"Robert J. Bradbury" <firstname.lastname@example.org> writes:
> You probably need to run Buckytube cables around the
> the thing to provide the strength necessary to support
> micrometeorite punctures and resist the pressures resulting
> from solar flares. Lots of calculations to do here to
> study the feasibility I suspect.
It is also likely that we need to take active countrol into account.
A quick estimate: Solar flares produce an increase of solar output
around DL=3.83e-9 (based on
http://lepjas.gsfc.nasa.gov/~thorpe/thesis/chapter5.html). This would
mean a change in force of DF=DL*L/(4 pi c r^2). Assuming the canonical
1 AU Dyson, I get DF=1.77e-14 N. Not much. But assuming that it pushes
over half the surface area of the dyson, I get 2.5e9 N total force,
which is 2.6e-3 N/m along the "equator". Seems manageable.
During a solar cycle the luminosity varies with at least 0.1%, but
this is isotropic. This is more serious: DF=4.66e-9 N, 263,000 times
more. This means the tension along a great circle would be 684
N. Still sounds within the realm of possibility to handle even using
current materials, although we need to make the cables very light for
the entire structure to act as a statite.
> I don't like Ander's application of all of the mass in the
> solar system to this application because it doesn't seem
> necessary. (I also get about twice as much material as he
> does to work with in the solar system -- something we need
> to resolve at some point...).
We can always spend some time at Extro5 going through it.
> A principle you can try to work with is how do you
> make the best use of the available energy with the
> smallest amount of material possible. If you only
> use a fraction of the available material for Jeff's
> Dyson *SPHERE* Lite, then Ander's can use the rest of
> it for building a Nutronomium-Brain (I forget what he
> calls these).
Jupiter brains, or ISOs. But I guess the different models will have
individual names. I suggested Ouranos, Zeus and Chronos, but in
reality they will be called Economy, DeLuxe, Business Edition etc :-)
> Now the question is what kind of a good computer architecture
> can you fit on top of a Dyson Shell Lite. The one that comes
> to mind for me is a 2-D cellular automata. I.e. no 1-cm^3
> rod-logic CPU's, instead you cover the surface with
> very thin CPU's that only communicate with their nearest
> neighbors. Now, what kind of calculation that is good for
> I don't know
Running extensive 2D partial differential equations?
I would suggest that connunications through the interior of the sphere
using laser would make it much more versatile. The delays are long,
but it would be able to run more like a small world network (2+1 D?).
> Lets try in the discussions to be careful with terms --
> a "shell" would be lots of nested orbiting satellites
> (like a Matrioshka Brain), a "sphere" would be a standard
> fully contiguous surface. These ideas have been misunderstood
> for too long and its time to set them right.
I agree! Maybe we should call this system of linked solar sails a
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! email@example.com http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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