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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Extraterrestrial UFO hypothesis | 4/5 | https://en.wikipedia.org/wiki/Extraterrestrial_UFO_hypothesis | reference | science, encyclopedia | 2026-05-05T09:19:39.670231+00:00 | kb-cron |
== Critical responses and positions of the ETH == People have had a long-standing curiosity about extraterrestrial life. Aliens are the subject of numerous urban legends, including claims that they have long been present on earth or that they may be able to assist humans in resolving certain issues. There is no scientific proof to back up these assertions, hence we cannot declare with certainty whether or not aliens exist. In spite of ardent believers that various UFO sightings are verifiable evidence for the ET hypothesis, no rigorous analysis has ever concluded as much.
=== U.S. military investigation and debunkery === On July 9, 1947, Army Air Forces Intelligence began a secret study of the best saucer reports, including that of Arnold's. A follow-up study by the Air Materiel Command intelligence and engineering departments at Wright Field, Ohio led to the formation of the U.S. Air Force's Project Sign at the end of 1947, the first official U.S. military UFO study. In 1948, Project Sign concluded without endorsing any unified explanation for all UFO reports, and the ETH was rejected by USAF Chief of Staff General Hoyt Vandenberg, citing a lack of physical evidence. Vandenberg dismantled Project Sign, and with this official policy in place, subsequent public Air Force reports concluded, that there was insufficient evidence to warrant further investigation of UFOs. In 1952, Life Magazine published "Have We Visitors From Space?" which popularized the Extraterrestrial Hypothesis and is thought to have triggered the 1952 UFO flap. Immediately following the great UFO wave of 1952 and the military debunking of radar and visual sightings, plus jet interceptions over Washington, D.C. in August, the CIA's Office of Scientific Investigation took particular interest in UFOs. Though the ETH was mentioned, it was generally given little credence. However, others within the CIA, such as the Psychological Strategy Board, were more concerned about how an unfriendly power such as the Soviet Union might use UFOs for psychological warfare purposes, exploit the gullibility of the public for the sensational, and clog intelligence channels. Under a directive from the National Security Council to review the problem, in January 1953, the CIA organized the Robertson Panel, a group of scientists who quickly reviewed the Blue Book's best evidence, including motion pictures and an engineering report that concluded that the performance characteristics were beyond that of earthly craft. After two days' review, all cases were claimed to have conventional explanations. An official policy of public debunkery was recommended using the mass media and authority figures in order to influence public opinion and reduce the number of UFO reports.
=== Involvement of scientists === The scientific community has shown very little support for the ETH, and has largely accepted the explanation that reports of UFOs are the result of people misinterpreting common objects or phenomena, or are the work of hoaxers. The physicist Stephen Hawking expressed skepticism about the ETH. In a 1969 lecture, U.S. astrophysicist Carl Sagan said:
"The idea of benign or hostile space aliens from other planets visiting the Earth [is clearly] an emotional idea. There are two sorts of self-deception here: either accepting the idea of extraterrestrial visitation by space aliens in the face of very meager evidence because we want it to be true; or rejecting such an idea out of hand, in the absence of sufficient evidence, because we don't want it to be true. Each of these extremes is a serious impediment to the study of UFOs." Similarly, British astrophysicist Peter A. Sturrock wrote
"for many years, discussions of the UFO issue have remained narrowly polarized between advocates and adversaries of a single theory, namely the extraterrestrial hypothesis ... this fixation on the ETH has narrowed and impoverished the debate, precluding an examination of other possible theories for the phenomenon." An informal poll done by Sturrock in 1973 of American Institute of Aeronautics and Astronautics members found that about 10% of them believed that UFOs were vehicles from outer space. In another poll conducted in 1977, Sturrock asked members of the American Astronomical Society to assign probabilities to eight possible explanations for UFOs. The results were:
The primary scientific arguments against ETH were summarized by astronomer and UFO researcher J. Allen Hynek during a presentation at the 1983 MUFON Symposium, where he outlined seven key reasons why he could not accept the ETH.
Failure of sophisticated surveillance systems to detect incoming or outgoing UFOs Gravitational and atmospheric considerations Statistical considerations Elusive, evasive and absurd behavior of UFOs and their occupants Isolation of the UFO phenomenon in time and space: the Cheshire Cat effect The space unworthiness of UFOs The problem of astronomical distances Hynek argued that: