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Where exactly would we be seeing all this stuff? I mean, how closely can we even look on planets in our galaxy? We are still discovering trillions of new galax

by eof 16y ago

Where exactly would we be seeing all this stuff? I mean, how closely can we even look on planets in our galaxy? We are still discovering trillions of new galaxies here and there. Our reach is virtually zero in the context of the universe. It seems from our vantage point, I would expect the universe to look exactly the same whether it was bustling with life or we were the only ones. I had never thought about searching for Dyson spheres (it made me replay a part from The Big Lebowski where the dude says, "We'll that's fucking interesting man."), but they strike me as a incredibly hard thing to search for. Don't we see into the universe with the energy escaping from stars, galaxies, etc..? If some species were able to actually harvest the output of a star to anything approaching 100%, wouldn't it be exactly the type of thing we would never see? > Arguably it's actually the best claim supported by evidence Unless I am fundamentally wrong about the resolution of our map of the universe, I don't think there is any evidence either way unless you believe in any 'encounters'

jerf 16y ago
"If some species were able to actually harvest the output of a star to anything approaching 100%, wouldn't it be exactly the type of thing we would never see?" You'd still have residual heat. Some have suggested that what we'd see is awfully similar to red giants though I rather expect we'd still see something odd about them. Besides, the one you really should have focused on is star-traversing ships. They're visible from a really long ways away. "I would expect the universe to look exactly the same whether it was bustling with life or we were the only ones." Allow me to re-add in the word "intelligent" to your "life". The universe looks the way it would be expected to work if absolutely nobody ever makes it off their planet to any reasonable degree, or there is no other intelligent life out there. Or we just happen to be the "precursors". Part of the problem with this debate is that most people are still participating in it with very 1960s ideas about the limits of technology, very Star Trek ideas about what technologically sophisticated aliens will be like. Of course the Federation could be floating around out there without us knowing, with its starships powered by magic, its technologies powered by magic, and humanoid aliens scattered about everywhere due to magic. (Yes, I know about the episode in question.) But that's not what it looks like. In reality, a modern conception of what a technologically-sophisticated culture would do results in a lot of things visible from a very great distance, the ones I previously mentioned before. And we see 0 of them. Personally I do not put much stock in the idea that intelligent life is abundant and easy and not a single one of them ever decides to go to another star. For such a society it just isn't that hard and the payoff of being the first in a star system is incomprehensibly enormous, well out of proportion to the difficulty of getting there. Something about standard story of easy, abundant intelligent life is very very wrong, and the most parsimonious explanation is that intelligent life is in fact not easy or abundant.
- eof 16y ago
  > You'd still have residual heat. What? No. If there is residual heat you aren't capturing all the energy. > In reality, a modern conception of what a technologically-sophisticated culture would do results in a lot of things visible from a very great distance, the ones I previously mentioned before. And we see 0 of them. This appears to be the crux of your argument. Can you go into or point to a place where I can find out more about what these ships would supposedly look like? I think the fact that we will almost certainly need a paradigm change before we can really conceive of interstellar travel combined with the radical shift in conceived ideas following a paradigm shift, current guesses about what a super advanced culture's vehicles act like doesn't really hold much weight for me.
  - jerf 16y ago
    You can't capture all the energy. Basic thermodynamics. You have to black-body radiate away the heat of the star driving the system, or the only alternative is that it is all collecting within the system, cooking everybody within in a fairly short period of time. I argue on the basis of real science that we know, not because we know it all but because we can't argue on the basis of science we don't know about. Given that, we damn well can make some guesses about what a space ship will look like, which inevitably includes some form of propulsion involving either the expulsion of very, very hot matter (to get optimum mass efficiency, propellant will be at a premium and no point dumping it out the back cold) or light directly (unlikely but at least plausible) in a directional manner. The topic came up a few months ago during the discussions on whether it is rational for an alien civilization to summarily execute any other civilizations it discovers with relativistic planet-killers, but unfortunately trying to Google up a specific discussion about spaceships and relativistic projectiles is an exercise in futility. Still, work the math on what it takes to get a decent payload (at least several thousand tons would be nice) up to ~.1c, and then recognize that thanks to Newton's laws, the resulting mass-energy number you find must actually be coming out the back of your spacecraft in as close to a single direction as possible. Possibly literally as a laser, though as I said I'm pretty skeptical about the utility of a pure light-drive. It's pretty damned bright. Look, I hate to be offensive, but if you don't fail basic thermodynamics and you actually take seriously the real science we already know, we don't have to retreat into romantic cliches about how we can't possibly understand advanced cultures. We can in fact put bounds on things if our understandings are basically correct, and if our understandings are basically incorrect then frankly we have bigger problems than the question of alien life. The upshot of this, going back to your first post, is that if either of us is retreating into "religious dogma", romantic conceptions of reality held onto despite rational examinations of the evidence and science, taking shelter in the possibility of who-knows-what magic science may produce in the future and refusing to use what we already know, it's you, not me.

by eof 16y ago

jerf 16y ago

"If some species were able to actually harvest the output of a star to anything approaching 100%, wouldn't it be exactly the type of thing we would never see?" You'd still have residual heat. Some have suggested that what we'd see is awfully similar to red giants though I rather expect we'd still see something odd about them. Besides, the one you really should have focused on is star-traversing ships. They're visible from a really long ways away. "I would expect the universe to look exactly the same whether it was bustling with life or we were the only ones." Allow me to re-add in the word "intelligent" to your "life". The universe looks the way it would be expected to work if absolutely nobody ever makes it off their planet to any reasonable degree, or there is no other intelligent life out there. Or we just happen to be the "precursors". Part of the problem with this debate is that most people are still participating in it with very 1960s ideas about the limits of technology, very Star Trek ideas about what technologically sophisticated aliens will be like. Of course the Federation could be floating around out there without us knowing, with its starships powered by magic, its technologies powered by magic, and humanoid aliens scattered about everywhere due to magic. (Yes, I know about the episode in question.) But that's not what it looks like. In reality, a modern conception of what a technologically-sophisticated culture would do results in a lot of things visible from a very great distance, the ones I previously mentioned before. And we see 0 of them. Personally I do not put much stock in the idea that intelligent life is abundant and easy and not a single one of them ever decides to go to another star. For such a society it just isn't that hard and the payoff of being the first in a star system is incomprehensibly enormous, well out of proportion to the difficulty of getting there. Something about standard story of easy, abundant intelligent life is very very wrong, and the most parsimonious explanation is that intelligent life is in fact not easy or abundant.

eof 16y ago
> You'd still have residual heat. What? No. If there is residual heat you aren't capturing all the energy. > In reality, a modern conception of what a technologically-sophisticated culture would do results in a lot of things visible from a very great distance, the ones I previously mentioned before. And we see 0 of them. This appears to be the crux of your argument. Can you go into or point to a place where I can find out more about what these ships would supposedly look like? I think the fact that we will almost certainly need a paradigm change before we can really conceive of interstellar travel combined with the radical shift in conceived ideas following a paradigm shift, current guesses about what a super advanced culture's vehicles act like doesn't really hold much weight for me.
- jerf 16y ago
  You can't capture all the energy. Basic thermodynamics. You have to black-body radiate away the heat of the star driving the system, or the only alternative is that it is all collecting within the system, cooking everybody within in a fairly short period of time. I argue on the basis of real science that we know, not because we know it all but because we can't argue on the basis of science we don't know about. Given that, we damn well can make some guesses about what a space ship will look like, which inevitably includes some form of propulsion involving either the expulsion of very, very hot matter (to get optimum mass efficiency, propellant will be at a premium and no point dumping it out the back cold) or light directly (unlikely but at least plausible) in a directional manner. The topic came up a few months ago during the discussions on whether it is rational for an alien civilization to summarily execute any other civilizations it discovers with relativistic planet-killers, but unfortunately trying to Google up a specific discussion about spaceships and relativistic projectiles is an exercise in futility. Still, work the math on what it takes to get a decent payload (at least several thousand tons would be nice) up to ~.1c, and then recognize that thanks to Newton's laws, the resulting mass-energy number you find must actually be coming out the back of your spacecraft in as close to a single direction as possible. Possibly literally as a laser, though as I said I'm pretty skeptical about the utility of a pure light-drive. It's pretty damned bright. Look, I hate to be offensive, but if you don't fail basic thermodynamics and you actually take seriously the real science we already know, we don't have to retreat into romantic cliches about how we can't possibly understand advanced cultures. We can in fact put bounds on things if our understandings are basically correct, and if our understandings are basically incorrect then frankly we have bigger problems than the question of alien life. The upshot of this, going back to your first post, is that if either of us is retreating into "religious dogma", romantic conceptions of reality held onto despite rational examinations of the evidence and science, taking shelter in the possibility of who-knows-what magic science may produce in the future and refusing to use what we already know, it's you, not me.