Fermi's Paradox and the Preparation for Contact Hypothesis
There are at least 100 billion, and perhaps as many as 400 billion, stars in our Milky Way Galaxy. Carl Sagan once said: "There may be a million worlds in the Milky Way Galaxy alone which are at this moment inhabited by other intelligent beings" (Cosmos, episode XI). A recent study of several hundred solar-like stars shows signatures of heavy elements in their spectra from which one can infer that material to form Earth-like planets should be abundant. Astronomer Norman Murray of the University of Toronto reported at the 2001 AAAS meeting that: "There is evidence that there is terrestrial-type material orbiting most of the stars in the solar neighborhood. So, the implication, if this result holds up, is that there are Earth-like bodies in orbit around most of the stars in our galaxy." Even if this turns out to be overly optimistic and the formation of habitable planets around solar-like stars proves to be less likely than that, one might expect there to be at least a few other civilizations in the Galaxy. If that is the case, one can draw the conclusion statistically that unless civilizations tend to extinguish themselves once they discover sufficient technology to do so, most alien civilizations would be older and more technologically advanced than we are. It can then pretty easily be argued that a few million years would suffice for such an advanced civilization to spread across the Galaxy even at sublight speed by colonizing habitable planets, eventually sending out second waves of colonization from those planets, then third waves, etc. Astronomer Ian Crawford recently wrote about this in Scientific American. His diffusion model leads to "full galactic colonization" in 5 to 50 million years (Sci. Am., Nov. 2000, p. 8), a small fraction of the age of the Galaxy. Naturally this all assumes human-like behaviour and motivation. The bottom line is that if even only a few alien civilizations have arisen in the 10 billion or so year history of our Galaxy, most of the habitable parts of the Galaxy would likely be colonized by now.
The famous physicist, Enrico Fermi, was referring to such an argument when he asked: "Where are they?" Since he was a prominent (and very smart) scientist, his simple question has been given a duly profound name: Fermi's paradox. The paradox is resolved, of course, if the answer is: "Well, they are already here!" (and possibly have been for a very long time and perhaps have even been involved in the rather sudden emergence of homo sapiens sapiens, but that may be over the top, so ignore that last conjecture if it is too much, though I seem to recall that even Sagan considered that possibility at some point). Their being here -- but surreptitiously -- would answer Fermi and at the same time address a second common objection to the UFO phenomenon by scientists: that the observations indicate such utterly nonsensical, bizarre behaviour that it just could not possibly be real. Intelligent visitors just would not pull such disreputable antics as have been reported.
Between 1969 and 1972 astronauts visited the moon about twice per year and, while there, did mostly (apart from a few astronaut shenanigans) reasonable and rational things that one would expect an intelligent alien observer to recognize as scientific exploration. The nature of the reported UFO sightings and encounters, on the contrary, does not reflect the kind of purposeful behavior that we terrestrial scientists would expect from our extraterrestrial colleagues. By some estimates over a million UFO events have been witnessed. Even if one discounts 90 percent as misperceptions or hoaxes, that leaves far too many events to attribute to the kind of careful, sophisticated, efficient, high-tech exploration we scientists would expect from our alien counterparts, especially ones who would necessarily be more advanced than we are to have gotten here in the first place. In addition, the kinds of objects sighted range from little floating things the size of a baseball to giant lighted craft bigger than a stadium (yes), again posing incredible inconsistencies.
It is tempting to argue, as some do, that since the visitors are not behaving like proper alien explorers, there are no visitors in the first place. (For some reason this logic brings to mind Galileo attempting to get the Cardinals to look through his telescope.) To counter this argument, I would like to suggest one possible rationale that might, in principle at least (no real world guarantees), account for the widespread, disjoint kind of behavior that the UFO phenomenon has manifested over 50 years. The reason for proposing this "preparation for contact hypothesis" (which is certainly no original idea of mine) is simply to facilitate a "suspension of disbelief" so that the UFO evidence can be confronted on its own terms without the mental roadblock that the phenomenon violates all common sense, or more precisely the common sense of modern western society, and that of the scientific community in particular, and hence cannot be real.
The discovery and open recognition that alien beings (especially more advanced than we) exist and that they are already here would be a fundamental turning point in civilization. That revelation would constitute a one-time phase transition in human knowledge like that from ice to water. The societal significance of initial contact seems to me to be indisputable, and it is only less indisputable by epsilon that whoever or whatever they are (if indeed they are here) they are well aware of the consequences of initial contact, since unless they happened to be the first civilization in the universe, they must have gone through initial contact once themselves. (And even the first civilization would have seen the effect of initial contact on another.)
The working hypothesis -- and that is all it is -- is thus that we are being monitored by extraterrestrials and that they are coaxing us into awareness of their existence slowly enough to not disrupt our self-centered civilization ("gradually turning up the gain" as one of my colleagues put it). We are beginning to take our first steps into space, and though our primitive behavior -- warfare, terrorism, bigotry, intolerance, senseless violence, greed -- is not yet a danger to any extraterrestrial civilization, it could be someday. It has also been suggested that the diversity of life on our planet constituting a rich genetic bank of living organisms may have something to do with it. Perhaps the Earth is a greenhouse and nursery of some importance and value beyond its own confines as a biological databank. It could be that wet, green, just-right worlds are not all that common, and perhaps the Earth is special within some limited region of the cosmos, such as the local neighborhood (astronomical jargon for the volume of space within a few dozen parsecs in our spiral arm of the Milky Way) as a repository or laboratory of life forms. Unfortunately we who happen to live on this biologically rich planet are on an ecologically destructive course that will eliminate a third or more of the Earth's species in this century. This lack of stewardship may not have gone unnoticed. For such reasons, perhaps events are being staged involving a few people at a time, so that little by little the belief system of our society is challenged and altered. Our neatly packaged worldview is being deliberately unraveled by things that do not fit into our reality. The dramatic "landing on the White House lawn" that scientists demand as confirmation is exactly not the right thing to happen. At least not yet.
To repeat, this is merely a mental-roadblock-clearing hypothesis. But on the other hand, there is no doubt that the attitude of society has changed dramatically over the last 50 years to the extent that over half the population in the U.S. now believes in the reality of ongoing extraterrestrial visitation of Earth. That was certainly not the case in 1950. If public opinion polls are correct, the average person today appears to be pretty prepared for open contact, while we scientists would be quite jolted if UFOs proved to be real and extraterrestrial. (A nice, safe, distant radio signal from Tau Ceti would be more to our liking.) The "preparation for contact" hypothesis is merely a plausible idea, but it may be part of the explanation of the seemingly bizarre UFO behavior.
In any event, whether the above is merely fantasy or not, the duty of the skeptic is to confront the evidence, even if it seemingly violates all common sense.