From: Emlyn (emlyn@one.net.au)
Date: Wed Dec 06 2000 - 21:30:56 MST
> > Radiation pressure, baby. It ain't big, but it's real.
>
> I thought about this long ago, and rejected it. As best I could figure at
> the time, any minor perturbation of the sphere (such as caused by a major
> asteroidal collision) would impart more energy than the restorative force
> of the solar radiation, although I admit that I didn't take the time to
> work in out on paper
Can't that be corrected by a seperate mechanism? The dyson sphere is, after
all, collecting energy. So, couldn't you use some kind of mechanical
mechanism (duh...) to straighten it out? Or, there must be some way to turn
a tiny bit of that massive amount of collected energy into precisely focused
thrust, capable of repositioning elements of the sphere.
>. I ended up being more concerned by the total lack of
> gravity on the inner edge of the sphere, and decided that that too, needed
> to be solved.
You could place a lot of rings on the inside of the sphere, like baby
ringworlds. Mount them like ferris-wheels on the inner surface, slightly
misaligned so that the inner surface of each ring receives some light - just
the part closest to the "ground" (inner dyson sphere surface. Then, spin all
the rings. The inner surface of each ring receives light sometimes, and is
dark sometimes.
If you pack the surface of the dyson sphere with said rings, there's a *lot*
of living space, replete with gravity, and light/dark cycles. Not elegant,
but it could work.
Or, you could build ring structures external to the sphere, in space, just
using the sphere to capture all the energy. Transmit it all out in some
manner (really heavy duty electrical extension lead?), to be used as the
external ring-dwellers see fit.
>
> > Someone may say that radiation forces are puny in the inertial arena. I
> > agree, but if they're the only forces in play, then they must dominate.
> > Response times are just very long.
>
> They are only the only forces in play if you have 1) swept the entire
> solar system clear of debris (I admit that this is likely) and 2) can
> guarantee that the sun will burn evenly, so that it produces a uniform
> flux. This last point worries me.
>
Again, we are collecting major amounts of energy; why is correction such a
big problem?
> > Candidate number two is something of a mystery to me. I know it's there,
> > but I frankly don't know how it acts on the system or how it compares
in
> > magnitude of effect to radiation pressure.
> >
> > Magnetic field effects.
> >
>
> Hmm. I must admit that I never even *considered* magnetic fields.
>
> What I came up with was to spin the sphere so as to cause pseudo-gravity
> by centrifical force at the inside equator (and really make it hard to
> image what substrate would be strong enough to build with). In order to
> ensure that the inner pseudo-gravity was strictly normal to the surface at
> all points, carefully sculpted masses would be added to the rotational
> poles, so that the gravity felt on the inside would be the sum of
> gravitational and centrifical vectors.
>
> The upshot of this would be that the dyson sphere would be stable on two
> axes, but still unstable along its rotational axis. Its not a total
> solution, but it does make the problem more managable.
>
Put a spinning dyson sphere inside a larger, spinning ring. They share a
center, and the outer ring passes over the two rotational poles of the inner
spinning sphere. Use something to attract the dyson sphere outward to the
ring at the poles, or maybe all the way around. Maybe magnetism? Somebody
creative could suggest something.
Maybe a lot of outer rings (3 place orthogonally to each other, plus more?)
plus some attractive mechanism, could be used to stabilise the otherwise
unstable sphere?
Emlyn
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