life according to the Kardashev scale.[36][11] The most commonly agreed-upon low probability event is abiogenesis: a gradual process of increasing complexity of the first self-replicating molecules by a randomly occurring chemical process. Other proposed great filters are the emergence of eukaryotes or of meiosis or some of the steps involved in the evolution of a brain capable of complex logical deductions.
The theories and principles in the Drake equation are closely related to the Fermi paradox.[32] The equation was formulated by Frank Drake in 1961 in an attempt to find a systematic means to evaluate the numerous probabilities involved in the existence of alien life. The speculative equation considers the rate of star formation in the galaxy; the fraction of stars with planets and the number per star that are habitable; the fraction of those planets that develop life; the fraction that develop intelligent life; the fraction that have detectable, technological intelligent life; and finally the length of time such communicable civilizations are detectable. The fundamental problem is that the last four terms are completely unknown, rendering statistical estimates impossible.
It has been suggested that some advanced beings may divest themselves of physical form, create massive artificial virtual environments, transfer themselves into these environments through mind uploading, and exist totally within virtual worlds, ignoring the external physical universe.[101]
The Fermi paradox can be stated more completely as follows:
There are multiple explanations proposed for the Fermi paradox, ranging from analyses suggesting that intelligent life is rare (the "Rare Earth hypothesis"), to analyses suggesting that although extraterrestrial civilizations may be common, they would not communicate, or would not travel across interstellar distances.
In 2016, Gray published an article in "Scientific American" about the Fermi paradox, which claims that if extraterrestrials existed, we would see signs of them on Earth, because they would certainly colonize the galaxy by interstellar travel. Gray argues that the Fermi paradox, named after Nobel Prize-winning physicist Enrico Fermi, does not accurately represent Fermi's views. Gray states that Fermi questioned the feasibility of interstellar travel, but did not say definitively whether or not he thought extraterrestrials exist.
In physics, the Fermi–Pasta–Ulam–Tsingou problem or formerly the Fermi–Pasta–Ulam problem was the apparent paradox in chaos theory that many complicated enough physical systems exhibited almost exactly periodic behavior – called Fermi–Pasta–Ulam–Tsingou recurrence (or Fermi–Pasta–Ulam recurrence) – instead of ergodic behavior. One of the resolutions of the paradox includes the insight that many non-linear equations are exactly integrable. Another may be that ergodic behavior may depend on the initial energy of the system.
Cosmologist Alan Guth proposed a multiverse solution to the Fermi paradox. This hypothesis uses the synchronous gauge probability distribution, with the result that young universes exceedingly outnumber older ones (by a factor of e1037 for every second of age). Therefore, averaged over all universes, universes with civilizations will almost always have just one, the first to develop. However, Guth notes "Perhaps this argument explains why SETI has not found any signals from alien civilizations, but I find it more plausible that it is merely a symptom that the synchronous gauge probability distribution is not the right one."[86]
There are two parts of the Fermi paradox that rely on empirical evidence—that there are many potential habitable planets, and that we see no evidence of life. The first point, that many suitable planets exist, was an assumption in Fermi's time that is gaining ground with the discovery of many exoplanets, and models predicting billions of habitable worlds in our galaxy.[37]
A temporal paradox, time paradox, or time travel paradox is a paradox, an apparent contradiction, or a logical contradiction that is associated with the idea of time and time travel. In physics, temporal paradoxes fall into two broad groups: consistency paradoxes exemplified by the grandfather paradox; and causal loops. More broadly, a variation of the Fermi paradox also applies to time travel.
The Fermi paradox, or Fermi's paradox, named after physicist Enrico Fermi, is the apparent contradiction between the lack of evidence and high probability estimates[1] for the existence of extraterrestrial civilizations.[2] The basic points of the argument, made by physicists Enrico Fermi (1901–1954) and Michael H. Hart (born 1932), are: