3 ms·

It doesn't all have to be at a single distance from the Sun. Some objects can be as far as Earth is and other objects can be at Mars level, at Merkur level or w

It doesn't all have to be at a single distance from the Sun. Some objects can be as far as Earth is and other objects can be at Mars level, at Merkur level or wherever else. There's plenty of space for this to be too hard.

naasking 5y ago
That doesn't matter if we're talking about scenarios where a significant fraction of the sun's surface area is covered. That requires enough mass for each fragment to make such a loose "shell" that they would influence each other gravitationally and perturb each other's orbits.
- naasking 5y ago
  Not to mention that that much surface area would catch a lot of solar wind, causing all sorts of rotational moments that will need constant correction. The control theory needed for this sort of thing is complicated and N body problems are undecidable in general.
  - kragen 5y ago
    It would catch approximately all the solar wind. "All sorts of rotational moments that will need constant correction" means that, if your orbiters are thin enough, they don't need reaction wheels or thrusters to change course to avoid an imminent collision — just solar-sail louvers. An occasional collision is unimportant to the viability of the system, like dust settling on solar panels, or dermis cells dying in a follicle to grow hair. N-body problem instances are never undecidable in the automata-theory sense; you can answer any question about the future trajectory from given initial conditions straightforwardly, if slowly, with interval arithmetic. The question of whether initial conditions exist that evolve to a given result is undecidable, but as with undecidability results in general, we do not need to decide it in order to build a working system, only to prove the optimality of a given program. You seem to be making up reasons to justify a preselected conclusion without bothering to think about whether they are true or relevant or not, and I wish you would not do that.
- kragen 5y ago
  Not significantly. Do the math: a thickness of 100 microns with existing silicon solar panels, or perhaps as little as 0.1 microns, out of, say, 1 AU (1.5e11 m). We're talking about filling 2e-15 of a 1-AU sphere with solid orbiters, totaling roughly the mass of Earth's moon, if we're using current silicon solar cells, and potentially a few orders of magnitude less than that. You could use a smaller or larger radius, resulting in higher or lower irradiance and higher or lower orbiter density, but we have a lot of experience with different kinds of solar panels at 1 AU, so we know it will work. No, there's no problem with orbital dynamics, control, computation, communication, or any of that nonsense. 50 years ago those were potentially challenging problems, but not now. Today the only remaining obstacles for a Dyson sphere are manufacturing and politics.

naasking 5y ago

That doesn't matter if we're talking about scenarios where a significant fraction of the sun's surface area is covered. That requires enough mass for each fragment to make such a loose "shell" that they would influence each other gravitationally and perturb each other's orbits.

naasking 5y ago
Not to mention that that much surface area would catch a lot of solar wind, causing all sorts of rotational moments that will need constant correction. The control theory needed for this sort of thing is complicated and N body problems are undecidable in general.
- kragen 5y ago
  It would catch approximately all the solar wind. "All sorts of rotational moments that will need constant correction" means that, if your orbiters are thin enough, they don't need reaction wheels or thrusters to change course to avoid an imminent collision — just solar-sail louvers. An occasional collision is unimportant to the viability of the system, like dust settling on solar panels, or dermis cells dying in a follicle to grow hair. N-body problem instances are never undecidable in the automata-theory sense; you can answer any question about the future trajectory from given initial conditions straightforwardly, if slowly, with interval arithmetic. The question of whether initial conditions exist that evolve to a given result is undecidable, but as with undecidability results in general, we do not need to decide it in order to build a working system, only to prove the optimality of a given program. You seem to be making up reasons to justify a preselected conclusion without bothering to think about whether they are true or relevant or not, and I wish you would not do that.
kragen 5y ago
Not significantly. Do the math: a thickness of 100 microns with existing silicon solar panels, or perhaps as little as 0.1 microns, out of, say, 1 AU (1.5e11 m). We're talking about filling 2e-15 of a 1-AU sphere with solid orbiters, totaling roughly the mass of Earth's moon, if we're using current silicon solar cells, and potentially a few orders of magnitude less than that. You could use a smaller or larger radius, resulting in higher or lower irradiance and higher or lower orbiter density, but we have a lot of experience with different kinds of solar panels at 1 AU, so we know it will work. No, there's no problem with orbital dynamics, control, computation, communication, or any of that nonsense. 50 years ago those were potentially challenging problems, but not now. Today the only remaining obstacles for a Dyson sphere are manufacturing and politics.