UFO is the abbreviation for Unidentified Flying Objects, and so any object in the sky that we cannot identify is by definition, a UFO. Unidentified flying objects are sometimes called UAPs (Unidentified Aerial Phenomena) by scientists instead, since the term UFO is often used by non-scientists to mean crafts flown by alien beings.
For scientists, UFOs are not articles of belief or unbelief, but are strictly unidentified objects. In common with all other phenomena scientists examine the evidence, put forward hypotheses, and test the observed facts against those hypotheses.
Typically, observers of unidentified objects report seeing lights or objects in the sky that seem not to be planes, helicopters, balloons or any other known man-made flying object, or objects that appear to by flying in ways that are not possible according to the known laws of science.
Most reported UFOs are eventually identified, and often turn out to be weather balloons catching the light in unexpected ways, planets, which appear as extremely bright lights in the sky under some climatic conditions, comets, space junk, aircraft contrails, or meteorites. Some photographs of UFOs are later proved to have been hoaxes. Faking of photographs is becoming much easier with programs such as Photoshop, which almost everyone has access to these days, but even before this kind of technology was available, photos were often faked, and indeed in some cases careful examination of UFO photographs can reveal obvious fakery such as strings holding up an object.
Most UFOs are eventually identified, but not all of them, and some remain unexplained even after many years of investigation. (The websites suggested below for further reading describe many of these unexplained phenomena, which remain true Unidentified Flying Objects.)
There are a number of theories about what these unidentified objects might be, but many theories suggest that UFOs are intelligently controlled craft that are not of Earthly origin. The most common theory is that they originate from civilisations elsewhere in the galaxy. Other theories suggest UFOs are vehicles flown by beings living inside the Earth, or by beings in a parallel Universe.
These theories are difficult to test, but predictions that might be derived from the theories are not evident. For example, if UFOs are craft flown by beings originating elsewhere in the galaxy, there ought to be observations of them in transit towards Earth, but no such observations have been made as yet.
The view of many scientists is that UFOlogists accept any report without question, but it can also be said that many scientists dismiss sightings without scientific investigation, and it is also true that scientists who do take the phenomenon seriously risk being ridiculed by their peers. Since most UFO sightings are fleeting and often leave no physical evidence other than photographic or video evidence, this can also make scientific investigation difficult.
Nevertheless, there have been scientific investigations, by organisations such as the CIA and the US, UK and French air forces. One of the first serious studies was that done in the UK by the ‘Flying Saucer Working Party’ which reported in 1951, and which dismissed all UFOs as hoaxes, illusions, or mis-identifications, even though there had been many UFO reports from air crews in World War II (called ‘foo-fighters’ by US airmen). So-called ‘phantom flights’ had also been seen many times in World War I and were not explained. A few months after the Working Party’s report, a rash of UFO sightings in Washington DC and reported by NATO and RAF crews taking part in ‘Exercise Mainbrace’ forced a re-think.
Scientific and non-scientific studies of the UFO phenomena continue around the globe. Several publications are available online, such as the US Air Force Project Blue Book files (http://www.bluebookarchive.org/). This investigation began in 1952 and ended in 1970 but has been discredited in some circles because its aim was to ‘explain away’ all sightings, and there was little real scientific expertise on the panel. A better study is the French Cometa report released in 1999. This report suggests that as there have been so many sightings of UFOs the phenomenon deserves proper scientific investigation, and that all hypotheses should be considered.
Are UFOs from somewhere in space? Since there are billions of stars in our own galaxy and many of them have planets, and there are at least millions of galaxies besides ours, it seems ridiculous to think that only one planet circling only one star has lifeforms sufficiently advanced to venture into space. However, if UFOs really are from extra-terrestrial civilisations, it seems an awfully long way to come just to fly by a few people in the middle of the night without making any real contact.
For most people, scientists or otherwise, these flying objects remain an unexplained enigma because observations are fleeting and impossible to predict, because so little evidence of them is convincing and it is so easy to fake photographic evidence, and because there seems no reason why UFOs should be seen most often at night, and often by just a few people in locations away from major urban centres (although there are notable exceptions to this). There is also the unanswered question that if UFOs turn out to be alien spacecraft, what do their occupants want, and why are they not seen in space in transit to Earth?
The late Carl Sagan dismissed UFOs saying that “Extraordinary claims require extraordinary evidence,” even though he was convinced that life exists elsewhere in the universe and approved of the SETI program (the search for extraterrestrial intelligence). This remains the predominant scientific viewpoint of UFOs, but since UFOs continue to be reported at regular intervals perhaps it is time for scientists to revisit the phenomenon and investigate it rigorously instead of dismissing it out of hand, often for fear of being ridiculed.
The following websites provide useful information: