4 ms·
A Dyson Sphere is impractical and not viable.
by jorgec 9y ago
A Dyson Sphere is impractical and not viable.
- khedoros1 9y agoI think that the actual theory was phrased as a “swarm of megastructures”. While also "impractical and not viable", a Dyson swarm would be less so than an enclosed sphere.
- vanderZwan 9y agoI dunno, the more I think about how we are a collective of trillions of cells coordinating a mobile, local, semi-closed ecosystem for decades before falling apart, the more I'm inclined to call us impractical and not viable too. Yet here we are.
- baking 9y agoWhen people say "Dyson Sphere" they are frequently talking about Dyson Swarms or Dyson Bubbles because a solid "Dyson Shell" is inherently unstable.
- CamperBob2 9y agoWhen people say "Dyson Sphere" they are frequently talking about Dyson Swarms or Dyson Bubbles because a solid "Dyson Shell" is inherently unstable. Gonna go out on a limb here and suggest that a civilization capable of building a Dyson structure is not entirely unfamiliar with control theory.
- Filligree 9y agoA more serious problem (with the solid version) is that no material imaginable could withstand the compressive forces involved.
- mulmen 9y agoI'm imagining a material that can withstand the compressive forces involved.
- ekianjo 9y agoDyson himself said the solid version would not work: > Dyson replied, "A solid shell or ring surrounding a star is mechanically impossible. The form of 'biosphere' which I envisaged consists of a loose collection or swarm of objects traveling on independent orbits around the star." Source: https://en.wikipedia.org/wiki/Dyson_sphere#cite_note-10 https://en.wikipedia.org/wiki/Dyson_sphere#cite_note-10
- taneq 9y agoScrith has enough tensile strength, so I'd imagine it could have similar compressive strength...
- SideburnsOfDoom 9y agoScrith is a fictional "unobtanium". "The tensile strength of scrith is theorized to be similar to the Strong nuclear force" which means "god-level magic involved". http://larryniven.wikia.com/wiki/Scrith http://larryniven.wikia.com/wiki/Scrith
- taneq 9y agoIt sure is imaginable, though.
- SideburnsOfDoom 9y agoThat's a low bar: we can imagine things that are impossible. We can imagine things that aren't even self-consistent. See the open pages of chapter 5 - "The Possible and the Actual" http://www.inf.fu-berlin.de/lehre/pmo/eng/Dennett-Darwin%27sDangerousIdea.pdf http://www.inf.fu-berlin.de/lehre/pmo/eng/Dennett-Darwin%27s...
- SideburnsOfDoom 9y ago> Gonna go out on a limb here and suggest that a civilization capable of building a Dyson structure A solid Dyson sphere is a habitat for beings such as ourselves. I am going to suggest that a civilisation capable of building a Dyson structure might be more comfortable with living off-planet, in zero G and/or vacuum and won't need something resembling a planet. If we're assuming cosmic time-scales and super-science, then civil engineering isn't the only science. Engineering the inhabitants to fit the habitat is also possible. Or a post-AI post-biological civilisation. We have no idea what's even likely at that level, but our best guesses have changed a lot since Dyson structures where proposed in 1960. Which is, in the context of this discussion, a mere instant ago.
- wyager 9y agoIt's astable, not unstable. The net gravitational force from the contained star is roughly zero for any positioning of the Dyson sphere. Therefore, it can drift away from perfectly centered, but there's no runaway instability. You can correct its position very cheaply by e.g. modulating the transparency of different sections of the sphere and using light pressure to keep it centered. Obviously there are other concerns, but positional instability isn't that bad, relatively speaking.
- taneq 9y agoActually, wouldn't light pressure automatically keep it centered (assuming it's consistent enough and therefore the net gravitational force is close enough to zero)?
- wyager 9y agoI'm not sure... I think it might cancel perfectly. I'd have to do the integral to make sure, but at least conceptually if you bisect the sun in half in any diresction, the net momentum flux is equal in both directions. That's only if the interior of the sphere is dark; I don't know how elastic reflections would figure in to this.
- Filligree 9y agoReflections make everything harder, but I think you're right. The situation seems isomorphic to the calculations that prove it's gravitationally astable.
- taneq 9y agoHmm. I think you're right - the fact that it's a closed surface means you can discard all that inverse-squared-law stuff and just go with conservation of momentum. Darn.
- komali2 9y agoWindows is the most superior operating system in existence. See that? See how untenable a statement like that is without any sort of evidence, sourcing, or even general thoughts beyond the initial contention? See how it adds as much value to the conversation as shouting "star trek rules!" at a star wars convention?
- somedangedname 9y agoYou're probably right. I remember reading that there are mundane explanations that are much more likely. I meant to say that "Dyson Sphere" was how it was reported in the press.