Re: Hole in a box

From: Anders Sandberg (
Date: Thu Feb 14 2002 - 15:41:08 MST

On Thu, Feb 14, 2002 at 10:48:03PM +0100, Amara Graps wrote:
> Anders Sandberg:
> >You would end up with the Eddington luminosity if the gas was just
> >gravitationally attracted. I guess a slightly different luminosity would
> >result if it was instead pressured. From the Second Fount of Knowledge
> >(, I
> >get: L_eddington = 4 pi c G M m / sigma_T
> This equation assumes a hydrogen gas sphere in hydrostatic equilibrium,
> with the total energy transport via radiation.
> Are these the assumptions that you want?

I don't know. I'm not enough of a physicist to tell. My intuition tells
me the assumption of equilibrium is not to be trusted at all - I can
easily imagine instabilities that cause radial convection. Of course,
using a black hole as a heat engine this way might be a practical
engineering solution, but it is so crude. I prefer machines with no
moving parts.

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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