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Lack of radio signals is a pretty tiny portion of the Fermi paradox. Fermi himself wasn't even thinking of them at the time according to the other Los Alamos sc

Lack of radio signals is a pretty tiny portion of the Fermi paradox. Fermi himself wasn't even thinking of them at the time according to the other Los Alamos scientists that were part of the conversation, but instead about having evidence of actual visitation. While the galaxy is mindbogglingly vast, even with the slower methods of interstellar travel that we could feasible achieve based on our current knowledge, we're talking about timeframes to traverse it that are not large on geological timescales, much less cosmological ones. There's lots of interesting reasons to pay attention to radio signals beyond 'Aliens broadcasting TV, music, and talk radio' - lots of neat stuff has radio waves as a consequence - and since we're already listening in and interpreting that data, it's pretty cost effective for us to also look for it in a technosignature context. But there's a reasonably wide variety of other technosignatures we actively look for today, and others that scientists attempt to infer out of data gathered for other reasons. Also, the whole way you've phrased your comment is kind of strange. The Fermi paradox doesn't advocate the idea that we're alone - it's about the discrepancy between how ubiquitous intelligence life should be in the universe at large based on our understandings of how life came into existence and how little evidence we have that that is the case. "We weren't looking at/for the right things" would 100% be a reasonable answer to the paradox that the overwhelming majority of scientists in the related fields would take no issue with if we suddenly discovered alien life through some different technosignature than we currently look for. Something like a dyson sphere or swarm would never have come into the conversation when Fermi first proposed the question (and he wasn't the first person to ask where everybody was, either) but are now seen as plausible enough that respected scientists in the field pour over things like the Kepler data looking for evidence of them. The Fermi paradox doesn't really need "proponents" - as long as we have no evidence of intelligent life or our understandings of how common intelligent life should be in the universe change, the paradox will stand. But I don't think there's any real faction of people that want it to stand, though. Every scientist or enthusiast on the subject I've ever spoken to or read thoughts on the subject would love to have an answer to the paradox.

vlovich123 2y ago
If the probability works out to 1 intelligent civilization per galaxy on average, then we wouldn't expect any other civilizations in our neck of the woods to discover (i.e. we could be the first or at least the only currently active one in our galaxy). If the probability works out to a few per galaxy, we don't actually know that it's possible for a civilization to practically leave their own solar system. Or it could be that in the amount of time since the Big Bang, we'd be the only ones that have had time to develop in our galaxy since the Big Bang. Or we could be the only ones to have developed in our neck of the woods for distances that aren't horribly relativistic (e.g. our furthest telescopes are looking back billions of years so who knows the current state of those places). As for the assumption that the galaxy would be teeming with life, it's not even clear that we can ever get to Alpha Centauri in a reasonable time frame. 80 years would require an average 5% the speed of light to get there (meaning much faster peak to do accelerate halfway / decelerate halfway). That's a lot of fuel so it's a huge stretch to claim we have that technology today. A 1% speed of life average speed would be a 400 year one-way trip. And even if we do build technology capable of this and go there, does that mean that Alpha Centauri then has the resources needed to bootstrap & proceed to the next star system or does it take a long time to build up a manufacturing base in the local star system to continue on the journey (i.e. you may be able to get to 1% the speed of light to travel between systems but traveling between planets within a system might still take a long time to collect resources & build out another space port)? In other words, how quickly do we go from star system to star system colonizing? There's no reason to believe that any intelligent civilization would be immune from economic pressures similar to humanity in terms of not taking on centennial or millennial interstellar projects. And as we can tell from humans on earth, there are economic, resource, technological, & timing reasons why we don't just start firing probes out into other star systems to try to do exploration. We also don't know how long the universe needed to cool & coalesce for before life had the appropriate conditions to evolve; it's not like life existed from the first moment Earth formed. It likely needed to exist for billions of years after the solar system coalesced & then for billions of years it was still getting pummeled by asteroids & comets within the orbital plane until it got cleared out. After all, Mars seems to have been similar in many ways but ended up dead so it's clearly a knife's edge (e.g. Jupiter protecting us from a bunch of incoming asteroids and comets). Finally, we have no idea whether intelligent civilizations have enough resources and survive long enough to leave their star system & to remain stable continuing to explore well beyond or collapse. And all of that isn't even touching that our ability to look for these technosignatures is extremely limited because we don't know what we're looking for, we don't know where to look for it, & we are blindly guessing at the signatures we might find. My point is - it's not a paradox unless you make some pretty wild assumptions that have no basis for them in the first place - we have no priors to inform probabilities to determine how many civilizations to look for. Nor do we even have search criteria for where to look. And we know that some pretty crazy technology that we have no way to detect is possible. As for visitation, I think people are way too optimistic about the ease with which such problems could be solved. & even if it does, we're at the outermost arm of the galaxy. Why would we be particularly interesting for aliens to visit? e.g. what star system would we pick to visit? Probably one with more resources that we've run out of rather than one with life if we've already convinced ourselves life is abundant in the universe & uninteresting to find.
- cthalupa 2y ago
  Everything you touch on is part of one or more potential answers to the Fermi paradox that have been proposed. And they're good points! One or all of them might be the answer. > My point is - it's not a paradox unless you make some pretty wild assumptions that have no basis for them in the first place (i.e. no priors to inform probabilities or search criteria). I think this is where there's a lot of talking past each other. All we have is our current understanding of things, and the paradox is simply going "Huh. Based on what we know, seems like there should be other intelligent life out there we'd have evidence of. Weird that isn't not there, right?" It's not really a matter of making wild assumptions, just going off of the evidence we have at current. Fermi asked the question while eating lunch - it wasn't a theory he wrote. It's not based on a body of theory and work specific to it. There's not some huge amount of scientific rigor behind it stating intelligent aliens aren't out there. It's just a question of why haven't we seen it. Most research on this subject is a byproduct of other research. There are very few scientists that would say their primary research is SETI - dozens to a hundred or so? And even some of the largest and best funded projects in this field like Breakthrough Listen generally don't have scientists working exclusively on it - it might be a significant portion of their time, but for most it is not their exclusive focus.
  - vlovich123 2y ago
    > All we have is our current understanding of things, and the paradox is simply going Actually based on what I’ve learned about it, the paradox is actually doing both things: it’s assuming over enough time scale our technology evolves rapidly enough to unlock new physics to traverse the universe we don’t have today while simultaneously being able to detect it using insanely primitive technology by comparison. It would be like asking someone to detect an atomic explosion in our solar system in 1930 - an explosion we’d likely not even notice today I suspect. There’s simply not enough understanding, we’re monitoring too little of the universe, and the equipment to do the monitoring is too primitive if technology really continues to advance at the pace posed by the Fermi paradox. Basically the Fermi paradox says “after the invention of modern science and Industrial Revolution, within a couple of hundred of years we were flying, within 50 years we’d left orbit and within 20 years or so we’d reached a moon. So surely after a few hundred thousand years the society should be able to reach and have colonized huge swaths of the galaxy”. But that kind of advancement would be at odds with our ability to detect such signatures and what we’re doing today is hypothesizing crazy sci-fi ideas and looking for those signatures with insanely primitive tools that have poor resolution. Communication we have 0 chance of spotting (encryption + energy efficiency = noise). Dyson spheres are interesting to look for but it’ll be a while before some novel ideas for how to spot them pan out (and that’s assuming the clever ideas are correct about what the footprint would look like and that Dyson spheres would be needed for long distance travel vs wormholes). However based on our current understanding of technology long distance travel is simply not possible - the Milky Way itself is 100k light years across. Even at 10% light speed that’s 1 million years to traverse the galaxy and ignores the challenges (surfing that kind of distance traveling at such speeds and avoiding all kinds of things flying through space). And visiting (let alone building major hubs) various star systems is going to take significantly more than that. If you can only manage 1% then that’s a 10 million year undertaking just to go from one end to another. It’s easy to imagine that visiting many star systems would take billions of years and that’s with technology we don’t know we can even build. And ignoring the practical challenges of going that fast, needing to survive, decelerating, and ignoring the economics of creating a craft that can undertake and last a 100k year journey at relativistic speeds. And saying we don’t have scientists working on this actually proves my point that there’s no paradox - no one is really working on this problem using very poor sensors trying to think as creatively as they can with basically 0 knowledge (compared to a civilization many thousands of years older than us) for signals we don’t know how or where to look for. So of course we haven’t found anything.

vlovich123 2y ago

If the probability works out to 1 intelligent civilization per galaxy on average, then we wouldn't expect any other civilizations in our neck of the woods to discover (i.e. we could be the first or at least the only currently active one in our galaxy). If the probability works out to a few per galaxy, we don't actually know that it's possible for a civilization to practically leave their own solar system. Or it could be that in the amount of time since the Big Bang, we'd be the only ones that have had time to develop in our galaxy since the Big Bang. Or we could be the only ones to have developed in our neck of the woods for distances that aren't horribly relativistic (e.g. our furthest telescopes are looking back billions of years so who knows the current state of those places). As for the assumption that the galaxy would be teeming with life, it's not even clear that we can ever get to Alpha Centauri in a reasonable time frame. 80 years would require an average 5% the speed of light to get there (meaning much faster peak to do accelerate halfway / decelerate halfway). That's a lot of fuel so it's a huge stretch to claim we have that technology today. A 1% speed of life average speed would be a 400 year one-way trip. And even if we do build technology capable of this and go there, does that mean that Alpha Centauri then has the resources needed to bootstrap & proceed to the next star system or does it take a long time to build up a manufacturing base in the local star system to continue on the journey (i.e. you may be able to get to 1% the speed of light to travel between systems but traveling between planets within a system might still take a long time to collect resources & build out another space port)? In other words, how quickly do we go from star system to star system colonizing? There's no reason to believe that any intelligent civilization would be immune from economic pressures similar to humanity in terms of not taking on centennial or millennial interstellar projects. And as we can tell from humans on earth, there are economic, resource, technological, & timing reasons why we don't just start firing probes out into other star systems to try to do exploration. We also don't know how long the universe needed to cool & coalesce for before life had the appropriate conditions to evolve; it's not like life existed from the first moment Earth formed. It likely needed to exist for billions of years after the solar system coalesced & then for billions of years it was still getting pummeled by asteroids & comets within the orbital plane until it got cleared out. After all, Mars seems to have been similar in many ways but ended up dead so it's clearly a knife's edge (e.g. Jupiter protecting us from a bunch of incoming asteroids and comets). Finally, we have no idea whether intelligent civilizations have enough resources and survive long enough to leave their star system & to remain stable continuing to explore well beyond or collapse. And all of that isn't even touching that our ability to look for these technosignatures is extremely limited because we don't know what we're looking for, we don't know where to look for it, & we are blindly guessing at the signatures we might find. My point is - it's not a paradox unless you make some pretty wild assumptions that have no basis for them in the first place - we have no priors to inform probabilities to determine how many civilizations to look for. Nor do we even have search criteria for where to look. And we know that some pretty crazy technology that we have no way to detect is possible. As for visitation, I think people are way too optimistic about the ease with which such problems could be solved. & even if it does, we're at the outermost arm of the galaxy. Why would we be particularly interesting for aliens to visit? e.g. what star system would we pick to visit? Probably one with more resources that we've run out of rather than one with life if we've already convinced ourselves life is abundant in the universe & uninteresting to find.

cthalupa 2y ago
Everything you touch on is part of one or more potential answers to the Fermi paradox that have been proposed. And they're good points! One or all of them might be the answer. > My point is - it's not a paradox unless you make some pretty wild assumptions that have no basis for them in the first place (i.e. no priors to inform probabilities or search criteria). I think this is where there's a lot of talking past each other. All we have is our current understanding of things, and the paradox is simply going "Huh. Based on what we know, seems like there should be other intelligent life out there we'd have evidence of. Weird that isn't not there, right?" It's not really a matter of making wild assumptions, just going off of the evidence we have at current. Fermi asked the question while eating lunch - it wasn't a theory he wrote. It's not based on a body of theory and work specific to it. There's not some huge amount of scientific rigor behind it stating intelligent aliens aren't out there. It's just a question of why haven't we seen it. Most research on this subject is a byproduct of other research. There are very few scientists that would say their primary research is SETI - dozens to a hundred or so? And even some of the largest and best funded projects in this field like Breakthrough Listen generally don't have scientists working exclusively on it - it might be a significant portion of their time, but for most it is not their exclusive focus.
- vlovich123 2y ago
  > All we have is our current understanding of things, and the paradox is simply going Actually based on what I’ve learned about it, the paradox is actually doing both things: it’s assuming over enough time scale our technology evolves rapidly enough to unlock new physics to traverse the universe we don’t have today while simultaneously being able to detect it using insanely primitive technology by comparison. It would be like asking someone to detect an atomic explosion in our solar system in 1930 - an explosion we’d likely not even notice today I suspect. There’s simply not enough understanding, we’re monitoring too little of the universe, and the equipment to do the monitoring is too primitive if technology really continues to advance at the pace posed by the Fermi paradox. Basically the Fermi paradox says “after the invention of modern science and Industrial Revolution, within a couple of hundred of years we were flying, within 50 years we’d left orbit and within 20 years or so we’d reached a moon. So surely after a few hundred thousand years the society should be able to reach and have colonized huge swaths of the galaxy”. But that kind of advancement would be at odds with our ability to detect such signatures and what we’re doing today is hypothesizing crazy sci-fi ideas and looking for those signatures with insanely primitive tools that have poor resolution. Communication we have 0 chance of spotting (encryption + energy efficiency = noise). Dyson spheres are interesting to look for but it’ll be a while before some novel ideas for how to spot them pan out (and that’s assuming the clever ideas are correct about what the footprint would look like and that Dyson spheres would be needed for long distance travel vs wormholes). However based on our current understanding of technology long distance travel is simply not possible - the Milky Way itself is 100k light years across. Even at 10% light speed that’s 1 million years to traverse the galaxy and ignores the challenges (surfing that kind of distance traveling at such speeds and avoiding all kinds of things flying through space). And visiting (let alone building major hubs) various star systems is going to take significantly more than that. If you can only manage 1% then that’s a 10 million year undertaking just to go from one end to another. It’s easy to imagine that visiting many star systems would take billions of years and that’s with technology we don’t know we can even build. And ignoring the practical challenges of going that fast, needing to survive, decelerating, and ignoring the economics of creating a craft that can undertake and last a 100k year journey at relativistic speeds. And saying we don’t have scientists working on this actually proves my point that there’s no paradox - no one is really working on this problem using very poor sensors trying to think as creatively as they can with basically 0 knowledge (compared to a civilization many thousands of years older than us) for signals we don’t know how or where to look for. So of course we haven’t found anything.