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What seems downright absurd to me is to dismiss the obvious fact that while a star might be incredibly inefficient relative to a working fusion reactor, the act

What seems downright absurd to me is to dismiss the obvious fact that while a star might be incredibly inefficient relative to a working fusion reactor, the actual energy output of a star will far outstrip that which can be collectively produced by artificial fusion for many centuries and millennia to come. Stars provide in abundance and for free, energy, mass (even for heavier elements they far outstrip that available on planets, asteroids, and comets), a star system spanning magnetosphere for protection from the interstellar medium, and a massive gravity well which can be used to anchor planets and mega structures alike While it's true that we won't strictly "need" them once we have working fusion, they are likely to be the hotspots of civilisation for a long time to come, probably as long as the stellar epoch of the universe is in play (so 100+ billion years).

ncmncm 6y ago
"Hotspots" is the key term here. For most high-civilization activities, heat is pollution, something that must be extracted and shed, in volume. Out in the Kuiper belt, cold is abundant and free. For most high-civilization activities, a gravity well is an anchor chain. Out in the Kuiper belt, material resources, including frozen fusible gases, are abundantly accessible with very little annoying gravitation. For many high-civiliation activities, proximity of other entities that could be put at risk, or that might put you at risk, creates hazards. Out in the Kuiper belt, room enough for anything is abundant and free. Extreme primitives like us and bacteria, who don't have abundant private energy sources, welcome the low-intensity energy influx from a nearby star. For anybody even mildly sophisticated, the energy is uselessly diffuse. At the same time, it keeps everything at a noisily high temperature that interferes with signal integrity and fine-grained processing.
- vimacs2 6y ago
  This is too much of an extrapolation even by the standards of envisioning things like Dyson Swarms. You are assuming that: * It is possible to export or even host consciousness onto a digital medium - we still have no evidence for this * All or most civilisations ultimately will want to transition entirely into a digital existence - the "entirely" part is important. If even 1% of a K-2 civilisation decided to stay organic, that would still lead to a Dyson swarm with a population approaching trillions. * Civilisations of this tech level would do a cost benefit analysis and decide that the several orders of magnitude more resources on a star is outweighed by the inconvenience of a gravity well - I don't think orbital rings are that mass or energy intensive to build and run for this to make any sense * There will be no future use of waste heat or method of disposal that goes beyond simple dispersal - the jury is still out on that, it may be possible to dispose of waste heat directly onto a black hole. If this turns out to be correct, the energy of a star is more than enough to power a sufficiently powerful laser array to create many in the gigatonne range.

ncmncm 6y ago

"Hotspots" is the key term here. For most high-civilization activities, heat is pollution, something that must be extracted and shed, in volume. Out in the Kuiper belt, cold is abundant and free. For most high-civilization activities, a gravity well is an anchor chain. Out in the Kuiper belt, material resources, including frozen fusible gases, are abundantly accessible with very little annoying gravitation. For many high-civiliation activities, proximity of other entities that could be put at risk, or that might put you at risk, creates hazards. Out in the Kuiper belt, room enough for anything is abundant and free. Extreme primitives like us and bacteria, who don't have abundant private energy sources, welcome the low-intensity energy influx from a nearby star. For anybody even mildly sophisticated, the energy is uselessly diffuse. At the same time, it keeps everything at a noisily high temperature that interferes with signal integrity and fine-grained processing.

vimacs2 6y ago
This is too much of an extrapolation even by the standards of envisioning things like Dyson Swarms. You are assuming that: * It is possible to export or even host consciousness onto a digital medium - we still have no evidence for this * All or most civilisations ultimately will want to transition entirely into a digital existence - the "entirely" part is important. If even 1% of a K-2 civilisation decided to stay organic, that would still lead to a Dyson swarm with a population approaching trillions. * Civilisations of this tech level would do a cost benefit analysis and decide that the several orders of magnitude more resources on a star is outweighed by the inconvenience of a gravity well - I don't think orbital rings are that mass or energy intensive to build and run for this to make any sense * There will be no future use of waste heat or method of disposal that goes beyond simple dispersal - the jury is still out on that, it may be possible to dispose of waste heat directly onto a black hole. If this turns out to be correct, the energy of a star is more than enough to power a sufficiently powerful laser array to create many in the gigatonne range.