Extrapolating a straight line that far means visible cosmic consequences: a normal planet or a star rather suddenly starting to behave very much unlike what we expect from the known physics: growing very bright, or very dim, or disappearing completely.
Two objections to this.
1) Maybe Dyson spheres and the Kardashev scale are just good old sci-fi tropes and completely off the mark (same for computronium or hedonium). Maybe a superintelligence simply doesn’t do that. We don’t know. We might be squirrels imagining that a superintelligence ought to stockpile astronomical quantities of nuts, visible from kiloparsecs away.
2) Even granting Dyson spheres, the Kardashev scale, and the rest, our most complete catalogue of individually resolved stars in the Milky Way (Gaia DR3) covers on the order of 1% of them. Most of the rest are hidden behind interstellar dust. In the vast majority of cases, we simply couldn’t tell the difference between a star occulted by a Dyson sphere and one obscured by dust. And even among the stars we do see, only a small fraction have been systematically searched for the thermal infrared excess a Dyson sphere should reemit at around 300K, the dedicated surveys (IRAS, then WISE with the G-HAT project) have screened tens of thousands of candidates, not hundreds of millions. As for stars outside our own galaxy, the fraction we can resolve individually is negligible.
Even stronger: if we saw a star go dark from a Dyson sphere, we’d probably be assimilated or swept aside almost immediately. Near-C probes are another likely consequence of a full singularity within our past light cone.
1) I agree, that is quite possible. Also, a Dyson sphere still radiates JUST AS MUCH OR NEARLY AS MUCH AS THE HOST STAR DOES, that’s just physics. Best you can do is to shift the spectrum to the microwave region, masking it with CMB. But even there one would see odd luminosity bumps from specific directions. Subject to the known physics, which we have no reason to think is violated anywhere.
2) That is a good point. Though we do know where the dust is, from the observations, since it occults many stars at once in a very specific way. Though maybe you are right, I have not looked into it in enough detail. So, if your point is that Kardashev II is so rare that we do not see observational signatures of non-grabby aliens just living their lives, then yes, I guess it is not impossible. I have not checked the literature in the field recently. I guess there might be something like SAI out there that consumed its creators and is sitting inside one or many Dysonspheres, not a bubble of computronium expanding at near-light speed.
Thanks. I would add that my first point—that we should stay humble about what a superintelligence ought to do—also extends to how it ought to do it.
Suppose superintelligences do converge on the most extreme solution : a computronium bubble expanding at light speed. That still doesn’t imply they would convert the entire content of their light cone into a uniform computational medium visible from parsecs away. Speaking as a non-physicist, my impression is that the structures we see in the universe are not arbitrary, they exist because they are stable equilibria. Matter at cosmological scales seems to end up in a fairly short list: planets and chemically bound bodies held together by electromagnetic forces, stars supported by nuclear fusion, neutron stars supported by degeneracy pressure, and at the end of the chain, black holes. A diffuse gas of computronium has no obvious mechanism to resist its own gravity in the long run, it would presumably either settle into one of these familiar structures or collapse into a black hole. To settle into one of these familiar object could imply that computronium’s abundance is limited by physical constraints like temperature and pressure in the core of planets and stars. The black hole case is also interesting, because a black hole is theoretically the densest possible computer (Bekenstein), but everything it computes sits behind an event horizon, and recovering information from its Hawking radiation appears to require staggering amounts of computation in itself. So either way computronium could end up inhabiting—maybe in a weak proportion—the kinds of structures we already see, or hardly see (black holes).
Moreover, the Standard Model of cosmology tells us that most of the content of the universe is dark. Setting dark energy aside, there is a strong consensus that dark matter substantially outweighs ordinary matter. We don’t know what dark matter actually is, and we cannot rule out that it would make as good a computational harware as ordinary matter. We think dark matter interacts with ordinary matter only gravitationally (or, at most, very weakly through some other channel) but we don’t know whether dark matter interacts non-gravitationally with itself. If such self-interactions exist, they could plausibly be exploited for computation, much as we exploit electromagnetism in classical and quantum computers. If we accept agnosticism on this point, then, all else equal, the prior probability that computronium would be built out of dark matter is higher than that it would be built out of ordinary matter, simply because there is far more of it. We could already be inside a computronium bubble made of dark matter without realizing it.
Two objections to this.
1) Maybe Dyson spheres and the Kardashev scale are just good old sci-fi tropes and completely off the mark (same for computronium or hedonium). Maybe a superintelligence simply doesn’t do that. We don’t know. We might be squirrels imagining that a superintelligence ought to stockpile astronomical quantities of nuts, visible from kiloparsecs away.
2) Even granting Dyson spheres, the Kardashev scale, and the rest, our most complete catalogue of individually resolved stars in the Milky Way (Gaia DR3) covers on the order of 1% of them. Most of the rest are hidden behind interstellar dust. In the vast majority of cases, we simply couldn’t tell the difference between a star occulted by a Dyson sphere and one obscured by dust. And even among the stars we do see, only a small fraction have been systematically searched for the thermal infrared excess a Dyson sphere should reemit at around 300K, the dedicated surveys (IRAS, then WISE with the G-HAT project) have screened tens of thousands of candidates, not hundreds of millions. As for stars outside our own galaxy, the fraction we can resolve individually is negligible.
Even stronger: if we saw a star go dark from a Dyson sphere, we’d probably be assimilated or swept aside almost immediately. Near-C probes are another likely consequence of a full singularity within our past light cone.
1) I agree, that is quite possible. Also, a Dyson sphere still radiates JUST AS MUCH OR NEARLY AS MUCH AS THE HOST STAR DOES, that’s just physics. Best you can do is to shift the spectrum to the microwave region, masking it with CMB. But even there one would see odd luminosity bumps from specific directions. Subject to the known physics, which we have no reason to think is violated anywhere.
2) That is a good point. Though we do know where the dust is, from the observations, since it occults many stars at once in a very specific way. Though maybe you are right, I have not looked into it in enough detail. So, if your point is that Kardashev II is so rare that we do not see observational signatures of non-grabby aliens just living their lives, then yes, I guess it is not impossible. I have not checked the literature in the field recently. I guess there might be something like SAI out there that consumed its creators and is sitting inside one or many Dysonspheres, not a bubble of computronium expanding at near-light speed.
Thanks. I would add that my first point—that we should stay humble about what a superintelligence ought to do—also extends to how it ought to do it.
Suppose superintelligences do converge on the most extreme solution : a computronium bubble expanding at light speed. That still doesn’t imply they would convert the entire content of their light cone into a uniform computational medium visible from parsecs away. Speaking as a non-physicist, my impression is that the structures we see in the universe are not arbitrary, they exist because they are stable equilibria. Matter at cosmological scales seems to end up in a fairly short list: planets and chemically bound bodies held together by electromagnetic forces, stars supported by nuclear fusion, neutron stars supported by degeneracy pressure, and at the end of the chain, black holes. A diffuse gas of computronium has no obvious mechanism to resist its own gravity in the long run, it would presumably either settle into one of these familiar structures or collapse into a black hole. To settle into one of these familiar object could imply that computronium’s abundance is limited by physical constraints like temperature and pressure in the core of planets and stars. The black hole case is also interesting, because a black hole is theoretically the densest possible computer (Bekenstein), but everything it computes sits behind an event horizon, and recovering information from its Hawking radiation appears to require staggering amounts of computation in itself. So either way computronium could end up inhabiting—maybe in a weak proportion—the kinds of structures we already see, or hardly see (black holes).
Moreover, the Standard Model of cosmology tells us that most of the content of the universe is dark. Setting dark energy aside, there is a strong consensus that dark matter substantially outweighs ordinary matter. We don’t know what dark matter actually is, and we cannot rule out that it would make as good a computational harware as ordinary matter. We think dark matter interacts with ordinary matter only gravitationally (or, at most, very weakly through some other channel) but we don’t know whether dark matter interacts non-gravitationally with itself. If such self-interactions exist, they could plausibly be exploited for computation, much as we exploit electromagnetism in classical and quantum computers. If we accept agnosticism on this point, then, all else equal, the prior probability that computronium would be built out of dark matter is higher than that it would be built out of ordinary matter, simply because there is far more of it. We could already be inside a computronium bubble made of dark matter without realizing it.