6 ms·

Whole concept of Dyson sphere/swarm is anachronistic. It is like trying to build the Internet based on carrying pigeons, while you have available fiber optics a

Whole concept of Dyson sphere/swarm is anachronistic. It is like trying to build the Internet based on carrying pigeons, while you have available fiber optics and advanced radio communication. Because the moment you have enough technological advancements to build and deploy such a thing, you can already build fusion reactors by million units a year and maybe you already have even better ways how to manage energy. In the end the matter itself is just a different form of energy.

javcasas 2y ago
The sun burns around 600 million tons of hydrogen per second https://cosmicopia.gsfc.nasa.gov/qa_sun.html https://cosmicopia.gsfc.nasa.gov/qa_sun.html I don't think you building a million new fusion reactors per year so that each of them burns maybe 100kg of hydrogen per year even starts to be comparable in a few thousand years. The energy emitted by the sun is just several orders of magnitude beyond what you can source from a planet. It's just that huge.
- TheLoafOfBread 2y ago
  But I can carry such reactor into Oort cloud and beyond. I can power my ship in a shadow of a planet or asteroid and most importantly I am not dependent on one megastructure, which can fail, be destroyed or taken over by hostile forces.
  - floxy 2y ago
    ¿Por qué no los dos?
  - javcasas 2y ago
    The dyson sphere can power a huge factory, capable of making thousands if not millions of warships per second. It can also power a star-sized laser capable of vaporizing pretty much any incoming army, or even bigger objects like small planets. Your dyson sphere will be safe to everything but civilizations capable of playing marbles with stars and black holes. Also you can use your star-sized factory to make starships with fusion reactors. Not a problem.
    - TheLoafOfBread 2y ago
      But if you want to get beyond Jupiter, then whole Dyson swarm is useless to you, because you don't have source of energy. And again when somebody will get control over such swarm, then such person has control over whole civilization around that star which was foolish enough to build it and rely on it at a first place.
      - javcasas 2y ago
        What stops you from using a bit of the sun's output that you are capturing to materialize a starship with it's own reactor and thrusters, and then open a window in the sphere to let that ship leave? I mean, it looks like you want to _contain_ all the energy of a sun for the sake of containing it, not to do cool stuff with it.
cletus 2y ago
That's a very optimistic view of the future of fusion, IMHO an unreasonably naive view. There are lots of problems with fusion that are unclear if they will ever be solved, specifically: 1. Energy loss from neutron escape. Stars don't have this issue because they are incredibly large (so your neutron will hit something else more likely than not) and gravity; 2. Vessel destruction from lost neutrons (ie neutron embrittlement); 3. Assuming D-T fusion, you're producing helium atoms. Helium is a pesky substance. It's chemically neutral and a helium atom is (AFAIK) the smallest atom, even smaller than a hydrogen atom. That means it is hard to contain and also has a tendency to damage your container; 4. Fusion reactors are, in a way, somewhat primitive. Why? Because ultimately you generate heat and turn a turbine like we do in every coal and natural gas plant. Moving parts are bad. 5. Fuel. Depending on what fuel you need, this is somewhere between a small problem (eg protium or even deuterium) to a hassle (eg tritium) to a major problem (eg He-3). 6. Waste. This depends on fuel somewhat eg do you need to use fissile materials to create Tritium? Much more detail [1]. We obviously don't know the economics of fusion yet because it doesn't exist, but the economics of nuclear fission are, well, terrible (in both capex and opex terms). Once you put a solar panel in space, it produces ~7 times the power. There's no loss to cloud cover, getting covered in dust/dirt, atmosphereic loss and the day/night cycle. For an orbital, you simply cover the exterior with solar panels and you're done for power generation. No moving parts, no catastrophic failure modes (eg meltdowns in nuclear plants), it's scalable and when panels break down you simply remove them and plug in a new one. I expect other forms of power generation will find a niche use far from the Sun in the same way that submarines have different operating characteristics to a suburb. But I'm skeptical fusion will ever be the preferred method of power generation. [1]: https://thebulletin.org/2017/04/fusion-reactors-not-what-theyre-cracked-up-to-be/ https://thebulletin.org/2017/04/fusion-reactors-not-what-the...
- TheLoafOfBread 2y ago
  Dyson swarm has some naive approaches too 1. You don't have a way how to transfer power from Dyson swarm without absurdly staggering losses. 2. Dyson swarm satellite would be heated up by incoming heat from Sun on one side and heated up by whatever mean you want to transfer that energy on the other side and unable to cool itself down because it is in vacuum of space. So even that power on the paper is eye popping, actual power would be fraction of a fraction of nameplate power because then you would overheated and destroy it. And now question would be, is such constrained satellite able to make more energy than it was invested into making of this satellite? Combine 1 and 2 together and real output from such structure would be close to zero.
yreg 2y ago
You still want to build space megastructures to get more area without moving into another gravity well.

javcasas 2y ago

The sun burns around 600 million tons of hydrogen per second https://cosmicopia.gsfc.nasa.gov/qa_sun.html https://cosmicopia.gsfc.nasa.gov/qa_sun.html I don't think you building a million new fusion reactors per year so that each of them burns maybe 100kg of hydrogen per year even starts to be comparable in a few thousand years. The energy emitted by the sun is just several orders of magnitude beyond what you can source from a planet. It's just that huge.

TheLoafOfBread 2y ago
But I can carry such reactor into Oort cloud and beyond. I can power my ship in a shadow of a planet or asteroid and most importantly I am not dependent on one megastructure, which can fail, be destroyed or taken over by hostile forces.
- floxy 2y ago
  ¿Por qué no los dos?
- javcasas 2y ago
  The dyson sphere can power a huge factory, capable of making thousands if not millions of warships per second. It can also power a star-sized laser capable of vaporizing pretty much any incoming army, or even bigger objects like small planets. Your dyson sphere will be safe to everything but civilizations capable of playing marbles with stars and black holes. Also you can use your star-sized factory to make starships with fusion reactors. Not a problem.
  - TheLoafOfBread 2y ago
    But if you want to get beyond Jupiter, then whole Dyson swarm is useless to you, because you don't have source of energy. And again when somebody will get control over such swarm, then such person has control over whole civilization around that star which was foolish enough to build it and rely on it at a first place.
    - javcasas 2y ago
      What stops you from using a bit of the sun's output that you are capturing to materialize a starship with it's own reactor and thrusters, and then open a window in the sphere to let that ship leave? I mean, it looks like you want to _contain_ all the energy of a sun for the sake of containing it, not to do cool stuff with it.

cletus 2y ago

That's a very optimistic view of the future of fusion, IMHO an unreasonably naive view. There are lots of problems with fusion that are unclear if they will ever be solved, specifically: 1. Energy loss from neutron escape. Stars don't have this issue because they are incredibly large (so your neutron will hit something else more likely than not) and gravity; 2. Vessel destruction from lost neutrons (ie neutron embrittlement); 3. Assuming D-T fusion, you're producing helium atoms. Helium is a pesky substance. It's chemically neutral and a helium atom is (AFAIK) the smallest atom, even smaller than a hydrogen atom. That means it is hard to contain and also has a tendency to damage your container; 4. Fusion reactors are, in a way, somewhat primitive. Why? Because ultimately you generate heat and turn a turbine like we do in every coal and natural gas plant. Moving parts are bad. 5. Fuel. Depending on what fuel you need, this is somewhere between a small problem (eg protium or even deuterium) to a hassle (eg tritium) to a major problem (eg He-3). 6. Waste. This depends on fuel somewhat eg do you need to use fissile materials to create Tritium? Much more detail [1]. We obviously don't know the economics of fusion yet because it doesn't exist, but the economics of nuclear fission are, well, terrible (in both capex and opex terms). Once you put a solar panel in space, it produces ~7 times the power. There's no loss to cloud cover, getting covered in dust/dirt, atmosphereic loss and the day/night cycle. For an orbital, you simply cover the exterior with solar panels and you're done for power generation. No moving parts, no catastrophic failure modes (eg meltdowns in nuclear plants), it's scalable and when panels break down you simply remove them and plug in a new one. I expect other forms of power generation will find a niche use far from the Sun in the same way that submarines have different operating characteristics to a suburb. But I'm skeptical fusion will ever be the preferred method of power generation. [1]: https://thebulletin.org/2017/04/fusion-reactors-not-what-theyre-cracked-up-to-be/ https://thebulletin.org/2017/04/fusion-reactors-not-what-the...

TheLoafOfBread 2y ago
Dyson swarm has some naive approaches too 1. You don't have a way how to transfer power from Dyson swarm without absurdly staggering losses. 2. Dyson swarm satellite would be heated up by incoming heat from Sun on one side and heated up by whatever mean you want to transfer that energy on the other side and unable to cool itself down because it is in vacuum of space. So even that power on the paper is eye popping, actual power would be fraction of a fraction of nameplate power because then you would overheated and destroy it. And now question would be, is such constrained satellite able to make more energy than it was invested into making of this satellite? Combine 1 and 2 together and real output from such structure would be close to zero.

yreg 2y ago

You still want to build space megastructures to get more area without moving into another gravity well.