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I hate the Kardashev scale. How is it useful in describing technological advancement? A civilization that technically had the ability to capture all the energy

I hate the Kardashev scale. How is it useful in describing technological advancement? A civilization that technically had the ability to capture all the energy output from a star may not decide to do so. There's also the fact capturing the energy of a star and capturing the energy of a galaxy is the exact same level of technology, given galaxies are made of stars. "Capturing the energy of a planet" isn't even a coherent concept.

darkwater 2y ago
The sun is pretty near, so it would be much easier to capture all of its energy, when compared to capture all of the energy of millions objects scattered over thousands of light years.
hulkmusic 2y ago
'"Capturing the energy of a planet" isn't even a coherent concept.' Galactus would like a word.
ben_w 2y ago
It's an arbitrary and flawed scale, but necessarily so given the only space-faring civilisation we can see is the one in the mirror. It does, however, give us a common point of reference for conversation about what may yet come.
valicord 2y ago
> capturing the energy of a star and capturing the energy of a galaxy is the exact same level of technology, given galaxies are made of stars That's like saying that building a house and building a metropolis is the same level of technology because cities are made of houses.
- causality0 2y ago
  Exactly. Houses do not predate cities by any appreciable margin.
perihelions 2y ago
- "Capturing the energy of a planet" isn't even a coherent concept." There's a perfectly cogent definition: it's the technological level where you can scale out solar photovoltaics (or equivalents) to within an order of magnitude of the solar energy incident on a planet. It's a useful framework of thinking. Human civilization in particular does not possess this technology level. We're four orders of magnitude short of this energy output, and we don't have the technical ability to reach it even if we really wanted to—i.e. today's manufacturing methods are too primitive, not automated, rely too heavily on manual labor. It's a framework to measure and then think about this technology gap. What's the difference between that imaginary civilization, and ours? We don't have advanced AI automation: we simply can't print O(100 trillion meter^2) of solar PV at any price. (The automation fraction is too low: human labor is the finite, limiting resource). Nor can we cover oceans with solar panels: we don't have the raw infrastructure power to build megastructures on that scale (again, some sort of an "automation" gap). And another: our (cheap) photovoltaics are an order of magnitude short of theoretical efficiency limits, waste most of the light that's incident on them. This one's a technology gap, and there's presumably a giant amount of physics understanding, computational power, and engineering ability that separates us from that end-game technology level. That separates our civilization from a hypothetical reference one. It's a framework to contemplate these kinds of questions.
- ben_w 2y ago
  > And another: our (cheap) photovoltaics are an order of magnitude short of theoretical efficiency limits, waste most of the light that's incident on them. I believe this is your only error: the cheap ones are about 20% efficient, the best are about 45%, and the theoretical maximum is about 69%. https://en.wikipedia.org/wiki/Solar-cell_efficiency#Thermodynamic-efficiency_limit_and_infinite-stack_limit https://en.wikipedia.org/wiki/Solar-cell_efficiency#Thermody...
azubinski 2y ago
A completely normal theory for a culture that determines the degree of development by the amount of available hydrocarbon mixtures (natural gas and oil). There is no point in hating such nonsense, but it is worth fearing.
RetroTechie 2y ago
It's a catch-all for the tech capabilities of a civilization. Expressed in terms of energy harvesting. Eg. capturing all energy output of a star, includes the ability to move (vehicles, robots etc) through space, build star-sized infrastructure, and so on. Personally I prefer the magnitude of energy production/consumption. MWatt → GW → TW etc. Or how advanced (or energy-dense) its source is: Burning stuff → electric power → nuclear fission → nuclear fusion → antimatter

darkwater 2y ago

The sun is pretty near, so it would be much easier to capture all of its energy, when compared to capture all of the energy of millions objects scattered over thousands of light years.

hulkmusic 2y ago

'"Capturing the energy of a planet" isn't even a coherent concept.' Galactus would like a word.

ben_w 2y ago

It's an arbitrary and flawed scale, but necessarily so given the only space-faring civilisation we can see is the one in the mirror. It does, however, give us a common point of reference for conversation about what may yet come.

valicord 2y ago

> capturing the energy of a star and capturing the energy of a galaxy is the exact same level of technology, given galaxies are made of stars That's like saying that building a house and building a metropolis is the same level of technology because cities are made of houses.

causality0 2y ago
Exactly. Houses do not predate cities by any appreciable margin.

perihelions 2y ago

- "Capturing the energy of a planet" isn't even a coherent concept." There's a perfectly cogent definition: it's the technological level where you can scale out solar photovoltaics (or equivalents) to within an order of magnitude of the solar energy incident on a planet. It's a useful framework of thinking. Human civilization in particular does not possess this technology level. We're four orders of magnitude short of this energy output, and we don't have the technical ability to reach it even if we really wanted to—i.e. today's manufacturing methods are too primitive, not automated, rely too heavily on manual labor. It's a framework to measure and then think about this technology gap. What's the difference between that imaginary civilization, and ours? We don't have advanced AI automation: we simply can't print O(100 trillion meter^2) of solar PV at any price. (The automation fraction is too low: human labor is the finite, limiting resource). Nor can we cover oceans with solar panels: we don't have the raw infrastructure power to build megastructures on that scale (again, some sort of an "automation" gap). And another: our (cheap) photovoltaics are an order of magnitude short of theoretical efficiency limits, waste most of the light that's incident on them. This one's a technology gap, and there's presumably a giant amount of physics understanding, computational power, and engineering ability that separates us from that end-game technology level. That separates our civilization from a hypothetical reference one. It's a framework to contemplate these kinds of questions.

ben_w 2y ago
> And another: our (cheap) photovoltaics are an order of magnitude short of theoretical efficiency limits, waste most of the light that's incident on them. I believe this is your only error: the cheap ones are about 20% efficient, the best are about 45%, and the theoretical maximum is about 69%. https://en.wikipedia.org/wiki/Solar-cell_efficiency#Thermodynamic-efficiency_limit_and_infinite-stack_limit https://en.wikipedia.org/wiki/Solar-cell_efficiency#Thermody...

azubinski 2y ago

A completely normal theory for a culture that determines the degree of development by the amount of available hydrocarbon mixtures (natural gas and oil). There is no point in hating such nonsense, but it is worth fearing.

RetroTechie 2y ago

It's a catch-all for the tech capabilities of a civilization. Expressed in terms of energy harvesting. Eg. capturing all energy output of a star, includes the ability to move (vehicles, robots etc) through space, build star-sized infrastructure, and so on. Personally I prefer the magnitude of energy production/consumption. MWatt → GW → TW etc. Or how advanced (or energy-dense) its source is: Burning stuff → electric power → nuclear fission → nuclear fusion → antimatter