Amid the discussions of the potential for contact with extra-terrestrial civilizations, there’s one big buzzkill I don’t recall ever hearing posited as a possibility for why we haven’t made contact yet: Because it can’t be done.
We are used to the idea that technology advances exponentially, that we are all riding the Moore’s Law Express to the Singularity, and that as long as we don’t destroy ourselves via world war, climate catastrophe, or extermination by the artificial intelligences we’ve created, we will be capable of wonders that we can’t even image today, just as our nomadic ancestors of 100,000 years ago could never have imagined a steam engine, library, vaccine, or iPhone.
It follows that any other species on another world that has developed intelligence will get to hitch a ride on the same train. The details will differ, what they figure out first, what they emphasize, and what they’re physically capable of manufacturing will be different, but given a clear path, they too will achieve unimaginably advanced technologies that will, among many other things, allow them to voyage the galaxy and make themselves known to its other inhabitants.
There are lots of reasons to think this won’t happen, or if it does, that we won’t ever be aware of it. In an excellent piece by Tim Urban that I found via John Gruber, several reasons for our ongoing celestial loneliness are offered, all pretty sensible (except the one about the government cover-up, which he also thinks is silly). Some examples:
Super-intelligent life could very well have already visited Earth, but before we were here. In the scheme of things, sentient humans have only been around for about 50,000, a little blip of time—if contact happened before then, it might have made some ducks flip out and run into the water and that’s it.
Getting the sole experience of First Contact is so like the ducks, you know?
Another follows the metaphor of ants trying to comprehend a nearby highway (one presumes they cannot):
[I]t’s not that we can’t pick up the signals from Planet X using our technology, it’s that we can’t even comprehend what the beings from Planet X are or what they’re trying to do. It’s so beyond us that even if they really wanted to enlighten us, it would be like trying to teach ants about the internet.
That’s very much in line with the Moore’s Law Express, where it just so happens that the Planet X-ians are so much further down the track that we can’t even see them.
Urban also puts forth the idea of a “Great Filter,” a kind of universal civilizational buffer zone that extraordinarily few species ever cross. Maybe it’s because of planetary or astrological cataclysms killing off entire biospheres before they can evolve, or maybe it’s a near-inevitability of intelligent species destroying themselves, but either way, there may be some Rubicon that finishes off nearly all civilizations before they can become space-faring, let alone Type II or III.
(A side note about Type III civs, the kind that harvest an entire galaxy's energy: Urban talks about how there might be a relatively small number of them that can inhabit any one galaxy, and I'm thinking, if they're defined by their ability to eat up the energy of a whole galaxy, I have to imagine it's a "there ain't room for both of us in this one-horse town" kind of thing, where it's not 1000 Types IIIs in a given galaxy, but one, ever. But I digress.)
And he posits many other possibilities, and you should read the whole piece, because it’s really good.
But my thinking, which again is a real bummer, is that we need to consider the possibility that we haven’t made contact with alien civilizations because it simply can’t be done. The Moore’s Law Express actually does have a final stop at which technological advancement more or less halts because of the limits of physics, or even just the limits of any intelligence (natural or artificial) tomanipulate physics.
It might just be that traversing light years in a span of time that allows for survival, proliferation, or communication is simply impossible. It may be that there is no way to send communications signals of any known kind across the vast stretches of nothing that would allow another intelligence to receive them, let alone understand them.
Maybe there can and will be no warp speed, no folding of space, no teleportation, no subspace communications, no navigation of wormholes, no uploading of consciousness to interstellar servers, no Dyson Spheres, and no Singularity. As opposed to a Great Filter that finishes off civilizations on the way up, there may instead by a Great Ceiling, a lid on reality that says we (meaning we on Earth and any other species in the Universe) can go this far, but no further.
Now look, I know that thinking this way sucks, and it’s no way to get kids excited about science and exploration, or to rally the public to support more investment in scientific research. It is in our interest as a species and a civilization to cheerfully ride the Moore’s Law Express as though it has no terminus. But if the conversation about why we haven’t made contact with aliens is going to be an honest one, I think it has to at least acknowledge this sad possibility: Not that “they” might not be out there, but that they are, and we simply can never know for sure, and nor can they.
Okay, now pretend you never read this.
By the way, one potential way to travel the stars is by way of a Bussard Collector, and I just happen to have written a song about one. See? I have hope.