A picture taken by J.S. Henrardi on June 15, 1990 during the Belgian UFO wave.^[1]

An unidentified flying object, or UFO, is any flying object that cannot be identified by the observer. UFOs have been spotted in many different places around the world. UFOs may later be identified, after investigation, and are known as IFOs or Identified Flying Objects. Approximately 90 to 95% of UFOs are later identifed, according to the The J. Allen Hynek Center for UFO Studies [4].

Reports of unusual aerial phenomena date back to ancient times^[2][3][4][5], but modern reports and first official investigations began during World War II with sightings of so-called foo fighters by Allied airplane crews and in 1946 with widespread sightings of European "ghost rockets." UFO reports became even more common after the first widely publicized United States UFO sighting, by private pilot Kenneth Arnold in the summer of 1947.

Many tens of thousands of UFO reports have since been made worldwide.^[6] But many sightings may yet remain unreported, due to fear of public ridicule because of the social stigma surrounding the subject of UFOs, and because most nations lack any officially sanctioned authority to receive and evaluate UFO reports.^[7]

History

On April 14, 1561 the skies over Nuremberg, Germany were reportedly filled with a multitude of objects.^[8] 1566 woodcut by Hans Glaser of 1561 Nuremberg event.

Main article: List of major UFO sightings

Unusual aerial phenomena have been reported throughout history.^[9] Some of these phenomena were undoubtedly astronomical in nature: comets, bright meteors, one or more of the five planets which can be seen with the naked eye, planetary conjunctions, or atmospheric optical phenomena such as parhelia and lenticular clouds.^[10] An example is the Comet Halley, which was recorded first by Chinese astronomers in 240 B.C. and possibly as early as 467 B.C.^[11]

"The Baptism of Christ", 1710, by Aert de Gelder. UFO proponents have drawn comparisons between modern UFO reports and aerial objects depicted in historical art, such as this religious painting.

Other historical reports seem to defy prosaic explanation, but assessing such accounts is difficult, because the information in a historical document may be insufficient, inaccurate, or embellished enough to make an informed evaluation difficult.

For example, in the Old Testament of the Bible, Ezekiel apparently had a first-hand encounter with something that might now be described as an Unidentified Flying Object, but which the Bible describes as a fiery chariot.

Whatever their actual cause, such sightings throughout history were often treated as supernatural portents, angels, or other religious omens.^[12][13] Art historian Daniela Giordano cites many Medieval-era paintings, frescoes, tapestries and other items that depict unusual aerial objects; she acknowledges many of these paintings are difficult to interpret, but cites some that depict airborne saucers and domed-saucer shapes that are often strikingly similar to UFO reports from later centuries.^[14] (See List of UFO sightings)

First modern reports

Main article: List of major UFO sightings

Photo of a purported UFO over New Hampshire in 1870; known as the mystery airship.

Before the terms “flying saucer” and “UFO” were coined in the late 1940s, there were a number of reports of unidentified aerial phenomena in the West. These reports date from the mid-nineteenth to early twentieth century. They include:

• On January 25, 1878, The Denison Daily News wrote that local farmer John Martin had reported seeing a large, dark, circular flying object resembling a balloon flying “at wonderful speed.”^[15]
• On November 17, 1882, a UFO was observed by astronomer Edward Walter Maunder of the Greenwich Royal Observatory and some other European astronomers. Maunder in The Observatory reported “a strange celestial visitor” that was "disc-shaped," "torpedo-shaped," "spindle-shaped," or "just like a Zeppelin" dirigible (as he described it in 1916).
• On February 28, 1904, there was a sighting by three crew members on the USS Supply 300 miles west of San Francisco, reported by Lt. Frank Schofield, later to become Commander-in-Chief of the Pacific Battle Fleet. Schofield wrote of three bright red egg-shaped and circular objects flying in echelon formation that approached beneath the cloud layer, then changed course and “soared” above the clouds, departing directly away from the earth after 2 to 3 minutes. The largest had an apparent size of about six suns.^[16][17]

Drawing of E. W. Maunder's Nov. 17, 1882, "auroral beam" by astronomer Rand Capron, Guildown Observatory, Surrey, UK, who also observed it.

• On 5 August 1926, while traveling in the Humboldt Mountains of Tibet's Kokonor region, Nicholas Roerich reported that members of his expedition saw "something big and shiny reflecting sun, like a huge oval moving at great speed"^[18]
• In both the European and Japanese aerial theatres during World War II, “Foo-fighters” (balls of light and other shapes that followed aircraft) were reported by both Allied and Axis pilots^[19]
• On February 25, 1942, the U.S. Army detected unidentified aircraft both visually and on radar over the Los Angeles, California region. No readily-apparent explanation was offered. The incident later became known as the Battle of Los Angeles, or the West coast air raid^[20].
• In 1946, there were over 2000 reports of unidentified aircraft in the Scandinavian nations, along with isolated reports from France, Portugal, Italy and Greece, then referred to as “Russian hail,” and later as “ghost rockets,” because it was thought that these mysterious objects were Russian tests of captured German V1 or V2 rockets. Over 200 were tracked on radar and deemed to be “real physical objects” by the Swedish military.^[21]

Kenneth Arnold's 1947 sighting

This shows the report Kenneth Arnold filed in 1947 about his UFO sighting.

The post World War II UFO phase in the United States began with a reported sighting by American businessman Kenneth Arnold on June 24, 1947 while flying his private plane near Mount Rainier, Washington. He reported seeing nine brilliantly bright objects flying across the face of Rainier towards nearby Mount Adams at “an incredible speed”, which he "calculated" as at least 1200 miles per hour by timing their travel between Rainier and Adams.^[22]

His sighting subsequently received significant media and public attention. Arnold would later say they “flew like a saucer would if you skipped it across the water” (it would ricochet) and also said they were “flat like a pie pan”, “shaped like saucers,” and “half-moon shaped, oval in front and convex in the rear. ...they looked like a big flat disk.” (One, however, he would describe later as being almost crescent-shaped.) Arnold’s reported descriptions caught the media’s and the public’s fancy and gave rise to the terms flying saucer and flying disk. Arnold’s sighting was followed in the next few weeks by hundreds of other reported sightings, mostly in the U.S., but in other countries as well.

Another case was a United Airlines crew sighting of nine more disc-like objects over Idaho on the evening of July 4.^[23] At the time, this sighting was even more widely reported than Arnold’s and lent considerable credence to Arnold’s report. In fact, American UFO researcher Ted Bloecher, in his comprehensive review of newspaper reports, found a sudden surge upwards in sightings on July 4, peaking on July 6-8. Bloecher noted that for the next few days most American newspapers were filled with front-page stories of the new “flying saucers” or “flying discs.” Starting with official debunkery that began the night of July 8 with the Roswell UFO incident, reports rapidly tapered off, ending the first big U.S. UFO wave.

Over several years in the 1960s, Bloecher (aided by physicist James E. McDonald) discovered 853 flying disc sightings that year from 140 newspapers from Canada, Washington D.C, and every U.S. state save Montana. ^[24]

The Falcon Lake incident report filed by the Royal Canadian Mounted Police on Stephen Michalak claimed incident with a UFO.

Starting July 9, Army Air Force intelligence, in cooperation with the FBI, began a formal investigation into selected sightings with characteristics that could not be immediately rationalized, which included Arnold’s and the United crew’s. The FBI used “all of its scientists” to determine whether or not “such a phenomenon could, in fact, occur.” The research was “being conducted with the thought that the flying objects might be a celestial phenomenon,” or that “they might be a foreign body mechanically devised and controlled.”^[25] Three weeks later they concluded that, “This ‘flying saucer’ situation is not all imaginary or seeing too much in some natural phenomenon. Something is really flying around.”^[26] A further review by the intelligence and technical divisions of the Air Materiel Command at Wright Field reached the same conclusion, that “the phenomenon is something real and not visionary or fictitious,” that there were objects in the shape of a disc, metallic in appearance, and as big as man-made aircraft. They were characterized by “extreme rates of climb [and] maneuverability,” general lack of noise, absence of trail, occasional formation flying, and “evasive” behavior “when sighted or contacted by friendly aircraft and radar,” suggesting a controlled craft. It was thus recommended in late September 1947 that an official Air Force investigation be set up to investigate the phenomenon.^[27] This led to the creation of the Air Force’s Project Sign at the end of 1947, which became Project Grudge at the end of 1948, and then Project Blue Book in 1952. Blue Book closed down in 1970, ending the official Air Force UFO investigations.

Use of UFO instead of flying saucer was first suggested in 1952 by Capt. Edward J. Ruppelt, the first director of Project Blue Book, who felt that flying saucer did not reflect the diversity of the sightings. Ruppelt suggested that UFO should be pronounced as a word — you-foe. However it is generally pronounced by forming each letter: U.F.O. His term was quickly adopted by the Air Force, which also briefly used “UFOB” circa 1954, for Unidentified Flying Object. Ruppelt recounted his experiences with Project Blue Book in his memoir, The Report on Unidentified Flying Objects (1956), also the first book to use the term.^[28]

Air Force Regulation 200-2, issued in 1954, defined an Unidentified Flying Object (UFOB) as “any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object.” The regulation also said UFOBs were to be investigated as a “possible threat to the security of the United States” and “to determine technical aspects involved.” As with any then-ongoing investigation, Air Force personnel did not discuss the investigation with the press.^[29][30][31]

In Canada, the Department of National Defence has dealt with reports, sightings and investigations of UFOs across Canada. In addition to conducting investigations into crop circles in Duhamel, Alberta, it still identifies the Falcon Lake incident in Manitoba and the Shag Harbour incident in Nova Scotia as "unsolved".^[32]

Ufological Research

Main article: Ufology

Ufology is a neologism coined to describe the collective efforts of those who study UFO reports and associated evidence. Not all ufologists believe that UFOs are necessarily extraterrestrial spacecraft, or even that they are objective physical phenomena. Even UFO cases that are exposed as hoaxes, delusions or misidentifications may still be worthy of serious study from a psychosocial point of view. While Ufology does not represent an academic research program, UFOs have been subject to various investigations over the years, varying widely in scope and scientific rigor. Governments or independent academics in the United States, Canada, the United Kingdom, France, Belgium, Sweden, Brazil, Mexico, Spain, and the Soviet Union are known to have investigated UFO reports at various times. No national government has ever publicly admitted that UFOs represent any form of alien intelligence. Perhaps the best known study was Project Blue Book, previously Project Sign and Project Grudge, conducted by the United States Air Force from 1947 until 1969. Other notable investigations include the Robertson Panel (1953), the Brookings Report (1960), the Condon Committee (1966-1968), the Project Twinkle investigation into green fireballs (1948-1951), the Sturrock Panel (1998), and the French GEIPAN (1977-) and COMETA (1996-1999) study groups.

Notable UFO-related sightings and events

Main article: List of major UFO sightings

In March 2007, the French Centre National d'Études Spatiales (CNES) published an archive of UFO sightings and other phenomena online.

• List of major UFO sightings

National Press Club press conference on November 12, 2007

At 11am on November 12, 2007, Former Arizona Governor Fife Symington moderated a panel of former high-ranking government, aviation and military officials from seven countries at the National Press Club^[33]; discussing the UFO topic and governmental investigations. The press conference was open for credentialed media and congressional staff only.^{[34][35][36][37][38][39]}

The following officials and former officials participated in the press conference:

• Fife Symington, Former Arizona Governor, Moderator
• Ray Bowyer, Captain, Aurigny Air Services, Channel Islands
• Rodrigo Bravo, Captain and Pilot for the Aviation Army of Chile
• General Wilfried De Brouwer, former Deputy Chief of Staff, Belgian Air Force (Ret.)
• John Callahan, Chief of Accidents and Investigations for the FAA, 1980’s (Ret.)
• Dr. Anthony Choy, founder, 2001, OIFAA, Peruvian Air Force
• Jean-Claude Duboc, Captain, Air France (Ret.)
• Charles I. Halt, Col. USAF (Ret.), Former Director, Inspections Directorate, DOD I.G.
• General Parviz Jafari, Iranian Air Force (Ret.) As a young Iranian Air Force pilot, Jafari was a participant in the 1976 Tehran UFO incident, one of the most famous and well-documented UFO incidents in modern times. ^[40]
• Jim Penniston, TSgt USAF (Ret.)
• Dr. Claude Poher, Centre National d’Etudes Spatiales, founder, French GEPAN
• Nick Pope, Ministry of Defence, UK, 1985-2006
• Dr. Jean-Claude Ribes, Centre National de la Recherche Scientifique, France, 1963-98
• Comandante Oscar Santa Maria, Peruvian Air Force (Ret.)

^[41]

Astronomers and other scientists

Although it is sometimes contended that astronomers never report UFOs, the Air Force's Project Blue Book files indicate that approximately 1% of all their reports came from amateur and professional astronomers or other users of telescopes (such as missile trackers or surveyors). In the 1970s, astrophysicist Peter A. Sturrock conducted two surveys of the American Institute of Aeronautics and Astronautics and American Astronomical Society. About 5% of the members polled indicated that they had had UFO sightings. [5] [6] In 1980, a survey of 1800 members of various amateur astronomer associations by Gert Helb and astronomer J. Allen Hynek of the Center for UFO Studies (CUFOS) found that 24% responded "yes" to the question "Have you ever observed an object which resisted your most exhaustive efforts at identification?"^[42]

Astronomer Clyde Tombaugh, who admitted to 6 UFO sightings^[43], including 3 green fireballs supported the Extraterrestrial hypothesis (ETH) for UFOs and stated he thought scientists who dismissed it without study were being "unscientific."^[44] Another astronomer was Dr. Lincoln LaPaz, who had headed the Air Force's investigation into the green fireballs and other UFO phenomena in New Mexico. LaPaz reported 2 personal sightings, one of a green fireball, the other of an anomalous disc-like object. Even later UFO debunker Dr. Donald Menzel filed a UFO report in 1949 ^[45].

Various public scientific studies over the past half century have examined UFO reports in detail. None of these studies have officially concluded that any reports are caused by extraterrestrial spacecraft (e.g., Seeds 1995:A4). Some studies were neutral in their conclusions, but argued the inexplicable core cases called for continued scientific study. Examples are the Sturrock Panel study of 1998 and the 1970 AIAA review of the Condon Report. Other private or governmental studies, some secret, have concluded in favor of the ETH, or have had members who disagreed with the official conclusions. The following are examples of such studies and individuals:

• One of the earliest government studies to come to a secret ETH conclusion was Project Sign, the first official Air Force UFO investigation. In 1948, they wrote a top-secret intelligence estimate to that effect. The Air Force Chief of Staff ordered it destroyed. The existence of this suppressed report was revealed by several insiders who had read it, such as astronomer and USAF consultant Dr. J. Allen Hynek and Edward J. Ruppelt, the first head of the USAF's Project Blue Book. (Ruppelt, Chapt. 3)
• An early U.S. Army study, of which little is known, was called the Interplanetary Phenomenon Unit (IPU). In 1987, British UFO researcher Timothy Good received a letter confirming the existence of the IPU from the Army Director of Counter-intelligence, in which it was stated, "...the aforementioned Army unit was disestablished during the late 1950s and never reactivated. All records pertaining to this unit were surrendered to the U.S. Air Force Office of Special Investigations in conjunction with operation BLUEBOOK." The IPU records have never been released. ^[46]

November 1948 USAF Top Secret document citing extraterrestrial opinion

• In 1967, Greek physicist Paul Santorini, a Manhattan Project scientist, publicly stated that a 1947 Greek government investigation that he headed into the European Ghost rockets of 1946 quickly concluded that they were not missiles. Santorini claimed the investigation was then quashed by military officials from the U.S., who knew them to be extraterrestrial, because there was no defense against the advanced technology and they feared widespread panic should the results become public. ^[47]
• A 1948 Top Secret USAF Europe document (at right) states that Swedish air intelligence informed them that at least some of their investigators into the ghost rockets and flying saucers concluded they had extraterrestrial origins: "...[Flying saucers] have been reported by so many sources and from such a variety of places that we are convinced that they cannot be disregarded and must be explained on some basis which is perhaps slightly beyond the scope of our present intelligence thinking. When officers of this Directorate recently visited the Swedish Air Intelligence Service... their answer was that some reliable and fully technically qualified people have reached the conclusion that 'these phenomena are obviously the result of a high technical skill which cannot be credited to any presently known culture on earth.' They are therefore assuming that these objects originate from some previously unknown or unidentified technology, possibly outside the earth." ^[48]
• Various European countries conducted a secret joint study in 1954, also concluding that UFOs were extraterrestrial. This study was revealed by German rocketry pioneer Hermann Oberth, a member of the study, who also made many public statements supporting the ETH.
• In 1958, Brazil's main UFO investigator, Dr. Olavo T. Fuentes wrote a letter to the American UFO group APRO summarizing a briefing he had received from two Brazilian Naval intelligence officers. Fuentes said he was told that every government and military on Earth was aware that UFOs were extraterrestrial craft and there was absolute proof of this in the form of several crashed craft. The subject was classified Top Secret by the world's militaries. The objects were deemed dangerous and hostile when attacked, many planes had been lost, and it was generally believed that Earth was undergoing an invasion of some type, perhaps a police action to keep us confined to the planet. This information had to be withheld from the public by any means necessary because of the likelihood of widespread panic and social breakdown. ^[49]
• An FBI field office letter to the FBI Director, dated January 31, 1949, stated "...the matter of 'Unidentified Aircraft' or 'Unidentified Aerial Phenomena,' otherwise known as 'Flying Discs,' 'Flying Saucers,' and 'Balls of Fire' ...is considered Top Secret by Intelligence Officers of both the Army and Air Forces." (emphasis included in original) ^[50]
• During the height of the flying saucer epidemic of July 1952, including highly publicized radar/visual and jet intercepts over Washington, D.C., the FBI was informed by the Air Force Directorate of Intelligence that they thought the "flying saucers" were either "optical illusions or atmospheric phenomena" but then added that, "some Military officials are seriously considering the possibility of interplanetary ships." FBI document
• The CIA started their own internal scientific review the following day. Some CIA scientists were also seriously considering the ETH. An early memo from August was very skeptical, but also added, "...as long as a series of reports remains 'unexplainable' (interplanetary aspects and alien origin not being thoroughly excluded from consideration) caution requires that intelligence continue coverage of the subject." A report from later that month was similarly skeptical but nevertheless concluded "...sightings of UFOs reported at Los Alamos and Oak Ridge, at a time when the background radiation count had risen inexplicably. Here we run out of even 'blue yonder' explanations that might be tenable, and we still are left with numbers of incredible reports from credible observers." A December 1952 memo from the Assistant CIA Director of Scientific Intelligence (O/SI) was much more urgent: "...the reports of incidents convince us that there is something going on that must have immediate attention. Sightings of unexplained objects at great altitudes and traveling at highs speeds in the vicinity of U.S. defense installation are of such nature that they are not attributable to natural phenomena or known types of aerial vehicles." Some of the memos also made it clear that CIA interest in the subject was not to be made public, partly in fear of possible public panic. (Good,331-335)
• The CIA organized the January 1953 Robertson Panel of scientists to debunk the data collected by the Air Force's Project Blue Book. This included an engineering analysis of UFO maneuvers by Blue Book (including a motion picture film analysis by Naval scientists) that had concluded UFOs were under intelligent control and likely extraterrestrial. ^[51]
• Extraterrestrial "believers" within Project Blue Book including Major Dewey Fournet, in charge of the engineering analysis of UFO motion. Director Edward J. Ruppelt is also thought to have held these views, though expressed in private, not public. Another defector from the official Air Force party line was consultant Dr. J. Allen Hynek, who started out as a staunch skeptic. After 20 years of investigation, he changed positions and generally supported the ETH. He became the most publicly known UFO advocate scientist in the 1970s and 1980s.
• The first CIA Director, Vice Admiral Roscoe H. Hillenkoetter, stated in a signed statement to Congress, also reported in the New York Times, February 28, 1960, "It is time for the truth to be brought out... Behind the scenes high-ranking Air Force officers are soberly concerned about the UFOs. However, through official secrecy and ridicule, many citizens are led to believe the unknown flying objects are nonsense.... I urge immediate Congressional action to reduce the dangers from secrecy about unidentified flying objects." In 1962, in his letter of resignation from NICAP, he told director Donald Keyhoe, "I know the UFOs are not U.S. or Soviet devices. All we can do now is wait for some actions by the UFOs." ^[52]
• Although the 1968 Condon Report came to a negative conclusion (written by Condon), it is known that many members of the study strongly disagreed with Condon's methods and biases. Most quit the project in disgust or were fired for insubordination. A few became ETH supporters. Perhaps the best known example is Dr. David Saunders, who in his 1968 book UFOs? Yes lambasted Condon for extreme bias and ignoring or misrepresenting critical evidence. Saunders wrote, "It is clear... that the sightings have been going on for too long to explain in terms of straightforward terrestrial intelligence. It is in this sense that ETI (Extra Terrestrial Intelligence) stands as the `least implausible' explanation of `real UFOs'." ^[53]
• Nick Pope, the head of the UK government UFO desk for a number of years, is an advocate of the ETH based on the inexplicable cases he reviewed, such as the Rendlesham UFO incident, although the British government has never made such claims.
• Jean-Jacques Velasco, the head of the official French UFO investigation SEPRA, wrote a book in 2005 saying that 14% of the 5800 cases studied by SEPRA were utterly inexplicable and extraterrestrial in origin. ^[54] Yves Sillard, the head of the new official French UFO investigation GEIPAN and former head of the French space agency CNES, echoes Velasco's comments and adds the U.S. is guilty of covering up this information. ^[55] Again, this isn't the official public posture of SEPRA, CNES, or the French government. (CNES recently announced that their 5800 case files will be placed on the Internet starting March 2007.)
• The 1999 French COMETA committee of high-level military analysts/generals and aerospace engineers/scientists declared the ETH was the best hypothesis for the unexplained cases. ^[56]

Physical evidence

Besides visual sightings, cases sometimes have an indirect physical evidence, including many cases studied by the military and various government agencies of different countries. Indirect physical evidence would be data obtained from afar, such as radar contact and photographs. More direct physical evidence involves physical interactions with the environment at close range—Hynek's "close encounter" or Vallee's "Type-I" cases—which include "landing traces," electromagnetic interference, and physiological/biological effects.

• Radar contact and tracking, sometimes from multiple sites. These are often considered among the best cases since they usually involve trained military personnel and control tower operators, simultaneous visual sightings, and aircraft intercepts. One such recent example were the mass sightings of large, silent, low-flying black triangles in 1989 and 1990 over Belgium, tracked by multiple NATO radar and jet interceptors, and investigated by Belgium's military (included photographic evidence).^[57] Another famous case from 1986 was the JAL 1628 case over Alaska investigated by the FAA.^[58]
• Photographic evidence, including still photos, movie film, and video, including some in the infrared spectrum (rare).
• Recorded visual spectrograms (extremely rare) — (see Spectrometer)
• Recorded gravimetric and magnetic disturbances (extremely rare)
• Landing physical trace evidence, including ground impressions, burned and/or desiccated soil, burned and broken foliage, magnetic anomalies, increased radiation levels, and metallic traces. See, e.g. Height 611 UFO Incident or the 1964 Lonnie Zamora's Socorro, New Mexico encounter, considered one of the most inexplicable of the USAF Project Blue Book cases). A well-known example from December 1980 was the USAF Rendlesham Forest Incident in England. Another less than 2 weeks later, in January 1981, occurred in Trans-en-Provence and was investigated by GEPAN, then France's official government UFO-investigation agency.^[59] Project Blue Book head Edward J. Ruppelt described a classic 1952 CE2 case involving a patch of charred grass roots.^[60] Catalogs of several thousand such cases have been compiled, particularly by researcher Ted Phillips.^[61][62]
• Physiological effects on people and animals including temporary paralysis, skin burns and rashes, corneal burns, and symptoms superficially resembling radiation poisoning, such as the Cash-Landrum incident in 1980. One such case dates back to 1886, a Venezuelan incident reported in Scientific American magazine.^[63]
• So-called animal/cattle mutilation cases, that some feel are also part of the UFO phenomenon. Such cases can and have been analyzed using forensic science techniques.
• Biological effects on plants such as increased or decreased growth, germination effects on seeds, and blown-out stem nodes (usually associated with physical trace cases or crop circles)
• Electromagnetic interference (EM) effects, including stalled cars, power black-outs, radio/TV interference, magnetic compass deflections, and aircraft navigation, communication, and engine disruption.^[64] A list of over 30 such aircraft EM incidents was compiled by NASA scientist Dr. Richard F. Haines.^[65] A famous 1976 military case over Tehran, recorded in CIA and DIA classified documents, resulted in communication losses in multiple aircraft and weapons system failure in an F-4 Phantom II jet interceptor as it was about to fire a missile on one of the UFOs. This was also a radar/visual case. (Fawcett & Greenwood, 81-89; Good, 318-322, 497-502)^[66][67]
• Remote radiation detection, some noted in FBI and CIA documents occurring over government nuclear installations at Los Alamos National Laboratory and Oak Ridge National Laboratory in 1950, also reported by Project Blue Book director Ed Ruppelt in his book.^[68]
• Actual hard physical evidence cases, such as 1957, Ubatuba, Brazil, magnesium fragments analyzed by the Brazilian government and in the Condon Report and by others. The 1964 Socorro/Lonnie Zamora incident also left metal traces, analyzed by NASA.
• Misc: Recorded electromagnetic emissions, such as microwaves detected in the well-known 1957 RB-47 surveillance aircraft case, which was also a visual and radar case;^[69] polarization rings observed around a UFO by a scientist, explained by Dr. James Harder as intense magnetic fields from the UFO causing the Faraday effect.^[70]

These various reported physical evidence cases have been studied by various scientist and engineers, both privately and in official governmental studies (such as Project Blue Book, the Condon Committee, and the French GEPAN/SEPRA). A comprehensive scientific review of physical evidence cases was carried out by the 1998 Sturrock UFO panel.^[71]

Attempts have been made to reverse engineer the possible physics behind UFOs through analysis of both eyewitness reports and the physical evidence. Examples are former NASA and nuclear engineer James McCampbell in his book Ufology online, NACA/NASA engineer Paul R. Hill in his book Unconventional Flying Objects, and German rocketry pioneer Hermann Oberth. Among subjects tackled by McCampbell, Hill, and Oberth was the question of how UFOs can fly at supersonic speeds without creating a sonic boom. McCampbell's proposed solution of a microwave plasma parting the air in front of the craft is currently being researched by Dr. Leik Myrabo, Professor of Engineering Physics at the Rensselaer Polytechnic Institute as a possible advance in hypersonic flight.^[72]1995 Aviation Week article

Explanations and opinions

An Air Force study by Battelle Memorial Institute scientists from 1952-1955 of 3200 USAF cases found 22% were unknowns, and with the best cases, 33% remained unsolved. Similarly about 30% of the UFO cases studied by the 1969 USAF Condon Committee were deemed unsolved when reviewed by the American Institute of Aeronautics and Astronautics (AIAA). The official French government UFO scientific study (GEIPAN) from 1976 to 2004 listed about 13% of 5800 cases as very detailed yet still inexplicable (with 46% deemed to have definite or probable explanations and 41% having inadequate information).^[73]

Despite the remaining unexplained cases in the cited scientific studies above, many skeptics still argue that the general opinion of the mainstream scientific community is that all UFO sightings could ultimately be explained by prosaic explanations such as misidentification of natural and man-made phenomena (either known or still unknown), hoaxes, and psychological phenomena such as optical illusions or dreaming/sleep paralysis (often given as an explanation for purported alien abductions).

Other skeptical arguments against UFOs include:

• Most evidence is ultimately derived from notoriously unreliable eyewitness accounts and very little in the way of solid or other physical evidence has been reported.
• Most UFO sightings are transitory events and there is usually no opportunity for the repeat testing called for by the scientific method.
  [7] Center for UFO Studies FAQ on UFO sightings.
• Occam's razor of hypothesis testing, since it is considered less incredible for the explanations to be the result of known scientifically verified phenomena rather than resulting from novel mechanisms (e.g. the extraterrestrial hypothesis).
• The market being biased in favor of books, TV specials, etc. which support paranormal interpretations, leaving the public poorly informed regarding more mundane explanations for UFOs as a possibly socio-cultural phenomenon only.

What appears interesting is that UFO sightings depend on the technological environment of their times. In the late 1800s, UFOs were described as airships larger, sturdier and more maneuverable than those commonly used. As planes were developed UFO descriptions involved those of planes with speed and maneuverability greater than in any known design. Nowadays UFOs are described as having many shapes, but are still described as performing maneuvers that no known contemporary aircraft is capable of doing; these include complete or near-complete silence when spotted, hovering, flight at very great speeds with very small turn radii, as well as the ability to make unusually rapid changes in altitude.

Popular UFO Hypotheses

To account for unsolved UFO cases, several hypotheses have been proposed by both proponents and skeptics.

Among proponents, some of the more common explanations for UFOs are:

• The Extraterrestrial Visitation Hypothesis (ETH) (most popular)
• The Interdimensional Hypothesis
• The Paranormal/Occult Hypothesis
• The hypothesis that they are time machines or vehicles built in a future time.
• Another is the Extraterrestrial energyzoa theory

Similarly, skeptics usually propose one of the following explanations:

• The Psychological-Social Hypothesis
• The man-made craft hypothesis
• The unknown natural phenomena hypothesis, e.g. ball lightning, sprites
• The Meteorological hypothesis--Peter F Coleman advanced a meteorological theory that many UFOs or unexplained lights are actually instances of visible combustion of a fuel (e.g., natural gas) inside an atmospheric vortex. He has argued his case in his book, Great Balls of Fire-a unified theory. ^[74] This vortex fireball theory was first published in Weather^[75] and later in the Journal of Scientific Exploration ^[76]
• The Earthquake lights/Tectonic Strain hypothesis
• The Autokinetic effect hypotheis.
• The "shiny-bodied insects" hypothesis^[77]

Hoaxes

Among the many people who have reported UFO sightings, some have been exposed as hoaxers. Not all alleged hoax exposures are certain, however, and many claimants have stuck by their stories, leaving the determination of specific cases as hoaxes contentious. Some of the controversial subjects include these:

• Perhaps most notably, Ed Walters' 1987 hoax, perpetrated in Gulf Breeze, Florida. Walters claimed at first having seen a small UFO flying near his home, and then in a second incident seeing the same UFO and a small alien being standing by his back door after being alerted by his dog. Several photographs were taken of the craft, but none of the being. Three years later in 1990, after the Walters family had moved, the new residents discovered a model of a UFO poorly hidden in the attic that bore an undeniable resemblance to the craft in Walters' photographs. Various witnesses and detractors came forward after the local Pensacola newspaper printed a story about the discovered model, and some investigators now consider the sightings to be a hoax. In addition, a six-figure television miniseries and book deal were nearly struck with Walters.^[78]
• Contactees such as George Adamski, who claimed he went on flights in UFOs. (Even some believers contend he had real experiences and later fictionalized others, leaving the subject murky.)
• Bob White (UFO hunter) claims to have an alleged UFO artifact.
• Billy Meier, some of whose photographs have been discredited.
• The Maury Island Incident
• The Ummo affair, a decades-long series of detailed letters and documents allegedly from extraterrestrials. The total length of the documents is at least 1000 pages, and some estimate that further undiscovered documents may total nearly 4000 pages. A Jose Luis Jordan Pena came forward in the early nineties claiming responsibility for the phenomenon, and most consider there to be little reason to challenge his claims.^[79]
• A video was posted as genuine footage to Youtube.com by a "barzolff814". It depicts two large UFOs flying over an observer on a tropical island, said to be Haiti in the title "Haiti Ufo". The video was quickly debunked by . The video was done entirely with CGI 3D Animation programs, (using such techniques as Match moving ), by French animator David Nicolas. ^{[80] [81]} It managed to fool many people; many still thoroughly believe that the video is real. The hoax was discerned by the identical palm trees in the video, which were originally in a 3D program called Vue Infinite.

UFO researchers

Main article: List of Ufologists

UFO organizations

Main article: UFO organizations

Physicists and UFOs

Certain physicists, some working for the US Military, others said to be associated with the US Intelligence Community are seriously interested in UFOs as extraterrestrial flying machines. Dr. Jack Sarfatti, in his book "Super Cosmos" (2005), has an extremely detailed "theory" based on the recent discovery of the repulsive anti-gravity field "dark energy" that is accelerating the expansion of the 3D space of our universe. Sarfatti also cites Alcubierre's weightless warp drive without time dilation as essential conditions for "propellantless propulsion" in what Puthoff has called "metric engineering." In his book "The Physics of Star Trek," Lawrence M. Krauss argues that it would be physically impossible to concentrate enough energy in one place to "warp" the fabric of space.

According to other physicists, taking advantage of certain experimentally verified quantum phenomena, such as the Casimir effect, may make the construction of Alcubierre type warp drives theoretically possible.^[82][83] However, if certain quantum inequalities conjectured by Ford and Roman (1996) hold, then the energy requirements for some warp drives may be absurdly gigantic, e.g. the energy -10⁶⁷g might be required to transport a small spaceship across the Milky Way galaxy. Counterarguments to these apparent problems have been offered (Krasnikov, 2003), but not all physicists are convinced they can be overcome. (For a detailed discussion, see: Alcubierre drive.)

Psychology

The study of UFO claims over the years has led to valuable discoveries about atmospheric phenomena and psychology. In psychology, the study of UFO sightings has revealed information on misinterpretation, perceptual illusions, hallucination and fantasy-prone personality. Many have questioned the reliability of hypnosis in UFO abduction cases.

Psychologists point out that almost all UFO-related claims are based solely on eyewitness and anecdotal evidence, which is extremely unreliable.^[84] It has further been shown that memory of an event can be unconsciously altered to suit a desired interpretation of what was remembered.^[85] For example, a person who has a supposed UFO sighting may simply be reinterpreting an older memory to fit a desired explanation. Many skeptics believe this to be the case with the Roswell incident and many other UFO claims.

UFO categorization

Some researchers recommend that observations be classified according to the features of the phenomenon or object that are reported or recorded. Typical categories include:

• Saucer, toy-top, or disk-shaped "craft" without visible or audible propulsion. (day and night)
• Large triangular "craft" or triangular light pattern
• Cigar-shaped "craft" with lighted windows (Meteor fireballs are sometimes reported this way, but are very different phenomena).
• Other: chevrons, equilateral triangles, spheres (usually reported to be shining, glowing at night), domes, diamonds, shapeless black masses, eggs, and cylinders.

Hynek system

^[86][87] Dr. J. Allen Hynek developed another commonly used system of description, dividing sightings into six categories. It first separates sightings based on proximity, arbitrarily using 500 feet as the cutoff point. It then subdivides these into divisions based on viewing conditions or special features. The three distant sighting categories are:

• Nocturnal Lights (NL): Anomalous lights seen in the night sky.
• Daylight Discs (DD): Any anomalous object, generally but not necessarily "discoidal", seen in the distant daytime sky.
• Radar/Visual cases (RV). Objects seen simultaneously by eye and on radar.

The distant classification is useful in terms of evidentiary value, with RV cases usually considered to be the highest because of radar corroboration and NL cases the lowest because of the ease in which lights seen at night are often confused with prosaic phenomena such as meteors, bright stars, or airplanes. RV reports are also fewest in number, while NL are largest.

In addition were three "close encounter" (CE) subcategories, again thought to be higher in evidentiary value, because it includes measurable physical effects and the objects seen up close are less likely to be the result of misperception. As in RV cases, these tend to be relatively rare:

• CE1: Strange objects seen nearby but without physical interaction with the environment.
• CE2: A CE1 case but creating physical evidence or causing electromagnetic interference (see below).
• CE3: CE1 or CE2 cases where "occupants" or entities are seen. (Hence the title of Steven Spielberg's movie, Close Encounters of the Third Kind)

Hynek's CE classification system has since been expanded to include such things as alleged alien abductions (CE4s) and cattle mutilation phenomena.

Vallee system

^[88]Jacques Vallee has devised a UFO classification system which is preferred by many UFO investigators over Hynek's system as it is considerably more descriptive than Hynek's, especially in terms of the reported behavior of UFOs.

Type I (a, b, c, d): Observation of an unusual object, spherical discoidal, or of another geometry, on or situated close to the ground (tree height, or lower), which may be associated with traces - thermal, luminous, or mechanical effects.

1. On or near ground.
2. Near or over body of water.
3. Occupants appear to display interest in witnesses by gestures or luminous signals.
4. Object appears to be "scouting" a terrestrial vehicle.

Type II (a, b, c): Observation of an unusual object with vertical cylindrical formation in the sky, associated with a diffuse cloud. This phenomenon has been given various names such as "cloud-cigar" or "cloud-sphere."

1. Moving erratically through the sky.
2. Object is stationary and gives rise to secondary objects (sometimes referred to as "satellite objects").
3. Object is surrounded by secondary objects.

Type III (a, b, c, d, e): Observation of an unusual object of spherical, discoidal or elliptical shape, stationary in the sky.

1. Hovering between two periods of motion with "falling-leaf" descent, up and down, or pendulum motion.
2. Interruption of continuous flight to hover and then continue motion.
3. Alters appearance while hovering - e.g., change of luminosity, generation of secondary object, etc.
4. "Dogfights" or swarming among several objects.
5. Trajectory abruptly altered during continuous flight to fly slowly above a certain area, circle, or suddenly change course.

Type IV (a, b, c, d): Observation of an unusual object in continuous flight.

1. Continuous flight.
2. Trajectory affected by nearby conventional aircraft.
3. Formation flight.
4. Wavy or zig-zag trajectory.

Type V (a, b, c): Observation of an unusual object of indistinct appearance, i.e., appearing to be not fully material or solid in structure.

1. Extended apparent diameter, non-point source luminous objects ("fuzzy").
2. Starlike objects (point source), motionless for extended periods.
3. Starlike objects rapidly crossing the sky, possibly with peculiar trajectories.

Source: 1. Jacques and Janine Vallee: Challenge To Science: The UFO Enigma, LC# 66-25843

Conspiracy theories

Main article: UFO conspiracy theory

UFOs are sometimes an element of elaborate conspiracy theories in which the government is said to be intentionally covering up the existence of aliens, or sometimes collaborating with them. There are many versions of this story; some are exclusive, while others overlap with various other conspiracy theories.

In the U.S., opinion polls again indicate that a strong majority of people believe the U.S. government is withholding such information. Various notables have also expressed such views. Some examples are astronauts Gordon Cooper and Edgar Mitchell, Senator Barry Goldwater, Vice Admiral Roscoe H. Hillenkoetter (the first CIA director), Lord Hill-Norton (former British Chief of Defense Staff and NATO head), the 1999 high-level French COMETA report by various French generals and aerospace experts, and Yves Sillard (former director of the French space agency CNES, new director of French UFO research organization GEIPAN ^[89]).

There is also speculation that UFO phenomena are tests of experimental aircraft or advanced weapons. In this case UFOs are viewed as failures to retain secrecy, or deliberate attempts at misinformation: to deride the phenomenon so that it can be pursued unhindered. This explanation may or may not feed back into the previous one, where current advanced military technology is considered to be adapted alien technology. (See also: skunk works and Area 51)

It has also been suggested by a few fringe authors that all or most human technology and culture is based on extraterrestrial contact. See also ancient astronauts.

Allegations of evidence suppression

Some also contend regarding physical evidence that it exists abundantly but is swiftly and sometimes clumsily suppressed by governments, aiming to insulate a population they regard as unprepared for the social, theological, and security implications of such evidence. See the Brookings Report.

There have been allegations of suppression of UFO related evidence for many decades. There are also conspiracy theories which claim that physical evidence might have been removed and/or destroyed/suppressed by some governments. (See also Men in Black) Some examples are:

• On July 7, 1947, William Rhodes took photos of an unusual object over Phoenix, Arizona.^[90] The photos appeared in a Phoenix newspaper and a few other papers. According to documents from Project Bluebook, an Army counter-intelligence (CIC) agent and an FBI agent interviewed Rhodes on August 29 and convinced him to surrender the negatives. The CIC agent deliberately concealed his true identity, leaving Rhodes to believe both men were from the FBI. Rhodes said he wanted the negatives back, but when he turned them into the FBI the next day, he was informed he wouldn't be getting them back, though Rhodes later tried unsuccessfully.^[91][92] The photos were extensively analyzed and would eventually show up in some classified Air Force UFO intelligence reports. (Randle, 34-45, full account)
• A June 27, 1950, movie of a "flying disk" over Louisville, Kentucky, taken by a Louisville Courier-Journal photographer, had the USAF Directors of counterintelligence (AFOSI) and intelligence discussing in memos how to best obtain the movie and interview the photographer without revealing Air Force interest. One memo suggested the FBI be used, then precluded the FBI getting involved. Another memo said "it would be nice if OSI could arrange to secure a copy of the film in some covert manner," but if that wasn't feasible, one of the Air Force scientists might have to negotiate directly with the newspaper.^[93][94] In a recent interview, the photographer confirmed meeting with military intelligence and still having the film in his possession until then, but refused to say what happened to the film after that.^[95]
• In another 1950 movie incident from Montana, Nicholas Mariana filmed some unusual aerial objects and eventually turned the film over to the U.S. Air Force, but insisted that the first part of the film, clearly showing the objects as spinning discs, had been removed when it was returned to him. (Clark, 398)
• During the military investigation of green fireballs in New Mexico, UFOs were photographed by a tracking camera over White Sands Proving Grounds on April 27, 1949. The final report in 1951 on the green fireball investigation claimed there was insufficient data to determine anything. However, documents later uncovered by Dr. Bruce Maccabee indicate that triangulation was accomplished. The data reduction and photographs showed four objects about 30 feet in diameter flying in formation at high speed at an altitude of about 30 miles. Maccabee says this result was apparently suppressed from the final report.^[96]
• Project Blue Book director Edward J. Ruppelt reported that, in 1952, a U.S. Air Force pilot fired his jet's machine guns at a UFO, and that the official report which should have been sent to Blue Book was quashed. 1952 newspaper articles of USAF jets being ordered to shoot down saucers
• Astronaut Gordon Cooper reported suppression of a flying saucer movie filmed in high clarity by two Edwards AFB range photographers on May 3, 1957. Cooper said he viewed developed negatives of the object, clearly showing a dish-like object with a dome on top and something like holes or ports in the dome. The photographers and another witness, when later interviewed by Dr. James McDonald, confirmed the story. Cooper said military authorities then picked up the film and neither he nor the photographers ever heard what happened to it. The incident was also reported in a few newspapers, such as the Los Angeles Times. The official explanation, however, was that the photographers had filmed a weather balloon distorted by hot desert air. McDonald, 1968 Congressional testimony, Case 41
• On January 22, 1958, when NICAP director Donald Keyhoe appeared on CBS television, his statements on UFOs were pre-censored by the Air Force. During the show when Keyhoe tried to depart from the censored script to "reveal something that has never been disclosed before," CBS cut the sound, later stating Keyhoe was about to violate "predetermined security standards" and about to say something he wasn't "authorized to release." What Keyhoe was about to reveal were four publicly unknown military studies concluding UFOs were interplanetary (including the 1948 Project Sign Estimate of the Situation and Blue Book's 1952 engineering analysis of UFO motion). (Good, 286-287; Dolan 293-295)
• Astronomer Jacques Vallee reported that in 1961 he witnessed the destruction of the tracking tapes of unknown objects orbiting the Earth. (However, Vallee indicated that this didn't happen because of government pressure but because the senior astronomers involved didn't want to deal with the implications.)
• In 1965, Rex Heflin took four Polaroid photos of a hat-shaped object. Two years later (1967), two men posing as NORAD agents confiscated three prints. Just as mysteriously, the photos were returned to his mailbox in 1993. detailed article and photos
• A March 1, 1967 memo directed to all USAF divisions, from USAF Lt. General Hewitt Wheless, Assistant Vice Chief of Staff, stated that unverified information indicated that unknown individuals, impersonating USAF officers and other military personnel, had been harassing civilian UFO witnesses, warning them not to talk, and also confiscating film, referring specifically to the Heflin incident. AFOSI was to be notified if any personnel were to become aware of any other incidents. (Document in Fawcett & Greenwood, 236).
• John Callahan, former Division Chief of the Accidents and Investigations Branch of the FAA, Washington D.C., also a Disclosure Project witness, said that following a 1986 encounter of a Japanese airlines 747 with a giant UFO over Alaska, recorded by air and ground radar, the FAA conducted an investigation. Callahan held a briefing a few days later for President Reagan's Scientific Study Group, the FBI, and CIA. After the briefing, one of the CIA agents told everybody they "were never there and this never happened," adding they were fearful of public panic. ^[97]
• In 1996, the CIA revealed an instance from 1964 where two CIA agents posed as USAF representatives in order to recover a film canister from a Corona spy satellite that had accidentally come down in Venezuela. The event was then publicly dismissed as an unsuccessful NASA space experiment.

UFOs in popular culture

UFOs constitute a widespread international cultural phenomenon of the last half-century.Gallup polls rank UFOs near the top of lists for subjects of widespread recognition. In 1973, a survey found that 95 percent of the public reported having heard of UFOs, whereas only 92 percent had heard of US President Gerald Ford in a 1977 poll taken just nine months after he left the White House. (Bullard, 141) A 1996 Gallup poll reported that 71 percent of the United States population believed that the government was covering up information regarding UFOs. A 2002 Roper poll for the Sci Fi channel found similar results, but with more people believing UFOs were extraterrestrial craft. In that latest poll, 56 percent thought UFOs were real craft and 48 percent that aliens had visited the Earth. Again, about 70 percent felt the government was not sharing everything it knew about UFOs or extraterrestrial life.^[98]

Another effect of the flying saucer type of UFO sightings has been Earth-made flying saucer craft in space fiction, for example the Earth-made craft Starship C-57D in Forbidden Planet, and the saucer part of the USS Enterprise in Star Trek.

Use in film and television

• See List of major UFO film and television shows
• See UFOs in Fiction

See also

References

UFO in Russia

General

Skepticism

Psychology

Histories

Technology

External links

• Wikinews - UFO Archive
• Huge UFO video & news archive
• All about UFO (in Russian)
• The British Earth & Aerial Mysteries Society UK Database of UFO Sightings & Reports
• National Aviation Reporting Center on anomalous phenomena
• The National UFO Reporting Center
• The University of Colorado UFO study 1969 a/k/a Condon Report
• UFO sightings at ICBM sites and nuclear weapons storage areas by R. Hastings, NICAP
• Project Blue Book Archive Online archives of USAF Project Blue Book files
• CIA educational summary on UFO
• NASA Institute for Advanced Concepts
• BBC article on Mexican Air-force videotape
• Popular Mechanics article - When UFOs Arrive: February 2004 Cover Story
• British Ministry of Defence (MoD) -- Unidentified Aerial Phenomena (UAP) in the UK Air Defence Region
• [9] The J. Allen Hynek Center for UFO Studies