Terminology-

The Oxford English Dictionary defines a UFO as "An unidentified flying object; a 'flying saucer'." The first published book to use the word was authored by Donald E. Keyhoe

The acronym "UFO" was coined by Captain Edward J. Ruppelt, who headed Project Blue Book, then the USAF's official investigation of UFOs. He wrote, "Obviously the term 'flying saucer' is misleading when applied to objects of every conceivable shape and performance. For this reason the military prefers the more general, if less colorful, name: unidentified flying objects. UFO (pronounced Yoo-foe) for short." Other phrases that were used officially and that predate the UFO acronym include "flying flapjack", "flying disc", "unexplained flying discs", "unidentifiable object", and "flying saucer".

The phrase "flying saucer" had gained widespread attention after the summer of 1947. On June 24, a civilian pilot namedKenneth Arnold reported seeing nine objects flying in formation near Mount Rainier. Arnold timed the sighting and estimated the speed of discs to be over 1,200 mph (1,931 km/h). At the time, he described the objects' shape as being somewhat disc-like or saucer-like, leading to newspaper accounts of "flying saucers" and "flying discs".

In popular usage the term UFO came to be used to refer to claims of alien spacecraft and because of the public and media ridicule associated with the topic, some investigators prefer to use such terms as unidentified aerial phenomenon (orUAP) or anomalous phenomena, as in the title of the National Aviation Reporting Center on Anomalous Phenomena (NARCAP).

   

Studies-

Studies have established that the majority of UFO observations are misidentified conventional objects or natural phenomena—most commonly aircraft, balloons, noctilucent clouds, nacreous clouds, or astronomical objects such as meteors or bright planets with a small percentage even being hoaxes. Between 5% and 20% of reported sightings are not explained, and therefore can be classified as unidentified in the strictest sense. While proponents of the extraterrestrial hypothesis (ETH) suggest that these unexplained reports are of alien spacecraft, the null hypothesis cannot be excluded that these reports are simply other more prosaic phenomena that cannot be identified due to lack of complete information or due to the necessary subjectivity of the reports.

While UFOs have been the subject of extensive investigation by various governments and although a few scientists have supported the extraterrestrial hypothesis, almost no scientific papers about UFOs have been published in peer-reviewed journals. There was, in the past, some debate in the scientific community about whether any scientific investigation into UFO sightings is warranted with the general conclusion being that the phenomenon was not worthy of serious investigation beyond a cultural artifact.

The void left by the lack of institutional scientific study has given rise to independent researchers and groups, including theNational Investigations Committee on Aerial Phenomena (NICAP) in the mid-20th century and, more recently, the Mutual UFO Network (MUFON) and the Center for UFO Studies (CUFOS).The term "Ufology" is used to describe the collective efforts of those who study reports and associated evidence of unidentified flying objects.

UFOs have become a prevalent theme in modern culture, and the social phenomena have been the subject of academic research in sociology and psychology.

    

Early history-

Unexplained aerial observations have been reported throughout history. Some were undoubtedly astronomical in nature:comets, bright meteors, one or more of the five planets that can be seen with the naked eye, planetary conjunctions, or atmospheric optical phenomena such as parhelia and lenticular clouds. An example is Halley's Comet, which was recorded first by Chinese astronomers in 240 BC and possibly as early as 467 BC. Such sightings throughout history often were treated as supernatural portents, angels, or other religious omens. Some current-day UFO researchers have noticed similarities between some religious symbols in medieval paintings and UFO reports though the canonical and symbolic character of such images is documented by art historians placing more conventional religious interpretations on such images.

On January 25, 1878, the Denison Daily News printed an article in which John Martin, a local farmer, had reported seeing a large, dark, circular object resembling a balloon flying "at wonderful speed." Martin, according to the newspaper account, said it appeared to be about the size of a saucer, the first known use of the word "saucer" in association with a UFO.

In April 1897 thousands of people reported seeing "airships" in various parts of the United States. Many signed affidavits. Scores of people even reported talking to the pilots. Thomas Edison was asked his opinion, and said, "You can take it from me that it is a pure fake."

On February 28, 1904, there was a sighting by three crew members on the USS Supply 300 miles (483 km) west of San Francisco, reported by Lieutenant 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 two to three minutes. The largest had an apparent size of about six Suns, he said.

The three earliest known pilot UFO sightings, of 1,305 similar sitings cataloged by NARCAP, took place in 1916 and 1926. On January 31, 1916, a UK pilot near Rochford reported a row of lights, resembling lighted windows on a railway carriage, that rose and disappeared. In January 1926 a pilot reported six "flying manhole covers" between Wichita, Kansas, and Colorado Springs, Colorado. In late September 1926 an airmail pilot over Nevada said he had been forced to land by a huge, wingless, cylindrical object.

On August 5, 1926, while traveling in the Humboldt Mountains of Tibet's Kokonor region, Russian explorer Nicholas Roerich reported, members of his expedition saw "something big and shiny reflecting the sun, like a huge oval moving at great speed. Crossing our camp the thing changed in its direction from south to southwest. And we saw how it disappeared in the intense blue sky. We even had time to take our field glasses and saw quite distinctly an oval form with shiny surface, one side of which was brilliant from the sun." Another description by Roerich was of a "shiny body flying from north to south. Field glasses are at hand. It is a huge body. One side glows in the sun. It is oval in shape. Then it somehow turns in another direction and disappears in the southwest."

In the Pacific and European theatres during World War II, "foo fighters" (metallic spheres, balls of light and other shapes that followed aircraft) were reported and on occasion photographed by Allied and Axis pilots. Some proposed Allied explanations at the time included St. Elmo's fire, the planet Venus, hallucinations from oxygen deprivation, or German secret weapons.

In 1946 more than 2,000 reports were collected, primarily by the Swedish military, of unidentified aerial objects over the Scandinavian nations, along with isolated reports from France, Portugal, Italy and Greece. The objects were referred to as "Russian hail" and later as "ghost rockets" because it was thought that the mysterious objects were possibly Russian tests of captured German V1 or V2 rockets. Although most were thought to be such natural phenomena as meteors, more than 200 were tracked on radar by the Swedish military and deemed to be "real physical objects." In a 1948 top secret document, Swedish authorities advised the USAF Europe that some of their investigators believed these craft to be extraterrestrial in origin.

  

Project Sign-

On June 24, 1947 while flying his small airplane near Mt. Rainer, Washington, businessman Kenneth Arnold said he witnessed nine disc- or saucer-like aerial objects. (A month later he added that one was actually more crescent-shaped.) By pacing their progress against known landmarks, Arnold conservatively calculated their speed at a then-fantastic 1,700 mph. Arnold, widely considered a sincere and credible witness, earned major press coverage, and his was easily the most prominent of the more than 800 "flying objects" (flying saucer was never used in his reports) reports made by Americans in the summer of 1947. Because of their extreme maneuvers that would kill a human pilot, Arnold initially concluded he'd witnessed either the test flight of a new military remote-controlled weapon or that the objects were from another world.

By the first week of July 1947, Pentagon officials were expressing alarm about the flying disk reports, due in no small part to a remarkable series of close encounters in and near the restricted airspace near Muroc Army Air Base (now Edwards AFB). On 7 July 1947 at about 10.00 a.m., pilot Major J.C. Wise was readying his XP-84 jet at Muroc when he observed a circular white-yellow object at about 10,000 feet. It flew to the east at what Wise estimated was 200 to 225 mph (320 to 360 km/h). On 8 July at about 8.00 a.m., three highway department employees near Yuma, Arizona reported three silvery disks flying at high altitude towards the northeast. At roughly 9.30 a.m., four military personnel at Muroc reported two circular objects flying against the wind at about 300 mph (480 km/h), making tight circular motions as they receded towards the horizon. At about noon at nearby Rogers Dry Lake test range, two technicians observing an ejection seat test also observed a silvery object at about 20,000 feet (6000 m) for about 90 seconds. At about 9.00 pm that evening, a P-51 pilot twice attempted to intercept what he would describe as a "flat object of light-reflecting nature," thought he was unable to reach its altitude. Though they occurred six months before Sign's official creation, the Muroc incidents were cataloged as the first case in Sign's files.

Following the Muroc incidents, military personnel were told to not publicly discuss flying saucers without permission. New orders were issued requiring all unexplained flying saucer incidents to be reported to the T-2 division at Wright Field. T-2, which studied enemy aircraft during WWII, would soon be renamed Technical Intelligence Division (TID).

In a document dated July 10, the office of Air Force Directorate of Intelligence at the Pentagon requested the assistance of other branches of the armed forces and the Federal Bureau of Investigation in compiling data and determining how to best investigate the flying saucer reports.

In a document dated 30 July 1947, Lt. Col. George Garrett at the Pentagon analyzed data from sixteen flying saucer reports which had occurred from 19 May to 12 July 1947; several had occurred at military facilities. Garrett's report noted that credible eyewitnesses, some of them with scientific or technical training, gave detailed descriptions of highly unorthodox aircraft that exhibited advanced flight capabilities and were seemingly under intelligent control. He wrote, "something is really flying around." Given the distinct lack of inquiries about the flying saucers from "topside" (i.e., higher-ranking officials), Garrett thought it probable that they were a newly developed "domestic aircraft." Garrett's report was forwarded to his superiors and to the FBI, both of whom inquired of military contacts to determine if the flying disks were in fact domestically-developed aircraft. The answer was a resounding no.

     

Project Grudge-

Project Sign was dismantled and became Project Grudge at the end of 1948. Angered by the low quality of investigations by Grudge, the Air Force Director of Intelligence reorganized it as Project Blue Book in late 1951, placing Ruppelt in charge. Blue Book closed down in 1970, using the Condon Committee's negative conclusion as a rationale, thus ending official Air Force UFO investigations. However, a 1969 USAF document, known as the Bolender memo, along with later government documents, revealed that non-public U.S. government UFO investigations continued after 1970. The Bolender memo first stated that "reports of unidentified flying objects that could affect national security ... are not part of the Blue Book system," indicating that more serious UFO incidents already were handled outside the public Blue Book investigation. The memo then added, "reports of UFOs which could affect national security would continue to be handled through the standard Air Force procedures designed for this purpose." In addition, in the late 1960s a chapter on UFOs in the Space Sciences course at the U.S. Air Force Academy gave serious consideration to possible extraterrestrial origins. When word of the curriculum became public, the Air Force in 1970 issued a statement to the effect that the book was outdated and that cadets instead were being informed of the Condon Report's negative conclusion.

It was announced that Grudge would take over where Sign had left off, still investigating UFO reports. But as Air Force Captain Edward J. Ruppelt wrote, "In doing this, standard intelligence procedures would be used. This normally means anunbiased evaluation of intelligence data. But it doesn't take a great deal of study of the old UFO files to see that standard intelligence procedures were not being followed by Project Grudge. Everything was being evaluated on the premise that UFOs couldn't exist. No matter what you see or hear, don't believe it." (Ruppelt, 59-60, emphasis his)

Ruppelt noted that some of "ATIC's [Air Technical Intelligence Center's] top intelligence specialists who had been so eager to work on Project Sign were no longer working on Project Grudge. Some of them had drastically and hurriedly changed their minds about UFOs when they learned the Pentagon was no longer sympathetic to the UFO cause." (Ruppelt, 60)

As Dr. Michael D. Swords writes, "Inside the military, [Maj. Aaron J.] Boggs in the Pentagon and [Col. Harold] Watson at AMC [Air Material Command] were openly giving the impression that the whole flying saucer business was ridiculous. Project Grudge became an exercise of derision and sloppy filing. Boggs was so enthusiastically antisaucer that General Cabell ordered General Moore to create a more proper atmosphere of skeptical respect for the reports and their observers." (Swords, 98)

Critics charged that, from its formation, Project Grudge was operating under a debunking directive: all UFO reports were judged to have prosaic explanations, though little research was conducted, and some of Grudge's "explanations" were strained or even logically untenable. In his 1956 book, Edward J. Ruppelt would describe Grudge as the "Dark Ages" of USAF UFO investigation. Grudge’s personnel were in fact conducting little or no investigation, while simultaneously relating that all UFO reports were being thoroughly reviewed. Ruppelt additionally reported that the word "Grudge" was chosen deliberately by the anti-saucer elements in the Air Force.

      

Scientific studies-

The study of UFOs has received little support in mainstream scientific literature. Official studies ended in the U.S. in December 1969, following the statement by the government scientist Edward Condon that further study of UFOs could not be justified on grounds of scientific advancement.The Condon Report and its conclusions were endorsed by the National Academy of Scientists, of which Condon was a member. On the other hand, a scientific review by the UFO subcommittee of the American Institute of Aeronautics and Astronautics (AIAA) disagreed with Condon's conclusion, noting that at least 30 percent of the cases studied remained unexplained and that scientific benefit might be gained by continued study.

Critics argue that all UFO evidence is anecdotal and can be explained as prosaic natural phenomena. Defenders of UFO research counter that knowledge of observational data, other than what is reported in the popular media, is limited in the scientific community and that further study is needed.

No official government investigation has ever publicly concluded that UFOs are indisputably real, physical objects, extraterrestrial in origin, or of concern to national defense. These same negative conclusions also have been found in studies that were highly classified for many years, such as the UK's Flying Saucer Working Party, Project Condign, the U.S. CIA-sponsored Robertson Panel, the U.S. military investigation into the green fireballs from 1948 to 1951, and the Battelle Memorial Institute study for the USAF from 1952 to 1955 (Project Blue Book Special Report No. 14).

Some public government reports have acknowledged the possibility of physical reality of UFOs, but have stopped short of proposing extraterrestrial origins, though not dismissing the possibility entirely. Examples are the Belgian military investigation into large triangles over their airspace in 1989–1991 and the 2009 Uruguayan Air Force study conclusion (see below).

Some private studies have been neutral in their conclusions, but argued that the inexplicable core cases call for continued scientific study. Examples are the Sturrock panel study of 1998 and the 1970 AIAA review of the Condon Report.

   

Notable cases-

According to records released on August 5, 2010, British wartime prime minister Winston Churchill banned the reporting for 50 years of an alleged UFO incident because of fears it could create mass panic. Reports given to Churchill asserted that the incident involved a Royal Air Force (RAF) reconnaissance aircraft returning from a mission in France or Germany toward the end of World War II. It was over or near the English coastline when it was allegedly intercepted by a strange metallic object that matched the aircraft's course and speed for a time before accelerating away and disappearing. The aircraft's crew were reported to have photographed the object, which they said had "hovered noiselessly" near the aircraft, before moving off. According to the documents, details of the coverup emerged when a man wrote to the government in 1999 seeking to find out more about the incident and described how his grandfather, who had served with the RAF in the war, was present when Churchill and U.S. General Dwight D. Eisenhower discussed how to deal with the UFO encounter. The files come from more than 5,000 pages of UFO reports, letters and drawings from members of the public, as well as questions raised in Parliament. They are available to download from The National Archives website.

In the April 1957 West Freugh incident in Scotland, named after the principal military base involved, two unidentified objects flying high over the UK were tracked by radar operators. The objects were reported to operate at speeds and perform maneuvers beyond the capability of any known craft. Also significant is their alleged size, which – based on the radar returns – was closer to that of a ship than an aircraft.

In the Rendlesham Forest incident of December 1980, U.S. military personnel witnessed UFOs near the air base at Woodbridge, Suffolk, over a period of three nights. On one night the deputy base commander, Colonel Charles I. Halt, and other personnel followed one or more UFOs that were moving in and above the forest for several hours. Col. Halt made an audio recording while this was happening and subsequently wrote an official memorandum summarizing the incident. After retirement from the military, he said that he had deliberately downplayed the event (officially termed 'Unexplained Lights') to avoid damaging his career. Other base personnel are said to have observed one of the UFOs, which had landed in the forest, and even gone up to and touched it.