4 ms·

Dyson spheres are probably really rare. It's just bad strategy, everyone within your galaxy knows you're there pretty much immediately when a star just up and d

Dyson spheres are probably really rare. It's just bad strategy, everyone within your galaxy knows you're there pretty much immediately when a star just up and disappears one day. Granted, the non-K2s just stare in awe maybe, but the other K2s will fuck your shit up. Can't exactly pack it up and run either, not with a medium-sized star in your suitcase.

thfuran 3y ago
>but the other K2s will fuck your shit up. [Citation Needed]
- asoberbeck 3y ago
  https://en.wikipedia.org/wiki/The_Dark_Forest https://en.wikipedia.org/wiki/The_Dark_Forest
hef19898 3y ago
Temporal displacement fields: Wrap you star system in one of those and remove from the normal universe with a time shift of a couple of seconds! Let those pesky K2 Dyson Sphere civilisation figure that out!
- TeMPOraL 3y ago
  Tried that, it didn't work; that's how I ended up stuck in this insane reality where JavaScript ate the world, and my nickname is all I have to show for it.
  - hef19898 3y ago
    Ah, sucks when this happens, doesn't it?
tastyfreeze 3y ago
> Can't exactly pack it up and run either, not with a medium-sized star in your suitcase. If you're K2 just take the star and solar system with you. Stellar engines can be used to move stars. https://en.wikipedia.org/wiki/Stellar_engine https://en.wikipedia.org/wiki/Stellar_engine
- ben_w 3y ago
  Eventually. Shkadov thruster: > After a period of one million years this would yield an imparted speed of 20 m/s, with a displacement from the original position of 0.03 light-years. After one billion years, the speed would be 20 km/s and the displacement 34,000 light-years, a little over a third of the estimated width of the Milky Way galaxy. Caplan thruster: > Caplan estimates that the Bussard engine would use 10^12 kg of solar material per second to produce a maximum acceleration of 10^−9 m/s2, yielding a velocity of 200 km/s after 5 million years. Svoronos Star Tug: > The Svoronos Star Tug can, in principle (assuming perfect efficiency), accelerate the Sun to ~27% the speed of light (after burning enough of the Sun's mass to transition it to a brown dwarf).
jandrese 3y ago
I would assume it takes more than a day to build a Dyson sphere. But more to the point from a distant observer's viewpoint the star isn't going to just blink out. The Dyson sphere has to radiate just as much energy as the star produces, so it would probably appear just as a red dwarf. Unless the alien civilization has some way to destroy energy it will be in a constant battle to avoid cooking the inhabitants of the sphere.
- foofie 3y ago
  > Unless the alien civilization has some way to destroy energy (...) If the point of a Dyson sphere is to collect energy, wouldn't it be enough to just use it or store it?
  - ben_w 3y ago
    To use, not to collect. And thermodynamics appears to say you can't just store it. A stellar mass black hole might be an interesting "cold end" in this regard… if you can find or make one, but to do that you'd need to start with a Dyson swarm.
    - foofie 3y ago
      > To use, not to collect. And thermodynamics says you can't just store it. I don't think these semantic games are productive. Thermodynamics says you can transform energy. "Collect" in this context means using energy in a way that allows you to retrieve it in the future. For example, charging a battery or condenser with light with a PV panel, powering a motor that accelerates a flywheel, coiling a spring, heating a material, etc.
      - jandrese 3y ago
        Unless your civilization has ways of infinitely storing energy or exporting it somehow you'll need to be in equilibrium over the long term. This means radiating away the waste heat, at stellar scale.
      - 3y ago
ben_w 3y ago
Anyone with only mildly better tech than we have now, can see your ecosystem changing over the course of the seasons before you invented fire, let alone built a Dyson swarm. We're just starting to have this capacity already in special cases, though we've not found any sign of an ecosystem, just "boring" diamond rain etc. A Dyson swarm will keep you safe from any threat smaller than another Dyson swarm — and while you may not be able to "pack it up", you can use one to run to other galaxies… in fact, almost all of them… at close enough to the same time that light cones matter… and get the settlers moving at a significant fraction of the speed of light… and have a lot of redundancy.

thfuran 3y ago

>but the other K2s will fuck your shit up. [Citation Needed]

asoberbeck 3y ago
https://en.wikipedia.org/wiki/The_Dark_Forest https://en.wikipedia.org/wiki/The_Dark_Forest

hef19898 3y ago

Temporal displacement fields: Wrap you star system in one of those and remove from the normal universe with a time shift of a couple of seconds! Let those pesky K2 Dyson Sphere civilisation figure that out!

TeMPOraL 3y ago
Tried that, it didn't work; that's how I ended up stuck in this insane reality where JavaScript ate the world, and my nickname is all I have to show for it.
- hef19898 3y ago
  Ah, sucks when this happens, doesn't it?

tastyfreeze 3y ago

> Can't exactly pack it up and run either, not with a medium-sized star in your suitcase. If you're K2 just take the star and solar system with you. Stellar engines can be used to move stars. https://en.wikipedia.org/wiki/Stellar_engine https://en.wikipedia.org/wiki/Stellar_engine

ben_w 3y ago
Eventually. Shkadov thruster: > After a period of one million years this would yield an imparted speed of 20 m/s, with a displacement from the original position of 0.03 light-years. After one billion years, the speed would be 20 km/s and the displacement 34,000 light-years, a little over a third of the estimated width of the Milky Way galaxy. Caplan thruster: > Caplan estimates that the Bussard engine would use 10^12 kg of solar material per second to produce a maximum acceleration of 10^−9 m/s2, yielding a velocity of 200 km/s after 5 million years. Svoronos Star Tug: > The Svoronos Star Tug can, in principle (assuming perfect efficiency), accelerate the Sun to ~27% the speed of light (after burning enough of the Sun's mass to transition it to a brown dwarf).

jandrese 3y ago

I would assume it takes more than a day to build a Dyson sphere. But more to the point from a distant observer's viewpoint the star isn't going to just blink out. The Dyson sphere has to radiate just as much energy as the star produces, so it would probably appear just as a red dwarf. Unless the alien civilization has some way to destroy energy it will be in a constant battle to avoid cooking the inhabitants of the sphere.

foofie 3y ago
> Unless the alien civilization has some way to destroy energy (...) If the point of a Dyson sphere is to collect energy, wouldn't it be enough to just use it or store it?
- ben_w 3y ago
  To use, not to collect. And thermodynamics appears to say you can't just store it. A stellar mass black hole might be an interesting "cold end" in this regard… if you can find or make one, but to do that you'd need to start with a Dyson swarm.
  - foofie 3y ago
    > To use, not to collect. And thermodynamics says you can't just store it. I don't think these semantic games are productive. Thermodynamics says you can transform energy. "Collect" in this context means using energy in a way that allows you to retrieve it in the future. For example, charging a battery or condenser with light with a PV panel, powering a motor that accelerates a flywheel, coiling a spring, heating a material, etc.
    - jandrese 3y ago
      Unless your civilization has ways of infinitely storing energy or exporting it somehow you'll need to be in equilibrium over the long term. This means radiating away the waste heat, at stellar scale.
    - 3y ago

ben_w 3y ago

Anyone with only mildly better tech than we have now, can see your ecosystem changing over the course of the seasons before you invented fire, let alone built a Dyson swarm. We're just starting to have this capacity already in special cases, though we've not found any sign of an ecosystem, just "boring" diamond rain etc. A Dyson swarm will keep you safe from any threat smaller than another Dyson swarm — and while you may not be able to "pack it up", you can use one to run to other galaxies… in fact, almost all of them… at close enough to the same time that light cones matter… and get the settlers moving at a significant fraction of the speed of light… and have a lot of redundancy.