Identified flying object
Encyclopedia
Identifying Unidentified Flying Objects is a difficult task due to the normally poor quality of the evidence provided by those who report sighting the objects. Nevertheless, most officially investigated UFO sightings, such as from the U.S. Air Force's Project Blue Book
, have been identified as being due to honest misidentifications of natural phenomena, aircraft, or other prosaic explanations. In early U.S. Air Force attempts to explain UFO sightings, unexplained sightings routinely numbered over one in five reports. However, in early 1953, right after the CIA's Robertson Panel
, percentages of unexplained sightings dropped precipitously, usually being only a few percent in any given year. When Project Blue Book closed down in 1970, only 6% of all cases were classified as being truly unidentified.
UFOs that can be explained are sometimes termed "IFOs" or Identified Flying Objects.
In contrast, much more conservative numbers for the percentage of UFOs were arrived at individually by astronomer Allan Hendry
, who was the chief investigator for the Center for UFO Studies
(CUFOS). CUFOS was founded by astronomer Dr. Allen Hynek
(who had been a consultant for the Air Force’s Project Blue Book) to provide a serious scientific investigation into UFOs. Hendry spent 15 months personally investigating 1,307 UFO reports. In 1979, Hendry published his conclusions in The UFO Handbook: A Guide to Investigating, Evaluating, and Reporting UFO Sightings. Hendry admitted that he would like to find evidence for extraterrestrials but noted that the vast majority of cases had prosaic explanations. He found 89% of reports definitely or probably identifiable and only 9% unidentified. “Hardcore” cases—well-documented events which defied any conceivable conventional explanation—made up only 1.5% of the reports.
Out of 3,201 cases, 69% were judged to be identified, 22% were unidentified, and 9% had insufficient information to make a determination.
BBSR further broke these results down based on whether the identification was considered certain or merely doubtful. For example, in both the astronomical and aircraft IFO categories, 12% were considered certain and 9% were doubtful. Overall, of the 69% listed as IFOs, 42% were thought to be solved with certainty, while 27% were still considered doubtful.
In addition, if a case was lacking in adequate data, it was placed in the insufficient information category, separate from both IFOs and UFOs.
The Battelle BBSR study included of many internal military reports; fully 38% of the cases were designated as military. Military witnesses tended to submit better quality reports, had much fewer reports rated as having insufficient information, and had higher percentages of unknowns. As in the previous breakdown, the percentage of UFOs again rose with case quality for both the military and civilian subcategories.
In the summary table, best reports are those rated excellent and good; worst reports are doubtful” and poor.
In the initial results, all characteristics except brightness tested significant at less or much less than 1% (brightness was greater than 5%). By removing "astronomical" sightings from the "knowns" and redoing the test, just two categories, number and speed, were significant at less than 1%, the remainder having results between 3% and 5%. This indicated that there was a statistically significant difference between the characteristics ascribed to UFOs and IFOs, but perhaps not as significant as the initial results suggested. For two characteristics, brightness and speed, the significance actually increased with the revised test.
found that only a small percentage of cases were hoaxes and that most sightings were actually honest misidentifications of prosaic phenomena. Hendry attributed most of these to inexperience or misperception.
Out of 1,307 cases Hendry deemed 88.6% had clear prosaic explanations (IFOs) and only 8.6% were unknowns (UFOs). Of the UFOs, Hendry reported that 7.1%, might still have a prosaic explanation while 1.5% (20 cases) had no possible plausible explanation and were completely unexplained. The remaining miscellaneous cases (2.8%) were “garbage” cases, where Hendry deemed the witnesses unreliable, the reports hopelessly contradictory, or lacking in sufficient information.
Overall, in the three major categories, 42% of all cases had astronomical explanations, 37% were aircraft, and 5% were balloons. A further breakdown allowed 77% to be readily explained by five main classes of objects: 29% were bright stars or planets, 19% were advertising planes, 15% were other aircraft, 9% were meteors and reentering space debris, and 5% were balloons of various types (mostly weather or advertising balloons but also a few prank balloons).
s and planets made up 29% of all cases while meteors (and to a much lesser extent, re-entering space debris) made up 9%. Hovering aircraft such as helicopters or blimps, or aircraft that appear to be hovering, such as airplanes seen at night from the front with their headlights on as they approach for landing can often confuse witnesses, as can aircraft strobe lights. BBSR reported a much higher percentage of balloons than Hendry.
Claims of misidentification are after-the-fact analyses, not direct observations, and are often misconstrued by skeptics and UFO advocates alike: They do not suggest that the experiences did not exist, but merely that they can be explained by prosaic causes. For instance, retrospective analyses of the Jimmy Carter UFO incident
of 1969 connect the sighting with the known position of the planet Venus for that time, date, and location. Gordon Cooper
, a strong advocate of the Extraterrestrial hypothesis
, claimed to have been fooled by the planet Venus when he was a fighter pilot, thinking it a distant enemy plane, and the 1967 "flying cross" of Devon, England and the 1966 Portage County UFO Chase
case have both been associated with astronomical sources.
There are several natural and man-made objects that are commonly suggested as explanations for UFO sightings:
Venus: Venus
is the brightest object in the sky (except for the sun, the moon and the International Space Station
), and is often visible in the early evening and morning sky. Even experienced witnesses, especially when they are in unfamiliar surroundings or unusual atmospheric conditions, can fail to identify Venus correctly. However, the location of Venus is easily calculable, and professional astronomers report that many of the phone calls they receive from concerned citizens reporting the presence of a UFO are due to observations of the planet. Astronomer Phil Plait, in particular, has suggested that Venus is responsible for a majority of all UFO reports
Meteors: The brightest meteors known as bollides are long lasting fireballs that leave a trail in the sky which can be visible for up to an hour after passing. Such events are relatively rare but can be witnessed by a large area of the Earth since most events occur kilometers up in the atmosphere. Those witnessing such events who are not familiar with meteors can be easily fooled into thinking that the meteor is a UFO. Because meteors are not predictable with the same degree of accuracy as planets, stars, or man-made objects such as satellites, these occurrences are more difficult to prove in retrospect, though UFO sightings during meteor showers, or where there are astronomical reports of bollides, are likely to be explained as such.
Weather balloons, aircraft, satellites and other man-made objects:
Lenticular clouds:
, caused by small, involuntary eye movements after staring at a star-like light against a black background without a frame of reference. To some observers, these may cause stars and planets to appear to start and stop, change direction, or dart around. Hendry and other UFO skeptics attribute complex patterns of apparent motion in UFO reports to the autokinetic effect, but this is disputed.
Another type of misperceived motion sometimes occurs when people are driving in a vehicle. Witnesses may believe the “UFO” was following them even though the celestial body was actually stationary. Even police and other normally reliable witnesses can occasionally be fooled by sightings of bright stars and planets.
In about 10% of Hendry’s cases caused by celestial bodies, witnesses greatly underestimated distances to the objects, giving distance estimates ranging from 200 feet to 125 miles (60 m to 200 km).
According to Hendry, moving clouds may also sometimes confuse observers by creating induced motion. Hendry believes this occasionally makes observers also believe objects have suddenly disappeared or make a rapid departure.
is a type of mirage
responsible for some UFO sightings, by making objects located below the astronomical horizon
appear to be hovering in the sky. It also magnifies images and makes them look unrecognizable.
The UFOs seen on radar
can also be due to Fata Morgana, since water vapor in the air can create radar mirages more readily than temperature inversions can create optical mirages. According to GEPAN/SEPRA, the official UFO investigation in France,
s, moondogs
, sundogs
, auroras
, ground lights such as street lights, and searchlights reflected off of clouds), and atmospheric phenomena such as clouds, dust and fog (including unusual cloud formations such as lenticular cloud
s, noctilucent cloud
s, rainbow effects, and high-altitude ice crystals). Other identified causes included kites, flares, reflections off windows, and windborn debris.
.jpg)
More recently, Professor Colin Price head of the Geophysics and Planetary Sciences Department at Tel Aviv University
has commented that occurrences of upper-atmospheric lightning
such as sprites, elves and blue jets could account for some of the strange reports of UFO sightings.
Project Blue Book
Project Blue Book was one of a series of systematic studies of unidentified flying objects conducted by the United States Air Force. Started in 1952, it was the second revival of such a study...
, have been identified as being due to honest misidentifications of natural phenomena, aircraft, or other prosaic explanations. In early U.S. Air Force attempts to explain UFO sightings, unexplained sightings routinely numbered over one in five reports. However, in early 1953, right after the CIA's Robertson Panel
Robertson Panel
The Robertson Panel was a committee commissioned by the Central Intelligence Agency in 1952 in response to widespread reports of unidentified flying objects, especially in the Washington, D.C. area. The panel was briefed on U.S...
, percentages of unexplained sightings dropped precipitously, usually being only a few percent in any given year. When Project Blue Book closed down in 1970, only 6% of all cases were classified as being truly unidentified.
UFOs that can be explained are sometimes termed "IFOs" or Identified Flying Objects.
UFO studies
The following are some major studies undertaken during the past 50 years that reported on identification of UFOs:- Project Blue Book Special Report No. 14 (referred to further below as BBSR) was a massive statistical study the Battelle Memorial InstituteBattelle Memorial InstituteBattelle Memorial Institute is a private nonprofit applied science and technology development company headquartered in Columbus, Ohio. Battelle is a charitable trust organized as a nonprofit corporation under the laws of the State of Ohio and is exempt from taxation under Section 501 of the...
did for the USAF of 3,200 UFO cases between 1952 and 1954. Of these, 22% remained were classified as unidentified (“true UFOs”). Another 69% were deemed identified (IFOs). There was insufficient information to make a determination in the remaining 9%.
- The official French government UFO investigation (GEPAN/SEPRA), run within the French space agency CNESCNESThe is the French government space agency . Established under President Charles de Gaulle in 1961, its headquarters are located in central Paris and it is under the supervision of the French Ministries of Defence and Research...
between 1977 and 2004, scientifically investigated about 6000 cases and found that 13% defied any rational explanation (UFOs), while 46% were deemed readily identifiable and 41%, lacked sufficient information for classification.
- The USAF-sponsored Condon CommitteeCondon CommitteeThe Condon Committee was the informal name of the University of Colorado UFO Project, a group funded by the United States Air Force from 1966 to 1968 at the University of Colorado to study unidentified flying objects under the direction of physicist Edward Condon...
study reported that all 117 cases studies were or could probably be explained. A 1971 review of the results by the American Institute of Aeronautics and AstronauticsAmerican Institute of Aeronautics and AstronauticsThe American Institute of Aeronautics and Astronautics is the professional society for the field of aerospace engineering. The AIAA was founded in 1963 from the merger of two earlier societies: the American Rocket Society , founded in 1930 as the American Interplanetary Society , and the Institute...
concluded that 30% of the 117 cases remained unexplained.
- Of about 5,000 cases submitted to and studied by the civilian UFO organization NICAP, 16% were judged unknowns.
In contrast, much more conservative numbers for the percentage of UFOs were arrived at individually by astronomer Allan Hendry
Allan Hendry
Allan Hendry is an American astronomer and ufologist. UFO historian Jerome Clark calls him "one of the most skilled investigators in the history of UFO research." He was the main investigator for the Center for UFO Studies in the 1970s....
, who was the chief investigator for the Center for UFO Studies
Center for UFO Studies
The Center for UFO Studies is a privately-funded UFO research group. It was founded in 1973 by Dr. J. Allen Hynek, the Chairman of the Department of Astronomy at Northwestern University in Illinois....
(CUFOS). CUFOS was founded by astronomer Dr. Allen Hynek
J. Allen Hynek
Dr. Josef Allen Hynek was a United States astronomer, professor, and ufologist. He is perhaps best remembered for his UFO research. Hynek acted as scientific adviser to UFO studies undertaken by the U.S. Air Force under three consecutive names: Project Sign , Project Grudge , and Project Blue Book...
(who had been a consultant for the Air Force’s Project Blue Book) to provide a serious scientific investigation into UFOs. Hendry spent 15 months personally investigating 1,307 UFO reports. In 1979, Hendry published his conclusions in The UFO Handbook: A Guide to Investigating, Evaluating, and Reporting UFO Sightings. Hendry admitted that he would like to find evidence for extraterrestrials but noted that the vast majority of cases had prosaic explanations. He found 89% of reports definitely or probably identifiable and only 9% unidentified. “Hardcore” cases—well-documented events which defied any conceivable conventional explanation—made up only 1.5% of the reports.
Project Blue Book Special Report No. 14
Project Blue Book Special Report No. 14 was compiled between 1951 and 1954, and included 3201 reported UFO sightings. Battelle employed four scientific analysts, who sought to divide cases into "knowns", "unknowns", and a third category of "insufficient information." They also broke down knowns and unknowns into four categories of quality, from excellent to poor. In order for a case to be deemed "identified", two analysts had to independently agree on a solution and for a case to be called "unidentified", all four analysts had to agree. A report classified as "unidentified" was defined as: "Those reports of sightings wherein the description of the object and its maneuvers could not be fitted to the pattern of any known object or phenomenon."Out of 3,201 cases, 69% were judged to be identified, 22% were unidentified, and 9% had insufficient information to make a determination.
Breakdown by category of IFO and case quality
| Category/Case Quality | All | Excellent | Good | Doubtful | Poor |
|---|---|---|---|---|---|
| Astronomical | 22% | 24% | 23% | 19% | 23% |
| Aircraft | 22% | 19% | 22% | 25% | 16% |
| Balloon | 15% | 12% | 17% | 17% | 13% |
| Light phenomena | 2.2% | .9% | 2.4% | 2.9% | 1.1% |
| Birds | 1.0% | 0.9% | 1.0% | 1.2% | 0.7% |
| Clouds, dust, etc. | 0.4% | 0% | 1.0% | 0.4% | 0% |
| Psychological | 2.0% | 0% | 0.5% | 3.3% | 3.3% |
| Other | 5% | 5% | 5% | 5% | 6% |
| Insufficient information | 9% | 4% | 4% | 14% | 21% |
| Unknown origin | 22% | 33% | 25% | 13% | 17% |
BBSR further broke these results down based on whether the identification was considered certain or merely doubtful. For example, in both the astronomical and aircraft IFO categories, 12% were considered certain and 9% were doubtful. Overall, of the 69% listed as IFOs, 42% were thought to be solved with certainty, while 27% were still considered doubtful.
In addition, if a case was lacking in adequate data, it was placed in the insufficient information category, separate from both IFOs and UFOs.
Military vs. civilian breakdown
| IFO | UFO | Insufficient Information | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Mil | Civ | All | Mil | Civ | All | Mil | Civ | All | |
| Best reports | 65% | 72% | 68% | 32% | 24% | 28% | 2% | 4% | 3% |
| Worst reports | 70% | 70% | 70% | 24% | 14% | 16% | 7% | 17% | 14% |
The Battelle BBSR study included of many internal military reports; fully 38% of the cases were designated as military. Military witnesses tended to submit better quality reports, had much fewer reports rated as having insufficient information, and had higher percentages of unknowns. As in the previous breakdown, the percentage of UFOs again rose with case quality for both the military and civilian subcategories.
In the summary table, best reports are those rated excellent and good; worst reports are doubtful” and poor.
Comparison of IFOs to UFOs by characteristics
A key study of BBSR was to statistically compare IFOs and UFOs by six characteristics: color, number of objects, shape, duration of observations, speed, and light brightness. If there were no significant differences, the two classes were probably the same, the UFOs then representing merely a failure to properly identify prosaic phenomena that could already account for the IFOs. On the other hand, if the differences were statistically significant, this would suggest IFOs and UFOs were indeed distinctly different phenomena.In the initial results, all characteristics except brightness tested significant at less or much less than 1% (brightness was greater than 5%). By removing "astronomical" sightings from the "knowns" and redoing the test, just two categories, number and speed, were significant at less than 1%, the remainder having results between 3% and 5%. This indicated that there was a statistically significant difference between the characteristics ascribed to UFOs and IFOs, but perhaps not as significant as the initial results suggested. For two characteristics, brightness and speed, the significance actually increased with the revised test.
Allan Hendry study
Like the Air Force, astronomer Allan HendryAllan Hendry
Allan Hendry is an American astronomer and ufologist. UFO historian Jerome Clark calls him "one of the most skilled investigators in the history of UFO research." He was the main investigator for the Center for UFO Studies in the 1970s....
found that only a small percentage of cases were hoaxes and that most sightings were actually honest misidentifications of prosaic phenomena. Hendry attributed most of these to inexperience or misperception.
Out of 1,307 cases Hendry deemed 88.6% had clear prosaic explanations (IFOs) and only 8.6% were unknowns (UFOs). Of the UFOs, Hendry reported that 7.1%, might still have a prosaic explanation while 1.5% (20 cases) had no possible plausible explanation and were completely unexplained. The remaining miscellaneous cases (2.8%) were “garbage” cases, where Hendry deemed the witnesses unreliable, the reports hopelessly contradictory, or lacking in sufficient information.
Overall, in the three major categories, 42% of all cases had astronomical explanations, 37% were aircraft, and 5% were balloons. A further breakdown allowed 77% to be readily explained by five main classes of objects: 29% were bright stars or planets, 19% were advertising planes, 15% were other aircraft, 9% were meteors and reentering space debris, and 5% were balloons of various types (mostly weather or advertising balloons but also a few prank balloons).
Breakdown of cases
Hendry also used a case classification system developed by his mentor Dr. J. Allen Hynek, who established CUFOS, where the study was carried out. In this summary table:- NL = “Nocturnal Lights”, lights seen in the sky at night.
- DD = “Daylight Discs”, objects seen in daytime (but not necessarily disc in shape).
- RV = “Radar/Visual” cases, objects observed by both witnesses and radar.
- CE = “Close Encounter” cases. For convenience, CE cases listed below are combined totals of Hynek’s CE1, CE2, and CE3 cases, where:
- CE1 cases were objects thought to be seen up close (within 500 feet).
- CE2 had purported physical interactions with the environment (physical trace cases or electromagnetic interference).
- CE3 cases were supposed to involve sightings of occupants.
| Category | NL | DD | CE | RV | Total Cases | Percent |
|---|---|---|---|---|---|---|
| Astronomical | ||||||
| bright stars or planets | 360 | 2 | 16 | 2 | 380 | 29% |
| meteors, re-entering man-made spacecraft | 113 | 5 | 4 | 0 | 122 | 9% |
| artificial satellites | 24 | 0 | 0 | 0 | 24 | 2% |
| moon | 22 | 0 | 0 | 0 | 22 | 2% |
| TOTAL (all cases) | 519 | 7 | 22 | 2 | 550 | 42% |
| Aircraft | ||||||
| advertising planes | 230 | 0 | 22 | 0 | 252 | 19% |
| other aircraft | 196 | 22 | 6 | 0 | 224 | 17% |
| missile launches | 9 | 0 | 1 | 0 | 10 | 0.7% |
| TOTAL | 435 | 22 | 29 | 0 | 486 | 37% |
| balloons | 23 | 35 | 2 | 3 | 63 | 5% |
| birds | 5 | 1 | 0 | 0 | 6 | 0.5% |
| clouds, dust | 10 | 2 | 0 | 0 | 12 | 0.9% |
| light phenomena (mirage Mirage A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirare, meaning "to look at, to wonder at"... , moon dog Moon dog A moon dog or moondog is a relatively rare bright circular spot on a lunar halo caused by the refraction of moonlight by hexagonal-plate-shaped ice crystals in cirrus or cirrostratus clouds. Moondogs appear to the left and right of the moon 22° or more distant... , ground lights, searchlight Searchlight A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used... s, etc.) |
9 | 1 | 4 | 0 | 14 | 1.1% |
| other (kite Kite A kite is a tethered aircraft. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates horizontal drag along the direction of the wind... s, flares, reflections, windblown debris, etc.) |
12 | 3 | 1 | 0 | 16 | 1.2% |
| Total Identified | ||||||
| Cases | 1024 | 71 | 58 | 5 | 1158 | 88.6% |
| Percent | 78.3% | 5.4% | 4.4% | .4% | 88.6% | |
| Total Unidentified | ||||||
| Cases | 79 | 18 | 16 | 0 | 113 | 8.6% |
| Percent | 6% | 1.4% | 1.2% | 0% | 8.6% | |
| MISC (insufficient information, inconsistent accounts, unreliable witnesses) | 36 | 2.8% | ||||
| Total all cases | ||||||
| Cases | 1103 | 89 | 74 | 5 | 1307 | 100% |
| Percent | 84.4% | 6.8% | 5.7% | 0.4% | 100% |
Common causes of misidentification and UFOs
Both BBSR and Hendry found that three classes of objects or phenomena—astronomical, aircraft, or balloons—accounted for a large majority of identifiable UFO reports (referred to as IFOs), 86% and 83% in the two studies. For example, in Hendry’s study, bright starStar
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s and planets made up 29% of all cases while meteors (and to a much lesser extent, re-entering space debris) made up 9%. Hovering aircraft such as helicopters or blimps, or aircraft that appear to be hovering, such as airplanes seen at night from the front with their headlights on as they approach for landing can often confuse witnesses, as can aircraft strobe lights. BBSR reported a much higher percentage of balloons than Hendry.
Claims of misidentification are after-the-fact analyses, not direct observations, and are often misconstrued by skeptics and UFO advocates alike: They do not suggest that the experiences did not exist, but merely that they can be explained by prosaic causes. For instance, retrospective analyses of the Jimmy Carter UFO incident
Jimmy Carter UFO incident
The Jimmy Carter UFO Incident is the name given to an incident in which Jimmy Carter reported seeing an unidentified flying object while at Leary, Georgia in 1969....
of 1969 connect the sighting with the known position of the planet Venus for that time, date, and location. Gordon Cooper
Gordon Cooper
Leroy Gordon Cooper, Jr. , also known as Gordon Cooper, was an American aeronautical engineer, test pilot and NASA astronaut. Cooper was one of the seven original astronauts in Project Mercury, the first manned space effort by the United States...
, a strong advocate of the Extraterrestrial hypothesis
Extraterrestrial hypothesis
The extraterrestrial hypothesis is the hypothesis that some unidentified flying objects are best explained as being extraterrestrial life or non-human aliens from other planets occupying physical spacecraft visiting Earth.-Etymology:...
, claimed to have been fooled by the planet Venus when he was a fighter pilot, thinking it a distant enemy plane, and the 1967 "flying cross" of Devon, England and the 1966 Portage County UFO Chase
Portage County UFO Chase
The Portage County UFO Chase was an unidentified flying object encounter that began in Portage County, Ohio on the morning of April 17, 1966, when police officers Dale Spaur and Wilbur Neff observed a metallic, disc shaped object flying in the skies....
case have both been associated with astronomical sources.
There are several natural and man-made objects that are commonly suggested as explanations for UFO sightings:
Venus: Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
is the brightest object in the sky (except for the sun, the moon and the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
), and is often visible in the early evening and morning sky. Even experienced witnesses, especially when they are in unfamiliar surroundings or unusual atmospheric conditions, can fail to identify Venus correctly. However, the location of Venus is easily calculable, and professional astronomers report that many of the phone calls they receive from concerned citizens reporting the presence of a UFO are due to observations of the planet. Astronomer Phil Plait, in particular, has suggested that Venus is responsible for a majority of all UFO reports
Meteors: The brightest meteors known as bollides are long lasting fireballs that leave a trail in the sky which can be visible for up to an hour after passing. Such events are relatively rare but can be witnessed by a large area of the Earth since most events occur kilometers up in the atmosphere. Those witnessing such events who are not familiar with meteors can be easily fooled into thinking that the meteor is a UFO. Because meteors are not predictable with the same degree of accuracy as planets, stars, or man-made objects such as satellites, these occurrences are more difficult to prove in retrospect, though UFO sightings during meteor showers, or where there are astronomical reports of bollides, are likely to be explained as such.
Weather balloons, aircraft, satellites and other man-made objects:
Lenticular clouds:
Misperception
Light distortion from air turbulence can cause celestial bodies to move to a limited degree as can a visual perceptual effect called the autokinetic effectAutokinetic effect
The autokinetic effect is a phenomenon of human visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move. It was first recorded by a Russian officer keeping watch who observed illusory movement of a star near the horizon...
, caused by small, involuntary eye movements after staring at a star-like light against a black background without a frame of reference. To some observers, these may cause stars and planets to appear to start and stop, change direction, or dart around. Hendry and other UFO skeptics attribute complex patterns of apparent motion in UFO reports to the autokinetic effect, but this is disputed.
Another type of misperceived motion sometimes occurs when people are driving in a vehicle. Witnesses may believe the “UFO” was following them even though the celestial body was actually stationary. Even police and other normally reliable witnesses can occasionally be fooled by sightings of bright stars and planets.
In about 10% of Hendry’s cases caused by celestial bodies, witnesses greatly underestimated distances to the objects, giving distance estimates ranging from 200 feet to 125 miles (60 m to 200 km).
According to Hendry, moving clouds may also sometimes confuse observers by creating induced motion. Hendry believes this occasionally makes observers also believe objects have suddenly disappeared or make a rapid departure.
Fata Morgana
Fata MorganaFata Morgana (mirage)
A Fata Morgana is an unusual and very complex form of mirage, a form of superior mirage, which, like many other kinds of superior mirages, is seen in a narrow band right above the horizon...
is a type of mirage
Mirage
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirare, meaning "to look at, to wonder at"...
responsible for some UFO sightings, by making objects located below the astronomical horizon
Horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...
appear to be hovering in the sky. It also magnifies images and makes them look unrecognizable.
The UFOs seen on radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
can also be due to Fata Morgana, since water vapor in the air can create radar mirages more readily than temperature inversions can create optical mirages. According to GEPAN/SEPRA, the official UFO investigation in France,
Other misidentifications
The BBSR and Hendry studies identified as rare causes for UFO reports based on misidentification, such objects and phenomena as birds, light phenomena (including mirageMirage
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirare, meaning "to look at, to wonder at"...
s, moondogs
Moon dog
A moon dog or moondog is a relatively rare bright circular spot on a lunar halo caused by the refraction of moonlight by hexagonal-plate-shaped ice crystals in cirrus or cirrostratus clouds. Moondogs appear to the left and right of the moon 22° or more distant...
, sundogs
Sun dog
A sun dog or sundog, scientific name parhelion ; , also called a mock sun or a phantom sun, is an atmospheric phenomenon that creates bright spots of light in the sky, often on a luminous ring or halo on either side of the sun.Sundogs may appear as a colored patch of light to the left or right of...
, auroras
Aurora (astronomy)
An aurora is a natural light display in the sky particularly in the high latitude regions, caused by the collision of energetic charged particles with atoms in the high altitude atmosphere...
, ground lights such as street lights, and searchlights reflected off of clouds), and atmospheric phenomena such as clouds, dust and fog (including unusual cloud formations such as lenticular cloud
Lenticular cloud
Lenticular clouds are stationary lens-shaped clouds that form at high altitudes, normally aligned perpendicular to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis , stratocumulus standing lenticular , and cirrocumulus standing lenticular...
s, noctilucent cloud
Noctilucent cloud
Night clouds or Noctilucent clouds are tenuous cloud-like phenomena that are the "ragged-edge" of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. The name means roughly night...
s, rainbow effects, and high-altitude ice crystals). Other identified causes included kites, flares, reflections off windows, and windborn debris.
Upper atmospheric lightning
Tel Aviv University
Tel Aviv University is a public university located in Ramat Aviv, Tel Aviv, Israel. With nearly 30,000 students, TAU is Israel's largest university.-History:...
has commented that occurrences of upper-atmospheric lightning
Upper-atmospheric lightning
Upper-atmospheric lightning or upper-atmospheric discharge are terms sometimes used by researchers to refer to a family of short-lived electrical-breakdown phenomena that occur well above the altitudes of normal lightning and storm clouds. Upper-atmospheric lightning is believed to be electrically...
such as sprites, elves and blue jets could account for some of the strange reports of UFO sightings.
Astronomical object misidentification
The frequent reporting of bright stars and planets as UFOs has caused at least one misidentification. In August 1965 the U.S. Air Force tried to explain widespread UFO sightings in the midwest as bright stars in or near the constellation Orion. However, Orion, a winter constellation, was still well below the horizon at the time, a fact quickly pointed out by some astronomers, and the Air Force was forced to make a hasty retraction.External links
- Astronomical Causes of UFOs (Ian RidpathIan RidpathIan William Ridpath is an English science writer and broadcaster made famous for his investigation and explanation of the Rendlesham Forest Incident of December 1980....
) - IFO cases caused by stratospheric balloons
- Common IFO Phenomenon (Robert MooreRobert MooreRobert Moore may refer to:*Robert Moore , Northern Ireland theologian and politician*Robert Moore , United States Congressman from Pennsylvania...
) - Text of UFO STUDY Part 1 (UFO Investigation), gives detailed description of various IFO types (Jenny RandlesJenny RandlesJenny Randles is a British author and former director of investigations with the British UFO Research Association , serving in that role from 1982 through to 1994.-Career:Randles specializes in writing books on UFOs and paranormal phenomena...
)