Explanations for a Majority of UFO Sightings
Majority of UFOs can be Identified as Ordinary Objects or Natural Phenomena

Explanations for a Majority of UFO Sightings
Majority of UFOs can be Identified as Ordinary Objects or Natural Phenomena

Unidentified flying object which is commonly abbreviated as UFO or U.F.O. is the popular term for any apparent aerial phenomenon whose cause cannot be easily or immediately identified by the observer.

The United States Air Force, which coined the term in 1952, initially defined UFOs as those objects that remain unidentified after scrutiny by expert investigators, though today the term UFO is colloquially used to refer to any unidentifiable sighting regardless of whether it has been investigated.

Studies show that after careful investigation, the majority of UFOs can be identified as ordinary objects or phenomena.

While there is some controversy over many UFO sightings there are quite a few sightings which can be explained by
ordinary objects and natural phenomena such as:
  • Astronomical objects (bright stars, planets, meteors, re-entering man-made spacecraft, artificial satellites, and the moon)
  • Aircraft (Aerial advertising and other aircraft, missile launches)
  • Balloons (weather balloons, prank balloons, large research balloons)
  • Other atmospheric objects and phenomena (birds, unusual clouds, kites, flares)
  • Light phenomena (mirages, fata morgana, moon dogs, swamp gas, searchlights and other ground lights, etc.)
  • Hoaxes
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.

Project Blue Book stated that UFOs sightings were generated as a result of:
  • A mild form of mass hysteria.
  • Individuals who fabricate such reports to perpetrate a hoax or seek publicity.
  • Psychopathological persons.
  • Misidentification of various conventional objects.
Although there are some people and organizations that cast doubt on the U.S. Air Force's Project Blue Book and its findings it is believed that up to 94% of UFO sightings can be explained due to ordinary objects and natural phenomena.

Lets explore the ordinary objects and natural phenomena to help us better understand what sometimes is being seen in the skies.

Most UFO sightings are astronomical objects, aircraft, balloons, other atmospheric objects and phenomena, as well as hoaxes.

It is believed that roughly 5%-20% of UFO reports do not follow under these categories and therefore they cannot be explained.

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 (the first two of its kind being Projects Sign and Grudge).

A termination order was given for the study in December 1969, and all activity under its auspices ceased in January 1970.


Astronomical Objects

Astronomical objects include bright stars and planets such as Venus, as well as meteors, comets, spacecraft which re-enter the Earths atmosphere, artificial satellites and the moon. These are all objects which are astronomical objects and are often mistakenly reported as a UFO. These objects are actually considered one of the top reasons for a UFO sighting.


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.


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, of 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.


Comets are another event which can be misidentified as a UFO. A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma (a thin, fuzzy, temporary atmosphere) and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet.

Comet nuclei are themselves loose collections of ice, dust, and small rocky particles, ranging from a few hundred meters to tens of kilometers across. Comets have been observed since ancient times and have historically been considered bad omens.

Comets have a wide range of orbital periods, ranging from a few years to hundreds of thousands of years. Short-period comets originate in the Kuiper Belt, or its associated scattered disc, which lie beyond the orbit of Neptune. Longer-period comets are thought to originate in the Oort Cloud, a spherical cloud of icy bodies in the outer Solar System.

Long-period comets plunge towards the Sun from the Oort Cloud because of gravitational perturbations caused by either the massive outer planets of the Solar System (Jupiter, Saturn, Uranus, and Neptune), or passing stars. Rare hyperbolic comets pass once through the inner Solar System before being thrown out into interstellar space along hyperbolic trajectories.

Satellites & Spacecrafts

Many man-made objects have been reported as UFOs. Man-made objects such as spacecraft entering the Earths atmosphere and satellites are commonly misidentified.

Thousands of satellites have been launched into orbit around the Earth. These originate from more than 50 countries and have used the satellite launching capabilities of ten nations. A few hundred satellites are currently operational, whereas thousands of unused satellites and satellite fragments orbit the Earth as space debris.

Satellites are used for a large number of purposes. Common types include military and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, and research satellites.

Satellites are tracked by United States Space Surveillance Network (SSN), which has been tracking every object in orbit over 10 cm (3.937 inches) in diameter since it was founded in 1957. There are approximately 3,000 satellites operating in Earths orbit today, according to the US National Aeronautics and Space Administration (NASA), out of roughly 8,000 man-made objects in total.

In its entire history, the SSN has tracked more than 24,500 space objects orbiting Earth. The majority of these have fallen into unstable orbits and incinerated during reentry into Earths atmosphere. The SSN also keeps track which piece of space junk belongs to which country.

Even the international space station can be misidentified as a UFO.


Even the moon which is a common sighting in the night time sky can be reported as a UFO. The fact that the moon has been misidentified as a UFO is an indication of how little certain people actually look up at the night time sky.

The Moon has an exceptionally low albedo, giving it a similar reflectance to coal. Despite this, it is the second brightest object in the sky after the Sun. This is partly due to the brightness enhancement of the opposition effect; at quarter phase, the Moon is only one-tenth as bright, rather than half as bright, as at full Moon.

Additionally, colour constancy in the visual system recalibrates the relations between the colours of an object and its surroundings, and since the surrounding sky is comparatively dark, the sunlit Moon is perceived as a bright object.

The edges of the full Moon seem as bright as the centre, with no limb darkening, due to the reflective properties of lunar soil, which reflects more light back towards the Sun than in other directions. The Moon does appear larger when close to the horizon, but this is a purely psychological effect, known as the Moon illusion, first described in the 7th century BC.


Aircraft is another very common reason behind UFO sightings. There are many more objects over the skies today then ever before.

These objects include normal everyday aircraft's. Commercial planes and small planes are very common over the skies which are reported as UFOs. There are many experimental aircraft's that the military fly over the skies generally at night which are commonly reported as UFOs as well.

For Example, the Northrop Grumman B-2 Spirit (also known as the Stealth Bomber) is an American heavy bomber with "low observable" stealth technology designed to penetrate dense anti-aircraft defenses and deploy both conventional and nuclear weapons.

It was a highly secretive aircraft which was unknown to most of the population for years. Its triangular design could easily trick the casual observer into thinking they were witnessing a UFO.

* Missile launches are another event which can cause wide-spread reports of UFOs.

* Blimps and other forms of advertising aircraft have also caused reports of UFOs.

Weather Balloons

Weather balloons have been widely known to be misidentified as UFOs. A weather or sounding balloon is a balloon (specifically a type of high altitude balloon) which carries instruments aloft to send back information on atmospheric pressure, temperature, humidity and wind speed aloft by means of a small, expendable measuring device called a radiosonde.

The balloon itself produces the lift, and is usually made of a highly flexible latex material, though Chloroprene may also be used. The unit that performs the actual measurements and radio transmissions hangs at the lower end of the string, and is called a radiosonde.

Specialized radiosondes are used for measuring particular parameters, such as determining the ozone concentration. The balloon is usually filled with hydrogen due to lower cost, though helium can be used as a good substitute.

The ascent rate can be controlled by the amount of gas with which the balloon is filled. Weather balloons may reach altitudes of 40 km (25 miles) or more, limited by diminishing pressures causing the balloon to expand to such a degree (typically by a 100:1 factor) that it disintegrates. In this instance the instrument package is usually lost.

Above that altitude sounding rockets are used. After sounding rockets, satellites are used for even higher altitudes. Weather balloons are sometimes cited as the cause for unidentified flying object sightings, and are also used for cluster ballooning.

Other Atmospheric Objects and Light Phenomena

Many everyday objects in the skies are reported as UFOs such as birds, unusual clouds, kites and flares. Birds flying in the skies as well as flocks of birds which are known to fly in a 'V' formation are reported as UFOs. Fireworks, light houses, parachutes and other man-made devices are often reported as UFOs.

Even some reports indicate that fireflies have been responsible for UFO sightings. Tropical fireflies, particularly in Southeast Asia, routinely synchronize their flashes among large groups.

Unusual clouds such as lenticular clouds which are stationary lens-shaped clouds that form at high altitudes are reported as UFOs as well. Headlights from automobiles generally when the automobile is going uphill, have attributed to UFO sightings. The fact that light can reflect off certain objects as well as the atmosphere under certain circumstances can create such a distortion that the observer believes they are witnessing a UFO.


Kites are another object which are often reported as a UFO especially LED kites which light up the night sky with multiple colors which sometimes pulsate.

These types of kites can often produce such a weird sight in the sky that many witnesses will believe they are actually seeing a UFO.

Kites vary by the nature of the main wing part (monoplane, flexible sail, stiffened flexible sail, rigid wing, biplane, multiplane, ram-air inflated, closed bladder gas inflated, rotating wing, object mimic (of animals, birds, boats, airplanes, insects, people, places, things).

For example, the main body of the kite—the wing part—may be made up of inflated gas bladders to give endless shapes. Such closed-bladder inflated wings differ from open-cell ram-air inflation like the Domina Jalbert parafoil kite. Open single-surface flexible sails are also often considered to be simply inflated by the wind.

The wing of the kite is also characterized as to its aspect ratio. Low-aspect ratio kites are tall compared to the front width of the kite's wing. High-aspect ratio kites have wings that are wide compared to their height or depth.

Also, the wing character construction type is frequently distinguished: stick-and-sail, monolithic solid (foam, wood, metal, plastic), inflated bladder, monocoque, highly trussed, or sail-only soft fully flexible; or a hybrid mix of fundamental construction types. Finally, wing character is typed by level of craftsmanship, from low to high.

* Hang Gliders have also been reported as UFOs. There are certain individuals that hang glide at night with LED lights attached to their glider. There have been reports of UFOs that have been attributed to this particular event. Generally the hang glider is equipped with LED lights which resemble a 'V' formation in the night sky.


Flares are sometimes reported as a UFO as well. A flare, also sometimes called a fusee, is a type of pyrotechnic that produces a brilliant light or intense heat without an explosion.

Flares are used for signaling, illumination, or defensive countermeasures in civilian and military applications. Flares may be ground pyrotechnics, projectile pyrotechnics, or parachute-suspended to provide maximum illumination time over a large area.

Projectile pyrotechnics may be dropped from aircraft, fired from rocket or artillery, or deployed by flare guns or handheld percussive tubes.

Flares produce their light through the combustion of a pyrotechnic composition. The ingredients are varied, but often based on strontium nitrate, potassium nitrate, or potassium perchlorate and mixed with a fuel such as charcoal, sulfur, sawdust, aluminium, magnesium, or a suitable polymeric resin.

Flares may be colored by the inclusion of pyrotechnic colorants. Calcium flares are used underwater to illuminate submerged objects.

Light Phenomena

Light distortion from air turbulence can cause celestial bodies to move to a limited degree as can a visual perceptual effect called the autokinetic effect, 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.

* Large fires and volcanoes, especially when seen from a distance can be misidentified as a UFO.

* Search lights and other ground lights have been attributed to UFO sightings. These particular lights are generally quite powerful and can cause reflections as well as they can be seen for miles away.

* Swamp gas is another event which has been attributed to UFO sightings especially in the past. This is not as common as it once was compared to the early 1950s and 60s. Many individuals believe that swamp gas was mostly used as an excuse by the government and military to cover-up a particular UFO event or possibly a top-secret military aircraft. Swamp gas is not fully understood by the scientific community.

Nevertheless, swamp gas is a gas consisting primarily of methane, typically with 0-20% higher hydrocarbons (primarily ethane). Most natural gas is created by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments.

Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material. Swamp gas under certain conditions can produce a lumination in the sky over a certain area. It is possible that this particular event could be misidentified as a UFO but it is quite rare.

* Ball lightning is another possibility of reports of UFOs. Ball lightning is a proposed atmospheric electrical phenomenon of which little is known. The term refers to reports of luminous, usually spherical objects which vary from pea-sized to several meters in diameter. It is usually associated with thunderstorms, but lasts considerably longer than the split-second flash of a lightning bolt. Many of the early reports say that the ball eventually explodes, sometimes with fatal consequences, leaving behind the odor of sulfur.

There are records of free-floating glowing balls that occur in total absence of thunderclouds, mainly in the valley of Hessdalen, Norway. One recent theory suggests that these light balls (Hessdalen Lights) are produced by the ionization of air and dust by alpha particles during radon decay in the dusty atmosphere.

Laboratory experiments have produced effects that are visually similar to reports of ball lightning, but it is presently unknown whether these are actually related to any naturally occurring phenomenon. Scientific data on natural ball lightning are scarce owing to its infrequency and unpredictability.

The presumption of its existence is based on reported public sightings, and has therefore produced somewhat inconsistent findings. Given inconsistencies and the lack of reliable data, the true nature of ball lightning is still unknown. Until recently, ball lightning was often regarded as a fantasy or a hoax, but some serious scientific discussions and theories have attempted to explain it.

* Aurora borealis are another form of light phenomena which could be misidentified as UFOs to the casual observer. Auroras, also known as northern and southern (polar) lights or aurorae (singular: aurora), are natural light displays in the sky, particularly in the polar regions, and usually observed at night. They typically occur in the ionosphere. They are also referred to as polar auroras. This is a misnomer however, because they are commonly visible between 65 to 72 degrees north and south latitudes, which place them in a ring just within the Arctic and Antarctic circles.

Aurorae do occur deeper inside the polar regions, but these are infrequent and often invisible to the naked eye. In northern latitudes, the effect is known as the aurora borealis, named after the Roman goddess of dawn, Aurora, and the Greek name for the north wind, Boreas, by Pierre Gassendi in 1621. The aurora borealis is also called the northern polar lights, as it is only visible in the sky from the Northern Hemisphere, with the chance of visibility increasing with proximity to the North Magnetic Pole.

Auroras seen near the magnetic pole may be high overhead, but from farther away, they illuminate the northern horizon as a greenish glow or sometimes a faint red, as if the Sun were rising from an unusual direction. The aurora borealis most often occurs near the equinoxes.

Its southern counterpart, the aurora australis or the southern polar lights, has similar properties, but is only visible from high southern latitudes in Antarctica, South America, or Australasia. Auroras can be spotted throughout the world and on other planets. They are most visible closer to the poles due to the longer periods of darkness and the magnetic field.

* Sundogs are another possibility for UFO reports. A sun dog or sundog 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 the sun, 22° distant and at the same distance above the horizon as the sun, and in ice halos. They can be seen anywhere in the world during any season, but they are not always obvious or bright. Sundogs are best seen and are most conspicuous when the sun is low.

Sundogs are formed by plate-shaped hexagonal ice crystals in high and cold cirrus clouds or, during very cold weather, by ice crystals called diamond dust drifting in the air at low levels. These crystals act as prisms, bending the light rays passing through them by 22°. If the crystals are randomly oriented, a complete ring around the sun is seen — a halo. But often, as the crystals sink through the air they become vertically aligned, so sunlight is refracted horizontally — in this case, sundogs are seen.

As the sun rises higher, the rays passing through the crystals are increasingly skewed from the horizontal plane. Their angle of deviation increases and the sundogs move further from the sun. However, they always stay at the same altitude as the sun. Sundogs are red-colored at the side nearest the sun. Farther out the colors grade through oranges to blue. However, the colors overlap considerably and so are muted, never pure or saturated. The colors of the sundog finally merge into the white of the parhelic circle (if the latter is visible).

It is theoretically possible to predict the forms of sundogs as would be seen on other planets and moons. Mars might have sundogs formed by both water-ice and CO2-ice. On the giant gas planets — Jupiter, Saturn, Uranus and Neptune — other crystals form the clouds of ammonia, methane, and other substances that can produce halos with four or more sundogs.

* Moondogs are another possibility for UFO sightings. 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. They are exactly analogous to sun dogs, but are rarer because to be produced the moon must be bright and therefore full or nearly full. Moondogs show little color to the unaided eye because their light is not bright enough to activate the cone cells of humans' eyes.

* Laser pointers (especially light created from a green laser) and holography (a technique that allows the light scattered from an object to be recorded and later reconstructed so that it appears as if the object is in the same position relative to the recording medium as it was when recorded. The image changes as the position and orientation of the viewing system changes in exactly the same way as if the object were still present, thus making the recorded image (hologram) appear three dimensional.) can be misidentified as a UFO as well.


Fata Morgana 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.

Inferior mirages produce images that are not stable. Hot air rises, and cooler air (being more dense) descends, so the layers will mix, giving rise to turbulence. The image will be distorted accordingly. It may be vibrating; it may be vertically extended (towering) or horizontally extended (stooping).

If there are several temperature layers, several mirages may mix together, perhaps causing double images. In any case, mirages are usually not larger than about half a degree high (same apparent size as the sun and moon) and from objects only a few kilometers away.

Superior mirages are another type of mirage that can attribute to UFO sightings. Superior mirages occur when the air below the line of sight is colder than that above. This is called a temperature inversion, since it does not represent the normal temperature gradient of the atmosphere.

In this case the light rays are bent down and so the image appears above the true object, hence the name superior. Superior mirages are in general less common than inferior mirages, but when they do occur, they tend to be more stable, as cold air has no tendency to move up or warm air to move down.

Superior mirages are most common in polar regions, especially over large sheets of ice with a uniform low temperature. They also occur at more moderate latitudes, although in those cases they are weaker and less smooth and stable.

A superior mirage can be right-side up or upside down, depending on the distance of the true object and the temperature gradient. Often the image appears as a distorted mixture of up and down parts.


Many hoaxes related to the pseudo scientific study of unidentified flying objects have been perpetrated.

Computer-generated imagery (CGI) and other computer effects have been widely used to create fake evidence of UFO sightings in recent years. Computer software has become extremely sophisticated and in some cases only highly trained individuals can spot the differences between real and false imagery. 

Some examples of UFO hoaxes which have occurred years ago include:

  • For April Fool's Day 1897, two practical jokers in Omaha, Nebraska set aloft a helium baloon with a burning wicker basket suspended beneath it.
  • On April 17th, 1897, The Dallas Morning News reported that the previous evening three boys hoaxed a mystery airship sighting by soaking a cotton ball in kerosene and tying it to the leg of a turkey vulture. When the bird was released, witnesses to its light shouted "Look, it's the airship!" The hoax was discovered when the bird landed on the roof of the local high school and the burning cotton ball caught fire to the school.
  • An account by Alexander Hamilton of Leroy, Kansas supposedly occurred about April 19th, 1897, and was published in the Yates Center Farmer’s Advocate of April 23rd. Hamilton, his son, and a tenant witnessed an airship hovering over his cattle pen. Upon closer examination, the witnesses realized that a red “cable” from the airship had lassoed a heifer, but had also become entangled in the pen’s fence. After trying unsuccessfully to free the heifer, Hamilton cut loose a portion of the fence, then "stood in amazement to see the ship, cow and all rise slowly and sail off." Some have suggested this was the earliest report of cattle mutilation (In 1982, however, UFO researcher Jerome Clark debunked this story, and confirmed via interviews and Hamilton's own affidavit that the story was a successful attempt to win a Liar's Club competition to create the most outlandish tall tale).

Note: This list is by no means to discredit UFO reports. It is merely a list to help explain what in many cases are misidentified objects or natural phenomena which attribute to UFO sightings. There are many cases throughout history of UFO reports which cannot be rationally explained by these types of ordinary objects and natural phenomena.