Dyson Sphere

[ydoaPs]

what is the minimum thickness for a dyson sphere(with a radius of 1AU) such that it won't fall apart?

[Sayonara]

I suppose that also depends what it's made from, and how sections are connected.

[ydoaPs]

i am trying to figure the total mass, and so far i have: [math]M=(9X10_{16})(\pi)(thickness)(density)[/math]

[Sayonara]

I see. Hmmm.

 

Perhaps you are doing it all backwards. The mass will determine the gravitational stresses on the superstructure, so you're probably going to want it to be within a very specific mass range. Which will determine the thickness of the sections.

[danny8522003]

Wikipedia suggests a 3m thickness.

[Inferno]

Question: If we did that to our sun, wouldnt Earth die out since it wouldnt be getting any sunlight? so whats the purpose of doing it, unless it is to another star?

[Cap'n Refsmmat]

I think we'd put the sphere slightly outside Earth's orbital radius.

[ydoaPs]

i was also asking about it, because if it is too thin, it will act like a solar sail and be puched outwards in all directions. on PF, the suggested using a thinn(few milimeter thick) reflective foil that reflects the energy to collectors. wouldn't there be a big pressure on the foil pushing against its frame?

[danny8522003]

Yes i expect there would. What's stopping space debris from smashing into it and causing major damage?

 

Although, if the outward pressure of the wind balanced out the inward force of gravity then i guess it could be thinner; but again it would be too easily damaged.

[Inferno]

unless the sphere had an opening, it would also restrict space travel to inside the sphere. well, i guess it depends on whether you had a dyson shell or a swarm. which are you talking about?

[Ophiolite]

What's stopping space debris from smashing into it and causing major damage?

For one thing you've rounded up all the asteroids, comets, meteors, plutinos, Kuiper Belt Objects, scattered disc objects, minor planets, Oort cloud planetesimals, and anything that moves, to make the sphere in the first place.

[Inferno]

For one thing you've rounded up all the asteroids, comets, meteors, plutinos, Kuiper Belt Objects, scattered disc objects, minor planets, Oort cloud planetesimals, and anything that moves, to make the sphere in the first place.

 

I doubt you could also round up all the dust that is out there, even up to a single AU. A particle of dust going 16,000 miles an hour can do a lot of damage.

[Daecon]

You'd probably need all the matter in a a dozen solar systems to make the whole thing, possibly more!

[[Tycho?]]

Wikipedia[/url'] suggests a 3m thickness.

 

The diagram does anyway, it doesn't seem to mention it in the article itself.

 

This depends largely on if you want your sphere to spin or not. I dont see why you'd want it to, but spinning would greatly increase the stress on the structure.

[Klaynos]

spinning would be more cool, so that could be a reason to make it spin?

[insane_alien]

if you want a spinning thing around a sun then you are better off with a ring than a sphere as the structural loads and stresses can be lower andhow the hell would you accelerate a sphere that size?

[Daecon]

Plus, the matter require to construct a ringworld around a star is... well, incredibly less than you'd need to totally encompass a star with the material bubble of a Dyson sphere.

[Sayonara]

I doubt you could also round up all the dust that is out there, even up to a single AU. A particle of dust going 16,000 miles an hour can do a lot of damage.

On the other hand, the vast majority of the inner surface is going to be unpopulated, so it can probably stand to take a good few hits, just like Earth does.

[insane_alien]

just thinking about the bowshock that the solar wind makes as the sun moves through the galaxy and i thought, if you make a dyson sphere then the solar wind is blocked and the galactic wind(is there a better name for it?) would eventually start hitting the sphere. Would this be serious or is it not worth bothering about?

[Daecon]

just thinking about the bowshock that the solar wind makes as the sun moves through the galaxy and i thought, if you make a dyson sphere then the solar wind is blocked and the galactic wind(is there a better name for it?) would eventually start hitting the sphere. Would this be serious or is it not worth bothering about?

Would it be like increasing the air pressure inside a glass bottle until it breaks?

[Thomas Kirby]

The reason to spin the sphere or ring is to generate artificial gravity. This is so old that it's new again. The enthusiasm for Jerry Pournelle's and Larry Niven's Ringworld stories apparently is well past its natural expiration date.

[CPL.Luke]

that idea has been around for a long time and considered by nasa quite often, although it takes a ship the length of the golden gate bridge in order to keep the astronauts from getting sick

 

 

however in a sphere the top and bottom and the rest of the shere except the area perpendicular to the axis of rotation (don't know a better way to say that) wouldn't get gravity

 

plus in the end if you have the tech to build this thing you have the tech to create artificial gravity, and heck you probably have the technology to get more energy than a star produces in its lifetime.

 

out of curiosity how much energy would it take just to move all that mass into an orbit of 1 au melt it all down smelt it and then make a sphere out of it. My guess more energy than a star produces in a billion years.

[insane_alien]

why not use velcro instead of artificial gravity from the centrifuge effect. much cooler.

[Xyph]

It seems like, given the vast internal surface area of a dyson sphere, even if the technology did exist to supply artificial gravity to the entire inner surface it would probably take a significant amount of the power generated by the star just to maintain it. If this were the case it would make the entire process pretty pointless, since the only real reason to build a dyson sphere in the first place is to harness the energy of the star within it - there are far easier ways to just get more living space.

[insane_alien]

yes let us dig down into the earth and become mole people!