Not too long ago, we looked at a recent study estimating that there are at least three dozen (and possibly “thousands”) of alien civilizations in our galaxy capable of communicating. Now another voice has popped up in the debate, claiming that alien civilizations are actually “few and far between.” Considering that there are so many things we don’t know about the rest of our galaxy (or even our own solar system, for that matter) it’s understandable that different scientists might deliver different findings. But when they come effectively back to back like this, I immediately wonder why they arrive at such wildly different conclusions.
But here’s the hilarious part. Both reports are talking about the same study. This new one is coming to us from Seth Shostak, a senior astronomer for the SETI Institute in Mountain View, California. Let’s see what he has to say on the subject.
According to a new analysis from scientists at the University of Nottingham in England we don’t have a lot of alien company.
On June 15, two researchers published a paper in the Astrophysical Journal arguing that the Milky Way — which sports an estimated several hundred billion stars — could host as few as 36 alien societies. That’s a surprisingly tiny number, although the authors also make a second, more generous analysis in which they say that the count might be as many as a thousand.
Either way, their conclusion is that, like stick-shift cars, extraterrestrial civilizations are few and far between. The implication is that our nearest cosmic chums are at least several thousand light-years away.
The reason Seth finds this both surprising and worthy of mention is that such a reality about the relative rarity of civilizations in the galaxy would make human beings “extraordinarily special.” In the past, every time we’ve come to the conclusion that we’re somehow unique or the center of the universe (a view that was still popular until the 1500s and beyond), we’ve turned out to be spectacularly wrong. The further we look into the depths of the cosmos, the more we realize that we exist in orbit around a rather commonplace star lurking out in one of the unfashionable arms of an equally unremarkable galaxy, as Douglas Adams once observed.
Seth does take exception to one aspect of the assumptions used to generate these estimates. The authors of the original study employed something known as the principle of mediocrity. Specifically, because we’ve been using radio and radar waves for approximately a century and are now working on moving on to better technology (quantum communications), then most other civilizations will go through the same phases at roughly the same rate. So if you only have 100 years to detect any given civilization out of the literally billions of years each star system is in existence, your odds of happening to be listening at the right moment in the galactic timespan are pretty low.
That brings us back to the lowball nature of the figure generated in the linked study. If we’re assuming that there are only roughly three dozen civilizations out there communicating by radio, there could be tens of thousands of more who have already graduated to something better and more efficient. (Probably ansibles, as we’ve discussed here previously.)
The other factor to plaster against this wall is the question of the longevity of species. Once a race reaches the point of developing advanced technology, is there a clock ticking? Will they eventually destroy themselves or at least use up all the resources on their planet needed to continue advancing? Looking around here, we probably shouldn’t rule that out. In other words, and not to disparage the work of the scientists trying to answer these questions too badly, we probably have no idea. You can say there are 36 advanced races in our galaxy or 36,000 of them. Or you can say there’s just one. And nobody, at least for now, can definitely say you’re wrong.
Personally, I have to believe that there are quite a few. But if so, why don’t they seem to want to talk to us? We can’t be that bad, can we? (Checks notes…) Okay, let’s skip that last question.