Extraterrestrial hypothesis

Extraterrestrial hypothesis


200px|thumb|Right|Amateur_photographs_from_Sheffield,_England,_4 March 1962 & Minneapolis, Minnesota, 20 October 1960. Taken from a 1997 CIA training manual. [Haines, Gerald K, [https://www.cia.gov/csi/studies/97unclass/ufo.html A Die-Hard Issue: CIA's Role in the Study of UFOs, 1947-90] , [https://www.cia.gov/csi/studies/97unclass/index.html Studies In Intelligence] . Vol 1#1, 1997] ]

The extraterrestrial hypothesis (ETH) is the hypothesis that some UFOs are best explained as being creatures or space aliens from other planets occupying physical spacecraft visiting Earth. A number of organizations such as NICAP and the Condon Committee have been set up to actively study UFO sightings and abductions reports in relation to ETH.


Origins of the term "extraterrestrial hypothesis" are unknown. It was used in a publication by French engineer Aimé Michel in 1967 [Michel Aimé (1967), "The Truth About Flying Saucers", Pyramid Books, ASIN B0007DRR38] and again by James Harder, while testifying before the Congressional Committee on Science and Astronautics, in July 1968 [http://ncas.sawco.com/ufosymposium/harder.html Testimony of Dr. J A Harder] before the Congressional Committee on Science and Astronautics, 29 July 1968 (October 2006)] . In 1969 physicist Edward Condon defined ETH as the "idea that "some" UFOs may be spacecraft sent to Earth from another civilization, or on a planet associated with a more distant star," while presenting the findings of the much debated Condon Report.


Although ETH, as a unified and named hypothesis, is a comparatively new concept - one which owes a lot to the "saucer sightings" of the 1940s-1960s - ETH can trace its origins back to a number of earlier iterations such as the now discredited Martian canals promoted by astronomer Percival Lowell, popular culture, including the writings of H. G. Wells and fellow science fiction pioneers, 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.Swedenborg, Emanuel (1758) "Concerning the Earths in Our Solar System....."]

Historical reports of extraterrestrial visits

An early example of speculation over extraterrestrial visitors can be found in the French newspaper "Le Pays". On June 17 1864, Le Pays published a story about two American geologists who 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. [Jacobs David M (2000), “UFOs and Abductions: Challenging the Borders of Knowledge”, University Press of Kansas, ISBN 0-7006-1032-4 (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.")]

A further report can be found in the Missouri Democrat (St. Louis), which, in October 1865, reported on the story of Rocky Mountain trapper James Lumley, who claimed to have discovered fragments of rock bearing "curious hieroglyphics" which seemed to form a compartmentalized object; which he believed was being used to transport "an animate being", after investigating a meteor impact near Great Falls, Montana. The newspaper goes on to speculate "Possibly, meteors could be used as a means of conveyance by the inhabitants of other planets, in exploring space".Missouri Democrat, October 19 1865, ( [http://www.rense.com/general16/histufocrashing.htm Transcript] ), (October 2006)]

Credit for popularizing the idea of Martian visitation and invasion probably goes to H. G. Wells in his 1898 science fiction classic War of the Worlds. However, even before Wells, there was a sudden upsurge in reports in "Mystery airships" in the U.S. UFO historians Jerome Clark and David M. Jacobs [http://www.ufoevidence.org/topics/DavidJacobs.htm] note that extraterrestrial visitation, particularly from Mars, was sometimes proposed to explain these mystery airship waves. 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." [ David Michael Jacobs, "The UFO Controversy In America", p. 29, Indiana University Press, 1975, ISBN 0-253-19006-1 ] 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 suggested "atomic powered spaceships from Mars.” [ Jerome Clark, "The UFO Book", 1998, 199-200 ]

Starting in the 1920s, 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, Flash Gordon serials have Earth being attacked from space by alien meteors, ray beams, and biological weapons. In 1938, a radio broadcast version " of War of the Worlds" by Orson Welles, using a modern setting for H. G. Wells’ Martian invasion, created some public panic in the U.S. This would later figure into some commentary on what was happening in 1947 when “flying saucers” finally hit the U.S.

UFOs and ETH

Regarding modern UFO sightings and their link to the ETH, literature professor and skeptic Terry Matheson wrote, "…sightings of unidentifiable lights the sky had been taking place for centuries, but only after Kenneth Arnold’s flying saucer sighting on June 24, 1947, near Mt. Rainier, Washington (see below), were they explicitly theorized to be extraterrestrial in origin." [ Matheson Terry (1998); “Alien Abduction: Creating A Modern Phenomenon”, Prometheus Books, ISBN 1-57392-244-7]

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. However, unlike earlier speculation of extraterrestrial life, interest in the ETH was also bolstered by many unexplained sightings investigated by government and private civilian groups, such as NICAP and APRO.

The 1947 U.S. flying saucer wave

On June 24 1947, at about 3.00 p.m. local time, pilot Kenneth Arnold reported seeing nine unidentified disk-shaped aircraft flying near Mt. Rainier. [Chicago Daily Tribune (June 26 1947)] [Arnold Kenneth, [http://www.project1947.com/fig/ka.htm Report on 9 unidentified aircraft observed on June 24 1947, near Mt. Rainier, Washington] ] , (October 1947)]

Arnold said the objects moved as if they were a saucer skipping across water, but also described the shape as thin, flat, and disc-like or saucer-like (also like a "pie-plate," "pie-pan," and "half-moon shaped")--see Kenneth Arnold article for detailed quotes. Three days later, the terms "flying disc" and "flying saucer" first appeared in newspapers and became the preferred terms for the phenomenon for a number of years, until largely replaced in the 1950s and 1960s by UFO.

Though he was impressed by their high speed and quick movements, Arnold did not initially consider the ETH, stating,

:"I assumed at the time they were a new formation or a new type of jet, though I was baffled by the fact that they did not have any tails. They passed almost directly in front of me, but at a distance of about 23 miles, which is not very great in the air. I judged their wingspan to be at least 100 feet across. Their flying did not particularly disturb me at the time, except that I had never seen planes of that type."

However, when no aircraft emerged that seemed to account for what he had seen, Arnold clearly did consider the possibility of the objects being extraterrestrial. In the same 1950 interview with journalist Edward R. Murrow Arnold added, "...if it's not made by our science or our Army Air Forces, I am inclined to believe it's of an extraterrestrial origin." [ Kenneth Arnold; Speaking to Journalist Edward R. Murrow (April 7 1950), ( [http://www.project1947.com/fig/kamurrow.htm Transcript] care of [http://www.project1947.com/ Project 1947] ]

When the flying saucer wave hit the U.S., even if people thought the saucers were real, they were generally unwilling to leap to the conclusion that they were extraterrestrial in origin. Various theories began to quickly proliferate in press articles, such as secret military projects, Russian spy devices, hoaxes, and mass hysteria, but the ETH was not generally among them. According to Murrow, the ETH as an explanation for "flying saucers" did not earn widespread attention until about 18 months after Arnold's sighting. Edward R. Murrow (April 7 1950) " [http://www.albany.edu/talkinghistory/arch2004jan-june.html The Case of the Flying Saucer] ", CBS News (Radio Documentary available in MP3/Real Media), (October 2006)]

These attitudes seem to be reflected in the results of the first US poll of public UFO perceptions released by Gallup on August 14 1947.Jacobs David M (2000), “UFOs and Abductions: Challenging the Borders of Knowledge”, University Press of Kansas, ISBN 0-7006-1032-4 (Compiled work: section sourced from Jerome Clark)] The term "flying saucer" was familiar to 90% of the respondents. It further showed that most people either held no opinion (33%), or believed that there was a mundane explanation for apparent UFOs. 29% thought they were an optical illusion, 15% a US 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 related to atomic testing.

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, 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.” [ Jerome Clark, "UFO Encyclopedia’’, p. 202-203 ] At the same time, several nationally syndicated columns by humorist Hal Boyle spoke of a green man from Mars in his flying saucer (see Little green men).

Even Arnold commented along these lines. In a June 28 article, he described an encounter he had with a near-hysterical woman in Pendleton, Oregon, shrieking, "there's the man who saw the men from Mars." Arnold then added, "This whole thing has gotten out of hand... Half the people I see look at me as a combination Einstein, Flash Gordon and screwball." [ Bremerton (Washington) "Sun", June 28, 1947, "Eerie 'Whatsit objects' In Sky Observed Here." ]

Military investigations begin: ETH conclusion and debunkery

On July 9, Army Air Force Intelligence began a secret study of the best saucer reports, including Arnold's. A follow-up study by the Air Materiel Command intelligence and engineering departments at Wright Field Ohio led to the formation the U.S. Air Force's Project Sign at the end of 1947, the first official U.S. military UFO study.

In the summer of 1948, Project Sign wrote their Estimate of the Situation, which concluded that the remaining unidentified sightings were best explained by the ETH. However, the report ultimately was rejected by the USAF Chief of Staff, General Hoyt Vandenberg, citing a lack of physical evidence, and its existence was not publicly disclosed until 1956 by later Project Blue Book director Edward J. Ruppelt. Ruppelt also indicated that Vandenberg dismantled Project Sign after they wrote their ETH conclusion.

With this official policy in place, all subsequent public Air Force reports concluded that there was either insufficient evidence to link UFOs and ETH, or that UFOs did not warrant investigation.

Immediately following the great UFO wave of 1952 and military debunkery of the radar and visual sightings plus jet interceptions over Washington, D.C. in August, the CIA’s Office of Scientific Investigation took particularly 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 [ Timothy Good, ‘’Above Top Secret’’, 328-335 ] , 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 only 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", "Earth vs. the Flying Saucers" (1956), and "Forbidden Planet" (1956).

Despite this, public belief in ETH seems to have remained low during the early 1950s, even among those reporting UFOs. A poll published in "Popular Mechanics" magazine, in August 1951, showed that 52% of UFO witnesses questioned believed that they had seen a man-made aircraft, while only 4% believed that they had seen an alien craft. However, within a few years, belief in ETH had increased due to the activities of people such as retired U.S. Marine Corp officer Maj. Donald E. Keyhoe, who campaigned to raise public awareness of the UFO phenomena. By 1957, 25% of Americans responded that they either believed, or were willing to believe, in ETH, while 53% responded that they weren't (though a majority of these respondents indicated they thought UFOs to be real but of earthly origin). 22% said that they were uncertain. Trendex Poll, St. Louis Globe Democrat (August 24 1957)]

During this time, the ETH also fragmented into distinct camps, each believing slightly different variations of the hypothesis. The "contactees" of the early 1950s said that the "space brothers" they met were peaceful and benevolent, but by the mid-1960s, a number of alleged Alien abductions; including that of Betty and Barney Hill, and of the apparent mutilation of cattle cast the ETH in more sinister terms.

Opinion polls indicate that public belief in the ETH has continued to rise since then. For example, a 1997 Gallup poll of the U.S. public indicated that 87% knew about UFOs, 48% believed them to be real (vs. 33% who thought them to be imaginary), and 45% believed they had visited Earth. [ [http://www.ufoevidence.org/documents/doc999.htm Summary of UFO opinion polls] ] Similarly a Roper poll from 2002 found 56% thought UFOs to be real and 48% thought they had visited Earth. [ [http://www.scifi.com/ufo/roper/05.html Roper poll results ]

Polls also indicate that the public believes even more strongly that the government is suppressing evidence about UFOs. For example, in both the cited Gallup and Roper polls, the figure was about 70%.

Analyzing 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.". Sagan Carl, Page Thornton (1972), “UFOs: A Scientific Debate”. Cornell University Press, ISBN 0-8014-0740-0]

Similarly, British astrophysicist Peter A. Sturrock wrote that 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."Sturrock Peter A (1999), “The UFO Enigma: A New Review of the Physical Evidence”, Warner Books, ISBN 0-446-52565-0]

Opinions among 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.

A cited example of this was an informal poll conducted in 1977 by astrophysicist Peter A. Sturrock, surveying the members of the American Astronomical Society. Sturrock asked polled scientists to assign probabilities to eight possible explanations for UFOs. The results were: John F. Schuessler (January 2000), [http://www.mufon.com/znews_publicopinion.html Public Opinion Surveys and Unidentified Flying Objects; 50+ years of Sampling Public Opinions] ]

An earlier poll done by Sturrock in 1973 of American Institute of Aeronautics and Astronautics members found that a somewhat higher 10% believed UFOs were vehicles from outer space.John F. Schuessler (January 2000), [http://www.mufon.com/znews_publicopinion.html Public Opinion Surveys and Unidentified Flying Objects; 50+ years of Sampling Public Opinions; http://www.ufoevidence.org/documents/doc592.htm More detailed account of Sturrock AIAA poll ]


The primary scientific arguments against ETH were summarized by Astronomer and UFO researcher J. Allen Hynek during a presentation at the 1983 MUFON Symposium. During which time he outlined seven key reasons why he could not accept the ETH. [Hynek, J. Allen (1983), “The case against ET”, in Walter H. Andrus, Jr., and Dennis W. Stacy (eds), MUFON UFO Symposium]

# "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:

#Despite world-wide radar systems and Earth-orbiting satellites, UFOs are alleged to flit in and out of the atmosphere, leaving little to no evidence.
#Space aliens are alleged to be overwhelmingly humanoid, and are allegedly able to exist on Earth without much difficulty (often lacking "space suits", despite the fact that extra-solar planets would likely have different atmospheres, biospheres, gravity and other factors, and extraterrestrial life would likely be very different from Earthly life.)
#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.
#The behavior of extraterrestrials reported during alleged abductions is often inconsistent and irrational.
#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
#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).
#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 7sn|19 Joules of energy to send the current space shuttle on a one-way, 50 year, journey to the nearest star, an enormous amount of energyWarp Drive, When?: [http://www.nasa.gov/centers/glenn/research/warp/scales.html A Look at the Scaling] , (October 2006)] ) and because of the level of technology that would be required to "circumvent" conventional energy/fuel/speed limitations using exotic means (see Faster than light travel).Clark Jerome (1998), “The UFO Book: Encyclopedia of the Extraterrestrial”, Visible Ink, ISBN 1-57859-029-9]

According to Hynek, points 1 through 6 could be argued, but point 7 represented an insurmountable barrier to the validity of the ETH.

More recently, Professor Stephen Hawking argued that because most UFOs turn out to have prosaic explanations, it was reasonable to presume that the "unidentified" UFOs also had prosaic origins.Hawking Stephen, [http://www.hawking.org.uk/lectures/warps3.html Space and Time Warps Cont...] ]


Physicist Bernard Haisch on his "ufoskeptic" website [ http://www.ufoskeptic.org/ Bernard Haisch "ufoskeptic" website ] presents a number of counterarguments to those of Hynek. Haisch argues he is convinced something is going on and that modern theories of physics and cosmology might support extraterrestrial or even interdimensional origins for UFOs.

In a 1969 report to the American Association for the Advancement of Science, the late American physicist James E. McDonald summarized his reasons for not dismissing ETH:

:"Present evidence surely does not amount to incontrovertible proof of the extraterrestrial hypothesis. What I find scientifically dismaying is that, while a large body of UFO evidence now seems to point in no other direction than the extraterrestrial hypothesis, the profoundly important implications of that possibility are going unconsidered by the scientific community because this entire problem has been imputed to be little more than a nonsense matter unworthy of serious scientific attention." McDonald, James E., (December 27 1969), [http://dewoody.net/ufo/Science_in_Default.htmlScience in Default: Twenty-Two Years of Inadequate UFO Investigations] ]


A list of those who have defended the ETH, at least as a viable hypothesis:
* American astronomer James C. Bartlett
* Belgian physicist Maurice A. Biot
* Astronaut Gordon Cooper
* Air Chief Marshall Lord Dowding (head of the Royal Air Force during World War II)
* Brig. General Arthur Exon, former commanding officer Wright Patterson AFB
* U.S. Navy Rear Admiral Delmar S. Fahrney, once head of the Navy's guided missile program
* Barry Goldwater, deceased U.S. Senator from Arizona, Presidential nominee, Brigadier General in the Air Force Reserve
* Physicist Bernard Haisch
* Astronomer Frank Halstead
* Professor of Engineering James Harder
* Former Canadian Defence Minister Paul Hellyer
* NACA/NASA aerospace engineer Paul R. Hill
* Rear Admiral Roscoe H. Hillenkoetter, first CIA director
* Swiss psychiatrist Carl Jung
* Physicist Michio Kaku
* Physicist Bruce Maccabee
* Commander Robert McLaughlin, former head of the Naval guided missile program at White Sands Proving Grounds
* James M. McCampbell, Former NASA and nuclear engineer, author of "Ufology" [http://www.nicap.org/ufology/cover.htm]
* Physicist James E. McDonald
* Astronaut Storey Musgrove
* Admiral Lord Hill-Norton, former Chief of Defense Staff, former NATO head, United Kingdom
* Astronaut Edgar Mitchell
* Hermann Oberth, German-American physicist and rocket expert
* Nick Pope, former head of the British Ministry of Defence UFO desk
* Walter Riedel, German rocket scientist
* Paul Santorini, Greek physicist, Manhattan Project scientist
* Psychologist David Saunders (psychologist), member of the Condon UFO Committee
* Robert Sarbacher, nuclear physicist and missile expert
* Wilbert Smith, Canadian government radio engineer, spearheaded Canadian UFO studies 1950-1962
* American astrophysicist Peter A. Sturrock
* American chemist Michael D. Swords
* Fife Symington, former governor of Arizona and military pilot
* Astronomer Clyde Tombaugh
* Russian scientist Felix Zigel
* 1999 French COMETA UFO study committee of aerospace experts and high-ranking military analysts
* The three heads of the official French UFO investigations GEPAN/SEPRA/GEIPAN, astronomer Claude Poher (GEPAN, 1977-1978), engineer Jean-Jacques Velasco (GEPAN/SEPRA, 1983-2004), and Yves Sillard (GEIPAN, 2005-), former head of the French space agency CNES.


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.Morrison David, Senior Scientist at the NASA Astrobiology Institute (June 2006), [http://nai.arc.nasa.gov/astrobio/astrobio_detail.cfm?ID=1538 Ask an Astrobiologist] , (October 2006)]

:"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 MorrisonMorrison David, Senior Scientist at the NASA Astrobiology Institute (July 2006), [http://nai.arc.nasa.gov/astrobio/astrobio_detail.cfm?ID=1551 Ask an Astrobiologist] , (October 2006)]

Despite public interest, NASA considers 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.

:"That whole subject is really irrelevant to our own human quest to travel to space ... if someone in the previous century saw a film of a 747 flying past, it would not tell them how to build a jet engine, what fuel to use, or what materials to make it out of. Yes, the wings are a clue, but just that, a clue." NASA. [Warp Drive, When?: [http://www.nasa.gov/centers/glenn/research/warp/warpfaq.html FAQ] , NASA, (October 2006)]


"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 A. 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 UFO's. 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 UFO's has been proved beyond a reasonable doubt" 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 percent) than believed in the existence of UFOs (54 percent), or in ETH itself (32 percent).


ee also

*The UFO Hostility Hypothesis
*Psychosocial Hypothesis
*Interdimensional hypothesis

External links

* [http://www.nicap.org/papers/zeiler-eth.htm Formulation and Predictions of the ETH, by Brian Zeiler]
* [http://www.featuringdave.com/Data/Webpage/ufo/eth.htm UFOs and the Extraterrestrial Hypothesis (ETH), by Dave LeBoeuf]
* [http://www.scientificexploration.org/jse/abstracts/v4n1a9.php Five Arguments Against the Extraterrestrial Origin of Unidentified Flying Objects] - Jacques Vallée, Ph.D.
* [http://www.solstation.com/stars.htm Notable Nearby Stars]
* [http://www.cem.msu.edu/~cem181h/projects/98/lightspeed/group.htm The Speed of Light: How Fast Can We Go?]
* [http://www.autodynamics.org/light_speed.html Light Speed]

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