"clipka" <nomail@nomail> wrote:
> >   After all, how would the external observer actually see the black hole
> > getting smaller?
>
> Smaller EH of course.

.... and - which I forgot to note - as it is absolutely impossible for anything
inside the EH to ever get back out, nothing inside it would get "re-exposed" to
the outside (if there ever *was* anything truly inside it :P); instead, the
whole spacetime near the EH would shrink with it - the nearer, the stronger the
shrinking effect (though at the same time the region would probably become less
distorted)...

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BTW, just a quick thought on the information paradoxon associated with black
holes:

Thinking about it, this is actually a non-issue.

Doesn't QM say (at least in some interpretations) that a particle's properties
are not determined until it interacts?

So assume a particle actually falls into a black hole; Is any information lost?
No - because it can no longer interact with anything; so its properties were
still undetermined when it fell in. So there goes a memory storage location,
but it wasn't used.

Why wasn't it used? Well, because all information it had before was passed on to
the last particle it interacted with.

But each particle can only store so much bits of information, so where did the
information go *that* particle carried? Simple: There wasn't any in it. After
all, the only thing it interacted with was a particle that is lost, so we have
no way of checking how it influenced that particle; so those properties cannot
be (indirectly) observed either - and were hence still undefined when it
interacted.

And so on.

So as it seems, a lot of matter out there is actually just unused spare memory,
ready to back-up information of other particles doomed to fall into black
holes... the queer thing is, we don't know *which* particles are used and which
aren't...

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clipka <nomail@nomail> wrote:
> Warp <war### [at] tagpovrayorg> wrote:
> >   If we assume the mass of the black hole would decrease, then the EH would
> > recess. The photons which were emitted extremely close to the EH will get
> > a speedup when the EH recesses. Basically the "point of entry" will stop
> > being *at* the EH and becomes being *above* it. Thus all the photons will
> > reach the external observer in finite time. The external observer will
> > end up actually "seeing" the falling object cross the EH.

> I guess it will rather be that as the black hole evaporates, the EH will shrink
> as you said, but the "victim" will still seem to "stick" to it.

  Why? Exactly how does that happen?

-- 
                                                          - Warp

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clipka escreveu:
> Darren New <dne### [at] sanrrcom> wrote:
>> I don't know either. By now, I'm entirely in BS mode. :-)
> 
> BS is actually a good fertilizer...

Yeah, great useful ideas may actually germinate thanks to it. :)

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clipka escreveu:
> Which leads me to believe that in fact, the very moment you reach the EH of a
> black hole you just simply evaporate.
> 
> Which, again, leads me to believe that there is actually no mass at all *inside*
> a black hole: All that makes up the gravity well is the stuff busy falling into
> it. From an outside observer unable to ever reach the EH - except due to
> quantum fluctuations. Which will cause them to reach it at last and instantly
> evaporate.
> 
> 
> Duh. That's sounds simple enough to actually be true!
> 
> 
> Now *why* would you evaporate if you reached the EH? Maybe because you would zip
> off straight towards the singularity because all those evil vectors head straigt
> there - but you can't stay there because, after all, it's a singularity, a "mu"
> location where nothing can be - not even you, although it looks like you just
> fell into there. But then again, *are* you really where you seem to be?

Well, if we can believe that matter and energy began out of nothing with 
a Big Bang, why not believe it can suddenly come out of existence with 
all but silence and darkness? :P

> Enter QM: If you *can't* be there where you most likely *are*, then you must be
> someplace where it's quite *unlikely* (though not perfectly impossible) that
> you're there... like, say, not in the grasp of That Nasty Big Black Hole after
> all... like, say, Hawaii... Alas! If only you hadn't opted for that job as a
> space cadet... But... hey, did you, after all? It's a bit unlikely that you
> did, given the fact that it made you end up somewhere you cannot possibly be...
> so maybe you stayed home after all - or at least one of your electrons did...
> Whoops! Off here goes one of your elementary particles... Or you could have
> died in that explosion at Tau Alpha Ceti 6, and be part of that fascinating
> dust cloud out there... Whoops! Here goes another one...

Perhaps only Phil Connor would know. :P

> Hey, I like this idea...
> 
> 
> Boys, I don't want to brag, but could it be that I'm just hatching an important
> idea here...?? It looks to me like things are falling into place this way:

hehe, are you sure you're not a mere crackpot? ;)

http://math.ucr.edu/home/baez/crackpot.html

> - It would explain what the singularity in the GR equations actually means: A
> "forbidden point" in spacetime. A place that is not. GR being unable to give
> proper results for this point because the only proper result is "mu". In fact,
> it would mean that giving nonsense results for such a point would actually be a
> *prerequisite* for a good theory, unless you're using it for Zen archery target
> practice. Fascinating!

Perhaps we get to know a universe in one single dimension?  "Hey, Phil, 
long time no see!  Somewhat overcrowded here, huh?"  well, except time 
wouldn't exist and so everything would be at the same time (damn word!). :P

Perhaps everything at the same time is nothing but a blur, a nothing. 
And this is my daily contribution of BS... :P

> - It would explain the fermion paradoxon: If there's no fermion at the
> singularity in the first place, there's no need to worry about a second fermion
> trying to occupy the same spot.

Yes.

>>   I don't think that's possible. When he is exactly at the EH, the entire
>> EH engulfs the entire view on all sides. He doesn't see anything else
>> than the EH. What he "sees" inside... I don't know.
> 
> "Mu" again.
> 
> As I pointed out previously, I see the EH as being identical to the singularity
> - a single point in spacetime blown up to macroscopic dimensions.
> 
> Actually, stating that the singularity is something which is not, this also
> means that the EH is something which is not. Spacetime ends an infinitesimal
> distance away from it. You can't reach it - being there is impossible, and
> impossible is less likely than the infinitesimally small probability of not
> having steered too close to the black hole in the first place.

Now that it's being considered that our universe could be a hologram, 
perhaps it's nothing but the slot to the credit card machine?  Freedom 
at last! :P

Well, I think we got into some wild scifi scenarios here and I'll be 
munching all of it away for quite a few time... :D

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Warp <war### [at] tagpovrayorg> wrote:
> > I guess it will rather be that as the black hole evaporates, the EH will shrink
> > as you said, but the "victim" will still seem to "stick" to it.
>
>   Why? Exactly how does that happen?

Suppose for argument's sake that the BH just suddenly happens to shrinks to half
its mass.

What happens to the EH? Simple: It recedes. A BH with less mass has a smaller
Schwartzschild radius.

What happens to the gravity well? Simple, too: Its slope gets less dramatic
where the EH used to be. Still catastrophic where the EH is *now*.

What happens to the point where the victim was "hanging out"?

Now this gets a bit more tricky. I'll present two approaches that sound
plausible to me; both would come to the conclusion I presented, and I guess
actually both would happen at the same time:

(a)

What does a "gravity well" mean? Well, it's distorted spacetime. I imagine it as
"compressed". So let's for the sake of argument use a very simplistic image;
say, a BH would just influence a radius double its EH radius, and the space
between that distorted linearly.

So let's assume that the "victim" has fallen 99% along this slope (he has had
enough time to do that), so he's just 1% of the EH radius away from the EH,
when all of a sudden the black hole goes on a diet: Pop! here goes the EH
radius to, say, half its diameter.

Space further away gets "un-distorted" - actually all the space up to the old EH
radius. But that's only the part up to 50% along the old slope. The remaining
50% are still "downhill", with our victim still on this slope. 98% along it,
actually. So 2% of the new EH radius away from the new EH.

So for practical purposes, he has almost exactly moved along with the receding
EH.

Note that in reality, the distortion close to the EH would be much stronger than
further away, and the "un-distortion" effect would be much weaker for areas very
close to the EH than for areas further away.

(b)

What would happen if the EH would suddenly recede and spacetime getting somewhat
"un-distorted", and our victim would *not* follow the EH?

Well, in that case, from an outside observer his wristwatch would speed up
again. But then what? Remember what the poor old sod was busy with when we left
him hanging at the edge of the EH? Right: Falling straigt towards the black
hole! So what will he do now in his newly recovered spare time? Um... continue
falling I guess...

So if the receding EH would also recede from our poor sod, he'd *very* quickly
catch up with it...


I guess both effects will happen, and they will combine. So there's reason
enough to believe that even as the EH recedes, that guy will still keep hugging
it, bound in eternal love... ("Oh darling, why can't this moment last forever!")

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clipka escreveu:
> Yes, Schwartzschild (an interesting name coincidence, by the way, that someone
> whose name translates to "Blackshield" should be the first to discover the
> formula for a black hole's event horizon) did his calculations for the most
> simple of black holes.

Indeed.  And thanks for the info, I was afraid he was son of 
Schwarzzenegger or something. :P

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clipka <nomail@nomail> wrote:
> What happens to the point where the victim was "hanging out"?

  The victim was not "hanging out" anywhere. There were simply some
leftover photons there, going out (with asymptotically lessening frequency).

  When the event horizon recedes, these leftover photons will be in a
less strong gravity field and will thus get a boostup. The photons which
were almost touching the EH will now be farther away, and will get out
in less time.

-- 
                                                          - Warp

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nemesis <nam### [at] gmailcom> wrote:
> Perhaps only Phil Connor would know. :P

Maybe - I don't know *him*... should I?


> hehe, are you sure you're not a mere crackpot? ;)
>
> http://math.ucr.edu/home/baez/crackpot.html

Hm.... let's check this out (BTW, I'm a fan of JOAN Baez, so it must be good
;))...


.... uh-oh! Looks like I'm making a *really poor* crackpot... a few points from
the first items, but I utterly fail at the real challenges...

I guess we *all* have to train still a bit more to qualify ;)

(We didn't even get into a flamewar about this... that's really poor! :P)

> Perhaps we get to know a universe in one single dimension?  "Hey, Phil,
> long time no see!  Somewhat overcrowded here, huh?"  well, except time
> wouldn't exist and so everything would be at the same time (damn word!). :P

The good thing is that it wouldn't last long :)

> Now that it's being considered that our universe could be a hologram,
> perhaps it's nothing but the slot to the credit card machine?  Freedom
> at last! :P

Yeah... so next step would be a few bit shift registers, accumulators, and - ah!
There you go: Correct pin, so spit out them greenbacks... :P

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nemesis <nam### [at] gmailcom> wrote:
> clipka escreveu:
> > Yes, Schwartzschild (an interesting name coincidence, by the way, that someone
> > whose name translates to "Blackshield" should be the first to discover the
> > formula for a black hole's event horizon) did his calculations for the most
> > simple of black holes.
>
> Indeed.  And thanks for the info, I was afraid he was son of
> Schwarzzenegger or something. :P

Just googled around a bit. Looks like Arnold "Arnie" Schwarzenegger (just one
"z" BTW) bears a surname derived from a Swiss location called "Schwarzenegg",
which in turn might translate to "black corner/region" or something alike.

Another BTW: With contemporary German orthography, "Schwartzschild" would lose
the "t" in his name... like "Rothschild" (which is "Redshield") would lose the
"h"...

..... I must confess though that this information has absolutely *nothing* to do
with black holes or cosmology or anything remotely close :P

(... except if you're opting for a holistic view on our universe ;))

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