INTRODUCTION: The concept that aliens have and are visiting Planet Earth is plausible in both theory and observation. The theoretical part is often called the Fermi Paradox and it goes something like this: Extraterrestrial intelligence (ETI) with advanced technology is plausible; interstellar travel violates no laws of physics; the time it takes to explore our galaxy is a small fraction of the age of our galaxy (the parallel, the time it takes life forms – be it bacteria or humans – to explore the surface of Planet Earth is a small fraction of the age of Planet Earth); there are valid reasons to 'boldly go', not the least of which is that stars and planets don't last forever; lastly, we can't hide from potential alien eyes. The 'paradox' part comes into the picture only if you maintain that they should be here and they're not. If they're here, or have been here there's no paradox. Of course in the exceedingly unlikely event there is no 'they', never has been, well that too resolves the 'paradox'.

The compliment to the theory is actual observational evidence, both for past (ancient astronauts) and present (the UFO extraterrestrial hypothesis – UFO ETH). Even if human eyeball testimony isn't considered really 'evidence' and is questionable according to sceptics, there are various physical types of evidence, from various physical traces (ground markings; physiological effects on biological tissues, etc.) to radar returns, as well as photographic (for example the Trent family McMinnville, Oregon 1950 photos) and motion picture images (such as the Nick Mariana, Great Falls, Montana 1950 film and the Delbert Newhouse, Tremonton, Utah 1952 film) that have withstood critical/sceptical analysis.

With both the existence of pure theory and applied evidence supporting the plausibility of the UFO ETH – where the UFO remains a UFO after appropriate expert analysis has failed to find a more terrestrial explanation – lets look at a few snippets of the phenomena.

ALIEN ABDUCTIONS: The subset of UFO reports collectively lumped together as 'close encounters of the fourth kind' is a minefield, and like the subset of ufology collectively known as 'contactees', lots of middle-of-the-road UFO investigators steer clear of the subject. Lots of others don't and boldly go not so much into outer space, but inner space – the inner space of the mind. I see both pro and con on the merits of the abduction phenomena. For example:

Con: The appearance of the aliens, the greys, reflects a tad too closely the stereotype of what humans will look like many millennia from now – enlarged heads; atrophied bodies as the shift from physical to mental labour intensifies. The trend to less and less body hair (we're much less furry than our ape relations) continues until we're all bald all 'round. The aliens aren't human, but still very humanoid, perhaps too much so.

Con: What's the physics behind the obvious artificial gravity our abductees must be experiencing (since they don't report any weightlessness on the alien's spaceship which is presumably in Earth orbit)? From orientations reported, it's not the UFO rapidly revolving, since reports indicate their presence on a level floor between top and bottom, not on one of the outside walls. Aliens have obviously mastered physics unknown providing artificial gravity.

Con: You'd really think there would be hundreds or thousands of independent witnesses to all these home invasions and alien takeaways!

Pro: There's a very high degree of consistency in abduction scenarios that's independent of age, sex, race, nationality, religion, occupation, etc. that needs to be explained away by sceptics.

Pro: The abduction scenario reflects what our wildlife biologists do – capture, study, tag and release. We are to the aliens what animal species are to wildlife biologists.

Pro: It's difficult to explain why so many people would independently imagine or hallucinate or dream up the sort of obviously traumatic nightmare abduction scenario, especially when it involves painful invasive medical procedures. If you're that sort of masochistic person, wouldn't you dream that it was a mad scientist/medical doctor doing the kidnapping instead of aliens? Why aren't we flooded with abduction reports by demons taking one to the underworld, or by leprechauns taking their victims to – well wherever leprechauns call home?

I remember a time, now long ago, even before the start of any media coverage of abductions, when the idea of UFOs as extraterrestrial vehicles was one thing, logical and acceptable, but the idea of actual occupants was just too far out to be seriously entertained. Why is beyond me since I would have thought the two concepts would have fitted together like hand and glove. It's like saying a Boeing 747 airliner is okay, but an actual pilot? That's just too far fetched.

ANCIENT ASTRONAUTS: If aliens stumbled upon our humble abode it would likely as not have been millions, maybe billions of years ago. Alas, terrestrial critters around then (trilobites or dinosaurs) couldn't leave behind any record of their observations! It's only when humans developed that some sort of record could have been entered into. So, there's no contradiction with suggesting that 'ancient astronauts' are only ancient in human terms since that doesn't exclude the possibility they were around millions of years before that. One bit of suggestive I find interesting for the credibility of 'ancient astronauts' is that ancient cultures from around the globe have myths and legends of 'sky beings' – the Australian aborigines; the American Indians; the Mesoamericans – Inca, Aztecs, Mayans; the Egyptians; the cultures of the Indian subcontinent; and of course the Romans, Greeks and Norse cultures all had tales of 'sky beings'. I suspect that detailed research would find the presence of 'sky beings' universal, or nearly so. A human culture needing to invent imaginary friends from the sky is probably less likely than the reality, or the possible/probable reality of actual 'sky beings'. [As an aside, maybe trilobites and T-Rex aren't totally kaput – if ancient astronauts (UFO aliens) were around way back then, doing their abduction thing, then maybe the descendents of these prehistoric life forms are alive and well in some cosmic zoo!]

CENSORSHIP: I received an email from a SETI scientist along the line that cover-ups are the usual excuse for the claim there's no obvious public evidence for the UFO ETH, and that's an argument from ignorance, so it has no force. It's also implausible that every government in the world is participating in a cover-up. I'm guessing here, but I'd wager that scientist hasn't ever been in the military (I have) or worked for any defence, security or diplomatic related agencies.

Well, any time the powers-that-be classify, conceal, deny, cover-up things, you're in the dark so obviously any debate or argument to the contrary by you is an argument or debate from your relative ignorance because you don't have all of the facts.

Regarding the question of censorship/cover-ups over things alien in nature, things like Martian microbes are too inconsequential to try to hide; 'ancient astronauts' are too old for a government to worry about; SETI aliens (if SETI succeeds) are too far away to worry about; but UFOs are a different kettle of fish. The possibility that highly advanced aliens with unknown motives might be present here and now – well can you imagine any government admitting to the great unwashed that they really have no control over their airspace! Any government that had, by accident, obtained alien technology would certainly not share that information with anyone, including allies, and thus wouldn't admit same to their citizens. Of course not all countries and their respective governments may even have the appropriate data which to cover-up. You can't hide what you don't know about in the first place.

Take Area 51 (Groom Lake, Nevada). Even assuming that the location has bugger-all to do with UFOs doesn't negate secrecy going on. There's no denying the place exists. That's on the public record. Satellite and ground photographs exist. There's no getting around the fact that signs are posted around the site that there will be 'no trespassing' and that if you do, 'use of deadly force is authorised' to keep you out. [That includes SETI scientists!] That too is on the public record, filmed and documented. Translated, there are things going on at Area 51 the American government doesn't want anyone to know about. Pine Gap in Central Australia is another such location. Many more exist throughout the world. You want cover-ups / censorship and related – call it what you will. Well, something that immediately comes to mind was the Manhattan Project. Then there's that U-2 spy plane (and a whole range of stealth military aircraft that remained top secret while in development). Likewise, the Project Mogul package designed to detect foreign nuclear weapons testing, launched to high altitudes by balloon, as beloved as an explanation for Roswell.

Nobody can deny that the military has levels of classified security ratings ranging from confidential through to secret and top secret. Anyone suggesting that the Americans (or British, Australians, Chinese, Russians, etc.) don't have skeletons in their respective closets are in serious denial or in delusion mode. A UFO case might be classified not so much because it's a UFO, but because the surveillance equipment, type of radar or spy satellite, etc. might be classified.

The number of classified confidential / secret / top secret projects worldwide must number in the tens of thousands. The total number of classified confidential / secret / top secret documents (plus photos and films and related) must be in the millions. The number of multi-decades old classified projects and documents are unknown, but some surely exist. Something old by itself doesn't equal declassified. And it's not just the military – all sorts of government civilian and diplomatic projects and decisions remain under wraps for a whole variety of reasons.

There's no doubt in my mind that UFOs could be one of hundreds to thousands or more topics somewhat too-hot-to-handle and pretty much under classified wraps. That's a conclusion that's fairly obvious to me when it came to light, after much denial by the CIA, but pressured via Freedom-of-Information requests, that the CIA had some quite considerable interest in UFOs. Alas, FOI not withstanding, a vast percentage of the text from those released documents are blacked out. And that too is on the public record.

When it comes down to all things classified (a fancy word for cover-up because classified things are covered-up and tucked away out of sight) there is a phrase called 'need to know'. If you don't need to know, and you want to, that's a cover-up as far as you're concerned. Now Australia had a very long serving Prime Minister (John Howard) who was finally defeated in a 2007 general election, and left politics. I'm sure he knows many secrets – military and diplomatic – from his years in the top job. But, like all good citizens, he's not telling tales out of class. Ditto all American ex-presidents and Commonwealth PM's and all other manner of retired statesmen.

There's also the aspect or concept of 'the superiority complex'. The 'I know something that you don't know' – ha, ha, ha – that helps feed our egos. Maybe someone does have THE knowledge and THE proof positive of what UFOs are, but why should they share it with you hence share the Nobel Prize? Or, maybe they are just internally satisfied that they alone are blessed with THE answer and that's the be-all-and-end-all of the matter.

CONDON (UNIVERSITY OF COLORADO] INVESTIGATION & REPORT: The USAF UFO Project Bluebook investigation was becoming a public relations disaster. The more the Air Force tried to downgrade the issue, the more the public smelled whitewash. So, in order to bring in qualified, independent, experts, restore credibility (and get a reason to get out of the UFO business) the USAF turned to the University of Colorado, and respected physicist Edward U. Condon, to look into the UFO issue.

Unfortunately, Dr. Condon, as head of the independent investigation, proved to be more a liability than an asset. Staffers uncovered a memo by his higher echelon team that strongly suggested that he had already made his mind up even before the formal and serious study began, that UFOs were a non-issue. That produced such dissention in the ranks, and media publicity, that the internal politics just about shattered any credibility to the investigation. Some members quit and offered scathing rebuttals to the inner workings of the University of Colorado study. True to form, the final report apparently dumped poo on the subject, or at least the introductory / summary chapter written by Condon himself.

Now of course when you issue a 1000+ page report to the press, who have deadlines to meet, all they have time for is to digest the introductory / summary and write their articles from what that says. What is says is that there's no meat on the bone; the USAF should stop wasting time on the subject – which is exactly what the USAF wanted to hear – bail out from this PR nightmare. Subject closed. Unfortunately, things didn't quite turn out that way.

So I don't want anyone to tell me that the University of Colorado UFO investigation on behalf of the USAF, the Condon Report, closed the book on the subject – not unless you have real the entire report and not just that introductory / summary first chapter. There is no similarity between the questions the actual report raises and the summary conclusions reached as given in that first chapter. Few people have taken the time to separate the wheat from the chaff in the Condon Report. The first chapter is the chaff; the bulk of the report contains the wheat.

What you'll find in the non-Condon written bulk of the University of Colorado report is that case after case (well about 30% of cases in fact) are unexplainable. How Condon can say that there's nothing to the subject in the summary, while his team suggests that 30% of what you've investigated is anything but 'nothing', remains a perplexing historical mystery – except for that earlier leaked memo which showed that Condon, despite being a scientist, had a closed mind on the subject. So, read the entire report – do so, and then talk to me! Contrary to popular opinion, the Condon report proved the need for heightened investigation, not the need to abandon the investigation.

Further readings regarding the (University of Colorado) Condon Report:

Fuller, John G. (Editor); Aliens in the Skies: The New UFO Battle of the Scientists: The Scientific Rebuttal to the Condon Committee Report: Testimony by Six Leading Scientists Before the House Committee on Science and Astronautics July 29, 1968; G.P. Putnam's Sons, N.Y.; 1969:

Harkins, R. Roger & Saunders, David R; UFOs? Yes! Where the Condon Committee Went Wrong; Signet Books, N.Y.; 1968: [Saunders was a member of the University of Colorado UFO Study.]

University of Colorado & Gillmor, Daniel S. (Editor); Final Report of the Scientific Study of Unidentified Flying Objects Conducted by the University of Colorado Under Contract to the United States Air Force; Bantam Books, N.Y.; 1969: [The Condon Committee Report.]

CROP CIRCLES: For better or worse, crop (or sometimes 'corn') circles have been associated with UFOs to a greater or lesser extent depending on whom you consult. Firstly, there's no doubt that crop circles exist – that's undisputed. Secondly, crop circles are the product of intelligence; there's no way Mother Nature can naturally make these complex geometric formations – that's undisputable. Thirdly, although there are isolated cases from other countries, crop circle formations are 99 & 44/100% reside in merry old England – no arguments there.

That third fact brings up question one: assuming crop circles are hoaxes, what is it about the British mind set that prompts them to commit these 'works of art'? That's never been explained. Maybe crop circle hoaxers might be reluctant to do their thing in the USA where farmers shoot first and ask questions later, but why not France, Canada, Australia and a host of other nations with major agricultural (crop) industries?

Question two, again assuming hoaxes, can the sum total of crop circle formations be explained by artistic human intelligence, keeping in mind the restraints of sheer numbers of circles; the period of limited darkness in which to operate (high summer in England); the fact that it is dark; the possibility of being caught (you don't want to use flashlights); not to mention additional time required for the ever increasing complexity of these crop circle formations?

Question three: assuming now not human, but extraterrestrial intelligence (the UFO connection – if any), what is the motive? Sceptics have pointed out, rightly so, that it is ludicrous in the extreme to suggest that extraterrestrials come here, from there (wherever there is) just to do geometrical graffiti using agricultural crops as their canvas! It's probably equally ludicrous to suggest that UFOs are alien tourist buses, the extraterrestrials on a holiday tourist tour, and England has been set aside as the area for extraterrestrial artists on tour to practice their art!

So, maybe crop circles are a smoking gun that we do live in a simulated Universe and on a simulated planet. All other 'rational' explanations are equally, if not more so, ridiculous. If extraterrestrials, their motive isn't at all obvious. If human in origin, crop circle graffiti should be way more widespread like ordinary back alley brick wall graffiti is, not to mention that a lot higher percentage of crop circle culprits or 'artists' should have been caught, tried, convicted, and fined for vandalism, destruction of private property and just plain trespassing.

EARLIER IS BETTER: the UFO phenomenon is now well over 60 years old. The public in this 21st Century has been well and truly saturated with UFO stories, mythology and lore. Thus, if Mr. or Mrs. Joe Blow Public reports anything UFO related today, well they have had a lot of previous bits and pieces to draw on – assuming they are making things up. However, if Mr. or Mrs. Joe Blow Public reported something from 1947, say through 1952, then that public saturation with all things ufological must have been quite a deal less. Thus, earlier reports seem to me to be more, all else being equal, credible – far less media, Hollywood, etc. coverage that could have had influence on the public mind.

That's of course not to say that everything post 1952 is bunk and junk. There have been many substantial solid cases over the most recent five decades. It's just the percentage of those types of cases, relative to the total, was probably higher and slightly more credible before the mythology solidified.

Abductions are an exception as the typical UFO abduction case didn't exist in the 40's and 50's; ditto astronaut sightings. But on balance, I'd place greater reliability and credibility in those earlier cases. One other reason for doing so is that today's CGI digital processing and manipulation of images can provide mind-boggling (but fake) UFO film and photographic 'evidence'. It was much harder to fake images in the 40's, 50's and 60's.

EVIDENCE: Many ideas or fads, be they in the sciences or the arts, don't last long – theories come and theories go and actual fashions and fashion in music change yearly. What's 'in' and what's 'out' is often pretty fickle. A lot of what was popular in 1947 (the birth year of the modern UFO era) has fallen by the wayside now – but, interestingly enough, not the UFO ETH. The UFO ETH is as popular as ever, maybe even more so now than in 1947, not that popularity equates of necessity to something factual. If a billion people believe a stupid idea – like an invisible friend who art in heaven – it's still a stupid idea. However, over six decades on, despite all the professional and amateur sceptics and the universal naysayer, the government denials, scientists professing 'no evidence', the 'giggle' factor and the 'silly season' publicity, the UFO ETH is alive and well thank you very much. Something must be driving this. Perhaps, at least to many of the great unwashed, there is some signal in the noise – some sort of evidence (albeit not physical enough to be acceptable to many professional scientists) that's swaying the general public.

It is suggested, with good reason, that the whole issue of the UFO ETH must be judged on the basis of the evidence. And, it is claimed, that the evidence for visitation is so poor that very few scientists find it convincing. And that is true, at least the part that few scientists, publicly at least, find the UFO ETH somewhat lacking in solid evidence. Thus, the UFO ETH has garnered somewhat of an aura of being a 'silly season' subject, unworthy of scientific study. [To be honest, I'd often like to survey academics / scientists for their private opinions!]

UFOs vs. evidence for the ETH – there is no absolute smoking gun – yet. I'd be the first to acknowledge that. I'd suggest however that this is a case of where there's smoke, there's smoke. The fire has yet to be seen through the smoke. There however has got to be something suggestive about the nature of that smoke to drive lots of people, even some quite intelligent people, to accept the possibility of the UFO ETH. I mean the idea just didn't pop out of the ether – out of thin air. Something very suggestive is driving it.

I would ask the question whether by evidence one means a physical artefact that can be put under the microscope, or is human testimony, the sort that would convict someone of a crime and put them on death row enough evidence? I'm 99% convinced scientists would say the former, yet the evidence for the UFO ETH is 99% the latter (plus a few radar returns and films). Actually IMHO it's ludicrous for UFO ETH sceptics to poo-poo and give the thumbs down to eyewitness testimony. After all, it's accurate eyewitness testimony that enables the trained investigators to properly identify the vast majority of UFO reports, turning them into identified flying objects. So, when sceptics need eyewitness testimony to be accurate and turn UFO cases into something with ordinary and mundane causes – that's fine. But when the tables are turned, sceptics turn turncoat as well so as to re-enforce their already-minds-made-up point of view. That is, eyewitness testimony that turns a UFO sighting into an unexplained bona fide UFO case, well then clearly the eyewitness testimony counts for nothing in terms of bona fide evidence.

Now there are lots of current concepts in science that have absolutely no evidence to support them, yet are taken quite seriously by physical scientists. A partial list would include concepts like the Multiverse, the Many Worlds interpretation of quantum physics, string theory, the Higgs Boson, the possible existence of ten or eleven dimensions, the Ekpyrotic (two branes colliding origin of the) Universe theory, and, shock horror for those interested in SETI, the total lack of any under-the-microscope, hard core evidence whatsoever for any intelligent life forms other than intelligent terrestrial life forms. Yet it is acceptable for scientists to research these areas without being subject to having their sanity questioned. I fail to see why the UFO ETH is an exception to this.

Scientists need more than 20 fingers and toes to list all of the there-is-no-evidence-for- these-way-out-theories in science that ultimately had to wait years, decades, longer even for experimental confirmation. If scientists had put these in the too hard basket, or dismissed them with a 'I just don't believe it – it can't be therefore it isn't' attitude, well we'd still all believe that the sun goes around the Earth, black holes would be confined to the pages of science fiction, and as for gravity bending light rays – forget it.

There are other 'the nature of the evidence' parallels with UFOs – physical phenomena that don't stand still; you can't poke and prod, put under the microscope, examine at your leisure and which are unpredictable in space and in time. Ball lightning comes to mind; ditto Transient Lunar Phenomena (TLP); and you can't rewind the clock and prepare for (instruments at the ready) and witness the one-off Tunguska event. There seems to be a double standard for evidence here. UFOs have a 'giggle factor'; ball lightning does not, yet both have theoretical underpinnings that make their existence plausible. In the case of UFOs, it's the Fermi Paradox as noted above.

Oh, by the way, that ultra overused phrase 'extraordinary claims require extraordinary evidence' is nonsense. Claims of course require evidence, but the word 'extraordinary' is in the mind of the beholder. What's extraordinary to one is routine, boring, commonplace and downright bloody obvious to another. And speaking of the common phrase, another one is 'absence of evidence is not the same thing as evidence of absence'.