If Aliens were real why wouldn't our sun be a prime target for an Alien Dyson Sphere?

[Gamefreak89]

Meaning that if a race of them were hostile in terms of Human perspective why wouldn't our sun be a good target for them? I know that there are many different types of Stars out there that would seemingly out class our sun by a few solar masses. Maybe is it because there is intelligent life on our planet (Meaning us), Our sun isn't the right size or class?, there are plenty of other stars out there than our own, or maybe the Extra-Terrestrials themselves actually have a semi-biased view on life?

[CaptainToonces]

The closest star is 5 light years away. The round trip journey takes thousands of years. Constructing dyson spheres and travelling star to star are major undertakings so you'd need a well advanced civilization, and then there's the fact that the universe is huge and we're just in one small corner of it. So there probably are aliens out there but they are unimaginably far away and won't get here for millions of years.

Right now the first man-made radio waves are reaching the general population of stars in our part of the milky way, so if they have really good detectors, they might notice us around about now and send something back that would take another 50 years to get here. Hopefully it would be friendly!?

[baric]

Right now the first man-made radio waves are reaching the general population of stars in our part of the milky way, so if they have really good detectors, they might notice us around about now and send something back that would take another 50 years to get here. Hopefully it would be friendly!?

It would be terrifying if the first thing we got from them was a nazi symbol.

[cjameshuff]

How would our sun be a target of an alien megastructure? Dyson spheres aren't generally the first thing that comes to mind when I think of potential attackers...

Do you mean "why wouldn't they build a Dyson sphere around our sun"? You can't really say they wouldn't. There are no known examples of alien Dyson spheres, so the fact that there isn't one around our star doesn't mean much. I would rather expect a redder, longer-lived star to be a better candidate, though.

[kleindoofy]

If the best "real" aliens can do is crash land in some hick's back yard in New Mexico, how on Earth can we expect them to build some huge monstrosity in space?

If I had advanced technological powers, I'd use them to allow myself to sip MaiTais in the shade on some nice beach all day instead of zipping around the galaxy bothering other life forms. Could "real" aliens actually be that stupid?

[gzhpcu]

It is estimated that there are between 10²² and 10²⁴ stars in the Universe. Odds of picking our sun? Man, and I thought winning at lotto was tough...

[Gamefreak89]

Well there are between 100 to 300 billion stars in our galaxy alone I think using the drake equation would lower that number down to a significant bunch to round up how many potential planets might harbor intelligent life. What I'm wondering is what would an Alien Dyson Sphere look like from our Point of View through our Satellites or Telescopes?

[galacsi]

Dyson spheres ? Dyson sphere are just a twentieth century fiftieth years fantasy ! Techno megalomania at maximum overdrive !

[Gamefreak89]

Dyson spheres ? Dyson sphere are just a twentieth century fiftieth years fantasy ! Techno megalomania at maximum overdrive !

What the?! Well back on to what I was saying.

[cjameshuff]

Well there are between 100 to 300 billion stars in our galaxy alone I think using the drake equation would lower that number down to a significant bunch to round up how many potential planets might harbor intelligent life. What I'm wondering is what would an Alien Dyson Sphere look like from our Point of View through our Satellites or Telescopes?

Very bright in the IR, with essentially nothing in the optical...like a red giant with an improbably low surface temperature. We might see the interior through gaps in the stuff orbiting the central star, so some reflected light and occasional glimpses of the star itself.

[trinitree88]

Very bright in the IR, with essentially nothing in the optical...like a red giant with an improbably low surface temperature. We might see the interior through gaps in the stuff orbiting the central star, so some reflected light and occasional glimpses of the star itself.

cj. Freeman Dyson is a very interesting and brilliant guy from Princeton. Heard him give a nice talk at BU once. Even bright people can conjur up ideas that will never materialize....witness the flying car from the fifties, and the nuclear/bomb powered rocket. I think Dyson spheres are one of those babies, but I'm not infallible (or I'd be at the track making money). pete

p.s. space travel to distant lands is looming closer by the decade, and you should note that nobody ever reports a potential "alien" craft that looks like:
1. our, or the Russian, Space Shuttle, or
2. starship Enterprise

[cjameshuff]

cj. Freeman Dyson is a very interesting and brilliant guy from Princeton. Heard him give a nice talk at BU once. Even bright people can conjur up ideas that will never materialize....witness the flying car from the fifties, and the nuclear/bomb powered rocket. I think Dyson spheres are one of those babies, but I'm not infallible (or I'd be at the track making money). pete

They're pretty much a natural development of a civilization that's spread out into space. The known limits on such a civilization's growth will be material and energy, there's no reason to think growth would stop short of being limited by those, and the star's a good source of the latter. There's a finite amount there in a more or less point source, and as the system is stripped of material and constructions move inward for energy and reduced communications lag, less and less light will get out.

[galacsi]

I want to give a very contrarian view of the Dyson Sphere. I know many people like the idea and think it is natural and Dyson may be a genious but IMO it has no merit. And it Irk me !!

There are several point against Dyson spheres :

• It is not stable and consume energy and matter to stay in orbit.
• It is dangerous because you are exposed to solar flares and asteroids.
• you need artificial gravity working seamlessly .
• A war would be disastrous if some stations are destabilized and bump into others.
• And Civilization is not like a mold in a Petri disk , does not need to expand ever and ever without any other aim than becoming bigger and bigger.In all the industralized world population is decreasing and sometimes very fast like in Italy , Taiwan , Japan , Germany .Modern people are no rabbit ! It is much easier to slow your reproductive activity than breaking barriers to growth.
• Breaking down whole planets to build D.S. will not be allowed , all powers when they age become prudent and malthusian.
• And why anybody having the tools to build a part of a D.S would do it ? For profit ? But what you will do with this profit , build an other habitat ?
• And what about the transhumanist singularity ? Does not need no Dyson sphere !

[cjameshuff]

I want to give a very contrarian view of the Dyson Sphere. I know many people like the idea and think it is natural and Dyson may be a genious but IMO it has no merit. And it Irk me !!

There are several point against Dyson spheres :

• It is not stable and consume energy and matter to stay in orbit.
• It is dangerous because you are exposed to solar flares and asteroids.
• you need artificial gravity working seamlessly .
• A war would be disastrous if some stations are destabilized and bump into others.
• And Civilization is not like a mold in a Petri disk , does not need to expand ever and ever without any other aim than becoming bigger and bigger.In all the industralized world population is decreasing and sometimes very fast like in Italy , Taiwan , Japan , Germany .Modern people are no rabbit ! It is much easier to slow your reproductive activity than breaking barriers to growth.
• Breaking down whole planets to build D.S. will not be allowed , all powers when they age become prudent and malthusian.
• And why anybody having the tools to build a part of a D.S would do it ? For profit ? But what you will do with this profit , build an other habitat ?
• And what about the transhumanist singularity ? Does not need no Dyson sphere !

Instability...what? Dyson spheres are not unstable, except so far as anything else is in an unstable orbit. Are you mixing up Dyson spheres with ringworlds? And do you really think a civilization that has assembled that much matter into such orbits would be short on energy with to maintain those orbits?

Solar flares aren't dangerous, asteroids will be long gone by the time your orbital structures are big enough to be a likely target (what do you think those structures would be made out of?)

You don't need artificial gravity. Seamless or otherwise, it's just not at all necessary. Why would you think it's needed?

Wars tend to be disastrous...haven't you paid attention in History class? Are you suggesting people will stop building because of the possibility that some future enemy might destroy what they build? Why would we ever build anything?
If reconstruction exceeds the rate of destruction due to war, you still end up with a Dyson sphere.

A non sequitur...aside from the fact that history shows otherwise, you're saying we're limiting our growth because it's easier than breaking barriers to continued growth, therefore we'd limit our growth in a situation without barriers.

Another non sequitur...who'll forbid use of planetary resources and how will they enforce it, and why would they do so? You think the planets will cut off their exports of raw materials because their distant descendants will eventually run out of stuff to sell? So they'll keep it rather uselessly piled up in a ball so...their distant descendants can sit on it instead of go elsewhere with the wealth they've gained?

Why would anyone build part of a city?

What about the transhumanist singularity? If such a thing ever occurs, the rest of your list becomes even more irrelevant, and the energy requirements of civilization grow faster than ever.

[galacsi]

Instability...what? Dyson spheres are not unstable, except so far as anything else is in an unstable orbit.

Exactly : And enormous control work must be done permanently.

Are you mixing up Dyson spheres with ringworlds?

Not at all (But I loved Ringworld from L. Niven)

And do you really think a civilization that has assembled that much matter into such orbits would be short on energy with to maintain those orbits?

Yes I do , and they will need reaction mass to move and control all these stations.

Solar flares aren't dangerous

Yes they are ! (But you can protect against . .)

Asteroids will be long gone by the time your orbital structures are big enough to be a likely target

Point acknowledged !

You don't need artificial gravity. Seamless or otherwise, it's just not at all necessary. Why would you think it's needed?

Because I need gravity , because you need gravity , In the long time human life impossible without gravity. (And I suppose it the same for all aliens )

Wars tend to be disastrous...haven't you paid attention in History class? Are you suggesting people will stop building because of the possibility that some future enemy might destroy what they build? Why would we ever build anything?

Have you paid any attention in Geography class ? Why some whole regions were deserted , why villages and townwere built on steep hill and not in the plain just below ?

A non sequitur...aside from the fact that history shows otherwise,

Only recent history show a long period of growth.

What about the transhumanist singularity?

Who need Dyson spheres in the virtual world ?

[cjameshuff]

Exactly : And enormous control work must be done permanently.

Not enormous. Certainly not to people who've been in space this long.

Yes I do , and they will need reaction mass to move and control all these stations.

You don't need reaction mass. Photon pressure from the sun and from laser stations constructed for the purpose should be plenty. Electrodynamic tethers might also be of use if the star has a strong enough field, or if you construct structures in orbit that have their own magnetic fields. And if you do need reaction mass for something, the star itself can supply it, if there aren't gas giants and ice balls still to be harvested.

And no, they will not be so energy starved that they can't keep their orbits straight. By the time you've got something you can call a Dyson sphere, you have a large chunk of the output of a sun...the required energy is a tiny, tiny fraction of that.

Yes they are ! (But you can protect against . .)

If you're aware that you can protect against them, why even mention them?

Because I need gravity , because you need gravity , In the long time human life impossible without gravity. (And I suppose it the same for all aliens )

You don't need gravity, you need acceleration. Centrifugally simulated gravity will do fine. Artificial gravity is completely unnecessary.

Have you paid any attention in Geography class ? Why some whole regions were deserted , why villages and townwere built on steep hill and not in the plain just below ?

...of course, fortifications exist, therefore we won't ever build anything for fear of someone else blowing it up. Seriously?

Only recent history show a long period of growth.

History generally shows growth approaching the limits of what could be supported, with occasional episodes of further growth when a limit was bypassed or broken, or shrinkage/collapse when those limits were exceeded (by growth or by changes that reduced them).

Who need Dyson spheres in the virtual world ?

What are you going to use to power your virtual world? Where will you put its computers so you can be certain nobody blows them up? What if lightning strikes?

[CaptainToonces]

Galacsi, I think you are mixing up the core concept of Dyson's sphere with elaborate versions involving habitation and so forth. Those are cool ideas too, but the central point of the dyson sphere is simply that a civilization harnesses a huge portion of the radiated energy from a star. This great amount of energy could be used for things like interstellar travel. So before worrying about things like artificial gravity and wars, think of many orbital solar panels first.

What would an alien dyson sphere look like to us? It may not be resonant in the IR in case the aliens are harnessing the IR output too, but it may be visible depending on how close it is and how much of the star we can see through the dyson sphere/dyson swarm. It could be rather invisible. The kepler mission's occultation method may be the best technique for looking.

[cjameshuff]

What would an alien dyson sphere look like to us? It may not be resonant in the IR in case the aliens are harnessing the IR output too, but it may be visible depending on how close it is and how much of the star we can see through the dyson sphere/dyson swarm. It could be rather invisible. The kepler mission's occultation method may be the best technique for looking.

The IR emissions don't have anything to do with resonance or making use of the sun's IR. There's still a star in that sphere, and at equilibrium, the surface of the sphere has to radiate just as much power as the star inside puts out. The surface area is much higher, so it would be a lot colder than the surface of the star inside, but cold enough that the radiation peak is below the IR seems very unlikely. (it would have to be a very big sphere, and moving outward would greatly increase material costs and transport and communications times for a minor increase in energy efficiency)

[Noclevername]

The closest star is 5 light years away. The round trip journey takes thousands of years.

Depends entirely on the method of travel. It could be off by a lot in either direction.

And galacsi, you are confusing the real Dyson Sphere concept (a swarm of orbiting structures) with the solid Dyson shell, which is a creation of bad sci-fi writers. See http://en.wikipedia.org/wiki/Dyson_sphere for the distinction.

[Gamefreak89]

What gets me the most is how much resources would you need if are on the brink of type 2 civilization?

[kleindoofy]

... type 2 civilization?

A what?

Which science fiction reference work do I have to consult to find out what a "type 2 civilization" is?

[caveman1917]

A what?

Which science fiction reference work do I have to consult to find out what a "type 2 civilization" is?

The Kardashev scale i presume.

[Gamefreak89]

The Kardashev scale i presume.

Yes that's right assuming that given with enough time a type 1 civilization would need extra resources or energy to power their civilization with so there first target would have to be their parent star unless its a white dwarf which wouldn't put out as much energy as a red dwarf or a yellow sun like our own.

[eburacum45]

Which science fiction reference work do I have to consult to find out what a "type 2 civilization" is?

Try this.
http://en.wikipedia.org/wiki/Kardashev_scale
Note that Kardashev wasn't writing science fiction, but attempting to determine the limits of detectability of a broadcasting civilisation. This sort of calculation is necessary to find out the maximum distance at which an extraterrestrial civilisation can be detected, assuming the civilisation uses all the power available to it.

[neilzero]

Present human technology is a long way from dyson sphere capability. There is a significant possibility that we can't even a million years from now, except a very thin net of orbiting bodies around the Sun. The very thin net could have a radius of 40 million kilometers in our solar system = inside Mercury's orbit, otherwise Mercury would tear up the sphere. Area = 4/3 3.14 1600 trillion square kilometers. An an average of one millimeter thick, requires 67,000 thousand cubic kilometers of material = likely more than the total carbon in our solar system, if the bodies are made of CNT = carbon nano tubes = why I suggested a very thin net. Several other materials will likely be invented eventually that are about as strong as optimistic specs for CNT. Neil

[kleindoofy]

Try this. ... Note that Kardashev wasn't writing science fiction ...

Perhaps, but that article refers almost exclusively to science fiction in its examples.

Surprisingly, when discussing the damage energy conservation would do to the usefulness of the scale, it avoids mentioning the flux capacitor.

[cjameshuff]

Present human technology is a long way from dyson sphere capability. There is a significant possibility that we can't even a million years from now, except a very thin net of orbiting bodies around the Sun. The very thin net could have a radius of 40 million kilometers in our solar system = inside Mercury's orbit, otherwise Mercury would tear up the sphere. Area = 4/3 3.14 1600 trillion square kilometers. An an average of one millimeter thick, requires 67,000 thousand cubic kilometers of material = likely more than the total carbon in our solar system, if the bodies are made of CNT = carbon nano tubes = why I suggested a very thin net. Several other materials will likely be invented eventually that are about as strong as optimistic specs for CNT. Neil

Glass fiber and film, silicones, metals and metal oxides...no need to make everything out of carbon. Mercury's no problem, it'll have been converted to building materials long before a complete sphere existed. The idea isn't that civilization someday decides to encase their sun, so they embark on a massive project to do so using the minimum amount of material. The idea is that a civilization building habitats and other structures using the sun as a power source will be limited in growth only by material and energy output of the sun, and that there's no apparent reason such a civilization wouldn't eventually have a sphere of structures blocking the bulk of the light from their sun.

[LotusExcelle]

I find this kind of speculation a bit silly. It is, to me, like saying that there is a sand grain on Mars that an alien would go across the galaxy to get.

[eburacum45]

Note that Kardashev wasn't writing science fiction ...

Perhaps, but that article refers almost exclusively to science fiction in its examples.

I think you are confusing cause and effect. Kardashev wrote a scientific paper concerning the detectability of distant hypothetical civilisations; a calculation which as been useful in the SETI program. He was not responsible for the flood of science fiction stories which it inspired. Are we to blame Goddard and Tsiolkovsky for Flash Gordon and Dan Dare?

[eburacum45]

The idea isn't that civilization someday decides to encase their sun, so they embark on a massive project to do so using the minimum amount of material.

A minimum mass Dyson bubble could be made from statites supported by light pressure, and could have comparable mass to a large asteroid (depending on its radius).

I'm not entirely sure that such a lightweight sphere could extract the optimum amount of energy, however- it would be so lightweight it couldn't absorb and store the energy very well.