Over at Universe Today there’s an article about rewriting Drake’s Equation, and after reading it some time earlier, it’s been stewing in my mind a little; potential posts about it have changed several times, and resulted in this one.
Long story short: an astronomer named Frank Drake wrote out a simple equation, back in the sixties, to examine the possibility of contacting alien life. This was right at the beginning of advanced radio astronomy, and it took place for a meeting that would give birth to SETI, the Search for Extra-Terrestrial Intelligence, a project that is still going on today. I’ve written about this equation several times in the past, largely regarding how little it tells us and the bare fact that it’s all speculative. Recently, another astronomer named John Gertz proposed several changes to the equation, based on information that we’ve gathered in the time since. Here’s what he produced:
The number of spots on the sky within our field of view
The fraction of stars with planets
The average number of bodies within each that could engender life
The fraction of those that actually do give birth to life
The fraction of systems with life that evolve technological intelligence
The fraction of technological life that is detectable by any means
The duration of detectability
The chances of contact.
It was gratifying to see several of the points that I’d written about in the past get covered, but that’s just ego talking. A few other points were covered too, but those weren’t included in Gertz’s rewrite of the equation. But what came to me as I hashed this out was that there are three classifications of the information.
The first three factors in the equation are cosmological, able to be determined at a distance and hewing within reasonable estimates based on our knowledge of physics – they’re the ones we have the most confident numbers of (and it’s not all that confident, despite the huge upsurge in exoplanet knowledge in the past two decades.)
But the third is also biological, as are the fourth and fifth; they rely on the likelihood of life developing, moreover to a certain level, and we know nothing at all about that except for the conditions that we know are hostile, and that’s assuming life forms very similar to our own. Within our knowledge of physics, it seems that a carbon-based life form is most likely by far, but how life developed even on our own planet is still up for grabs, to say nothing of how likely this is to occur again elsewhere. These numbers are little more than wild guesswork, because we have nothing to support them. It’s the reason why I’ve said that the Drake Equation wasn’t actually an equation, because there’s no way to support it and testing it would require numerous examples of just the kind of contact it’s being used to predict.
The sixth and seventh factors are sociological, depending on the life from the previous factors actually engaging in practices or developments that we’d be able to detect, and to say that we’re spectacularly out to sea on these is putting it mildly. Intelligence isn’t this discrete concept; it’s a gradient, a spectrum of mental activity, and no matter what level you pick, you can find that it’s not necessary for life to sustain, not guaranteed or even likely to increase as a species develops, and possibly not even a lasting benefit (given how rapidly we’re depleting our resources and how serious our weapons of ‘defense’ are – targeted solely at our own species as well. But then again, as others have said, maybe we’re not actually intelligent.)
And as I’ve asked before as well, what are the chances of an extra-terrestrial species finding it a good idea to even make themselves known, much less initiate contact? Their own environment is going to guide how they develop, so are they competitive, or protective, or even just incurious about other life? It almost stands to reason that any species initiating contact does not feel threatened by this, and what should we infer from that?
Then there’s the attenuation of signal aspect. With all star systems light-years distant from us as well as one another, the ability to even transmit a signal would require enormous energy, becoming weaker with distance, so the species would have to be okay with disposing of this energy in the slim chance of making beneficial contact.
And if/when they do, what are the chances that they (or we) could even comprehend anything more than bare proof that it’s not a naturally-occurring signal? By what means are either of us going to translate any message?
So personally, I’d add a couple of factors into this equation, down at the bottom:
The fraction of technological life that is motivated to make contact
The fraction of technological life that would generate a signal that could reach us
The fraction of those signals that we would recognize as such
The fraction of technological life that would not present an enormous hazard to contact
That last one kinda throws a wrench in things, because it’s another number that we not only can’t calculate in the slightest, it can only be determined by taking the risk in the first place. I’ve mentioned before that we’re a stupidly gambling species, accepting certain risks if the reward seems worth it, and all too often the reward is entirely subjective. When we’re talking about an advanced species – one more advanced than us, since we’re considering it capable of something that we aren’t, yet – the risk of contacting something that could eradicate us is unknown in quantity, but undoubtedly present. For… what reason, really? Our curiosity? The chance that we might get some beneficial knowledge from them? The rather base instinct of being social? Yes, the idea of hostile aliens has been a science fiction trope for decades now – which doesn’t make it untrue in the slightest; some clichés are entirely accurate. Passively listening for signals likely entails little risk, but then, what do we do when we receive one? How low is the likelihood of any extra-terrestrial civilization openly transmitting useful information? Assuming for the sake of argument that we actually figure out how to translate such signals, how do we then figure out what the risks are? Are we going to psychoanalyze another species, much less based on their selected (and likely simple) transmissions? How trustworthy could we possibly consider this?
It’s funny; the more I think about the subject, the more I’m convinced that wild imagination and wishful thinking are playing more of a part than rational consideration. Receiving a definitive signal could be exciting and fascinating, but what happens after demands some careful thought.
* * *
Further posts along these lines: