But flying saucers, that is, alien spacecraft, never have.

It really is about time we put down the whole UFO-spaceship thing as part of the past; part of an old-fashioned view of the mysteries of space.

At best, they were a delusion, wishful thinking by some who didn't want to know better.

At worst they were, in some instances, a con as unscrupulous people exploited others.

We have had UFOs for more than 50 years now. During that time, we are supposed to have had innumerable sightings of alien craft in our atmosphere, numerous encounters with strange beings as well as a great many abductions.

Fuzzy logic

And what have we got to show for it? Remarkably little - a few amazing stories told by those who claim to have been witnesses and abductees, as well as a fuzzy photographs and videos, and of course, lots of fakes.

Is it not strange that of all the photos and film shot of UFOs are poor and inadequate. You might have thought that at least one of them would be a close-up and in focus.

Out there...or perhaps not

Indeed, the aliens can be small or tall, the spacecraft saucer or triangular shaped but the one constant thing in all UFO sightings and alien encounters is that nobody has any evidence that can be looked at.

One can talk to researchers, or read their books, and be told that they did have hard evidence, sometimes in the form of alien artefacts.

But enquire a little more, or read on, and one always gets to the part where the evidence vanishes for some reason or another that sometimes involves somebody dressed in black stealing it.

Faced with this lack of evidence the alien advocates have to rely on the last resort of a failed argument: conspiracy.

Only the gullible

There must be something in it, they say, as they unearth another secret memo or report that in fact sheds no new light on the reality of the phenomenon.

The fact that governments got involved is no evidence that there was anything in the UFO phenomenon.

Nor indeed are the many books being published about UFOs.

Putting to one side that they frequently contradict each other - all the plethora of books show is how gullible people are.

And there we have the reason why the UFO phenomenon lingers on.

So after 50 years we have no evidence to speak of, lots of books and a handful of extremely vocal pundits.

Couldn't someone beam them up?