This article proclaims ‘The Copernican Principle Rules Out BLC1 as a Technological Radio Signal’. I don’t get this. Wouldn’t information about extra-terrestrial technological civilizations be required to apply it? Would the fact that there is life here make us privileged observes of the universe? I’m willing to learn… And yeah, I hope we find evidence of alien technology in my lifetime.
From the paper, in the Discussion section:
Here, we applied the Copernican principle to an order-of-magnitude estimate of the prevalence radio- transmitting civilizations, without boundary assumptions that have influenced some previous Copernican frameworks (Spiegel & Turner 2012; Westby & Conselice 2020), and showed that BLC1 as a candidate for a radio transmission signal from the Alpha Centauri sys- tem would be in violation of the Copernican principle by about eight orders of magnitude, since the median of the derived probability distribution for any given Sun-like star presently hosting a radio-transmitting civilization is ~10−8 (see Figure 3). The only caveat to our conclusion is if technological life on Earth and the nearest stars is correlated, for example if the seeds for it were planted by panspermia (natural or directed) at the same time (Ginsburg et al. 2018). Here, we ignore this possibility, because Homo sapiens appeared on Earth ~0.3 Myr ago (Hublin et al. 2017; Richter et al. 2017), before Alpha Centauri became our nearest star system.
The only plausible way to avoid violating the Copernican principle here would be to invoke some a priori argument that falls outside of the purview of the Copernican principle, such as panspermia between the Earth and the Alpha Centauri system. We also showed that the Copernican principle is consistent with the vast majority of FRBs being natural in origin.
In other words, assuming that technological civilizations are randomly distributed throughout the galaxy, it i so unlikely that we’d actually find two within such close proximity as to be effectively impossible unless essentially every star system has such a civilization. There are a couple of problems with this line of reasoning, chief among them assumes that all stars in the galaxy are equally likely to support civilizations and that the systems that are would be randomly distributed rather than perhaps occupying groups of F- and G-type stars with high metallicity in areas that are not subject to large amounts of galactic radiation that may sterilize emerging life on a planet. We may actually be in a comfortable tropical zone of life. This does, however, beg the question that if civilized life is so close and using signals we can observe, why don’t we see evidence elsewhere nearby?
Personally, I think this will be eventually explained as a natural phenomenon, and that even if technological civilizations are ‘common’ they are going to be widely distributed enough that detection, much less communication, via radio frequency emissions will be unlikely at best. Our galaxy could host tens of thousands of concurrent civilizations distributed widely enough that they would never have a chance of communicating with one another, and over the potential span of time they could have emerged so far the odds that two would develop at the same relative time within a few dozen lightyears is vastly improbably unless such development is virtually inevitable.
The astronomical scale of the galaxy is so vast that the normal comprehension of scale utterly fails us in terms of intuiting the likelihood of contacting another civilization even if they exist. If there were a civilization a couple hundred light years away, we would not know they existed unless they constructed gigantic megastructures or sent an a signal with the power of a small star directed specifically at us, and 200 lightyears is but a jump and skip away compared to the scale of the galaxy.
Stranger
I seems that the idea that humans are the only species on Earth to have developed technology would violate the Copernican Principle. Why are humans privileged? The question is would we be able to tell if an advanced civilization on Earth destroyed itself 66 million years ago? Maybe a previous civilization from Earth put a beacon on Proxima b. And yeah I like SF.
66 million years? On Earth? I would say you are over by a factor of ten. Finding evidence of a civilization at our level of technology that existed six million years ago is improbable, and Earth will remain geologically active for probably close to half the rest of our star’s main sequence (at least another three or four billion years).
It is unlikely that a life-hosting planet would be less geologically active, so evidence of past civilizations will just not be there. Space is really big and things like Voyager are ridiculously small, so running across a hundred million year old space probe from Beta Reticuli is just going to be happening. Space and time are together just too big, and civilization is tiny in comparison.
Of course, the thing about randomness is that it is incredibly random. Throw a 20-sided die a thousand times and occasionally the same number could come up on consecutive throws, and some numbers might never come up. Probability allows that there could be a civilization on a planet around ε-Eridani or τ-Ceti right now, or that our system is the only one to host life in the entire galaxy in a 20 billion year span. Either way, I think it highly unlikely that the popular sci-fi paradigm of interstellar concourse between Pak Protectors and Ferengi and Wookiees and humans would ever resemble reality.
“Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.”
- D. Adams