But even in the last few years, there have been UFO sightings that can't easily be explained away, along with testimony from highly credible witnesses.
At the 20th annual International UFO Congress, or IUFOC, nearly 30 speakers will travel from around the world to Scottsdale, Ariz., on Wednesday for a five-day conference with topics including alien technology, government cover-ups, black projects, crop circles and ultimate disclosure of extraterrestrial visits to Earth.
"This year is pretty exciting because we have a very credible lineup -- we're really bringing a strong ex-military presence. We have six retired military personnel, three of whom were officers," said Alejandro Rojas of Open Minds Production, which is hosting the event.
The list of IUFOC speakers reads like a Who's Who of all things otherworldly. It includes Paul Hellyer, former Canadian minister of national defense; retired U.S. Army Col. John Alexander, a UFO myth and reality insider; Linda Moulton Howe, an Emmy Award-winning TV producer and investigative reporter; nuclear physicist Stanton Friedman; best-selling cover-up and conspiracy author Jim Marrs; award-winning space and missile defense consultant Carol Rosin; and retired U.S. Air Force Col. Charles Halt, the highest ranking U.S. military officer speaking about his personal, dramatic UFO experiences while in the military.
Also on hand at the event will be Nick Pope, author of "Open Skies, Closed Minds" (Dell), who was, essentially, Britain's real-life Fox ("X-Files") Mulder when he headed up the British government's UFO project at the Ministry of Defense, or MoD.
Pope's analysis of UFOs and his access to classified government files on the subject eventually convinced him that while some unidentified flying objects represented a real mystery, they didn't seem to threaten Britain's national security.
"I was charged to investigate every UFO sighting reported to the ministry and to assess whether there was evidence of anything of any defense significance. Was there a threat or was there anything else of any more general defense interest?" Pope told AOL News.
"For example, if any of these sightings could have told us anything interesting about aerodynamics and propulsion systems, irrespective of what these things are, whether we detected any threat or not, that might have been interesting from a technological perspective."
During Pope's 21-year career at the Defense Ministry, he wore different hats, serving in a number of positions. In 1991, when he began his three-year stint in charge of the UFO division, he was initially skeptical about it all.
"The MoD's position was: We don't know what these things are, we don't believe that they're of any defense significance [because in the decades that they'd been investigating this, there'd been no evidence of any hostile intent], but the Ministry of Defense said it remained open-minded about the possibilities of extraterrestrial life. In other words, the department really wasn't taking a view one way or the other."
"I think, like all those who have gone before me in any government UFO program, I found that most of these things, of course, had conventional explanations. I'd say 80 percent are explained as misidentifications of all the usual objects and phenomena that you would expect: aircraft lights, weather balloons, satellites, meteors, bright stars and planets, etc. I'd say about 15 percent insufficient information to make a meaningful assessment either way. And 5 percent unknown."
Even though he had access to all kinds of UFO reports to pore over in his "X-Files" job, Pope was most interested in that elusive 5 percent of unknowns.
"With my Ministry of Defense background, it was very much sightings from police officers, pilots -- both commercial and military -- and sightings from radar operators (again, both civilian air traffic controllers and military fighter control). So, it's those sorts of sightings that were of most interest to me."
While Pope began his government research as a UFO skeptic, he didn't end up a true-blue believer in little green men, either.
"But I certainly did come out a little less dogmatic in my skepticism, and I came out thinking, 'Well, hey, wait a minute, there's more to this than just aircraft lights and weather balloons and misidentifications and hoaxes and delusions.'
"I'm not saying that these things are extraterrestrial, but I emerged from that job thinking, 'Well, you know what? I can't rule out that possibility.' I think my headline-finding, as it were, was that I knew what it wasn't, but I didn't know what it was."
At this week's IUFOC conference, Pope plans to talk about recent discussions by Britain's prestigious Royal Society concerning the possibilities of contact with extraterrestrials.
"You hear a lot of people say that the day after it's announced that we're not alone -- whatever form that announcement takes -- you hear people say that the world will change forever. And one of the interesting points that was made at the Royal Society was, you know, actually it won't."
Whether or not UFO disclosure is around the corner, Pope says he'd be happy if one of the more exotic theories -- such as extraterrestrials or interdimensionals -- ends up being true.
And like his fictional counterpart, Fox Mulder, this investigator wants to believe the truth is out there.
"I absolutely hope that it turns out to be something like aliens. It would be a far more interesting world with aliens in it than not."
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