How do we explain strange sights?

Ufology is the study of UFOs (unidentified flying objects). Some are convinced that contact from outer space is real.

Others would rather put an extra o after the f in ufology as a way of expressing their contempt. Either way, UFOs have fascinated many, whether seen as evidence of visitors to Earth or natural phenomenon.

The media, notably with the strange lights and inexplicable radar readings off Kaikoura in December 1979, can swing into action and speculation builds.

Sometimes the authorities become involved, and last week it emerged that the Defence Force has been keeping files on hundreds of UFO sightings.

In one instance, an investigation was launched.

What are we to make of what we do not understand? While few would suggest it represents any type of alien contact, the South this month has had its own minor mystery in the "vapour trail" or "chemtrail" or strange cloud of whatever it was that crossed the sky.

At one extreme are those ready to believe that selected unexplained phenomenon represent evidence of outside life.

Others apply thorough-going scepticism.

Not only are little green men far-fetched, but everything else can be explained or, at least could be with more knowledge of how nature works and more details about the sightings.

As astronomer Carl Sagan put it: "The reliable cases are uninteresting and the interesting cases are unreliable."

An open mind dictates that most anything is possible.

In an infinite universe, who knows?But an open, questioning mind should also be highly doubtful that sightings have extra-terrestrial meaning.

Sure, there are strange lights and shapes and effects on radar.

Sure, eye-witnesses are usually genuine in what they believe they saw.

But where is any physical evidence? Where are the reliable witnesses? As knowledge and understanding increases, more explanations will come forth, shrinking the unexplained down.

The human mind plays unusual tricks, as does nature through light and other forces.

Throw in birds, meteors, weather balloons, missiles and so on, and chances are a physical explanation is possible.

Just look at how magicians and psychic showmen like Uri Geller - of bent-spoon fame - can trick or mislead the sharpest eyes and minds.

Nature in its wonder, diversity and complexity can do the very same thing, without even the slightest intent.

UFO hoaxes also show how easy it is to be fooled and how apparently bewildering sights can be explained.

The USSR was not adverse to using UFO sightings as cover for military tests, and one of the most successful deceptions was perpetrated from Dunedin by students and their Knox College Grand Interplanetary Hoax of 1952.

The elaborate string of pretend sightings fed to media through the country caused great interest and made its way into UFO literature for many years.

Although ufology is seen by much of mainstream science as bordering on, or moving into, full-blown pseudoscience, and although most mainstream astronomers veer strongly towards natural explanations for the unidentified, many governments have taken matters seriously enough to investigate.

A New Zealand Defence Force spokesman might have said the number of reports had fallen in the past 10 to 20 years and the Defence Force had "no official interest" in UFOs.

And Defence Minister Wayne Mapp said he believed "a quick scan of the files indicates that virtually everything has a natural explanation".

But French authorities have had a team on cases since 1977, and the US military took it seriously through the 1950s and 1960s.

The issue, though, keeps coming back to lack of evidence.

To believe strange sights are evidence of contact from outer space requires a leap of faith that is difficult to make.

Without some from of concrete proof, perhaps UFOs are best left to Hollywood and the film industry: leave it to ET to call home.