Merged Where Are the Dyson Spheres (and Ringworlds)?/Undetectable Dyson Spheres

[Fudbucker]

The lack of Von Neumen devices can perhaps he explained as Sagan did: "perhaps civilizations would realize the risk of building such devices, and not do so" (paraphrasing).

But I don't understand why we haven't found D spheres or large-scale orbital structures around stars (e.g., Ringworlds). We have the capability of finding rocky planets now. You would think we might have observed such a system by now. It is disconfirming evidence of the existence of advanced intelligent life.

 

[Gord_in_Toronto]

The lack of Von Neumen devices can perhaps he explained as Sagan did: "perhaps civilizations would realize the risk of building such devices, and not do so" (paraphrasing).

But I don't understand why we haven't found D spheres or large-scale orbital structures around stars (e.g., Ringworlds). We have the capability of finding rocky planets now. You would think we might have observed such a system by now. It is disconfirming evidence of the existence of advanced intelligent life.

I'm not really too sure how to answer this but surely you must realize that there are so many places to look? Give the astronomers a change will ya?

 

[arthwollipot]

Since a Dyson sphere is designed to capture all the radiation from a star, I'm not sure how we would be able to detect one. Perhaps through gravitational lensing, but even then without a method of travelling there to check it out, we'd have no reason not to just classify it as "dark matter".

 

[PixyMisa]

But I don't understand why we haven't found D spheres or large-scale orbital structures around stars (e.g., Ringworlds). We have the capability of finding rocky planets now. You would think we might have observed such a system by now. It is disconfirming evidence of the existence of advanced intelligent life.

Physical impossibility might enter into it.

 

[Roboramma]

Since a Dyson sphere is designed to capture all the radiation from a star, I'm not sure how we would be able to detect one. Perhaps through gravitational lensing, but even then without a method of travelling there to check it out, we'd have no reason not to just classify it as "dark matter".

Thermodynamics: it would still give off radiation in the infrared.

 

[Roboramma]

Physical impossibility might enter into it.

A rigid structure that can capture all the radiation put out by a star may be physically impossible, but a swarm of objects in different orbits, some close in to the star others progressively further and further away, ought to be able to be relatively stable (such that only a small percentage of the energy captured would need to be put into keeping the orbits stable) and capture a high percentage of the star's output.

Want to capture an even higher percentage? Go to further and further orbits. Though this will have diminishing returns: the investment in a solar power satelite at pluto's orbit will take a long time to pay off, even if all the other real estate in the solar system is already taken up.

 

[Puppycow]

Probably because no Dyson spheres exist close enough to detect, or perhaps at all.

It's only a hypothetical concept after all.

Perhaps a very advanced civilization would use something else we haven't discovered yet.

Perhaps a Dyson sphere is impractical.

 

[steve s]

Where are you going to get enough material to build a sphere around a star? We could raid the entire asteroid belt for material and it probably wouldn't come close to meeting our needs.

Steve S

 

[Lukraak_Sisser]

There is also the fact that maybe someone DID build one. About 450 million years ago, which lasted a million years before collapsing. Around a star 448.99 million lightyears away.

Even if other life exists (which I consider quite likely) and if that life evolved intelligence (far less likely) and if it happened to be in our direct neighbourhood (extremely less likely), why assume its also co-temporal?

 

[Fudbucker]

I'm, not assuming anything. The argument I'm making is as follows:
1. Intelligent species may engage in large-scale projects visible to our telescopes.
2. No such projects have been found.
ergo, there is LESS reason to believe such species exist. Not to say there's no reason (or even a good reason). But I can't see it as anything other than disconfirming evidence of at least one kind of intelligent life. The set of intelligent alien life is not infinite, and when we have disconfirming evidence of a member of that set, the probability of the set itself is reduced.

 

[geni]

The lack of Von Neumen devices can perhaps he explained as Sagan did: "perhaps civilizations would realize the risk of building such devices, and not do so" (paraphrasing).

But I don't understand why we haven't found D spheres or large-scale orbital structures around stars (e.g., Ringworlds). We have the capability of finding rocky planets now. You would think we might have observed such a system by now.

We might have. This fits a dyson sphere:

http://arxiv.org/abs/1012.3457

In practice its generaly thought there is no practical way to build a dyson sphere.

 

[Fudbucker]

Physical impossibility might enter into it.

You remind me of the patent clerk who claimed "everything that can be invented has been invented"
*












*Yes, I know the story is most likely apocraphyl

 

[Fudbucker]

We might have. This fits a dyson sphere:

http://arxiv.org/abs/1012.3457

In practice its generaly thought there is no practical way to build a dyson sphere.

...that we know of.

20 years ago, there was no practical way to build the computers we're routinely using (no way that they knew about, which amounts to the same thing).

 

[PixyMisa]

You remind me of the patent clerk who claimed "everything that can be invented has been invented"

Reality, Fudbucker. Fudbucker, reality. Looks like you two have some catching up to do.

 

[PixyMisa]

A rigid structure that can capture all the radiation put out by a star may be physically impossible, but a swarm of objects in different orbits, some close in to the star others progressively further and further away, ought to be able to be relatively stable (such that only a small percentage of the energy captured would need to be put into keeping the orbits stable) and capture a high percentage of the star's output.

I don't think that's possible either - the orbits wouldn't be stable in the long term.

 

[geni]

...that we know of.

20 years ago, there was no practical way to build the computers we're routinely using (no way that they knew about, which amounts to the same thing).

1993? No but we could see how it might be done and it didn't seem to violate any laws of physics. If anything the molecular computing mob might actualy be disapointed by current systems.

Dyson spheres however seem to require far too much matter to be practical.

Dyson shells are even worse.

 

[geni]

I don't think that's possible either - the orbits wouldn't be stable in the long term.

That is less of a problem. By the time you've put enough mass into a dyson sphere for us to see the thing the extra mass needed to allow the satilites have some ΔV isn't really a problem. Throw in good use of fuzzy orbitals and you could matain the thing for a reasonable time period if you could build it in the first place.

 

[PixyMisa]

That is less of a problem. By the time you've put enough mass into a dyson sphere for us to see the thing the extra mass needed to allow the satilites have some ΔV isn't really a problem. Throw in good use of fuzzy orbitals and you could matain the thing for a reasonable time period if you could build it in the first place.

I suspect you're underestimating the difficulty and energy requirements, but I haven't done the calculations myself so I won't press the point.

 

[Puppycow]

We might have. This fits a dyson sphere:

http://arxiv.org/abs/1012.3457

That's tantalizing, but my money's on a much more mundane explanation eventually being accepted as the most likely one. E.g., the explanation actually put forward in the abstract:

We propose that Object X is a M>30 M_sun evolved star obscured in its own dust ejected during episodic mass loss events over at least half a century.

 

[Roboramma]

I don't think that's possible either - the orbits wouldn't be stable in the long term.

That's why I suggested that they'd need to actively keep them stable. It's only necessary that the energy necessary to do so be a small enough percentage of the total harvested.