I see the difficulty of communications as the X factor here which is not so unknown. Our telescopes are not good enough to see a civilization like ours even on Alpha Centauri. It’s thought now we could observe a civilization like ours around a single star if we launch a probe past 500 au to the Sun’s gravitational lens. NASA wishes they could do that but it looks out of reach for now.
A ‘type ii’ civilization which could disassemble terrestrial planets could point a big-ass laser at us which we could see but maybe they don’t all (or ever) get that big. And they have to be motivated to do it.
If you want to visit another star you have to stop at the destination which is almost as hard as getting to speed but if you want to communicate a message which cannot be misunderstood you could bomb a planet with relativistic speed projectiles. Now maybe the average type ii civilization would not do that but maybe the fear that another one could so that might motivate a preemptive attack. It adds up to it being risky to attempt contact so why try?
to a star cluster 25,000 light years away. Even if somebody in that 300,000 star cluster has a telescope pointed in the right direction and the right time we could be long gone by the time they get a message back to us or maybe we forgot we sent it or now most of us live on another star…
rbanffy · 1d ago
We wouldn't be able to see, but radio detection is definitely possible. A type II civilization would possibly leave technosignatures we could detect with optical telescopes as well.
FrankWilhoit · 1d ago
"heard from" "aliens". Two sets of scare quotes, to make the point: suppose we had heard from them, how would we know? Why should we imagine (I know why we do imagine, but there is still no reason why we should) that their modalities of communication would have anything in common with ours? If they did, it would be a fantastically improbable coincidence. We have enough problems crossing language barriers between humans (and typically greatly overestimate the effectiveness of such communication); each new study of possible communication among animals, whether or not it appears parallel with what we call "language", reveals inconceivably basic differences, not just between their methods and ours, but, crucially, their purposes and ours. We have scientists who claim to be able to measure the information content of arbitrary signals, but upon inspection, their criteria invariably turn out to embody deep, unconscious assumptions that...whoever...would build those signals the same way we would. Again, there is simply no reason whatever to make such assumptions.
was repeated I’m sure most civilizations could figure out that it was a raster but if it is sent once the odds are awful. Past that what would they understand? If we sent it today we wouldn’t put Pluto on the planet list. Maybe 10k years from now there are a trillion people living on Ceres and it would be unthinkable to waste volatiles to fly to some dry spot like Earth and we’d again send a different message.
Figuring out the raster structure of NTSC television seems straightforward and even if they never figure out how color was encoded I think they’d still get a lot out of it even if their senses were different and they couldn’t “watch” TV. I am skeptical though that anybody would figure out how to decode the current ATSC signals, never mind the new ATSC 3 standard or 4G or 5G wireless signals that people stream TV over.
FrankWilhoit · 1d ago
Who says raster is a universal way to serialize an image? Who says a serializable image is probably rectangular? Who says the notion of serialization is a universal? What are alternatives to any of these? Can we exhaust the alternatives? (Finally, a question that has an answer: no.) Who says sampling or quantization are universals?
In order to know what they might do, let alone how, we would first have to know why. And their why is not going to be our why. Anybody's why is determined by what they are right up against. (This is why evolution immiserates, because it guarantees that we spend most of our time at the boundary of our envelope.)
PaulHoule · 22h ago
I'll argue that serialization is universal, there are so many cases in technology where you can scan something with a rotating or moving platform, it takes rather sophisticated electronics to implement "holographic" protocols such as the FFT, Borrows-Wheeler Transform, Deep Interleaving, Forward Error Correction, etc and I just don't see how you get to the place where you can build that kind of thing without breaking things down logically into systems that use serialization.
I am sure that aliens who can build computers know about the halting problem but they probably formulate it differently. [1] I doubt they have 8-bit bytes. They probably, like us, skipped Indium Phosphide, Gallium Arsenide and such for Silicon, but I'm not so sure about that.
[1] Turing started out with a line of though that seems oddly disreputable now: we know most of Cantor's phony numbers (that we call the "reals") don't have names [2], but some of them, like π do. Is the difference between the named and nameless ones that we can program a Turing machine to print out the named ones?
[2] ... hence less "real" than the integers
FrankWilhoit · 21h ago
Zoom out. Remember all the technologies that have been backed into wrong-way-first. Future humans, leave aside aliens, will be unable to distinguish between the engineering drawings of anything that has moving parts and the cartoons of Rube Goldberg. Remember Haldane (the quote is also attributed to Jeans, Hoyle, Eddington, and various others): "The Universe is not only queerer than we suppose, but queerer than we can suppose."
(The one thing that they will have, even if to their distaste, is powers of 2.)
ETA: If Turing was trying to make a distinction between the finiteness of the symbol for (say) the square root of three, versus the infinitude of the process that must be executed to evaluate it, that would be not so much disreputable as nonsensical. He was fond of setting up straw men; let us suppose that this was one of them.
beardyw · 1d ago
If the alien life is like the scum on a pond you might be expecting too much.
Or the alien life may consider us to be akin to scum on a pond and not worth communicating with.
A ‘type ii’ civilization which could disassemble terrestrial planets could point a big-ass laser at us which we could see but maybe they don’t all (or ever) get that big. And they have to be motivated to do it.
If you want to visit another star you have to stop at the destination which is almost as hard as getting to speed but if you want to communicate a message which cannot be misunderstood you could bomb a planet with relativistic speed projectiles. Now maybe the average type ii civilization would not do that but maybe the fear that another one could so that might motivate a preemptive attack. It adds up to it being risky to attempt contact so why try?
Consider this message
https://en.wikipedia.org/wiki/Arecibo_message
to a star cluster 25,000 light years away. Even if somebody in that 300,000 star cluster has a telescope pointed in the right direction and the right time we could be long gone by the time they get a message back to us or maybe we forgot we sent it or now most of us live on another star…
https://en.wikipedia.org/wiki/Arecibo_message
was repeated I’m sure most civilizations could figure out that it was a raster but if it is sent once the odds are awful. Past that what would they understand? If we sent it today we wouldn’t put Pluto on the planet list. Maybe 10k years from now there are a trillion people living on Ceres and it would be unthinkable to waste volatiles to fly to some dry spot like Earth and we’d again send a different message.
Figuring out the raster structure of NTSC television seems straightforward and even if they never figure out how color was encoded I think they’d still get a lot out of it even if their senses were different and they couldn’t “watch” TV. I am skeptical though that anybody would figure out how to decode the current ATSC signals, never mind the new ATSC 3 standard or 4G or 5G wireless signals that people stream TV over.
In order to know what they might do, let alone how, we would first have to know why. And their why is not going to be our why. Anybody's why is determined by what they are right up against. (This is why evolution immiserates, because it guarantees that we spend most of our time at the boundary of our envelope.)
I am sure that aliens who can build computers know about the halting problem but they probably formulate it differently. [1] I doubt they have 8-bit bytes. They probably, like us, skipped Indium Phosphide, Gallium Arsenide and such for Silicon, but I'm not so sure about that.
[1] Turing started out with a line of though that seems oddly disreputable now: we know most of Cantor's phony numbers (that we call the "reals") don't have names [2], but some of them, like π do. Is the difference between the named and nameless ones that we can program a Turing machine to print out the named ones?
[2] ... hence less "real" than the integers
(The one thing that they will have, even if to their distaste, is powers of 2.)
ETA: If Turing was trying to make a distinction between the finiteness of the symbol for (say) the square root of three, versus the infinitude of the process that must be executed to evaluate it, that would be not so much disreputable as nonsensical. He was fond of setting up straw men; let us suppose that this was one of them.
Or the alien life may consider us to be akin to scum on a pond and not worth communicating with.