Extraterrestrial UFO hypothesis explained

The extraterrestrial hypothesis (ETH) proposes that some unidentified flying objects (UFOs) are best explained as being physical spacecraft occupied by extraterrestrial intelligence or non-human aliens, or non-occupied alien probes from other planets visiting Earth.

Etymology

Origins of the term extraterrestrial hypothesis are unknown, but use in printed material on UFOs seems to date to at least the latter half of the 1960s. French ufologist Jacques Vallée used it in his 1966 book Challenge to science: the UFO enigma. It was used in a publication by French engineer Aimé Michel in 1967,[1] by James E. McDonald in a symposium in March 1968[2] and again by McDonald and James Harder while testifying before the Congressional Committee on Science and Astronautics, in July 1968.[3] Skeptic Philip J. Klass used it in his 1968 book UFOs--Identified.[4] In 1969 physicist Edward Condon defined the "extraterrestrial hypothesis" or "ETH" as the "idea that some UFOs may be spacecraft sent to Earth from another civilization or space other than Earth, or on a planet associated with a more distant star," while presenting the findings of the much debated Condon Report. Some UFO historians credit Condon with popularizing the term and its abbreviation "ETH."

Chronology

Although the extraterrestrial hypothesis (ETH) as a phrase is a comparatively new concept, one which owes much to the flying saucer sightings of the 1940s–1960s, its origins can be traced back to a number of earlier events, such as the now-discredited Martian canals and ancient Martian civilization promoted by astronomer Percival Lowell, popular culture including the writings of H. G. Wells and fellow science fiction pioneers such as Edgar Rice Burroughs, who likewise wrote of Martian civilizations, and even to the works of figures such as the Swedish philosopher, mystic and scientist Emanuel Swedenborg, who promoted a variety of unconventional views that linked other worlds to the afterlife.[5]

In the early part of the twentieth century, Charles Fort collected accounts of anomalous physical phenomena from newspapers and scientific journals, including many reports of extraordinary aerial objects. These were published in 1919 in The Book of the Damned. In this and two subsequent books, New Lands (1923) and Lo! (1931), Fort theorized that visitors from other worlds were observing Earth. Fort's reports of aerial phenomena were frequently cited in American newspapers when the UFO phenomenon first attracted widespread media attention in June and July 1947.

The modern ETH—specifically, the implicit linking of unidentified aircraft and lights in the sky to alien life—took root during the late 1940s and took its current form during the 1950s. It drew on pseudoscience, as well as popular culture. Unlike earlier speculation of extraterrestrial life, interest in the ETH was also bolstered by many unexplained sightings investigated by the U.S. government and governments of other countries, as well as private civilian groups, such as NICAP and APRO.

Historical reports of extraterrestrial visits

An early example of speculation over extraterrestrial visitors can be found in the French newspaper Le Pays, which on June 17, 1864, published a story about two American geologists who had allegedly discovered an alien-like creature, a mummified three-foot-tall hairless humanoid with a trunk-like appendage on its forehead, inside a hollow egg-shaped structure.[6]

H. G. Wells, in his 1898 science fiction classic The War of the Worlds, popularized the idea of Martian visitation and invasion. Even before Wells, there was a sudden upsurge in reports in "Mystery airships" in the United States. For example, The Washington Times in 1897 speculated that the airships were "a reconnoitering party from Mars", and the Saint Louis Post-Dispatch wrote: "these may be visitors from Mars, fearful, at the last, of invading the planet they have been seeking."[7] Later, there was a more international airship wave from 1909-1912. An example of an extraterrestrial explanation at the time was a 1909 letter to a New Zealand newspaper suggesting "atomic powered spaceships from Mars."[8]

From the 1920s, the idea of alien visitation in space ships was commonplace in popular comic strips and radio and movie serials, such as Buck Rogers and Flash Gordon. In particular, the Flash Gordon serials have the Earth being attacked from space by alien meteors, ray beams, and biological weapons. In 1938, a radio broadcast version of The War of the Worlds by Orson Welles, using a contemporary setting for H. G. Wells' Martian invasion, created some public panic in the United States.

The 1947 flying saucer wave in America

On June 24, 1947, at about 3:00 p.m. local time, pilot Kenneth Arnold reported seeing nine unidentified disk-shaped aircraft flying near Mount Rainier.[9] [10] When no aircraft emerged that seemed to account for what he had seen, Arnold quickly considered the possibility of the objects being extraterrestrial. On July 7, 1947, two stories came out where Arnold was raising the topic of possible extraterrestrial origins, both as his opinion and those who had written to him. In an Associated Press story, Arnold said he had received quantities of fan mail eager to help solve the mystery. Some of them "suggested the discs were visitations from another planet."[11] [12] [13] [14]

When the 1947 flying saucer wave hit the United States, there was much speculation in the newspapers about what they might be in news stories, columns, editorials, and letters to the editor. For example, on July 10, U.S. Senator Glen Taylor of Idaho commented, "I almost wish the flying saucers would turn out to be space ships from another planet," because the possibility of hostility "would unify the people of the earth as nothing else could." On July 8, R. DeWitt Miller was quoted by UP saying that the saucers had been seen since the early nineteenth century. If the present discs weren't secret Army weapons, he suggested they could be vehicles from Mars, or other planets, or maybe even "things out of other dimensions of time and space."[15] Other articles brought up the work of Charles Fort, who earlier in the twentieth century had documented numerous reports of unidentified flying objects that had been written up in newspapers and scientific journals.[16]

Even if people thought the saucers were real, most were generally unwilling to leap to the conclusion that they were extraterrestrial in origin. Various popular theories began to quickly proliferate in press articles, such as secret military projects, Russian spy devices, hoaxes, optical illusions, and mass hysteria. According to journalist Edward R. Murrow, the ETH as a serious explanation for "flying saucers" did not earn widespread attention until about 18 months after Arnold's sighting.[17]

These attitudes seem to be reflected in the results of the first U.S. poll of public UFO perceptions released by Gallup on August 14, 1947.[18] The term "flying saucer" was familiar to 90% of the respondents. As to what people thought explained them, the poll further showed, that most people either held no opinion or refused to answer the question (33%), or generally believed that there was a mundane explanation. 29% thought they were optical illusions, mirages, or imagination; 15% a U.S. secret weapon; 10% a hoax; 3% a "weather forecasting device"; 1% of Soviet origin, and 9% had "other explanations," including fulfillment of Biblical prophecy, secret commercial aircraft, or phenomena related to atomic testing.[19]

U.S. military investigation and debunkery

On July 9, 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.[20] 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,[21] 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.

Evolution of public opinion

The early 1950s also saw a number of movies depicting flying saucers and aliens, including The Day the Earth Stood Still (1951), The War of the Worlds (1953), Earth vs. the Flying Saucers (1956), and Forbidden Planet (1956). A poll published in Popular Science magazine in August 1951 reported that of the respondents who self-reported as UFO witnesses, 52% believed that they had seen a man-made aircraft, while only 4% believed that they had seen an alien craft; an additional 28% were uncertain, with more than half of these stating they believed they were either man-made aircraft, or "visitors from afar."[22] By 1957, 25% of Americans responded that they either believed, or were willing to believe in the ETH, while 53% responded that they were not. 22% reported that they were uncertain.[23]

A Roper poll in 2002 reported that 56% of respondents thought UFOs were real, with 48% believing that UFOs had visited Earth.[24]

Fewer sightings despite camera phone technology

As the proliferation of smartphone camera technology across the population has not led to a significant increase in recorded UFO sightings, the claimed phenomenology of UFOs has been called into question.[25] This goes counter to the predictions of supporters of the extraterrestrial hypothesis, even causing a crisis of confidence among some within the informal UFO research community.[26]

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. Professor Stephen Hawking has expressed skepticism about the ETH.[27] 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."[28]

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."[29]

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.[30] [31] In another informal poll conducted in 1977 by astrophysicist Peter A. Sturrock, he surveyed members of the American Astronomical Society. Sturrock asked polled scientists to assign probabilities to eight possible explanations for UFOs. The results were:[30]

23% An unfamiliar natural phenomenon
22% A familiar phenomenon or device
21% An unfamiliar terrestrial device
12% Hoax
9% An unknown natural phenomenon
7% Some specifiable other cause
3% An alien device
3% Some unspecified other cause

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.[32]

  1. Failure of sophisticated surveillance systems to detect incoming or outgoing UFOs
  2. Gravitational and atmospheric considerations
  3. Statistical considerations
  4. Elusive, evasive and absurd behavior of UFOs and their occupants
  5. Isolation of the UFO phenomenon in time and space: the Cheshire Cat effect
  6. The space unworthiness of UFOs
  7. The problem of astronomical distances

Hynek argued that:

  1. Despite worldwide radar systems and Earth-orbiting satellites, UFOs are alleged to flit in and out of the atmosphere, leaving little to no evidence.
  2. Space aliens are alleged to be overwhelmingly humanoid, and are allegedly able to exist on Earth without much difficulty often lacking "space suits", even though extra-solar planets would likely have different atmospheres, biospheres, gravity and other factors, and extraterrestrial life would likely be very different from Earthly life.
  3. The number of reported UFOs and of purported encounters with UFO-inhabitants outstrips the number of expeditions that an alien civilization (or civilizations) could statistically be expected to mount.
  4. The behavior of extraterrestrials reported during alleged abductions is often inconsistent and irrational.
  5. UFOs are isolated in time and space: like the Cheshire Cat, they seem to appear and disappear at will, leaving only vague, ambiguous and mocking evidence of their presence
  6. Reported UFOs are often far too small to support a crew traveling through space, and their reported flight behavior is often not representative of a craft under intelligent control (erratic flight patterns, sudden course changes).
  7. The distance between planets makes interstellar travel impractical, particularly because of the amount of energy that would be required for interstellar travel using conventional means, (According to a NASA estimate, it would take 7 joules of energy to send the then-current Space Shuttle on a one-way 50-year journey to the nearest star, an enormous amount of energy[33]) and because of the level of technology that would be required to circumvent conventional energy/fuel/speed limitations using exotic means, such as Einstein-Rosen Bridges as ways to shorten distances from point A to point B. (see Faster-than-light travel).[34]

According to the personal assessment of Hynek at the time, points 1 through 6 could be argued, but point 7 represented an "insurmountable" barrier to the validity of the ETH.[34]

Recent support

Others have argued that (unless mechanisms of repulse or dissolution and/or data-manipulation and/or cloaking technologies are and remain sufficiently deployed to prevent this), self-replicating spacecraft or their communications networks could potentially be detectable within our Solar system or in nearby star-based systems,[35] if they are located there.[36] Other research has since also addressed earlier arguments about the distance-related bottleneck with potential solutions other civilizations may have developed such as embryo space colonization[37] and Alcubierre drives. A 2021 scientific review concluded there to be robust rationale for organizing missions for searching artifacts – including probes – within the Solar system.[38] [39]

The sentiment in the scientific community about the extraterrestrial hypothesis in relation to UFO reports and data shifted substantially after serious news reports about the topic by large media outlets within the U.S. and Canada and a public debate including former and present public servants in anticipation of a report by the U.S. intelligence apparatus. During this change of attitude in early summer 2021, still small but increasing numbers of scientists first began to publicly discuss UFOs and systematic investigations of them in a sober manner on large platforms.[40] [41] [42] [43] [44] [45] [46] [47]

NASA

NASA frequently fields questions in regard to the ETH and UFOs. As of 2006, its official standpoint was that ETH has a lack of empirical evidence.

"no one has ever found a single artifact, or any other convincing evidence for such alien visits". David Morrison.[48]

"As far as I know, no claims of UFOs as being alien craft have any validity -- the claims are without substance, and certainly not proved". David Morrison[49]

Despite public interest, up until 2021, NASA had considered the study of ETH to be irrelevant to its work because of the number of false leads that a study would provide, and the limited amount of usable scientific data that it would yield. On the History Channel UFO Hunters episode "The NASA Files" (2008), Former NASA astronauts have commented; Gordon Cooper wrote that NASA and the government "swept these and other sightings under the rug". Brian O'Leary stated "some of my fellow astronauts and scientists astronauts that did go up and who have observed things, very clearly, they were told - not to report it".

In June 2021, NASA Administrator Bill Nelson announced that he had directed NASA scientists to investigate Unidentified Aerial Phenomenon.[50] During an interview at the University of Virginia, Bill Nelson explored the possibility that UAP could represent extraterrestrial technology.[51]

NASA scientist Ravi Kopparapu advocates studying UAP.[52]

In August 2021, at the American Institute of Aeronautics and Aviation, Kopparapu presented a paper[53] from the American Association for the Advancement of Science, 134th Meeting General Symposium that supported ETH. Kopparapu stated he and his colleagues found the paper "perfectly credible".

Conspiracy theories

See main article: UFO conspiracy theory.

A frequent concept in ufology and popular culture is that the true extent of information about UFOs is being suppressed by some form of conspiracy of silence, or by an official cover-up that is acting to conceal information.

In 1968, American engineer James Harder argued that significant evidence existed to prove UFOs "beyond reasonable doubt," but that the evidence had been suppressed and largely neglected by scientists and the general public, thus preventing sound conclusions from being reached on the ETH.

"Over the past 20 years a vast amount of evidence has been accumulating that bears on the existence of UFOs. Most of this is little known to the general public or to most scientists. But on the basis of the data and ordinary rules of evidence, as would be applied in civil or criminal courts, the physical reality of UFOs has been proved beyond a reasonable doubt."[3] J A Harder

A survey carried out by Industrial Research magazine in 1971 showed that more Americans believed the government was concealing information about UFOs (76%) than believed in the existence of UFOs (54%), or in ETH itself (32%).[30]

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. Despite these myths, the truth is that there is no scientific proof to back up these assertions, hence we cannot declare with certainty whether or not aliens exist.[54]

Documents and investigations regarding ETH

Other private or government studies, some secret, have concluded in favor of the ET hypothesis, or have had members who disagreed in contravention with official conclusions reached by the committees and agencies to which they belonged. The following are examples of sources that have focused specifically on the topic:

Official White House position

In November 2011, the White House released an official response to two petitions asking the U.S. government to acknowledge formally that aliens have visited Earth and to disclose any intentional withholding of government interactions with extraterrestrial beings. According to the response, "The U.S. government has no evidence that any life exists outside our planet, or that an extraterrestrial presence has contacted or engaged any member of the human race."[66] [67] Also, according to the response, there is "no credible information to suggest that any evidence is being hidden from the public's eye."[66] [67] The response further noted that efforts, like SETI, the Kepler space telescope and the NASA Mars rover, continue looking for signs of life. The response noted "the odds are pretty high" that there may be life on other planets but "the odds of us making contact with any of them—especially any intelligent ones—are extremely small, given the distances involved."[66] [67]

See also

Notes and References

  1. Book: Aimé, Michel . 1967 . The Truth About Flying Saucers . Pyramid Books . B0007DRR38.
  2. Web site: The Calgary Herald - Google News Archive Search. news.google.com.
  3. Web site: Testimony of Dr. J. A. Harder before the Congressional Committee on Science and Astronautics, 29 July 1968 . October 2006 . dead . https://web.archive.org/web/20060206064749/http://ncas.sawco.com/ufosymposium/harder.html . 6 February 2006 .
  4. Book: Klass, Philip J.. UFOs--identified. 1 February 1968. Random House. 9780394450032. Google Books.
  5. Swedenborg, Emanuel (1758) Concerning the Earths in Our Solar System ...
  6. Jacobs David M (2000), "UFOs and Abductions: Challenging the Borders of Knowledge", University Press of Kansas, (Compiled work quoting Jerome Clark; "So far as is known, the first mention of an extraterrestrial spacecraft was published in the 17 June 1864 issue of a French newspaper, La Pays, which ran an allegedly real but clearly fabulous account of a discovery by two American geologists of a hollow, egg-shaped structure holding the three-foot mummified body of a hairless humanoid with a trunk protruding from the middle of his forehead.")
  7. David Michael Jacobs, The UFO Controversy In America, p. 29, Indiana University Press, 1975,
  8. Jerome Clark, The UFO Book, 1998, 199-200
  9. Chicago Daily Tribune (June 26, 1947)
  10. Arnold Kenneth, Report on 9 unidentified aircraft observed on June 24, 1947, near Mt. Rainier, Washington, (October 1947)
  11. Associated Press story, July 7, 1947, e.g., Salt Lake City Deseret News, p. 3, "Author of 'Discs' Story To Seek Proof" https://news.google.com/newspapers?nid=Aul-kAQHnToC&dat=19470707&printsec=frontpage
  12. Chicago 'Times', July 7, 1947, p. 3
  13. Kenneth Arnold; Speaking to Journalist Edward R. Murrow (April 7, 1950), Transcript care of Project 1947
  14. Spokane Daily Chronicle, p.1, June 27, 1947, "More Sky-Gazers Tell About Seeing the Flying Piepans"https://news.google.com/newspapers?nid=ddB7do2jUx8C&dat=19470627&printsec=frontpage; Eugene (OR) Register-Guard, p.1, June 27, 1947; Bremerton (Washington) Sun, June 28, 1947, "Eerie 'Whatsit objects' In Sky Observed Here."
  15. Jerome Clark, UFO Encyclopedia, p. 202-203
  16. Web site: Schenectady Gazette - Google News Archive Search . news.google.com.
  17. [Edward R. Murrow]
  18. Jacobs David M (2000), "UFOs and Abductions: Challenging the Borders of Knowledge", University Press of Kansas, (Compiled work: section sourced from Jerome Clark)
  19. https://news.google.com/newspapers?nid=feST4K8J0scC&dat=19470815&printsec=frontpage Gallup poll in August 15, 1947, St. Petersburg Times, p. 6
  20. Book: Mazur, Allan. Implausible Beliefs: In the Bible, Astrology, and UFOs. July 5, 2017. Routledge. 978-1-351-51322-7 . Google Books.
  21. Timothy Good, Above Top Secret, 328-335
  22. Web site: Popular Science Archive . . 2011-01-30 . 2016-01-07 . https://web.archive.org/web/20160107005919/http://www.popsci.com/archive-viewer?id=lyEDAAAAMBAJ&pg=74&query=flying+saucer . dead .
  23. Trendex Poll, St. Louis Globe Democrat (August 24, 1957)
  24. http://www.scifi.com/ufo/roper/05.html Roper poll results
  25. Web site: Why have we stopped seeing UFOs in the skies? – Stuart Walton - Aeon Essays.
  26. News: Jaekl. Philip. 2018-09-21. What is behind the decline in UFO sightings?. en-GB. The Guardian. 2020-04-30. 0261-3077.
  27. Hawking Stephen, Space and Time Warps
  28. Sagan Carl, Page Thornton (1972), "UFOs: A Scientific Debate". Cornell University Press,
  29. Sturrock Peter A (1999), "The UFO Enigma: A New Review of the Physical Evidence", Warner Books,
  30. John F. Schuessler (January 2000), Public Opinion Surveys and Unidentified Flying Objects; 50+ years of Sampling Public Opinions
  31. http://www.ufoevidence.org/documents/doc592.htm More detailed account of Sturrock AIAA poll
  32. Hynek, J. Allen (1983), "The case against ET", in Walter H. Andrus, Jr., and Dennis W. Stacy (eds), MUFON UFO Symposium
  33. Warp Drive, When?: A Look at the Scaling, (October 2006)
  34. Clark Jerome (1998), "The UFO Book: Encyclopedia of the Extraterrestrial", Visible Ink,
  35. A novel SETI strategy targeting the solar focal regions of the most nearby stars . Acta Astronautica . 1 February 2014 . 94 . 2 . 629–633 . 10.1016/j.actaastro.2013.09.009 . 30 April 2021 . en . 0094-5765. 1309.7586 . Gillon . Michaël . 2014AcAau..94..629G . 53990678 .
  36. News: Self-replicating alien probes could already be here . 30 April 2021 . phys.org . en.
  37. Edwards . Matthew R. . Android Noahs and embryo Arks: ectogenesis in global catastrophe survival and space colonization . International Journal of Astrobiology . April 2021 . 20 . 2 . 150–158 . 10.1017/S147355042100001X . 2021IJAsB..20..150E . 232148456 . 22 July 2021 . en . 1473-5504.
  38. News: Carter . Jamie . Revealed: Why We Should Look For Ancient Alien Spacecraft On The Moon, Mars And Mercury According To NASA Scientists . 17 April 2021 . Forbes . en.
  39. Concepts for future missions to search for technosignatures . Acta Astronautica . 1 May 2021 . 182 . 446–453 . 10.1016/j.actaastro.2021.02.029 . 17 April 2021 . 2103.01536 . en . 0094-5765. Socas-Navarro . Hector . Haqq-Misra . Jacob . Wright . Jason T. . Kopparapu . Ravi . Benford . James . Davis . Ross . TechnoClimes 2020 workshop participants . 2021AcAau.182..446S . 232092198 .
  40. News: Opinion We're asking the wrong questions about UFOs . Washington Post . 13 June 2021.
  41. Web site: EarthSky US Pentagon UFO report due in June . earthsky.org . 13 June 2021 . 2021-05-28.
  42. News: David . Leonard . Experts Weigh In on Pentagon UFO Report . 24 June 2021 . Scientific American . en.
  43. News: MIT Researcher Says UFO Research Could Lead to New Laws of Physics . 24 June 2021 . Futurism.
  44. News: Loeb . Avi . A Possible Link between ʻOumuamua and Unidentified Aerial Phenomena . 24 June 2021 . Scientific American . en.
  45. News: Wattles . Jackie . NASA is getting serious about UFOs . 24 June 2021 . CNN.
  46. News: UFO studies and the possibility of alien origin . 22 July 2021 . wbtv.com . en.
  47. News: Gertz . John . Maybe the Aliens Really Are Here . 22 July 2021 . Scientific American . en.
  48. Morrison David, Senior Scientist at the NASA Astrobiology Institute (June 2006), Ask an Astrobiologist, (October 2006)
  49. Morrison David, Senior Scientist at the NASA Astrobiology Institute (July 2006), Ask an Astrobiologist, (October 2006)
  50. Web site: 2021-06-08 . EarthSky NASA and UFOs: Space agency to take closer look . 2023-05-04 . earthsky.org . en-US.
  51. Web site: 2021-10-20 . Space Jam: Former Senator Talks Aliens, Asteroids and 'Star Trek' With Larry Sabato . 2023-05-04 . UVA Today . en.
  52. News: Opinion We're asking the wrong questions about UFOs . en-US . Washington Post . 2023-05-04 . 0190-8286.
  53. James E. McDonald, Professor of Atmospheric Sciences University of ArizonaTucson, Arizona, (December, 1969) http://noufors.com/Documents/scienceindefault.pdfstating
  54. Web site: Extraterrestrial Intelligence In the Solar System: Resolving the Fermi Paradox . 2022-11-05 . www.rfreitas.com.
  55. Good (1988), 23
  56. Document quoted and published in Timothy Good (2007), 106–107, 115; USAFE Item 14, TT 1524, (Top Secret), 4 November 1948, declassified in 1997, National Archives, Washington D.C.
  57. http://www.mufon.com/MUFONNews/znews_oberth.html Schuessler, John L., "Statements About Flying Saucers And Extraterrestrial Life Made By Prof. Hermann Oberth, German Rocket Scientist" 2002
  58. Dolan, 189; Good, 287, 337; Ruppelt, Chapt. 16
  59. Web site: Ruppelt's private notes . 2009-03-20 . dead . https://web.archive.org/web/20100124112743/http://www.ufologie.net/htm/ruppeltwhoiswho.htm . 2010-01-24.
  60. Good, 347
  61. David Saunders, UFOs? Yes
  62. Web site: Archived copy . 2010-05-05 . dead . https://web.archive.org/web/20090716113351/http://www.ufoevidence.org/newsite/files/COMETA_part2.pdf . 2009-07-16 .
  63. http://www.ufoevidence.org/documents/doc1627.htm Velasco quoted in La Dépêche du Midi, Toulouse, France, April 18, 2004
  64. https://cnes.fr/en/web/CNES-en/5866-geipan-uap-investigation-unit-opens-its-files.php CNES report, March 26, 2007
  65. Web site: Official French Gov't UFO study project to resume with new director . UFO Evidence . www.ufoevidence.org.
  66. Web site: Larson. Phil. Searching for ET, But No Evidence Yet. 5 November 2011. White House. 2011-11-06. dead. https://web.archive.org/web/20111124052154/https://wwws.whitehouse.gov/Petitions#!/response/searching-et-no-evidence-yet. 24 November 2011.
  67. Web site: Atkinson . Nancy . No Alien Visits or UFO Coverups, White House Says. 5 November 2011 . . 2011-11-06 .

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