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> and if you want to collect _all_ the energy from a star, For what? What are you doing with it? Not to forget the fact that all energy used eventually turns i

> and if you want to collect _all_ the energy from a star, For what? What are you doing with it? Not to forget the fact that all energy used eventually turns into heat. All of it (with the exception of electrochemical transformations). You're bringing all of that into Earth you're cooking everybody alive. How are you bringing that energy from the sphere to (wherever place)? Putting solar panels on Earth itself works much better. Heck, make a Dyson sphere on Earth (facing outside), that makes more sense.

ansible 5y ago
It is typically assumed that by the time you are making a Dyson swarm, that most life exists digitally. And spread out through the solar system. So in the best case scenario, you are powering computronium, upon which trillions of sophonts live out their digital lives. Hopefully doing some science, or at least playing some interesting games. A vast distributed network. In the worst case scenario, Blockchain and spam emails. Either way, people will put that energy to use. With a Dyson swarm, energy is received on the inside, towards the star, and heat is radiated outward. Lower power systems can run off the heat radiation of the inner swarm similarly. It is all eventually released as very low level heat, but diffused across the entire outer surface of the swarm. No hotspots... because someone would come along and use it. The Earth would also likely be deconstructed by this time, so don't worry about the biosphere, there won't be any.
naasking 5y ago
> For what? What are you doing with it? One example: powering lasers for light sail ships to colonize other star systems.
- raverbashing 5y ago
  You are not pushing a light sail ship to another star system, sorry. Light sails are "theoretically" possible but you don't need that much energy to push something that's feasible to push. Or better, there's a better source of light radiation: the sun itself. No need for a laser, just use a focusing mirror and you can have 100x more pressure than just from the sun itself.
  - ansible 5y ago
    Light sails are practical, and have already been tested in orbit. https://www.planetary.org/articles/lightsail-2-successful-flight-by-light https://www.planetary.org/articles/lightsail-2-successful-fl... Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years.
    - webmaven 5y ago
      > Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years. To expand on your point, those characteristics become even more important when using the light received to decelerate at your destination, though it is worth noting that there are alternative means of deceleration that don't have the same requirements (eg. electric and magnetic sails).
  - naasking 5y ago
    Why not? Light sails can reach 10% the speed of light, and sending out thousands of colony ships in multiple directions seems like a feasible way to colonize a galaxy relatively quickly. As the other poster mentioned, harnessing the sun's energy and turning it into a better form suited for light sails is the way to go. Sailing on the solar wind within a star system is a different tech with a different purpose.
ben_w 5y ago
> Heck, make a Dyson sphere on Earth (facing outside), that makes more sense. I’m missing something here, because even if we decided to build a Dyson swarm of course we are going to start with putting solar on and around Earth because this is where all the stuff we care about is. That’s just the first step in a journey of a miles miles. (TIL where that quote comes from: https://en.wikipedia.org/wiki/A_journey_of_a_thousand_miles_begins_with_a_single_step https://en.wikipedia.org/wiki/A_journey_of_a_thousand_miles_...). This seems so obviously it can’t be what you’re taking about though.

ansible 5y ago

It is typically assumed that by the time you are making a Dyson swarm, that most life exists digitally. And spread out through the solar system. So in the best case scenario, you are powering computronium, upon which trillions of sophonts live out their digital lives. Hopefully doing some science, or at least playing some interesting games. A vast distributed network. In the worst case scenario, Blockchain and spam emails. Either way, people will put that energy to use. With a Dyson swarm, energy is received on the inside, towards the star, and heat is radiated outward. Lower power systems can run off the heat radiation of the inner swarm similarly. It is all eventually released as very low level heat, but diffused across the entire outer surface of the swarm. No hotspots... because someone would come along and use it. The Earth would also likely be deconstructed by this time, so don't worry about the biosphere, there won't be any.

naasking 5y ago

> For what? What are you doing with it? One example: powering lasers for light sail ships to colonize other star systems.

raverbashing 5y ago
You are not pushing a light sail ship to another star system, sorry. Light sails are "theoretically" possible but you don't need that much energy to push something that's feasible to push. Or better, there's a better source of light radiation: the sun itself. No need for a laser, just use a focusing mirror and you can have 100x more pressure than just from the sun itself.
- ansible 5y ago
  Light sails are practical, and have already been tested in orbit. https://www.planetary.org/articles/lightsail-2-successful-flight-by-light https://www.planetary.org/articles/lightsail-2-successful-fl... Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years.
  - webmaven 5y ago
    > Light from the Sun isn't coherent, and you can't focus it with mirrors very far away. Lasers have many orders of magnitude less divergence when talking about distances measured in light-years. To expand on your point, those characteristics become even more important when using the light received to decelerate at your destination, though it is worth noting that there are alternative means of deceleration that don't have the same requirements (eg. electric and magnetic sails).
- naasking 5y ago
  Why not? Light sails can reach 10% the speed of light, and sending out thousands of colony ships in multiple directions seems like a feasible way to colonize a galaxy relatively quickly. As the other poster mentioned, harnessing the sun's energy and turning it into a better form suited for light sails is the way to go. Sailing on the solar wind within a star system is a different tech with a different purpose.

ben_w 5y ago

> Heck, make a Dyson sphere on Earth (facing outside), that makes more sense. I’m missing something here, because even if we decided to build a Dyson swarm of course we are going to start with putting solar on and around Earth because this is where all the stuff we care about is. That’s just the first step in a journey of a miles miles. (TIL where that quote comes from: https://en.wikipedia.org/wiki/A_journey_of_a_thousand_miles_begins_with_a_single_step https://en.wikipedia.org/wiki/A_journey_of_a_thousand_miles_...). This seems so obviously it can’t be what you’re taking about though.