As published in the INUFOR Digest & The Australasian Ufologist Magazine
 
 

 I do not expect a witness to be other than an inexperienced, untrained observer. This comment is in no way intended to give offence to anyone who reports a UFO sighting, it is merely an acknowledgment that most people do not have an above average knowledge of astronomy, meteorology or aircraft. When investigating a sighting, I prefer to start from the premise that a witness may have misidentified a common object and history has shown that this is indeed the case in the vast majority of instances. 

Ethical UFO investigators owe it to themselves to seriously consider all the possibilities before labeling a sighting as 'unidentified'. This is particularly important in cases of nocturnal lights as this category probably contains the greatest number of possible misidentifications. 

It should be stressed that the compilation of the list below in no represents an attempt to 'explain sightings away'. It is merely that I refuse to fall into the trap of 'identifying' every mysterious light in the sky as a flying saucer. Bearing all this in mind, here is my list of commonly misidentified objects. If you can think of anything that should be added please let me know. We must not forget that an object is only a UFO until it has been positively identified.

It is unfortunate that the acronym UFO has become synonymous with 'flying saucer', as the two are not necessarily the same. This free association of terms undoubtedly undermines the credibility of serious researchers in the minds of many people, including the scientific community.
 

Aircraft	Natural	Astronomical	Other
Planes	Birds (solo or flocks)	Stars	Neon signs
Helicopters	Lenticular clouds	Planets	Fireworks
Advertising planes	Noctilucent clouds	Meteors and bolides	Flares
Model aircraft	Fires	Comets	Spotlighters
Hang-gliders	Atmospheric inversion layers	The Moon	Emergency vehicles (flashing lights)
Parachutes	Mirages	Sun dogs (parhelia)	Car headlights
Kites	Ball lightning	Moon dogs	Beacons
Satellites	Sprites and jets		Searchlights
Weather balloons	Earth lights		Hoaxes
Helium-filled balloons
Blimps
Hot-air balloons

It should be the aim of every investigator to make an identification whenever possible provided of course, that such an explanation does not require distortion of the evidence. There are many examples where researchers have been so keen to positively identify a reported sighting that they have grabbed at the first explanation that comes to mind and have overlooked many of the stranger aspects of the report. This has frequently resulted in explanations that verge on the ridiculous under closer scrutiny. Such 'explaining away' has been employed by some individuals and organisations in an effort to disguise the true magnitude of the phenomenon. They are unwilling to admit that people sometimes see things that defy rational explanation in terms of our present understanding of the nature of things. This is not to say that better explanations may not come to light with new scientific advances. After all, it was not so long ago that scientists avowed it impossible for stones to fall from the sky. Some of the natural phenomenon I have listed in the above table, such as ball lightning, sprites, jets and earthlights, are still not well understood. It is possible that reports, which may fall into these categories, could be of use to physicists and geologists who are researching these phenomena.

Having said that, let's explore some of the circumstances under which misidentifications can occur.

Gauging Height and Distance

It is frequently very difficult for even experienced observers to gauge the height and distance of an object seen in the sky. This, in turn, leads to problems in estimating the object's actual size. This is why, when investigating a sighting, I ask witnesses to compare the object's apparent size to that of a familiar object held at arm's length. This problem can be exacerbated if the witness has poor eyesight, or if the atmosphere is unstable. It can be further complicated if the sighting occurs around sunrise or sunset, when the sun's rays can illuminate objects from below. It should, therefore, come as no surprise to learn that sunrise and sunset are among the most frequently reported times of UFO sightings.

Conventional Aircraft

The wings of an aircraft can seem to magically disappear when viewed from some perspectives. This illusion may be reinforced by bright landing lights, navigation lights, or cabin lights. Add to this illumination from below by a setting sun and the resulting image could be very deceptive. The image may even appear to be stationary or rising vertically if the plane is coming directly towards the observer. Contrails from the aircraft can also appear flame-like or wispy like smoke.

Modern supersonic aircraft with their delta wing configurations, tremendous speeds and maneuverability are frequently misidentified. Although we do not see many of them unless there is an Air Force base nearby, we should not rule them out. A call to the Air Force should either confirm or deny this type of activity in our skies. Military planes often fly in formation and jets have afterburners, which may be employed on occasion, although this is not usually done over cities.

Weather balloons can be very deceptive. Usually silver in colour, they can, obviously, appear metallic. The sun or sky can also tint them. They can be stationary for long periods of time or may drift slowly or rapidly, depending on the prevailing wind. It should be remembered that the direction of the wind at ground level might differ from that at higher altitudes. The movement of a balloon may appear erratic and quite abrupt changes in direction can occur. These balloons also appear more inflated the higher they rise, as the outside air pressure decreases. They may appear as almost featureless spheres when viewed from below.

The gas burners used to heat the air in hot-air balloons illuminate them from both within and without. This illumination, combined with their beautifully coloured fabric skins, can give them a very ethereal appearance. These balloons are frequently launched at sunrise, although they are not usually flown after dark.

Gliders, with their long wingspans and relatively small fuselages, may also be easily misidentified. Totally silent and able to achieve altitudes of many thousands of feet, they are capable of performing a wide range of aerobatic feats. Loops, dives and undulating motions are common and pilots will often circle or spiral upwards, riding thermal currents to gain altitude. Their activities may be visible for many miles and they are often flown until dusk.

The same can more or less be said of hang-gliders, although their antics are more restricted in area. Parachutists and skydivers may also be visible for many miles and it is not until one gets relatively close that the figure hanging underneath the chute can be distinguished.

In any scenario, we must not lose sight of the power of perspective to distort the shape of the familiar into something quite unrecognisable. A winged aircraft, when viewed from an oblique angle, many take on a boomerang shape. How often have we heard reports of boomerang-shaped craft performing aerobatic feats? Gliders, perhaps? Well, not necessarily, however, we should consider the possibility.

It is important for investigators to become familiar with the areas used by glider pilots, parachutists, model aircraft enthusiasts, hot-air balloonists, etc. A study should be made of the flight paths and landing approaches used by private, commercial and defence force aircraft.

Helicopters should always be seriously considered in any UFO investigation as they probably have the greatest potential for misidentification. There is an increasing amount of helicopter activity in our skies and of course, helicopters frequently fly at night. Helicopters can hover and are very maneuverable. They often carry searchlights and have a different configuration of navigation lights to planes. We think of them as noisy, this is not necessarily the case. The noise can also be muffled by distance, carried away by the wind or drowned out by more immediate sound. In this discussion I have tried to address some of the situations in which conventional aircraft could be subject to misinterpretation. As we have seen, there is a great deal to be taken into consideration and I have barely scratched the surface. 

Satellites and Astronomical Phenomena

As an astronomer, I am perhaps more aware than most of the ability of astronomical objects to confuse the observer. The planet Venus is probably the most commonly misidentified object in our skies, but is not alone. In this section I will discuss how even the most knowledgeable observers can misinterpret astronomical objects.

To begin I would like to tell you a true story. The witness is a friend of mine; a professional astronomer of many years’ experience and his story illustrates my point very well. The witness was driving home one morning after a long night's observing at a well-known Australian observatory. He was tired, the road was long and empty and it was just before dawn. As any good driver should, he was checking his rear vision mirror when he noticed an intensely bright light in the sky behind him. It was so bright that he didn't know what to make of it. He drove on, but kept his eye on the light in the rear vision mirror. 

He is usually very skeptical of UFO reports, but all his skepticism left him left him for a while on the road that morning. After some time he began to think that the object was following him and started to worry. He had gone some distance and suffered a good deal of anguish before he finally realised that his mysterious object was in fact the planet Venus. He laughs today about his encounter with the planet, but I guarantee that he did not find it so funny at the time. If a professional astronomer can be fooled by Venus, albeit for a short while, then what chance does an inexperienced observer have of making the correct deduction?

Venus is the brightest of all the planets and is always brighter than any star. It is so bright that it can hold its own against quite a bright sky and can even be seen in broad daylight if you know just where to look. Its brightness varies with its phase and position. The only other planet that approaches the brilliance of Venus is Jupiter. Known to most people as either the Morning or Evening Star, Venus is in fact both. Because Venus is closer to the Sun than the Earth, it is never far away from the Sun in the sky. As the Morning Star, it rises before the Sun, and as the Evening Star it sets after the Sun. The difference in the rise and set times of the Sun and Venus varies throughout the year but it usually no more than a couple of hours. You will never find Venus in the sky at midnight unless you're in the polar regions. The same applies to Mercury, which is much faster moving and will change its position against the background stars quite noticeably from day to day. Mercury is much smaller and nowhere near as bright as Venus.

Many people are under the impression that you can tell the difference between a star and a planet because the planets do not twinkle. This is not true. A planet will twinkle as much as a star if the atmospheric conditions are right, particularly when seen close to the horizon where the Earth's atmosphere is thickest. The twinkling of stars and planets is more correctly termed scintillation and is caused by the light being bent (or refracted) by pockets of different air density in our own atmosphere. This refraction of the light breaks the white light up into its component spectral colours and causes the star or planet to flash different colours, usually red to white to green, but any of the colours of the rainbow can be seen. This effect is most noticeable early in the evening after a warm day when the atmosphere is at its most unstable. When someone reports a bright light close to the horizon, that flashed different colours, a bright scintillating star or planet should always be considered as the likely culprit.

Meteors are another common cause of confusion. Most people can readily identify a common shooting star and several of these per hour can be seen during the course of any normal evening. Most shooting stars are caused by particles no larger than a grain of sand entering the Earth’s atmosphere. The ensuing friction heats the particles to the point where they begin to ionise the air and this causes a glowing flash. Most of these particles burn up completely before they reach the ground. 

Meteor showers occur when the Earth’s orbit takes it through an area where a comet has been. Debris from the comet’s tail collides with the Earth and we see a substantial increase in the number of meteors in a confined region of the sky corresponding to the orbit of the comet.

The Earth also sometimes encounters larger bodies, like small asteroids, which can be anything from the size of a small boulder up to that of a mountain. Fortunately we encounter few of the latter, but several of the former collide with Earth every year. INUFOR has recently received several reports of glowing objects, which do sound suspiciously like large meteors. These objects do not always burn up completely before reaching the lower atmosphere and are very spectacular events. 

Far from being short-lived, larger meteors can travel hundreds of kilometres across our skies before burning up, exploding or actually impacting the ground. They turn night into day and frequently exhibit a green or blue glow. Many of them travel quite slowly and they usually enter the atmosphere at quite oblique or even grazing angles. The leading edge of the Earth tends to collect them so they frequently seem to come from the west, rather than the east.

Exploding meteors are called bolides. The explosion causes a bright flash which can been seen over hundreds of square kilometres and is often, but not always, accompanied by a loud percussive sound like thunder or a sonic boom. They have been known to shake the ground, even if there is no actual impact and to trigger the light sensors on streetlights at night. One should also expect some electromagnetic effects due to the ionisation of the atmosphere.

Unlike meteors and bolides, comets do not flash across the sky in seconds or even minutes. Their motion is slow and almost imperceptible against the background stars. Brighter comets, such as Hyakutake or Hale-Bopp exhibit tails, which can stretch long distances across the sky, but always point away from the Sun. They do not usually look to the naked eye quite like they do in photos appearing more like fuzzy stars than anything else.

The Moon can be a real trickster, particularly if seen under cloudy or foggy conditions. The glow of the rising moon can be seen for anything up to an hour or more before it finally creeps above the horizon. The same applies for the setting moon. I once stopped the car on a country road to investigate a bright glow that seemed to be coming from a domed object nestled amongst the trees on a nearby hill. I got out of the car and was about to climb a fence to get a closer look when I realised that it was only the rising moon.

Like Venus, the moon and stars can also appear to pace cars. This of course, is only an optical illusion, but it can be a very convincing one. Fast moving clouds can also make a stationary background object appear to move. I once spent half an hour on the phone to a friend less than a kilometre away who claimed that bright objects were performing all sorts of acrobatic feats above his house. On going outside, I could see what he was so excited about. He took some convincing, but finally had to acknowledge that they were only bright stars against a foreground of fast moving cloud.

Sundogs, or parhelia, are usually seen in colder weather when lots of tiny ice crystals form in the upper atmosphere. They are also known as ‘mock suns’ and appear like bright spots in the sky. They are frequently associated with haloes around the Sun and can come singly or in pairs. They are a phenomenon often reported by pilots or passengers in aircraft. The ice crystals, which cause them, can be quite invisible or associated with cirrus cloud.

Moondogs are caused by the same conditions as sundogs, but appear at night in conjunction with the Moon rather than the Sun. 

Satellites and space junk are becoming increasingly common in our skies. At any time there are literally thousands of these objects in orbit. Each satellite has its own distinct orbit and satellite transits or passes vary in length and direction. The brighter satellites, like the Mir space station, tend to be in relatively low Earth orbit and cross the sky in a matter of minutes. Higher satellites can take hours to make a transit. The space shuttle orbits the Earth in around 90 minutes and is visible to the naked eye if you know when and where to look.

Mir is the largest and brightest of all the satellites and can appear as bright as aircraft landing lights. It is crosses over Australia quite regularly and can be quite disconcerting the first time you see it.

Satellites do not shine with their own light, but with reflected sunlight and are only visible for as long as they are illuminated by the Sun. It is not uncommon for a satellite to suddenly disappear as it passes into the Earth’s shadow or to suddenly appear as it comes out of shadow and into the sunlight. Many satellites spin and appear to flash on and off as they cross the sky. This is particularly true of odd-shaped or elongated satellites and those with large solar-panel arrays.

Man-made Objects

Several years ago, I was out for a drive one evening when my attention was drawn to a bright green light which seemed to be hovering in the distance over a newly built shopping centre in Canberra. I was immediately excited and drove on towards the object. As I approached, the object eventually resolved itself into a neon sign, which was newly erected on a tower over the shopping complex. The sign is now is now a well-known landmark, but at the time, was very deceptive. Neon signs should always be considered in cases of bright lights observed over built-up commercial areas. The sign may appear to be moving if the witness is moving. 

If you find yourself in the position of investigating such a report, it is a good idea to take the witness back to the scene and retrace their steps as precisely as you can. If a sign is the source of the report, then it should be immediately apparent. If not, then you can cross this possibility of the list.

Fireworks displays are usually well publicised events, at least the larger public events are, and it should be relatively easy to check whether or not there were any such displays on any given night. However, it is almost impossible to determine whether private individuals may have been setting them off. Fireworks may be illegal in some states, but not all. They are still readily available in the ACT and can be bought over the counter in the weeks leading up to the traditional Cracker Night on the Queen’s Birthday weekend in June. 

Flares have frequently been source of confusion to many unwitting observers. There are several types in use. Some are used by the military at night to illuminate the ground. It is my understanding that these give off a fairly steady glow, which may last for several minutes. Others are used by ships in distress and the like to attract attention to themselves. All flares give off a bright light and will gradually fade and drift to the ground.

Spotlighters are a common sight in rural areas at night. They can be seen for several kilometres. The spotlights are usually attached to motor vehicles, but it is not always possible to see the vehicle or its headlights. I have occasionally seen spotlighters in the hills on dark evenings when I have been out observing. If the night is dark enough, it is not always possible to see the hills and the light can appear to be in mid air. This can be very deceptive, however, if observed for long enough, the light will usually appear to flicker as it passes behind the trees and bushes and will usually appear to be close to the horizon as it is in fact on the ground.

Emergency vehicles are less likely to be mistaken in built up areas. Most people are familiar with the lights on ambulances, police, fire engines and NRMA vehicles, but they can come as a surprise on dark country roads, particularly in foggy or wet conditions when the observer may only be able to make out indistinct flashing lights. The confusion could be compounded at the scene of an accident or a fire, where there may be several emergency vehicles with different lights going all at once. The vehicles will not necessarily have their sirens going, so the witness may not hear any sound or make the connection. The investigator should always check with Emergency Services in cases where flashing lights near the ground are reported.

Car Headlights can be seen for many kilometres and if the car is on a distant hill, they may appear to be up in the air. It has often been reported that a car can be seen coming from as far away as a hundred kilometres on long flat stretches of road, such as are found on the Nullabor Plain or similar, flat outback highways. This effect is mostly due to the light being refracted by the Earth’s atmosphere and is in fact a type of mirage. 

Beacons and searchlights are frequently misidentified. We don’t have all that many beacons in Australia, except for lighthouses and the odd inland example, such as the one in Goulburn. I have the light from the Goulburn beacon from as far away as Mittagong when the atmospheric conditions have been right. The light appears as a beam that flashes or sweeps around the sky. The effect is most pronounced when there are clouds, which are illuminated from below by the beam. There are frequently coloured beacons, usually red, on the top of hills near airports. These are designed to flash and act as a warning to aircraft, but may occasionally be misidentified by observers unfamiliar with the area.

I always receive phone calls when one of the local clubs decides to promote itself with searchlights. It does this periodically, when it is cloudy, and it never fails to cause confusion. The searchlight beams can been seen from all over the city and usually appear as a group of lights playing on or within the clouds. The beams themselves cannot usually be seen.

One of the cleverest and most popular hoaxesof recent years involves the use of garbage bags, usually orange, and fires-starters or the cold light sticks, which are available from camping stores. The garbage bags are inflated with helium and then illuminated from within and released. The people responsible for these tricks have been very ingenious and have come up with all sorts of variations on the theme. Sometimes several of the bags are tied together. They have even been known to tow them behind cars or attach them to fishing rods so that they travel against the prevailing wind. This is one of the most effective hoaxes ever devised and is very difficult to detect, unless some of the debris is found. The lights will usually burn for around 10 to 15 minutes before they gradually decrease in brightness and finally go out. 

There have been so many hoaxes devised over the years that it is almost impossible to list them all, but when investigating any report researchers should always ask themselves, if I wanted to, how could I hoax this? The wary investigator should also remember that the ‘witness’ might be hoaxing, after all sometimes people just tell lies. 

Natural Objects and Phenomena

Birds flying in vee-formation have frequently caused confusion. Large light coloured birds, such as geese, or pelicans, which can have wingspans of several feet, are more likely to be misidentified than smaller, darker varieties, like sparrows. This is most likely to occur in the late afternoon or early evening, when they tend to flock and the sun can illuminate them from below. If they are high enough, they might just appear as a string of glowing objects. Many birds, such as eagles and hawks are often observed circling and can also appear to hover.

Lenticular or lens-shaped clouds are common in our skies and do look remarkably like a classic flying disk. These clouds can form at quite low altitudes and are shaped by winds, which may not be felt at ground level. They can be almost any size.

Noctilucent clouds are usually high altitude cirrus clouds. They appear to shine with their own light although they are actually still catching and refracting the rays of the sun or a bright moon, which may be well below the horizon. As the name implies, they are only seen at night.

Fires are not usually considered as a possible source of UFO reports, but I think that they should be whenever anyone reports a glowing object near or on the ground. Many witnesses who have reported landed craft, say that their attention was drawn to what they first thought was a fire. As with emergency vehicles, a call to the local fire department should decide the matter one way or the other.

Atmospheric inversion layers and mirages are not well understood by most people. We are all familiar with the ‘phantom lake’ on hot days, but mirages can take on far more mysterious guises. Under certain conditions, the atmosphere can act like a mirror. Any reasonably bright light source, such as the lights of ships at sea, aircraft landing lights or cities hundreds of miles away can be reflected over the horizon by layers of air at different temperatures, just like the ionosphere reflects radio waves around the world. This can give the illusion that the source of the light is quite close and objects that are actually on the ground or at sea level may appear to be up in the air. The Bureau of Meteorology is the best place to check out such possibilities.

Ball lightning is still a mystery to science. We know that it exists, because it can be created in the laboratory. It occurs when a strong electrical discharge ionises the air. How it may be triggered and sustained in nature is not well understood, although it is most likely to occur during thunderstorms. Ball lightning is usually only a few inches in diameter and is considered to be of fairly short duration.

Sprites and jets are another little understood form of natural atmospheric electrical discharge. Their existence has only recently been officially confirmed, although pilots have been reporting them for years. They occur high in the atmosphere near the tops of thunderstorms. They are of very brief duration and are not likely to be visible from the ground, although they should be considered in cases where witnesses in aircraft report strange flashing lights.

Earth lights, or ‘spooklights’ as they are also called, may be closely akin to ball lightning and some think that they are triggered by the piezoelectric effect in rocks, although this is still speculation. They are most frequently reported as small orange or blue glowing spheres, which seem to haunt particular locales. Witnesses have often reported that they appear to exhibit intelligent behaviour and that they even ‘play games’ with them. There is some evidence that earthlights are associated with mineral deposits and geological faulting and they seem to be more prevalent in mountainous areas. They are probably closely related to the phenomenon known as earthquake lights – an auroral type of light, which sometimes precedes an earthquake.