Re: cosmology and quantum gravity

[Jack Uretsky <jlu@HEP.ANL.GOV>]

On Fri, 28 Apr 2000, Joel Rauber wrote:

> A lot of the technical details I added were intended merely for the
> interested reader and are admittedly superfluous as Jack pointed out below.
> However, I must reiterate, there are no physical effects that blow up at the
> event horizon of a Schwarzchild black hole, at least in the usual physics
> sense of the words "blow up", which I interpret as loose language for
> diverging to infinity.  That does not mean interesting things don't happen
> at the event horizon, as several well known interesting things do occur at
> the event horizon.
>
> To be further superfluous and add one more item of technical detail.
>
> The Ricci tensor, a measure of gravitational effects in a local region of
> space, does not diverge at the event horizon of a Schwarzchild black hole.
        The words "blows up" are correct; the metric tensor, "in the usual
metric" blows up - meaning that it becomes infinite.  The statement,
admittedly terse, may need amplification, but it does not need correction.
                                Regards,
                                        Jack
> Joel Rauber
> > On Fri, 28 Apr 2000, Joel Rauber wrote in part:
> >
> > > Jack wrote in part:
> > > . . .
> > > > The static gravitational effects that we can observe are
> > > > embedded in the
> > > > metric (more strictly, the curvature) outside of the
> > horizon.  In the
> > > > usual metric, the gravitational effects get larger and
> > larger as we
> > > > approach the black hole until they blow up at the horizon,
> > > > where there is
> > > > a coordinate singularity.   . . .
> > > --------------------------------------snip-------------------
> > ---------