Darren New <dne### [at] sanrrcom> wrote:
> You give one particle that is constantly emitting photons in all directions
> a push due south towards the singularity. You have an observer due north of
> the singularity looking south.  The observer due north will continue to see
> photons coming off the particle indefinitely?

Yes - they'll just seem to come at ever longer intervals (and with an ever
stronger redshift).

Of course, there is only a limited number of photons the particle can emit
before hitting the EH. However, from the observer's point of view, the very
last such photon will arrive at (roughly) infinite time after the second to
last.

Roughly, if that last photon is emitted a finite time before the particle passes
the EH.

Exactly, if the last photon is emitted at the very moment the particle passes
the EH.


>
> > it sounds logical to me that
> > in fact the event horizon *is* the singularity...
>
> But it's not.

Sure? Were you there and had a look? Do you grok the formulae? I don't ;)

>
> > If you'd take that trip, you'd experience it as being torn to
> > pieces by tidal forces,
>
> Tidal forces are a difference in gravity gradient between head and feet.
> It's not an absolute number. A sufficiently small pebble would experience
> very little tidal effect regardless of how close to the primary it orbits. :-

No, tidal forces are a difference in gravitational *force* - which (possibly
very simply speaking, as I'm not perfectly familiar with the terms) *is* the
gravity gradient. And they don't jsut rip apart your head and feet

If it was just your feet being pulled away from your head, you would be torn in
two because the force would pull on the whole chain of electromagnetic forces
tying your feet to your head, and some "weakest link" will give way.

This is not the case for tidal forces due to a gravity gradient: These will pull
on each link in the chain of electromagnetic forces separately - each link
subject to its own little gradient.

This will allow you to sustain a lot more gradient between your head and your
feet, possibly even without much adverse effect. But when it will ultimately
rip the skin off your feet, it will just as well rip apart the grains of sand
in your shoes.

Oh, and BTW, once you hit the EH, I guess there'll probably be no floating
around... with so much mass in so little space, there'll probably be not enough
room to swing a cat...

.... but then again, that place may be quite crowded already even outside the EH.

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