Dyson Spheres

[Nurd_boy]

I was watching that episode of ST:TNG that featured the dyson sphere that got me thinking.

[thinking]...the amount of material and energy required to close a normal G star 1AU radius, with a usable thickness structure, I think would conpletely strip not only the solar system its in, but several besides...maybe an 'empty quadrant' with stars and a few trace belts might be the only clue to ones existance.

what kind of tech would that require? how long the construction? could something like that been kept secret in an interstellar community or would it become legend and folklore, like a flying dutchman?


any thoughts?

 

[Tom Schoene]

It actusally tankes a suprisningly small anmount of material to make a Dyson Sphere. One solar system is likely to be sufficient.

Dyson Sphere FAQ.

The real question, IMO, is why build one? By the time that you have the requisite technology, you don't need a Dyson sphere.

 

[Nurd_boy]

that faq tlked about thin shells...

if ancients built one as a fortress against grandfather it would be much thicker.

why build on?...like I said.

 

[TKalbfus]

"The real question, IMO, is why build one? By the time that you have the requisite technology, you don't need a Dyson sphere." The Answer is that a Dyson Sphere would have the land area of 1 billion Earths. You could find that land area naturally by settling a large fraction of the Galaxy's habitable planets. Some of those planets would inevitable have to be made habitable through terraforming, but terraforming a planet would only make available one additional planets surface in each case. The real problem lay with communication delays as all of the planets would be spread out hundreds or thousands of light years across the galaxy, and that makes it impossible to have a single civilization with 1 billion Earths of habitable surface area unless you build something like a Dyson Sphere. A Dyson Sphere can be run under 1 government and this provides alot of political power for the governmental leaders. The Third Imperium has 11,000 worlds and it takes over a year for a communication from the capital to the furthermost reaches of the Imperium. A Dyson Sphere would outweigh the Imperium by a factor of 100,000 times its population contributing to the economy of the Dyson Sphere. A Dyson Sphere with 100,000 times the population of the Third Imperium would not seem any more crowded than the Imperium, since the population density of the habitable psace of both would be the same. in addition communications and decision making would be much quicker for the Dyson Sphere since it would all be in one system. A Dyson Sphere would also be better able to defend itself against an external enemy since it would be able to react to aggression within an hour instead of the two years it would take the Imperium to react to aggression on its territory. This would be the motivation for building a dyson sphere.

 

[TKalbfus]

Here's how I think a Dyson Sphere might be discovered in the Traveller Universe. A Scout ship is traveling in Jump Space toward some destination, and it emerges in Real space somewhere other than it intended. Apparently in the midst of interstellar space. The Scout ship's jump fuel is exhausted and they only have fuel for manuevering. They send out a distress signal, no answer, so they keep on transmitting. Their first assumption is that they misjumped. Still there may be some interstellar comets nearby from which they can refuel. They check there sensor readings and dead ahead they discover a large anomoulous heat source about 200 AU distant. Spectragraphic readings detect a large spherical gas cloud composed of nitrogen, and oxygen. The cloud is radiating infrared heat that can only be generated by a central star located somewhere within. The mass detector confirms it, there is a stellar object within. The scoutship moves closer. Several days pass and the scoutship enters the gas cloud. The stars begin to twinkle and reentry plasma begins to form around the scoutship as it enters the cloud. the air is still very diffuse and it is not yet breathable. The scoutship lows further into the atmosphere. The crew hears the whine of diffuse wind as the atmosphere thickens slowly. The stars completely vanish from sight and the atmosphere develops a slightly blue-black glow with a brighter dark blue patch directly ahead. As the scoutship proceeds further the wind sounds grow louder and more audible. The sky brightens up all around the ship and a yellow sun becomes visible. There are dark shadowy clouds of ice crystals and water vapor directly ahead. Eventually the the light increases to Earthlike day levels. And there are various flying forms of flora and fauna around the ship. The plant life is composed of natural greenish colored hot air balloons. The air inside is not very hot, only slightly warmer than the air outside. Gravity is not very strong here. (The Sun's gravity pull is very weak at a distance of 1 AU) There are various flying animals here grazing on the balloon plants. The Scoutship enters a water cloud to collect fuel for their Jump drive while others record their observations into the log. The water droplets of the cloud are very fat, some as big as a human fist. Collecting the necessary water is an easy matter as the ship's artificial gravity field causes the fat water droplets to rain down on the top of the ship. In the midst of refueling one of the crew members is attacked by a flying preditory animal. A fight ensues and the crew prevails with only minor wounds. Refueling is complete and the ship's sensors finally detect the surface of the ringworld, it is transparent allowing light to pass through but preventing the atmosphere from falling into the sun.

 

[shield]

There is a rebellion era adventure in challenge that had the PCs stubbling on a derlict from the terran confederation / rule of man. A small 300tn escort misjumped into the middle of nowhere and eventually spotted an ancient's dyson sphere (remember it completely hides the system star so is difficult to spot). They found the sphere deserted, but managed to repair their ship and jump back. The sphere was empty because an ancient killer shape shifting robot had killed everybody, and unfortunately it killed on of the crew and took his place.

Oops

Nice stuff about the dyson sphere.

Cheers
Richard

 

[TKalbfus]

Thanks, the more conventional Sci Fi view is to have people living on the inside of the sphere the same as they would in a ringworld. The sphere would be rotated just like the ringworld, but the atmosphere would cling only to the sphere's equator. If we employ artificial gravity generators we could make more of the sphere's inside habitable, but not all of it. The reason is that an inward directed field from all directions would cancel out leaving the only net pull as that toward the sun. My solution was to build a sphere that accomodates near zero gravity conditions on the outside of the sphere and is also transparent. Because of the weak gravity at this distance from the sun, the atmosphere around the sphere would attenuate very gradually as one moved outward. A lot of atmospere is needed to produce 1 atmospheric pressure at the sphere's surface. All this gas with this thickness of atmosphere would backscatter all the visible light coming from the star for the same reason that you can't see through Jupiter even though its made of hydrogen, a clear colorless gas. The atmosphere's warmth would be detectable through IR detectors though. Whatever life that lived there would have to adapt to near zero gravity conditions. The transparent material that makes up the sphere would have to actively clean itself as sediment would slowly settle their. There could be a fluid on top of the sphere that pours into recessed jets that blows the sediment back up into the atmosphere. Genetically engineered microorganisms or perhaps nanotechnology would eat the algae that accumulates and blocks light from the sun. the balloon plants would be limited by the amount of nutrients in the air preventing a perpetual cloud balloon forest from covering the whole sphere, much the way algae works in the ocean.

 

[Nurd_boy]

i can see an evolved herd species creating a sphere...think about it, wouldn't the k'kree just love to pull all its members into a giant superherd, in a single place (of their own construction) free from ANY kind of predetor? and defendable against an obvious hostile universe?

similar to the puppeteers i'd think....

 

[pauldrye]

Originally posted by Nurd_boy:
i can see an evolved herd species creating a sphere...think about it, wouldn't the k'kree just love to pull all its members into a giant superherd, in a single place (of their own construction) free from ANY kind of predetor? and defendable against an obvious hostile universe?

Hmmmm. I just had something like that published in JTAS earlier this week. Though the sphere is not that large (its sun is tiny), and the Vargr, Aslan, and Humaniti got there first.

The K'kree just arrived, and they've got the tech advantage over the other refugees. Mayhem ensues.

 

[TKalbfus]

There is another sort of Dyson Sphere that can be build, but this one centers on a gas giant instead of a star. The planet Jupiter has a diameter of 142,984 km and a gravity of 2.68 g. If a civilization were to build a sphere around such a gas giant that was 1.64 times its diameter or 234,074 km in diameter, the surface gravity of that sphere would be 1 g. Using the Traveller UWP scale this would be size 146, there's not enough letters in the alphabet to express it so to produce the UWP of such a world you would enclose it in Parenthesis like this A(146)67B70 H. The letter B indicates a population of hundreds of billions, which is kind of low for an artificial planet of this size. The tech level H is required to build the sphere. naturally the gas giant should

 

[Nurd_boy]

Originally posted by Nurd_boy:
i can see an evolved herd species creating a sphere...think about it, wouldn't the k'kree just love to pull all its members into a giant superherd, in a single place (of their own construction) free from ANY kind of predetor? and defendable against an obvious hostile universe?

similar to the puppeteers i'd think....

the puppeteers used a rosetta (rosella?) worlds that they moved around space to avoid contact (its in ringworld by niven)...

or perhaps a machine/A.I. species that build one not only for defense, but for power (solarpowered A.I's !? >

 

[shield]

Try reading the novel by Timothy Zhan called Spinneret. It details earths first colony in a universe already full of stellar empires. The colonists find a spinneret hidden on their planet that produces long super conducting cables.

Apparently an alien race were enclosing their system in a dyson sphere that appeared from the outside to be a red giant. They were hiding from an enemy (who found them before they completed).

Nice book with some nice aliens.

Cheers
Richard

 

[The Hinterworlds Rambler]

My lords...

About Dyson Spheres and all that...

I have done some theoretical work for another (to date unreleased) Sci Fi project that deals with the concepts you all have touched on here.

In the afformentioned background, certain species (lets call them "Species X") have the level of technology neccessary to produce such structures. The main line of reasoning behind their construction is in answer to a growing population problem.

In this yet to be seen project, the line between biological and technological life is so blurred, that virtual immortality is available to almost every citizen through advanced medical procedures. The only downside is, there is no known means of 100% effective contraception, as there are psychic factors at work, as well as physiological ones. It boils down to a society that has almost no negative population growth, but plenty of positive.

To combat this problem, Species X long ago came upon what is known amoung them as the "order of settlement" a logical progression of star system development. It is a program designed to run over hundreds of years (people tend to reckon time differently when live live for a long, long time) and with predictable results.

Step 1:

A star system is selected to be developed, provided that it meets certain criteria, namely, A single, relatively stable, young to average age star, with billions of years left to it, and of average mass. (too large a star and the "Orbital Environment" would be too large to be cost effective.) an uninhabited system is preferrable.

Step 2:

A stellar orbit is selected in the "best" part of a star's habitable zone. Several large "Service Satellites" are deployed into the selected orbit, serving as little more than huge construction platforms and facilities for workers. It is also at this step that organic samples are taken from surrounding worlds for "Genetic Tailoring" to fit them into the final Ecosystem. Raw materials needed for construction are also prospected and processed at this time.

Step 3

Over the next 50-75 years, most of the star system's raw materials are converted into forms used in construction. The Service Satellites are connected into a superstructure along the perimeter of the orbit. By the end of this time period, the "ring" in "ringworld" starts to take shape.

Step 4

The next 50 or so years are spent plating up the superstructure, providing a good basic foundation for the Ecosystem to take hold. Gas from Gas Giants is refined and processed to form the desired atmosphere for the ringworld. Kilometers tall "gravitic stabilizer" towers are installed on the edges of the ring. These exert a subtle, self maintaining force of gravity keeping the ring stable, as well as keeping it at a steady rotation. It is also during step four that temporary "artificial night" plates are put into orbit above the Ring, getting the new ecology used to a regular day/night cycle.

Step 5

Now that the ring is done, the next 50-100 years are spent processing the star system's remaining raw materials and locating / importing more raw materials from a (hopefully) nearby system(s) It is when these sources of materials are secured that the expansion of the ring environment begins. The edges of the ring are built up with more massive superstructure, and the Sphere starts to take form around the star, with the already established Ring as its equator.

Step 6

The Final phase is a busy one. The next 100 or so years of construction, the rest of the spherical superstructure is plated up (no small task) and the ecology is expanded/transplanted everywhere around the sphere. Prefabricated buildings and other structures are added to the sphere's interior surface, and a permanent "artificial night" is put into place. No problem.


The above exposition assumes a technological development far and away from what is seen in Traveller, but it gives some sort of thematic idea as to what would be involved in the construction of so fantastic a thing. It assumes that some form of matter rearangement can be done, to convert raw materials and gasses, as well as superadvanced automated systems geared to work on a near unimagineable scale. It establishes an idea of both the Ringworld and Dyson Sphere as stages in a mother of a construction project...

"The Home Depot" in that part of space must be very impressive indeed...


(Bows) By your leave, Lords...

 

[bromdenlong]

I can see the advantage of having a huge population with effectively instantaneous communication, but you'd also be putting all your eggs in one basket - if your enemy comes up with a way to punch through the shell or a 'star trigger' to make your sun unstable, you don't just lose a world, you lose everything.

Of course, you could have many Dyson spheres around many stars, but they have the same communication problem between spheres as everyone else has - and you still have far more eggs in far fewer baskets.

 

[The Hinterworlds Rambler]

Indeed, sir...

But I would postulate that a culture capable of such engineering would have little to fear from either eggs or baskets. you would have a lot of room for several starship bases on the exterior surface, to say nothing of some nasty TL? weaponry... in either case it would be an awesome battle to behold...

 

[far-trader]

Originally posted by Baron Saarthuran:
Indeed, sir...

But I would postulate that a culture capable of such engineering would have little to fear from either eggs or baskets. you would have a lot of room for several starship bases on the exterior surface, to say nothing of some nasty TL? weaponry... in either case it would be an awesome battle to behold...

Certainly a possibility Baron, but you presume such a society would be bellicose. I think were that the case they would follow all other such examples and build great fleets of warcraft and go out conquering new worlds. No, I believe if a society found the resources and will to build these marvelous creations they would likely have started from a utopian desire of nothing more than to live the way they wish in peace for all eternity. These structures, once complete, would probably grant that desire as they would be next to impossible to discover. If such a place were found by chance it would almost certainly be found by a warlike expansionistic power that would find no resistance or help from the population. Just my own humble observation sir.

 

[TKalbfus]

A conventional Dyson sphere would also require a transparent inner sphere that generates an antigravity field toward the outer sphere. This would make the direction of "down" away from the sun. The outer sphere would need gravity generators on the outside to negate the antigravity field, otherwise the sphere would slowly accelerate out of the galaxy, unless that is what was intended in the first place.
Defense wise a Dyson Sphere has the inner lines of communication and its military force would be much more effective than that of a typical Interstellar empire. Assuming the Travellers slow communication is in effect, the Imperium would need to gather its entire interstellar navy into that one system leaving the rest of the Empire vulnerable in order to have a chance of taking the sphere. The Emperor would not be aware that the Imperium was invaded by some outside force until 1 year latter. Thats why it has Dukes in charge of regional sector navies ably to respond to outside threats more quickly than the Emperor could. The Dyson Sphere's entire fleet can be engaged all at once without leaving other parts of the sphere vulnerable. The political leader of the Sphere can react to outside threats within hours of the enemies first appearance within the system. Not so for the Imperium.

 

[The Hinterworlds Rambler]

Certainly a possibility Baron, but you presume such a society would be bellicose. I think were that the case they would follow all other such examples and build great fleets of warcraft and go out conquering new worlds. No, I believe if a society found the resources and will to build these marvelous creations they would likely have started from a utopian desire of nothing more than to live the way they wish in peace for all eternity. These structures, once complete, would probably grant that desire as they would be next to impossible to discover. If such a place were found by chance it would almost certainly be found by a warlike expansionistic power that would find no resistance or help from the population. Just my own humble observation sir.

Alas, Lord Burns, I merely ruminated on the topics of defensibility of such a structure, not the good or evil intentions of its masters, What?
It would seem though, unfortunately, that the capacity for violence does not diminish with technical advancement in most cases, unless those gigantic Ancient war robots strewn around the galaxy were some form of overcompensative farming equipment.

Sociologically, one could postulate that those that could build such a thing would be beyond what you and I could consider conventional morality (hands burns glass of Promethean cognac) as they could do just about anything, and want for nothing. One thing is for sure, to them, you and I would most certainly be Neaderthals, if not baboons, by comaprison...

Finding even the ruins of such a thing has been a dream of mine for quite some time...

Why do you think that the Dyson spheres and ringworlds in literature and the vids are almost always "a failure" ?
Niven's Ringworld had gone a little wild to say the least,
The Dyson Sphere on ST:TNG was unpopulated...

Even Arthur Clarke's Rama, if it could be ranked among such creations, had long since lost its population as well.

I wonder if it a Egyptian Pyramid analogy, or at least a cautionary "fool and his money are soon parted" story, what?


Your observation was most estute, and certainly welcome, Lord Burns...

 

[TKalbfus]

Why do you think that the Dyson spheres and ringworlds in literature and the vids are almost always "a failure" ?
Niven's Ringworld had gone a little wild to say the least,
The Dyson Sphere on ST:TNG was unpopulated...


This is for a very simply reason a ringworld or a Dyson Sphere is an artificial world. A successful ringworld of Sphere with a teaming population would be quite a civilized place. You'd have an advanced 17+ tech level culture of at least one billion billion people or some number followed by 18 zeroes. This culture is not outwardly expansionistic, they know about jump drives but they are not interested in other star systems until they completely fill their Dyson Sphere. They would have so many internal economic resources that they wouldn't even feel threatened by any visitors from the Imperium. Their life would be quite easy when compared to the Imperium and they would be much more tightly organized and governed the the Imperium because they can be. Nothing on their world is further away than 300 million km. The government of the Sphere has no reason to establish colonies in other star systems since that would loosen their control over them. A successful Sphere is completely civilized, well explored, and boring to any group of adventurers. If the PCs wanted to find out about any part of the ringworld they would simply look it up in the ringworld's directory, then hop in the ringworld's mass transportation system and immediately arrive there. Lost ruins are much more interesting to explore.

 

[manley_t]

Two things come to mind for two different types.

Dyson Sphere civilization and economy would be different from what we currently understand. There is no growth or expansion and there is no resource based economy. The capability to produce food and water for the max-cap population of the sphere has to be built into the sphere. The only abundant resource would be the energy put out by the sun. The downside of this is that any flare or 'burst' from the sun wouldn't just spew into deep space, it would impact a section of the sphere causing unheard of damage.

It would be interesting.....and the species that would build such a thing would be interesting as well.

On a second note, the comment mentioned earlier about a sphere around a gas giant so that the external surface of the sphere has 1G gravity is quite interesting. But, other than mining the gas giant (which can be done normally) I'm hard pressed to find a credible benefit to such a thing. The huge benefit to a dyson sphere is that you capture 100% of the Sun's energy.

just some comments.....