Aliens on earth...grey skinned, bug-eyed, three feet tall, being interrogated by sunglassed goons from the CIA.
This footage exists. It's somewhat grainy, to be sure, and the background is a little...dark, but there does appear to be an extraterrestrial being "debriefed" by intelligence officers somewhere in the US - the S-4 base, probably. This is only part of the evidence, of course. There are the revelations of Bob Lazar, who has claimed that there have been aliens in the bowels of secret Air Force bases since 1948; there are strange photographs of blood-red creatures lying beside bushes; and there are the accounts of aliens in Brazil. Not to mention the bases somewhere around, or underneath, Puerto Rico.
But could there really be aliens, living here on earth?
Firstly, travelling from somewhere at least fifty or sixty light years away to Earth is a gargantuan use of resources, however advanced your civilisation. Since the speed of light is reserved for just that - light - an alien spacecraft would need to use another propulsion system, such as nuclear energy, and would need volunteers prepared to spend years and years, even generations, on board ship. Even if a civilisation could find the energy or propulsion to travel at 50% of the speed of light, they would still need beings willing to spend over 100 years in space.
Secondly, suppose they did spend all that time and energy getting here. It takes a mammoth effort of will to imagine that they would then consent to being hidden away by the US government or whoever, such that no-one apart from a few men with beards and ancient copies of Timothy Good books and X Files videos knows where they are. Consider the planning meetings, the strategists' seminars, the governmental research on the part of the aliens. These would all have to conclude that yes, it would be worth coming here, just to be kept secret from the entire planet and released only on scratchy VHS tapes or Youtube videos.
One cannot second guess intelligent aliens, but it seems to require more rationality than the UFO phenomenon provides.
All this is relevant because any society that could expend such thought as to bring themselves across space to Earth would clearly be rational and highly intelligent, not to mention far more technologically advanced than humans.
Suppose that they came here and were trading technology with the US government, as we've been told by Bob Lazar and others. What are we getting from it? When was the last time humans went to the Moon? 1972. President Bush came up with an idea to go back to the Moon in around 2020 but guess what - the designs were just updated copies of the Apollo craft and the plans were cancelled by President Obama (to be redrawn slightly). No alien influence there. Have we cured cancer? We are making strides, but incremental ones, completely consistent with human-based research and development. And what would the aliens be getting in return that could possibly be of any use to them?
In the early 1990s, Bob Lazar was claiming that the US were reverse-engineering anti-gravity craft from crashed UFOs. Well, if they were, then they have made zero progress with all that alien technology. Indeed, the US cancelled the shuttle program and currently do not send humans into space at all, except for the few private space journeys that take place outside NASA's influence.
Some people, often inspired by the books of Erich von Daniken, maintain that there have been alien visitors to Earth for thousands of years. This is based in part on paintings and depictions of beings that seem to wear helmets or who are ascending into the sky. Others interpret scripture, or other religious texts, as implying UFO and alien contact.
The problem taking this seriously is simply that the evidence isn't there. How can you base a serious idea on a literal reading of single verses of ancient, poetic texts? On pictures that might look like, could look like, astronauts? Much more likely than there having been alien astronauts is that such texts depict gods. We know that ancient civilisations believed in many different types of deity. Why then stretch theory to its limits by postulating that they had contact with alien civilisations but somehow just forgot to clearly describe it?
Another idea is that of anomalous objects. Some cultures apparently have artefacts that they couldn't possibly have made. However, many of these have simply been incorrectly dated, or proven to be hoaxes. An example of something similar is the knowledge of the Dogon tribe of Mali, of the orbit of Sirius B, a white dwarf star. The theory goes that they could have had no way of knowing this. But modern research has revealed that this knowledge may have been given to them by anthropologists and has cast doubt on previous "certainties" that the Dogon people had never had enough contact with scientific knowledge.
Let’s return to the “evidence” gained by modern encounters with flying saucers. There are very few photographs or videos that have survived extensive computer analysis. One is the famous Trent Farm photo, taken in 1950, which shows a saucer-shaped craft near a farm house. This has not, despite intensive debate by skeptics, been proven to be a fake. Another example is the 1991 footage taken from the shuttle Discovery, which appears to show a streak in the sky moving intelligently. There are lots of photos of purported aliens on the Internet, but no evidence that these pictures are genuine. In the past, such photos have turned out to be models made for films, dead or diseased humans, or definite hoaxes. There are very few that have not already been debunked. And none that have made the mainstream media as depictions of possible aliens.
Then there is the abduction phenomenon. Aliens are abducting people in the dead of night - and it has to be at night. They are then performing experiments on them. For what reason? To create a hybrid species or something. Again, consider this rationally. If a species, two or three hundred years more advanced than humans, needed to do this, they would use a sophisticated technique which would make use of tissue samples and individual strands of DNA. There would simply be no need for the anal probes that are often alleged.
To demonstrate the gullibility of the UFO-seeking community, look at Tim Good, author of Alien Liaison and Alien Base. He's intelligent, not bonkers; yet he accepts the frankly pathetic George Adamski "evidence" at face value. Adamski was a famous "contactee" of the 1950s and 1960s who took numerous photos, talked with dignitaries from Venus and elsewhere and even met Pope John XXIII two days before the pontiff's death (allegedly). In Alien Base (1998) there is a reproduction of one of Adamski's photos, showing him looking out of the porthole of a flying saucer. The portholes in the photo are all different sizes and Adamski's "head" is far too big for the supposed size of the craft. To make all of this worse, Adamski's flying saucers have clearly obvious hooks on the top. You have to will yourself not to see this when you look at the photographs.
So at every turn, the evidence is limited, disputed, and reliant on subjective interpretation. In any other field, such an idea would have been quietly dropped by now.
But ufology (yes, it pretends to be a science) doesn't just fade away. Instead it descends into conspiracy and paranoia. Absence of evidence equals cover-up. Explanation equals explaining away.
There might be aliens out there, in the depths of space. In fact there almost certainly are. They're just not here.