Interesting thoughts, size would definitely matter, though...d

Good summary of the various types of hypothetical Dyson constructs, Deb! People often get hung up on the idea of a rigid sphere.

It's understandable, I think, when the usual artwork for Dyson constructs looks anything like this:
http://en.es-static.us/upl/...

Not that I'm actually complaining: it's cool artwork, and a cool image - I'm a sucker for science fiction and fantasy, and I'd really prefer seeing speculative artwork over something a little more down-to-earth - it's the way my brain is wired.

It's just natural, I think, that after seeing enough artwork depicting a solid shell, that's what we picture first.

True. And doesn't everyone look at that depiction of the star throwing off energy bolts and hear a "nnnzzzzt...nnnzzzzt" sound?

Maybe if we tell the artists often enough, though, they'll start depicting clouds of solar collectors. I bet Vincent diFate or John Berkey would have loved doing that.

No mention of sizzling sounds, but there were one or two mentions of beaming energy to Earth and to the collectors and such :)

I bet some talented artists could paint some evocative pictures of a Dyson "Sphere" of individual collectors. I keep imagining some of those old-school science fiction paperback covers, perhaps in this case with clouds of solar collectors, with a "lighthouse" on an asteroid in the foreground manned by robot lighthouse keepers, to warn space light sail sailing ships bound to and from the outer solar system away from collisions....

Probably the zappity bits are what's keeping the star at the center.

Hmm. I rather like that. Wouldn't there need to be more of them, though? That's only one axis. Of course, it's not complete yet...

I would think so, but maybe they (can) only activate one set at a time.

https://uploads.disquscdn.c...

It's already built

A solid shell would not be mechanically impossible but the system would be unstable. Larry Niven (author of "Ringworld") talks about that sort of thing in at least one essay.

The instability (actually an astability) that Niven describes comes from the fact that a hollow, spherically symmetrical shell and a small (compared to the cavity) object inside it exert no net gravitational force on each other. https://en.wikipedia.org/wi...

In the absence of other forces, left stationary relative to each other, they'd stay in the same relative position forever. However, the universe would never permit the absence of other forces.

Apparently, a non-rotating Ringworld would be astable in its orbital plane and stable along the axis the plane it occupies and stable along the perpendicular axis*. A rotating one is unstable (and non-linearly so) because its rotation introduces a gyroscopic component to any combination of axial and planar deviation. The math is fairly hideous. I was about able to understand it but deriving it would have been beyond me.

It occurs to me that a combined planar/axial deviation would also lead to instability, but it would be a much gentler and simpler one to calculate. (I've never seen that scenario addressed.)

I heard that Niven was cheerfully hounded through the corridors of an SF convention in the late 1970s by Cal Tech students chanting, "The Ring-world is un-STAY-ble!" I guess someone made it their class project :)

That was my understanding.

I think that any civilization with the technological, energy production, manufacturing, and other capabilities for building a solid shell would very likely be able to meet the engineering and design challenges of stabilizing such a monster, but again, think of the energy required to do so! I still don't see how any civilization that could afford to expend the energy on building a Dyson Sphere and keeping it functional would really need one... if they build such a vast White Elephant, they did it just to show off, or as a alien Dadaist art project, or just to amuse themselves because they have the luxury of time, materials, and energy to waste on doing it for fun or just because they want to prove they can....

Still, I think it's worthwhile to search for evidence consistent a Dyson Sphere: it's inexpensive to look for, it's a great way to gather all sorts of other useful data at the same time, and anything that looks like a Dyson Sphere will be pretty interesting and probably valuable to discover and learn about, whether it turns out to be an actual alien artifact or not. And if they DO find an actual Dyson Sphere out there, how cool would that be to find out who built it, how and why they made it work, and what else they are capable of?

What if DYSON sphere(S) were actually what constrains our Universe and all the others in a multiverse? We always seem to give ourselves more credit and importance than is provable.
What if such spheres were actually inevitable due to a still undiscovered law of physics (nature).
There is nothing to say that on an infinite scale even one of THOSE spheres isn't comparatively as small as a quark in the Universe of which it resides.
There is also nothing to stop OUR universe from being the SMALLEST yet created.
Nor the largest.

Or, what if it's not a sphere, but a sort of extra-dimensional Dyson construct for which a sphere would be a mere three-dimensional slice or shadow? I think that one of the last cutting-edge theories I'd heard was that some of the peculiarities about the universe could be explained by extending it out into 19 dimensions. I have trouble wrestling with imagining four or five, let alone nineteen, and can't imagine making sense of anything with a 19-dimensional model, but I was never very good at mathematics, and I take it it's largely a mathematical model, so who knows? If there are that many dimensions, I can't imagine it wise to rule out the possibility that human life on Earth is limited only to common space-time without extending in some way into additional dimensions, let alone alien life, and perhaps an extra-dimensional Dyson structure is a relatively simple project for something that freely moves, imagines, reasons, invents, and builds in five, six or more dimensions.

To put energy scale in perspective, let's see if I can recall that line from Ringworld about how the meteor defense system operated, as described in retrospect.
"The sun generated a solar flare that expanded for approximately thirty minutes directly towards us. Then it lased in violet."

Once the sun is relegated to being a sort of tame fusion reactor, some things get a bit easier...

Why would you build a sphere or even a ring? There is substantial power loss with transmission. A collector might make lots of energy and be 200 million miles away. Doesn't seem wise. Building a swarm of such collectors near the planet that needs them would seem to make mode sense. You still have to get the energy from a satellite to the earth somehow.

I'm certainly NO expert, or physicist, but what you say seems to make sense. One other thing is that maybe we want to make solar truly economically viable here on this planet, first; maybe...d

That's quite true if the purpose of the collectors is to power activity on Earth. But in a Dyson construct, very little of the energy collected would be beamed back to Earth. By the time even a small fraction of the sphere/cloud was completed, focusing that energy back to Earth could boil the oceans, for one thing. We're talking roughly one billion times more solar energy than Earth intercepts on its own.

The purpose of the sphere is to collect energy to be used within the sphere's components. Energy would not likely travel very far (on planetary scales) after being absorbed. In a "statite sphere", each individual object would probably absorb and process its own energy; or there could be local hubs that some energy is concentrated at if needed. If whoever builds this is sentimental, they'll keep Earth around as a park and a museum and carefully shield it from the sphere's activity. If they're not...

Seems like it would be hard to beat keeping the Earth around as a good, solid, stable, well-protected part of a Dyson system... just resurface the planet with collectors for solar energy. There's probably not enough material on Earth to build much of the Dyson system from, but there is still a lot of material on the Earth, and it wouldn't need to be moved very far to turn the Earth into one of the Solar System's larger natural solar energy collectors.

I suppose that, in a way, the Earth is its own, miniature "Dyson Sphere", with much of the Earth's mantle and crust absorbing energy radiated by whatever goes on in the (still poorly understood) core of the Earth (it's been many years, but I seem to recall hearing something to the effect that most of the Earth's heat does not come from the sun, but is instead generated within the Earth, in part by the decay of radioactive materials). I doubt that any civilization advanced enough to build a Dyson system would long neglect the Earth itself as even a small source of additional power. In fact, I bet that a civilization that advanced could find ways to "soup up" Earth's internal generation of power in various ways to get more energy "bang" for Earth's "buck".

I suppose they could, but it'd be that extra one-billionth bit of power compared to the main Dyson construct. In terms of mass it's more one-thousandth, so the utility of using the planet for mass is much greater.

Also, if the construct's radius is close to Earth's orbital radius, there might have to be a Hitchhiker's Guide style demolition phase first so Earth doesn't mess up the construct. The one I designed started out inside Saturn's orbit and evolved inward gradually until Jupiter started to interfere. Depending on the system it's constructed in, and whichbodies are consumed and which aren't, other conditions might apply.

And that's before we even get into the amount of power required to build a sphere or even a ring, let alone maintain it. No matter how I look at it, it seems that a civilization capable of building a Dyson Sphere wouldn't need it....

It would more likely grow and evolve over centuries or millenia. You would build out new habitats--probably rotating rings for 1G habitation--and power them with nearby collectors.

I can't help but think that any other civilization, no matter how advanced, would face the same resource limitations as we do -insomuch as building one of those monstrosities (Dyson Spheres) is concerned. It's an interesting idea, but not feasible enough to be taken seriously.

That's been my thought exactly: the concept of the Dyson Sphere assumes that...

1) the civilization has the vast amounts of energy and resources to spare to build the thing (in which case, do they actually need it?), and...

2) that the energy requirements of a civilization capable of both building and benefiting from the monstrosity will scale up to those of 21st Century Earth (when experience on 21st Century Earth suggests that as modern technology advances, a civilization is able to do more and more with less and less energy and resources - compare the power and material requirements vs. computing capability of a computer from the 1950s or 1960s with the power and material requirements vs. computing capability of the average "smart phone" today.... To put that in perspective, suppose someone from the 1950s were to try to calculate the energy, resource, and monetary requirements of a civilization that could distribute the equivalent of, say, a few billion of those 1950s-era room-sized supercomputers into the hands of its public, AND make those supercomputers portable. They would probably conclude that we would require a Dyson Sphere just to keep 21st Century technology operating! And that's after only 50 years... now, try to picture what we'll be able to do with the same amount of energy required to manufacture, power, and operate the equivalent of a modern cell phone five hundred years from now, and then 5,000 years....)

http://images.computerhisto...
Image: a CDC6600 Supercomputer, c. 1964... it cost the 1960s equivalent of US$50,000,000 each to manufacture and distribute, required a pickup truck to transport, required enough energy and cooling to maintain a small home, required a team of specialists to operate and maintain, and had the equivalent of less than 1/100000 of the processing power of the latest cell phone....

You're not taking into account that building such a thing is very much a 'bootstrap' process.

There is that. However, Moore's Law is not infinite, and at some point it will run into a limit. Using black holes as computers is about the densest application I've heard speculated about.

I think some of the very....active...proponents of transhumanism (aka The Rapture of the Nerds) feel that no amount of computing power can be called enough, because more power means more simulated universes for our uploaded consciousnesses to dwell in. I suppose it's like explaining to Paul Revere why I might feel that a car with 135 horsepower isn't quite zippy enough -- I want at least 150 horsepower. "One hundred and fifty horses? Are you mad?"

What I found intriguing about a statite sphere (when I designed one for an SF story) was not so much the sheer size and computing power -- although that was colossal enough -- but the durability over billions of years and the ability to shrug off things that would destroy a planetary civilization. Massive redundancy is no bad thing if a rogue planet plows through your cloud, or a supernova 30 light years away spikes half the statites. So if the laws of physics turn out not to support interstellar colonization, or the speed of light means that distant colonies will inevitably drift away culturally or even biologically from the home world, something like this gives options.

Also, as one of the links points out, you don't have to commit enormous resources at the beginning of construction; you can build a portion at a time and then use its energy-gathering ability to power the next stage, and so on.

I'd never thought of powering simulated universes. Considering the amount of time involved in communicating between star systems and such, one might even imagine that would be one reason why advanced civilizations aren't bothering to talk to the outside world, and why the universe seems so quiet so far: after a certain point, why bother looking for life outside of your Dyson Sphere, when, by that time, you can manufacture all the alien life and alien worlds you wish, all within easy reach of even your most primitive space flight technology? Perhaps as civilizations grow more and more advanced, they naturally turn further and further inwards... we might be alone in trying to communicate with an outside universe full of introverts with their alien noses buried in the advanced civilization equivalent of a really good book, and they don't want to be disturbed by those rude strangers from Earth who keep wanting to interrupt them....

The durability of a solid Dyson construct is something that worries me off an on, and for those reasons you mentioned: rogue planemos, comets, dark matter (if it exists), space junk, and so on (I remember being struck by an article on Earthsky a while back that caused me to realize just how difficult it is to get rid of old space junk, and how even if we could collect it, it's not really much good for recycling). And then there's the effects of just plain, ordinary entropy... a Dyson Sphere of any sort would, long before the project is completed, start becoming its own vast junkyard in space full of tons of antique and obsolete Dyson components. While newer components are being built, archaeologists will be pondering the mysteries of the most ancient bits. Civilizations will rise and fall, technological revolutions will come and go during the construction of such a thing.

The vast amounts of time involved in the construction are thus something that occurs to me when I think about the Dyson Spheres. Then again, what, I suppose, does time mean to a civilization capable of building and benefiting from a Dyson construct? Mortality as we understand it is just a minor, built-in, organic limitation, and one that should be easily bypassed by any civilization that would require the vast amounts of power we're talking about.

Yes, the notion of a non-uniform society across any type of Dyson construct is interesting: 'the Old Ones are gone and we short-lived beings do what we can'. Niven's Ringworld had its rise and fall of various civilizations, too. But even a 'cloud' type construct could incorporate millions of asteroid-sized habitats that allowed for physical habitation (as opposed to uploaded Nerdvana), or abandon hard, you-can-walk-on-it places entirely. Ie. "The Integral Trees" or Karl Schroeder's very enjoyable "Virga" series.

Hello everybody,

I guess i find a realistic way to produce Dyson Sphere.
Belive me we don't need to wait 500 years or 5000 years, we can start building this mega structur around our own Star .
I have an idea, a realistic idea and we can start building this with in a year time but first i have to get some kind of patant for my idea and discovery.
I have the best idea and discory to make Dyson Sphere but i have no money, i don't know how to manage funding, do i you think that would be better to set up a kickstarter project ?

I realize most don't wish to acknowledge this but it's entirely possible, though disappointing that WE are the BEGINNING of intelligent life.
It has to start somewhere regardless of the odds.
It's also possible that once a second point of life begins, fed by seed from our home that life will then progress exponentially.
It's also possible that by the time a THIRD in the series arrives , we (the Earth and our entire solar system) might have already ceased to be viable if not completely disappeared.
Given the massive distances involved, ''exponential'' is also only constrained by infinity.
It's also possible, given the short lifespan of mankind to this point that life will expand exponentially ALONG with the discoveries of mankind and populate vast swathes of the Universe in less than a few million years.

If aliens exist around other stars this is how they may make a structure for some odd reason. For protection against stuff or if the asteroid belt is closer to the inner star it would help them exploilt the energy from their star if they need. As per the MAT RING story below. The MAT RING would be easier to protect as it would be less material to hit and after the habit counter spinning centrifical gravity ring on the side is built it could be fitted with railguns that move along the ring on a train system to protect it. Also could be resintered to move it to a closer orbit around the star if need be. Tell your friends.

Mat... Not sure about the plauseability of a Dyson sphere. Probably not enough material around the average star. Plus what would happen if it was hit by a medium to large asteroid at direct or bad angle. Difficult to protect such a large item from a meteor shower. It would crumble like my intelligence at a nasa conference. Joking i have medeoker IQ. Thank goodness. However a . MAT RING. Around a star is possible with current technology. First you send several hundred solar powered sintering rover robot dealios to the inner asteroid belt and solar powered robots to collect water for fuel. Water collector robots would be placed at twentyfive equally placed intervals around the sun.Then the bots sinter asteroids into elongated asteroids using the debris from around them into finned or ridged shapes. After they look like lots of old elongated wrickled chips. Now I'm getting a craving for chips. Send flying robots to use the water fuel collected from some of the asteroids to join the chips, I mean long asteroids together. By sintering, or coarse. Some gaps would be best left between some areas so as to add more material in to be sintered in like a pin being built up into it. Sintering works in miserious ways. Believe me, it would be to make it stronger. Then flying bots send the sintering bots to the inner asteroid belt to do the same thing all over again. The the fying bots send the sintering robots to the outer asteroid belt and do the whole thing all over again. As each stage progresses they keep joining together until a solid ring is formed around the sun. If more material is needed it could be taken from planet crossing asteroids and jupiters trojan asteroids. Could take a while to biuld the more robots sent the qiucker it would be built. If all the pieces were to be brought in slightly closer to mars it would also be better. Smaller ring less material. Then it could be exploited for other endevours in space. Anyway thats possibly how one starts that around a star. Thanx for reading. The Mat ring.

Si-fi writer Larry Niven wrote a series in the 70's entitled Ringworld .......
In my opinion not a real practical idea .