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/sci/ - Science & Math

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2192986 No.2192986 [Reply] [Original]

Dyson Shperes- will they work?

>> No.2192989
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2192989

nope

>> No.2193006

There is absolutely no reason why enough effort couldn't give us a dyson swarm, right now.

A solid sphere would require materials that we don't know are possible, yet.

>> No.2193012
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2193012

I always thought energy generation was never efficient enough. So that is why I invented the Dyson Sphere.

>> No.2193024

>>2193006
oh, really, you mean other than the fractured state of mankind?

>> No.2193071

it'd be so close to the sun that general relavity and shit

>> No.2193072

Dyson Sails are more robust.

>> No.2193078

>>2193072
Here's what I had in mind.
http://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm
http://en.wikipedia.org/wiki/Dyson_sphere#Dyson_bubble

>> No.2193085
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2193085

the problem with a full sphere is that gravity cancels itself out, so it will not be kept in relative position to its host star by gravity.

The other problem is that centrifugal force only keeps the equatorial section in "orbit". The polar regions would experience the full force of the host star's gravity and would have to maintain their position purely through tensile strength of the material of the sphere.

A set of rings would be much easier to construct than a full sphere

>> No.2193087

>>2192986

That's not a Dyson sphere, its a Dyson shell, which even the man thought was a stupid idea. A Dyson sphere is a bunch of loose objects in orbit around a star.

>> No.2193097

>>2193085 with a full sphere is that gravity cancels itself out
Nope.
With a hollow sphere you get an unstable gravitational equilibrium at the exact centre. Move a micron off centre and the forces become unbalanced; pulling you ever further away from the centre.

>> No.2193103

>>2193085
It WILL keep relative position to the star so long as nothing hits it. An object in motion stays in motion.

>> No.2193113

>>2193097
You are very wrong. Do the vector calculus yourself. A hollow sphere with a homogeneous surface density applies zero net gravitational force on any massive object within it.

>> No.2193114

>>2193097
i meant the net effect of the host star's gravity on the sphere assuming it is perfectly centered.

But yes, the entire thing is unstable

>> No.2193117

>>2193097
Nope. You see, I have sources.

http://en.wikipedia.org/wiki/Gauss'_law_for_gravity#Spherically_symmetric_mass_distribution

>> No.2193125

>>2193114
>>2193097
You both are idiots.

>> No.2193130

>>2193085
This is right.

The internal net gravitational force is zero, so there's no stabilizing force (except radiation pressure). That might be enough.

But a dyson shell requires materials we're not even close to having. A dyson swarm is a better idea, or maybe a dyson bubble if we can get the material density low enough.

>> No.2193134

>>2193125
does it matter? the net effect is almost the same. the sphere is not gravitationally bound to its host star

>> No.2193139

>>2193130
or loads of statites

>> No.2193143

>>2193134
>gravitationally bound
Nope, it is. That's not what you mean - use the correct term to express what you're trying to say.

>> No.2193145

>>2193134
An object in motion STAYS IN MOTION. If it has the same velocity as the star then it will remain with the star unless something hits it.

>> No.2193154

>>2193139
>or loads of statites
That's what I meant by a dyson bubble. I like the idea of it self-adjusting the distance from the star in response to local solar flares.

>> No.2193156

>>2193143
What do YOU mean by gravitationally bound? A star within the sphere would apply zero net force to the sphere.

>> No.2193170

>>2193156
If something is gravitationally bound, that means that it cannot escape the gravitational well. Which is the case here.

I think you mean gravitationally stable, or something. At any rate, yes, the net force of gravity is zero, but radiation pressure would be an equilibrating force. Not sure if it would be enough.

Dyson shells/spheres are sci-fi anyway. A Dyson swarm is doable.

>> No.2193174

>>2193156
Assuming that the sphere is Newtonianly represented as a point.

>> No.2193182

>>2193170
a stable orbit maybe?

>> No.2193191

>>2193117
>>2193113
I was wrong. Feels Bad Man. Won't make this mistake again.

>> No.2193193

>>2193174
>Assuming that the sphere is Newtonianly represented as a point.
Do you mean the star?

Anyway, as long as the star is roughly spherical, the approximation is still good. It doesn't need to be a point mass.

>> No.2193202

>>2193191
>feels bad man
Wow, penitence? I guess not all tripfriends are tripfaggots.

>> No.2193204

>>2193191
Respect for admitting it. That puts you above 95% of this board, and 99.99% of this website.

>> No.2193215

>>2193174
Physics 101, everything is considered a point mass if it can be accurately represented that way. In this case it can.