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Dracoraptor
18th Jul 2002, 00:42
Welcome to Space Discussions Weekly. This is a post that will be posted weekly for debates or beliefs on several space and space related topics.

No. I: Dyson Spheres-Possible or Impossible?

On this weeks SDW, we shall discuss the possibility of a Dyson Sphere. If you don't know what a Dyson Sphere is, I will explain. A Dyson Sphere is a massive object or several billion objects that are man made, and orbit the sun to use the energy from it at one hundred percent effiecency. These are very massive objects, or can consist of many small objects. There are three types of Dyson Spheres...

Dyson Sphere Type I: Several billion objects orbiting the sun to effeciently use the energy. They can be any thing from space-station to solar collectors and such. This is the most commonly known Dyson Sphere Type, and is just usually refered to as a Dyson Sphere. Building something like this, would require the amount of materials equivlent to the mass of the planet Jupiter. From a vertical view in space, it would look like a giant egg yolk.

Dyson Sphere Type II: The second most popular design, this Sphere is literally, a giant sphere covering the Sun/Star. More materials would be required to make a Type II than a Type I. But if something like this was created, it would be more massive than any known planet in existance. If its radius was one Astronamical Unit, it would sixty-five million times larger in total surface area than the planet Earth. This means it could support a large population of humans/aliens/whatever. This one appeared in an episode of Star Trek: The Next Generation before, and does not appear very often besides that. There are many problems involved with a Type II. Such as gravity*, resources, and the superhot rays from the sun.

*=Even if the Type II Sphere rotated on its axis, gravity would get weaker until it reached Zero-Gs in the poles. This prooves as an emminse problem.

Dyson Sphere Type III: Is a ringed shaped object that orbits the sun. Not only does its rotation provide gravity, but its design is very small. In fact, it uses less materials than the other types of Dyson Spheres. But it does not gather as much energy as the others as a result.

We do not know if any Dyson Spheres exist, or if they are even possible to construct. But we do know that if we saw one, it would be a dimly lit star giving off immense energy signatures.

NZrevenge
18th Jul 2002, 13:08
Before I launch into the debate of whether or not a Dyson sphere is viable, I would like to make a point about their possible side-effects.

For trillions of years, our sun has been pumping out a fairly constant amount of energy. Much of this energy would shoot out into space and dissapate into the cold of space. What little energy hit a planet would be absorbed by the flora and fauna of the planet and eventually vented back into the atmosphere (body-heat, etc). This is balance that has by and large maintained itself. There have been ice ages, and desert ages, and things have returned to their equilibrium point. The energy that "dissapears" into space would not be waste. Stars heat space, and keep it a hell of a lot warmer than it would normally be. If we were to start covering moons and planets in solar panels, or if we were to harvest the energy off the star itself, the effects on that solar system and perhaps it's surround systems would be catastrophic. With every bit of heat energy collected and stored, we deprive the cycle of nature from that energy. If we were to re-release the heat later on (heating our house, cooking in an oven. etc), then the cycle would complete. If we were to transport the energy elsewhere (ie we put solar panels on the moon and ship batteries to Earth), then one place would get too cold, and one place would get too warm.

If we were to use a Dyson sphere, we would be harvesting the energy before it even hit a planet, and now we would have planets getting colder without any counter balance (ie if we start using energy from a dyson sphere to power spaceships or even just the sphere itself).

Dyson Sphere Type I: Like all types of the sphere, it would have a serious issue trying to find an orbit height that would not result in the sphere melting. Another problem would be the size. Any two objects will have a natural gravitation towards each other. Two people standing a metre apart will feel about 0.0000005 Newtons of forces towards each other, that's about 0.005 grams of pressure. Two objects, one being the sun and the other one having the same mass as Jupiter, would feel such an enormous pull that the sphere would have to rotate around the Sun at incredibly huge speeds. I have a physics class tomorrow, and I will return with some solid calculations to support this next time I post.

Dyson Sphere Type II: This type of sphere would completely blot out the sun, destroying all life in the surrounding solar system. Any life would be soley situated on the sphere itself. This type would be the closest to planet building we'd ever get. Our Dyson sphere would merely be a manufactured crust around the core, or Sun. Solar power on this type of sphere might be less practical than using the heat radiating outwards to turn turbines. Melting issues would be incredibly serious here too, since you would require a relatively close proximity to the sun. To compensate, you would need to create this sort of sphere incredibly thick, and expect much of the inner "crust" to melt as it shields from the heat. We would end up with layers of heat just like Earth's crust. The only gravity issue would be that there might be too much. Such a huge structure would contain so much mass that the gravity would crush any living organism. Let's not forget we would not be able to move on Jupiter's surface, and even Jupiter's size pales compared to the sun.

Dyson Sphere Type III: Same as before, melting and extreme gravity would plague this sort of structure. This structrure would be the least detrimental to the surrounding planets, save for the huge shadows it'll cast. Once again, the sun will have more than enough mass to cause too much gravity. (Remember that mass is the important decider of gravity, centripital force only fakes it).

On another note, any miscalculation on the exact size, speed and orbit height of the dyson sphere has a chance of creating a massive intergalactic disaster. I'm imagining that instead of causing oil spills in the future, we'll cause supernovas...

AlphaOmega
19th Jul 2002, 01:17
We do not know if any Dyson Spheres exist, or if they are even possible to construct.
With our current technology, it could be done, however it would be brutally slow, incredibly cost ineffective, and basically useless to us. I'd wait about 1000-2000 years on this one, but, if the human race can survive long enough to make it into a "harmony" period (being no conflict, and a general focus on science, elimination of religion) we will need a source of energy that can only be supplied off-planet. (With the exceptions of Fusion power, or possible things we can't even imagine.)

NZ: Negative on most of your comments. Learn more here:
http://users.rcn.com/jasp.javanet/dyson/
http://www.aleph.se/Trans/Tech/Megascale/dyson_page.html <- Construction Ideas
http://www.student.nada.kth.se/~nv91-asa/dysonFAQ.html <- Dyson FAQ (Very Good)

Ghyron
19th Jul 2002, 02:27
Originally posted by AlphaOmega
if the human race can survive long enough to make it into a "harmony" period (being no conflict, and a general focus on science, elimination of religion)


I didn't know elimination of religion was a prerequisite for harmony...

AlphaOmega
19th Jul 2002, 07:29
My own vision, Clarke-based. With no religious differences 90% of the worlds conflict is resolved. When you have nothing to fight about, what do you turn to? Arts, sciences, exploration, self understanding.

Probably a theroy best discussed over PM though for obvious reasons, if you want to chat, argue, listen, teach, converse, or whatever, drop me a PM.

NZrevenge
20th Jul 2002, 14:50
Okay, I can see I was quite mistaken about the shape of the Dyson spheres, so I retract most of my previous points... I still argue that any energy we gather directly from the sun would still have a detrimental effect on the surrounding solar system.

Perhaps I am still working on screwy assumptions here, but it seems to me that eventually the Dyson sphere would begin blotting out the sun (a type to would completely cover it). Does my coldness arguement still hold?

kool_kats_rule
20th Jul 2002, 15:25
Is this anything to do with a dyson vacuum cleaner? It would explain the colours....

NZrevenge
20th Jul 2002, 15:28
:confused:

Unless this vacuum cleaner sucks dirt up at 100% efficiency and wont be built in our lifetime, then no...

Bomber777
21st Jul 2002, 08:14
Ok... that got off to a vacuum cleaner somehow:confused: but back to the topic. If it was possible to make these Dyson Spheres right now, it would take a very long time to make enough to cover the sun, not to mention some research to make a material to be able to withstand the suns heat being that close to it. We could be able to install some in the future but than, like NZrevenge said, it would cause many problems with planets caught in the shadow of the building/ contraption that we are trying to put up there. There might be a way though to make a material that could gain some energy but still allow the suns rays to past through the object. Than it would just be a darker than normal day on the planet(s) that got caught in the shadow. But it will gain alot of energy if we could get something like that up there. More than we could use for milions of years.

Davidg
21st Jul 2002, 08:34
Even if we solved the gravity, and shadow problems, we whould stiil need resources to build it. It would take more resources to build thanexist in the Solar sytem, so you whould need to develop interstellar travel to find more reources, then build ships to get it to where you're building, then you whould need to build imense factories to refine the materials into components for the sphere. The of course you whould have to produce millons of crunstruction ships, and hire the crews for them. Then you whould need trillons of tons of supplies to feed, clothe, and supply those crews. So designing the sphere isn't thereal problem, it's building it.

SkrasherSmasher
21st Jul 2002, 19:33
Yes. I don't think we would have the materials to set up a complete dyson sphere. One question though, the one where there are a few big rings of metal going around the star, could we put just one dyson 'ring' around the sun and use that? Or would it get gravity screwed too??

Arctic_Wolf
22nd Jul 2002, 00:48
Hmm, we cannot at out level of technology build a Dyson's Sphere/Ring/group of space stations. The earth simply does not have enough materials, neither would all nine planets combined. It would probably take millions of planets and their natural minerals to build just one Dysons sphere/ring/group of space stations.

I don't know a lot about physics so I'll probably be wrong so I'll just carry on talking about the amount of materials space and time it would take.