



   > >  What  evidence  indicates that Gamma Ray bursters are very far away?

   > >Given the enormous  power,  i was just wondering,  what if they are
   > >quantum  black holes or something  like that  fairly close by?

   > >Why would they have to be at  galactic ranges?   

   . . . David gives good explaination of the deductions from the isotropic,
   'edged' distribution, to whit, they are either part of the Universe or
   part of the Oort cloud.

   Why couldn't they be Earth centred, with the edge occuring at the edge
   of the gravisphere? I know there isn't any mechanism for them, but there
   isn't a mechanism for the others either.

What on Earth is the "gravisphere"?
Anyway, before it's decay the Pioneer Venus Orbiter
had a gamma ray detector, as does Ulysses, they 
detect the brightest bursts that the Earth orbit detectors
do, so the bursts are at least at Oort cloud distances.
In principle four detectors spaced out by a few AU would
see parallax if the bursts are of solar system origin.

_The_ problem with Oort cloud sources is that absolutely
no plausible mechanism has been proposed. It would have
to involve new physics as far as I can tell. Closest to
"conventional" Oort sources is a model of B-field pinching
by comets, it's got too many holes in it to count, but at
least it was a good try...