Re: Hole in a box

From: Anders Sandberg (
Date: Thu Feb 14 2002 - 01:04:38 MST

On Thu, Feb 14, 2002 at 04:00:00PM +1030, Emlyn O'regan wrote:
> Is it possible (in an entirely extreme, SI-complete context) to wrap a dyson
> sphere (or layers of computronium, etc) around a black hole, instead of a
> star? By pouring matter into it (or via some other mechanism???), would one
> get capturable energy? Is this scenario useful, or would it be a dumb thing
> to do?

Sounds entirely doable. Dyson shells (the ones composed of independently
orbiting pieces) are held in place by gravity, and will be in free fall.
So if you build it with a reasonable radius, tidal forces will not be
too problematic. Rigid dyson shells on the other hand likely require
unobtainum-like substances to build and need to be kept stable using
active controls.

As for energy production, it seems likely it would work to drop stuff
into the hole and use radiated gamma rays. A small hole would radiate
intense Hawking radiation, and if kept stable by adding enough matter to
keep it from evaporating it would be a small and handy reactor. Rotating
holes can have their angular momentum extracted using the Penrose
process, although for this you don't need a Dyson.

I think having small black holes inside mini-dysons is a good way of
producing energy, and doable (in the sense "the laws of physics doesn't
forbid it").

Anders Sandberg                                      Towards Ascension!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y

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