Lexicon

Short, factual explanations of the organizations, people and concepts that keep coming up in the news.

Organizations

AARO – AARO (All-domain Anomaly Resolution Office) is an office of the U.S. Department of Defense established in 2022 that investigates and analyzes reports of UAP phenomena (unidentified aerial, maritime and space objects).
Air Technical Intelligence Center – The Air Technical Intelligence Center (ATIC) was the U.S. Air Force's technical intelligence center from 1951 to 1961 at Wright-Patterson Air Force Base in Ohio. Project Blue Book, the Air Force's official UFO investigation program, belonged to it.
Area 51 – Area 51 is a heavily guarded U.S. Air Force facility in Nevada, next to the Groom Lake dry lakebed, where secret and experimental aircraft have been tested since 1955. In UFO culture, it is the legendary site of the secret study of extraterrestrial craft.
Asbest Mining and Processing Combine – The Asbest Mining and Processing Combine is an asbestos mine and processing plant in Yasveny (Sverdlovsk Oblast), Russia, which appears in UFO literature as one of the site-related connections to the 1959 Dyatlov Pass mystery.
Bigelow Aerospace Advanced Space Studies – Bigelow Aerospace Advanced Space Studies (BAASS) was a Las Vegas company owned by entrepreneur Robert Bigelow that, as a contracted researcher for the Pentagon's AAWSAP program between 2008 and 2010, also investigated UAP phenomena.
Bigfoot Field Researchers Organization – The Bigfoot Field Researchers Organization (BFRO) is an American nongovernmental organization that collects and investigates sightings of the hypothetical creature called Bigfoot (Sasquatch). Its database and field expeditions have made it one of the best-known sources on the subject.
Central Intelligence Agency – The Central Intelligence Agency (CIA) is the United States' civilian foreign intelligence agency, established in 1947. It is a recurring figure in UFO research because of the 1953 Robertson Panel and the controversies surrounding classified UFO documents.
Centro Ufologico Nazionale – The Centro Ufologico Nazionale (CUN) is one of Italy's oldest and best-known civilian ufology organizations, which has been collecting, investigating and documenting UFO sightings since the 1960s.
Counter Intelligence Corps – The Counter Intelligence Corps (CIC) was the US Army's counterintelligence organization from 1942 to 1961. In UFO literature it is mentioned mainly because of the 1947 Roswell incident, since one of its agents took part in collecting the debris.
CRIDOVNI – CRIDOVNI (Comisión Receptora e Investigadora de Denuncias de Objetos Voladores No Identificados) is a commission of the Uruguayan Air Force, operating since 1979, that receives and investigates UFO sightings reported in Uruguayan airspace.
Defense Intelligence Agency – The Defense Intelligence Agency (DIA) is the military intelligence organization of the United States and part of the Department of Defense. In the UFO/UAP field it comes up mainly because from 2008 to 2012 it oversaw the program called AAWSAP, under which studies on advanced flight technologies were produced.
Department of War – The Department of War was the name of the United States war ministry from 1789 to 1947. Since September 2025, under an executive order, it has been used as a secondary name for the Department of Defense.
Federal Aviation Administration – The Federal Aviation Administration (FAA) is the civil aviation authority of the United States, responsible for directing and regulating air traffic. In the UFO/UAP context, it comes up mainly because of its role in airspace safety, pilot reporting and drone matters.
Federal Bureau of Investigation – The FBI (Federal Bureau of Investigation) is the federal investigative agency of the United States and falls under the Department of Justice. In UFO research it comes up mainly because of early Cold War cases and files that were later made public.
Gabinetto RS/33 – The Gabinetto RS/33 (Ricerche Speciali) is one of the best-known stories of disputed origin in Italian UFO literature: according to the references, it was a secret group from the Mussolini era that investigated crashed flying objects starting in 1933.
Galileo Project – The Galileo Project is a scientific initiative launched in 2021 at Harvard University under the leadership of physicist Avi Loeb, which set out to conduct a systematic, instrument-based search for traces of extraterrestrial technology.
GEIPAN – GEIPAN (Groupe d'Études et d'Information sur les Phénomènes Aérospatiaux Non-identifiés) is an official body operating within CNES, the French space agency, that investigates and documents unidentified aerial phenomena reported in France.
Heavens-Above – Heavens-Above is a free astronomy website of German origin that provides the times and paths of satellite passes, including those of the ISS, tailored to the observer's location.
Hungarian Astronomical Association – The Hungarian Astronomical Association (MCSE) is Hungary's largest amateur astronomy organization, dedicated to popularizing astronomy and coordinating amateur observations.
Institute of Hispanic Ufology – The Institute of Hispanic Ufology is a US-based outfit led by Scott Corrales that, through its publication Inexplicata, relays UFO cases from the Spanish-speaking world in English.
Minot Air Force Base – Minot Air Force Base is a U.S. Air Force base in North Dakota that operates nuclear bombers and intercontinental missiles. In UFO literature it is known mainly for the radar and eyewitness incident of October 1968.
MUFON – MUFON (Mutual UFO Network) is a civilian organization founded in the United States in 1969 that collects and investigates reports of UFO/UAP sightings through a network of volunteer field investigators.
NASA – NASA is the civilian space and aeronautics research agency of the United States. It comes up in the UAP topic because of its independent study team, which operated in 2022–2023, and that team's report.
NASA Independent UAP Study Team – In 2022, NASA set up a 16-member independent expert team to examine unidentified anomalous phenomena (UAP) from a scientific perspective. In its report released in 2023, the panel primarily made methodological recommendations and did not analyze specific UAP cases.
NICAP – NICAP (National Investigations Committee on Aerial Phenomena) was an American civilian UFO research organization that operated from 1956 to 1980 and focused on collecting eyewitness reports and criticizing official U.S. UFO policy.
NORAD – NORAD (North American Aerospace Defense Command) is the joint aerospace and maritime warning and air defense command of the United States and Canada, which monitors North American airspace with radars.
Nuclear Regulatory Commission – The Nuclear Regulatory Commission (NRC) is an independent federal agency of the United States that oversees the safety of civilian nuclear materials and facilities. It appears only rarely in the UFO/UAP field; it is mostly mentioned in connection with sightings over nuclear facilities.
NUFORC – NUFORC (National UFO Reporting Center) is an American civilian organization founded in 1974 that collects public UFO sightings through telephone and online reports and publishes them in a public database.
Office of the Director of National Intelligence – The Office of the Director of National Intelligence (ODNI) is the coordinating body of the US Intelligence Community, established in 2004. It matters in UAP matters because it issued the first official UAP reports addressed to Congress.
Operation Snowbird – Operation Snowbird is, on the one hand, a real winter training program of the U.S. Air National Guard and, on the other, the name of a UFO legend stemming from a 1980s document now considered a forgery, according to which a craft of alien origin was tested in Nevada from 1972 onward.
Osservatorio Siciliano – The Osservatorio Siciliano is a Sicilian cultural association founded in 2025 that monitors UFO/UAP phenomena; its president is Filippo Finocchiaro. Its project called Oculus would continuously monitor the sky and Mount Etna; no independent assessment of its work is known.
OVRA – The OVRA was the political secret police of Fascist Italy. In UFO literature it is mentioned in connection with the Gabinetto RS/33 legend because, according to documents not proven to be authentic, it took part in covering up an alleged UFO crash in 1933.
Pentagon – The Pentagon is the Arlington headquarters of the United States Department of Defense, and also the common name for the department itself. Both the investigations and the public communication on UFO/UAP matters are coordinated there.
Project Blue Book – Project Blue Book was the U.S. Air Force's official UFO investigation program, operating from 1952 to 1969, which documented and analyzed thousands of sightings. The program was closed following the Condon Report, which found that most cases had conventional explanations.
Project Mogul – Project Mogul was a secret U.S. Air Force program between 1946 and 1949 that tried to detect the sound waves of Soviet nuclear tests using microphones mounted on balloon trains floating at high altitude. According to the Air Force's 1994 report, the Roswell debris most likely came from a Mogul balloon train.
Scientific Coalition for UAP Studies – The Scientific Coalition for UAP Studies (SCU) is an American civilian research group founded in 2017 that studies unidentified aerial phenomena (UAP) using scientific methods.
Skywatcher – In the general sense, a skywatcher (Hungarian: égboltfigyelő) is an amateur observer who regularly watches the sky. Since 2025 it has also been the name of a controversial UAP research group founded by Jake Barber, which claimed it was able to lure UAPs to a location.
Solar and Heliospheric Observatory – SOHO (Solar and Heliospheric Observatory) is a joint ESA and NASA solar space observatory that, after its 1995 launch, observed the Sun for nearly three decades and discovered more than 5,000 comets. People sometimes believe they spot “UFOs” in its public images, but these are image artifacts and data dropouts.
Starlink – Starlink is SpaceX's satellite internet service, made up of thousands of satellites orbiting in low Earth orbit. Because of the bright points moving in a line that are often seen in the sky, it is a regular source of UFO reports.
UAP Science Advisory Council – The UAP Science Advisory Council is a volunteer scientific advisory body formed in June 2026 that assists the U.S. government's UAP investigations. It is led by Harvard astrophysicist Avi Loeb, and its members include the skeptic Michael Shermer.
UAP Task Force – The UAP Task Force (UAPTF) was a working group of the U.S. Department of Defense, established in 2020 and operating within naval intelligence, that collected and analyzed data on unidentified aerial phenomena (UAP). In November 2021 it was replaced by the AOIMSG.

People

Aldo Rebelo – Aldo Rebelo is a Brazilian politician, a former minister and former president of the Chamber of Deputies. In the UFO/UAP field, his name usually comes up in connection with Brazilian parliamentary transparency efforts and public UAP hearings.
Anna Paulina Luna – Anna Paulina Luna is a Republican U.S. Representative from Florida who has repeatedly pressed for greater transparency on the UAP issue. She chairs the Task Force on the Declassification of Federal Secrets, which operates alongside the House Oversight Committee and also examines UAP matters.
Avi Loeb – Avi Loeb is an Israeli-American astrophysicist and Harvard University professor who raised the possibility of an artificial origin for the interstellar object known as Oumuamua, and who leads the Galileo Project, a research program investigating UAPs and technosignatures.
Bruce Maccabee – Bruce Maccabee (1942–2024) was an American optical physicist who worked for the U.S. Navy and was known for analyzing UFO photographs and films. He was a longtime, controversial advocate of the scientific study of UFO phenomena.
Charles Halt – Charles Halt is a retired US Air Force colonel who, as a lieutenant colonel at the time of the events near Rendlesham Forest in December 1980, was deputy commander of the RAF Woodbridge–Bentwaters air base. The incident is regarded as one of the best-known British UFO cases.
David Fravor – David Fravor is a U.S. Navy pilot who, in 2004, as a member of the USS Nimitz aircraft carrier group, took part in the famous "Tic Tac" UFO incident. Since then, he has been one of the most frequently heard witnesses and public figures on the subject.
David Grusch – David Grusch is an American intelligence officer and UAP whistleblower who claimed at a 2023 congressional hearing that the United States runs secret programs to reverse-engineer crashed vehicles of non-human origin and their wreckage.
Edward Ruppelt – Edward J. Ruppelt (1923–1960) was a U.S. Air Force captain, the first head of Project Blue Book, and one of the key figures of early UFO research. The popularization of the term "unidentified flying object" (UFO) is attributed to him.
Edward Teller – Edward Teller (1908–2003) was a Hungarian-born American theoretical physicist, a participant in the Manhattan Project, one of the key figures in the development of the hydrogen bomb, and one of the Hungarian “Martians.” In UFO literature he comes up because of the birth of the Fermi paradox, the 1949 green fireball conference, and Bob Lazar’s claims.
Eric Burlison – Eric Burlison is a Republican politician from Missouri who has been a member of the U.S. House of Representatives since 2023. On the UAP topic, he is among the representatives in Congress calling for transparency, and he has taken part in hearings dealing with the subject.
Eric W. Davis – Eric W. Davis is an American astrophysicist who works on advanced propulsion concepts and the frontier areas of physics. On the UFO/UAP topic, he is known for organizing studies for the AAWSAP program, for the Wilson memo leaked in 2019, and for his claims about vehicles not made on Earth.
Fife Symington – Fife Symington III is an American Republican politician who was Governor of Arizona from 1991 to 1997. Ten years after the 1997 Phoenix Lights case, he said publicly that he himself had seen a huge object of unknown origin.
Guillermo Roncoroni – Guillermo Roncoroni is an Argentine ufologist known mainly for his 1977 write-up of the 1960 Yacanto UFO photo linked to an Argentine Air Force officer.
Hal Puthoff – Harold E. "Hal" Puthoff is an American physicist and engineer who, together with Russell Targ, led remote viewing research at the Stanford Research Institute funded by the CIA and military intelligence. He later also played a role in studies connected to the Pentagon's UAP program and in the company To The Stars.
Ian Ridpath – Ian Ridpath is a British science writer and a well-known figure in astronomy popularization. As one of the representatives of skeptical UFO research, he interprets the Rendlesham Forest incident and other sightings with natural explanations.
J. Allen Hynek – J. Allen Hynek was an American astronomer who worked for decades as the scientific adviser to the Air Force's UFO investigations and who, after his initial skepticism, called for serious research into the phenomenon.
Jacques Vallée – Jacques Vallée is a French-American astronomer, computer scientist and UFO researcher who has studied the phenomenon since the 1960s and is one of the best-known proponents of the so-called interdimensional hypothesis.
Jared Isaacman – Jared Isaacman is an American businessman and pilot, the founder of Shift4 Payments, commander of the Inspiration4 and Polaris Dawn private spaceflights, and head of NASA since December 2025. In 2026 he made several statements about UAP: in his view there is unexplained footage, but he does not know of any alien craft or bodies.
Jay Stratton – Jay Stratton is a U.S. intelligence official, a senior analyst at the Office of Naval Intelligence (ONI), and former director of the Pentagon's UAP Task Force (UAPTF). Since 2025 he has claimed that he has seen non-human craft and beings with his own eyes.
Jeremy Corbell – Jeremy Corbell is an American documentary filmmaker and podcaster who has been publishing UFO- and UAP-related material for years, including military footage and interviews. His work is hotly debated both by those interested in the subject and by skeptics.
Jesse Marcel – Jesse Marcel (1907–1986) was an officer in the U.S. Army Air Forces who took part in recovering the Roswell debris in 1947. He later claimed that the debris consisted of materials that were not of terrestrial origin.
Jimmy Carter – Jimmy Carter (1924–2024) was the 39th president of the United States from 1977 to 1981. On the UFO topic, he is known for having seen a bright, unusual object in the sky with the naked eye in 1969, and for promising open government handling of UFO data in his campaign.
Jonathan McDowell – Jonathan McDowell is a British–American astronomer who, until his retirement in 2026, worked at the Harvard–Smithsonian Center for Astrophysics, and is one of the best-known data compilers of space activity. In the UAP debate he appears as a skeptical commentator with a scientific approach.
Kenneth Arnold – Kenneth Arnold was an American businessman and private pilot whose June 1947 sighting is considered the starting point of the modern flying saucer phenomenon and led to the spread of the term "flying saucer."
Luis Elizondo – Luis Elizondo is a former U.S. intelligence officer who, by his own account, led the Pentagon's UFO program, AATIP, and then publicly resigned from his post in 2017 to draw attention to the UAP phenomenon.
Marco Langbroek – Marco Langbroek is a Dutch archaeologist, astronomer and satellite observer, and a lecturer at Delft University of Technology. He is a well-known expert in tracking classified satellites and identifying spectacular sky phenomena.
Michael Garrett – Michael Garrett is a Scottish radio astronomer, a professor at the University of Manchester and director of the Jodrell Bank Centre for Astrophysics. He is a well-known researcher in SETI, the search for extraterrestrial intelligence.
Michael Shermer – Michael Shermer is an American science writer and skeptic researcher, the founder of Skeptic magazine, who regularly examines and refutes claims related to UFO phenomena from the standpoint of pseudoscience.
Michio Kaku – Michio Kaku is an American theoretical physicist, one of the early researchers of string theory, and a well-known science communicator who has argued in several interviews that UAP phenomena should be investigated with scientific seriousness.
Mick West – Mick West is a British-born American skeptic researcher and the founder of the Metabunk forum, who analyzes UFO/UAP videos and reports and looks for scientific explanations.
Paola Harris – Paola Leopizzi Harris is an Italian-American journalist and UFO researcher and a well-known proponent of exopolitics. Her best-known work is Trinity: The Best-Kept Secret, co-written with Jacques Vallée, about an alleged 1945 UFO crash in New Mexico.
Paul Hellyer – Paul Hellyer (1923–2021) was a Canadian politician and minister of national defence from 1963 to 1967. In his retirement years, from the 2000s on, he claimed that Earth is visited by several alien species and that Western governments are concealing this; he became one of the highest-ranking public advocates of the subject.
Philip Corso – Philip J. Corso (1915–1998) was an American intelligence officer who claimed in his 1997 book The Day After Roswell that he had passed alien technology from the Roswell wreckage to American companies. Critics identified numerous factual errors and impossible chronologies in the book.
Philip J. Klass – Philip J. Klass (1919–2005) was an American electrical engineer and journalist, an editor at Aviation Week & Space Technology, one of the best-known skeptical researchers of UFO phenomena, and a founding member of CSICOP.
Robert Bigelow – Robert Bigelow is an American billionaire businessman, founder of the Budget Suites hotel chain and Bigelow Aerospace, and one of the best-known private funders of research into UFOs and paranormal phenomena.
Robert F. Kennedy Jr. – Robert F. Kennedy Jr. is an American lawyer and politician who has been U.S. Secretary of Health since 2025. As a presidential candidate, he spoke out on several occasions in favor of the government disclosing UAP matters.
Robert Sheaffer – Robert Sheaffer is an American skeptic writer and researcher who has been examining UFO reports and stories for decades and looks for natural or mundane explanations for them. He is the author of the Bad UFOs blog.
Roberto Pinotti – Roberto Pinotti is an Italian journalist and ufologist, the founder and president of the Centro Ufologico Nazionale (CUN). A well-known figure in Italian UFO research, he is the main promoter of the disputed Gabinetto RS/33 and Magenta story.
Ryan Graves – Ryan Graves is a former U.S. Navy F/A-18 pilot who, together with fellow pilots, repeatedly observed unidentified anomalous phenomena (UAP) during live training exercises. Since then he has campaigned for transparency and pilot safety, and he has also testified before Congress on the subject.
Sean Kirkpatrick – Sean Kirkpatrick is an American physicist and intelligence official, the first director of AARO (All-domain Anomaly Resolution Office), who led the investigation of UAP matters at the Pentagon from the office's establishment until 2023.
Stanton Friedman – Stanton T. Friedman (1934–2019) was a Canadian-American nuclear physicist, one of the best-known figures in UFO research, the modern-day rediscoverer of the Roswell incident, and a lecturer who argued for vehicles of alien origin.
Tom DeLonge – Tom DeLonge is an American musician, a co-founder of Blink-182 and the frontman of Angels & Airwaves. As the founder of the To The Stars Academy of Arts and Science, and through his role in the public release of the Navy UAP videos, he became one of the well-known advocates of the UAP topic.

Concepts

'Oumuamua – ‘Oumuamua is the first known interstellar object, which passed through the Solar System in 2017. Because of its unusual shape and its motion deviating slightly from gravity, astrophysicist Avi Loeb also raised the possibility of an artificial origin, but most scientists consider it a natural object.
2024 New Jersey drone wave – Starting in November 2024, numerous reports came in of drones said to be of unknown origin over New Jersey and the surrounding states. According to the authorities, most of the sightings were legal drones, conventional aircraft or stars.
3I/ATLAS – 3I/ATLAS is the third known interstellar object to pass through the Solar System; it was discovered in July 2025 with the ATLAS telescope network. Astronomers identified it as a comet.
AATIP – AATIP (Advanced Aerospace Threat Identification Program) was a U.S. Department of Defense program that investigated unidentified aerial phenomena (UAP) between 2007 and 2012. The program's existence was made public by the New York Times in 2017.
AAWSAP – AAWSAP (Advanced Aerospace Weapon System Applications Program) was a research program that ran from 2008 to 2012, funded by the US Defense Intelligence Agency, which studied UFO/UAP phenomena and presumed advanced aerial threats.
abduction – Abduction (abduction by aliens) refers to the phenomenon in which a person claims that unknown beings – often the presumed crew of UFOs – took them against their will and subjected them to examinations.
Apollo 17 blue dots – The Apollo 17 blue dots are tiny dots visible on a 1972 Apollo 17 photo, which the Pentagon published, highlighted, among its UFO files in May 2026. Some UFO researchers consider them unknown objects; according to skeptical experts, they are common flaws of the film stock and its development.
autokinetic effect – The autokinetic effect is an apparent motion: a stationary point of light, viewed for a long time in darkness without a reference point, appears to the observer to waver and shift. It is a common explanation for some nighttime UFO/UAP sightings.
Black Knight – The Black Knight is one of the best-known modern legends in UFO and conspiracy-theory literature: an allegedly roughly 13,000-year-old artificial object orbiting the Earth.
Bokeh – In photography, bokeh is the aesthetic quality of the out-of-focus, blurred area, mainly the appearance of the blurred spots of light visible in the background. It comes up in the analysis of UFO/UAP photos and videos because a light source recorded out of focus often looks like a "strange object."
close encounter – In UFO research, a close encounter is a category based on the distance between the observer and the observed object, and on their interaction. It was systematized by astronomer J. Allen Hynek, who distinguished three basic types.
contactee – A contactee is a person who claims to have come into conscious, voluntary contact with extraterrestrial beings, as opposed to abduction victims (abductees). The term originates in the UFO culture of the 1950s.
crash retrieval – In ufology, the term "crash retrieval" (roncsmentés) refers to alleged operations in which government or military bodies recover and classify crashed aircraft of unknown origin and their wreckage, possibly also remains.
disclosure – In the UFO/UAP field, "disclosure" refers to the process, or the demand, by which governments, militaries and intelligence services would make public the information they hold related to UFOs or extraterrestrial life.
drone swarm – A drone swarm is a group of a large number of unmanned aerial vehicles operating in coordination with one another. In the UAP topic, it has become a frequently mentioned concept in connection with the group appearances of unidentified drones observed over military bases.
Face on Mars – The Face on Mars is a hill in the Cydonia region that, in a 1976 image taken by the Viking 1 probe, showed a formation resembling a human face. According to later, higher-resolution images, it is a natural formation.
fireball – A fireball (bolide) is an unusually bright meteor that glows because a fragment of an asteroid or comet heats up as it enters Earth's atmosphere. It often prompts UFO reports because it is spectacular and fast.
five observables – The “five observables” is a set of concepts used by UFO/UAP researchers – including Hal Puthoff and staff members of To The Stars Academy – to describe recurring, physically hard-to-explain characteristics of unidentified aerial phenomena.
flying saucer – Flying saucer is a popular term for disc-shaped flying objects of unknown origin that spread in the wake of the 1947 American sightings.
Freedom of Information Act – The Freedom of Information Act (FOIA) is a 1966 United States law that allows anyone to request the release of documents held by federal government agencies. In UFO research, it is the main tool for obtaining government records.
GoFast video – GoFast is an infrared recording made in 2015 by a U.S. Navy fighter jet, in which a small object appears to move quickly above the sea. It became public in 2018, and the Pentagon officially released it in 2020. According to later analyses, the appearance of fast motion is caused by parallax.
Halt memorandum – The Halt memorandum is a one-page note written in 1981 by U.S. Lieutenant Colonel Charles I. Halt about unexplained light phenomena that occurred near Rendlesham Forest in December 1980. It is one of the best-known documents among British UFO cases.
Kecksburg incident – The Kecksburg incident took place on December 9, 1965, in the Kecksburg area of Pennsylvania: after a fireball seen in several states, according to locals an acorn-shaped object fell into the woods. The Air Force and astronomers considered it a meteor, and according to the trajectory calculation it ended near Lake Erie; NASA's investigation records were lost.
Lens flare – Lens flare is an optical artifact that occurs when strong light – the sun, a lamp, a spotlight – scatters and reflects within the lens system of a camera or video camera. In UFO footage it often appears as a floating spot of light.
lenticular cloud – A lenticular cloud is a lens- or disc-shaped cloud that forms on the lee side of mountains as a result of wavelike airflow. It is often mistaken for a flying saucer.
mothership – In UFO literature, a mothership is a hypothetical, large alien spacecraft that would carry or launch smaller flying craft. There is no scientifically accepted evidence of its existence.
National Defense Information – National Defense Information is a key concept of the U.S. Espionage Act: information related to the national defense and closely held by the government, the unauthorized obtaining or transmission of which is punishable under the law.
non-human intelligence – “Non-human intelligence” (NHI) is an umbrella term used in debates about UFO/UAP phenomena for hypothetical intelligent beings or entities that are not of human origin
Orb – In UFO/UAP reports, an orb is a spherical object that glows or has a metallic sheen; it may be a genuine sighting, but it is often a photographic artifact or a known object.
parallax – Parallax is the apparent shift an object shows against its background when the observer's position changes. In astronomy it is the basis of distance measurement, and in UFO sightings it helps in judging distance and size.
Phoenix Lights – Phoenix Lights is the collective name for the light phenomena seen by many people in and around Arizona on March 13, 1997, one of the most frequently cited cases in American UFO history.
pileus – A pileus is a small, cap- or hood-shaped accessory cloud that forms above the top of a rapidly growing cumulus cloud or thundercloud. Its unusual appearance has also prompted UFO speculation.
PURSUE – PURSUE (Presidential Unsealing and Reporting System for UAP Encounters) is a U.S. government program launched in May 2026 that publishes declassified UAP records from various federal agencies in installments, in a public collection.
reentering space debris – Reentering space debris is the portion of the defunct, human-made objects orbiting in space that burns up on entering the atmosphere or partially falls to the surface. It can cause spectacular light phenomena that are often mistaken for UFOs.
reptilians – Reptilians are reptile-like, shape-shifting humanoid beings featured in modern conspiracy theories who, according to some theories, secretly live among humans and control the world. The idea was spread mainly by British author David Icke; there is no evidence of their existence.
Roswell incident – The Roswell incident is a case connected to debris found near Roswell, New Mexico, in Summer 1947, which ufologists interpret as the crash of an extraterrestrial spacecraft. According to the official finding, it was the remains of a secret military balloon program.
sky lantern – The sky lantern (Chinese lantern) is a paper lantern that works like a small hot-air balloon, heated from inside by an open flame. It frequently causes UFO reports, because at night it appears as an orange light, a slowly floating object.
temperature inversion – A temperature inversion is an atmospheric condition in which air temperature increases rather than decreases with altitude. It matters in the investigation of UFO phenomena because it changes how light and radar waves propagate.
Tic Tac – The “Tic Tac” got its name from a 2004 case: pilots from the USS Nimitz strike group saw an elongated, white object with no wings or engines off the coast of Southern California, which an infrared camera also recorded later that day. There is still no official explanation for it, but according to skeptics, an instrument error, a misinterpretation or a distant aircraft could also be behind it.
tractor beam – A tractor beam is a hypothetical beam, familiar from science fiction, that can attract or move objects from a distance. In UFO literature it appears as an alleged capability of UFOs, mainly in abduction stories; in physics, only microscopic-scale counterparts are known.
UFO and UAP – The term UFO was introduced by the US Air Force in the 1950s. It originally denoted only the fact that something was unidentified, but in the public mind it became intertwined with the image of alien spacecraft. For this reason, official US usage today prefers the more neutral UAP, which covers not only aerial phenomena but also those observed underwater and in space.
UFO wave – A UFO wave is the term for a short period when an unusually high number of UFO reports come in from a given area. Opinions on the causes differ: according to skeptics, the number of reports is often driven up by public attention and media coverage.
Varginha UFO crash – The event known as the Varginha UFO crash took place in January 1996 in the city of Varginha, Brazil, where, according to witnesses, alien beings were found. According to the official finding, the case is not of extraterrestrial origin.