Global warming. Species extinction. The end of fossil fuels. Without doubt, there are plenty of problems to cause you to sweat and fret if you’re concerned about our planet’s near-future. But how about adding this to your plate: alien invasion. Sure, it happens regularly in the movies, but what if it’s for real.
One-third of the populace thinks it is real. The exact fraction varies a bit, depending on when and where you do the surveys, but for the last half-century, roughly one in three Americans has given thumbs up to the idea that visitors from distant star systems are buzzing our country’s fruited plain and occasionally plucking citizens from their bedrooms to perform unwholesome experiments on their bodies and their virtue. The percentage of people who believe this is the same in Canada, Australia and England.
Frankly, I’m skeptical that UFOs or some fraction of them are piloted by aliens. Mind you, as a SETI researcher I’m more than comfortable with the idea of a myriad other worlds frosted with intelligent beings. The latest results from NASA’s Kepler project suggest that at least a few percent of all stars have planets that, in principle, could boast liquid oceans and a thick atmosphere. That means there are billions of such worlds in our galaxy alone. It’s hard to imagine they’re all as sterile as autoclaves, or that none has evolved intelligent creatures. So I don’t argue against extraterrestrial visitors because I think we’re the only clever critters inhabiting the Milky Way.
No, my skepticism derives from two other lines of argument: (1) the unreasonableness of having alien visitors now, and (2) the weakness of the evidence.
Consider the first point, the matter of timing. Really, why have they chosen to pay a house call just at the moment when we can all watch it on Fox TV The Earth has been around for 4.6 billion years, and there’s been life carpeting the planet for at least three-fourths of that time. Homo sapiens have been strutting the landscape for a few hundred thousand years, or put another way, for ten thousand generations.
So why are the aliens here now How did we win the lottery
The usual answer given by UFO proponents is that we’ve inadvertently prompted the aliens to visit. These beings are unhappy with our warlike ways or our environmental depredations a motivation similar to what we’ve seen in the movie,’The Day the Earth Stood Still.’ Mind you, I don’t see much evidence that the extraterrestrials have done anything to ameliorate either of these problems. But a far stronger point is that they don’t know about them! Our high-frequency, high-powered radio, television, and radar transmissions began around 1940. Even assuming that the extraterrestrials can travel at the speed of light, their home planet can’t be more than 4 light-years’ distant if we propose that they’ve picked up these signals, decided we are a danger to ourselves or our planet, and have come here in time to produce all the saucer sightings of the late 1940s.
But there are no stars within 4 light-years.
The only way to negate this argument is to assume that the aliens are always here (or nearly always). In that case if our planet has had a constant extraterrestrial presence then where’s the inevitable detritus of their existence Where’s their garbage Are we really to believe that a coterie of advanced beings has been sharing the planet with terrestrial life for thousands, millions, or billions of years, and not left anything lying around for the archaeologists (or the coal miners) to dig up.
That would be extraordinary. However, given that we’re talking about aliens, a lot of people are willing to accept the extraordinary. The extraterrestrials have warp drive, or time travel, or cloaking technology, or who-knows-what, they say. And true enough, the extraterrestrials can be as advanced, in theory, as we wish them to be. Consequently, arguments against visitation based on reasonable conclusions from physics are, in the end, unconvincing for the hard-core believers because after all we don’t know all of physics.
So in the end it comes down to this: what’s the evidence Forget their motivations and their motive power. Just show me the proof.
Let’s be clear, tens of thousands of sightings of UFOs each year doesn’t do it for me. There were lots of sightings of leprechauns in Ireland, after all. Plenty of people claim to have espied bigfoot too, not to mention ghosts and angels. But in the end, most of that boils down to stories about what people have seen. And witness testimony is hardly convincing if you’re talking science (it’s not all that compelling in criminal trials either).
We should look at the physical evidence. But that’s thin on the ground. Where’s the stuff we could stack up in museums, or haul off to academic research labs If aliens really made a last-minute navigation error over Roswell, New Mexico in 1947, where are the bits and pieces of their craft The usual rejoinder is that the government, in a rare display of efficiency, has scooped up all such evidence, and carted it away.
While the idea of a federal conspiracy to deny us access to Exhibit A in any UFO incident is appealing, it quickly becomes a so-called argument from ignorance. ‘Yes, there’s good evidence for alien craft, but it’s kept under wraps, and that’s why I can’t show it to you.’ That’s not terribly persuasive.
The bottom line is that, despite at least 63 years of intense UFO reports, very few scientists seem to spend their time hunting for proof that we share our planet with alien houseguests. That’s not because it wouldn’t be an interesting phenomenon, if true. It’s only that weighing the arguments and the evidence they’ve voted with their research time and their grad students, and concluded that there’s very little likelihood that aliens are truly hanging out in the hood.
By Seth Shostak, Ph.D.
Seth is the Senior Astronomer at the SETI Institute in Mountain View, California, and the 2004 winner of the Klumpke-Roberts Award awarded by the Astronomical Society of the Pacific in recognition of his outstanding contributions to the public understanding and appreciation of astronomy.
He hosts the SETI Institute’s radio program Are We Alone Each week, Shostak interviews guests about the latest scientific research on a variety of topics: cosmology, physics, genetics, paleontology, evolutionary biology and astrobiology, and once a month hosts “Skeptic Check”, a show focused on debunking pseudo-science, U.F.O.s and practices such as astrology and dowsing. Are We Alone is available for download at the SETI Institute’s website ,and through podcasts.
Shostak has been an observer for Project Phoenix (SETI) as well as an active participant in various international forums for SETI research. He is also Chair of the International Academy of Astronautics SETI Permanent Study Group.