"tuppence" wrote in message ...
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"Dirk Van de moortel" wrote
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"tuppence" wrote in message
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Tuppence comments below:

"Dirk Van de moortel"
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"tuppence" wrote in message
...
If we observe, from the outside, matter falling into a black hole its
time
gets slower and slower, or the wavelength of radiation it emits gets
longer
and longer ... until it gets to the surface described by the
Schwarzschild
radius, where the wavelength of the radiation becomes infinite, and
then
we
can no longer observe it from the outside. Now, let's say we are
inside
the
black hole. The observable universe seems to fit that. If we take the
Schwarzschild formula

R = (2GM)/c^2

it fits the observable universe quite well. So, now as we look towards
the
surface described by R from the inside, we see the same thing
happening.
As
matter gets closer and closer to this surface, its time gets slower
and
slower and the wavelength of its radiation gets longer and longer. It
appears that when the matter reaches R its time will stop and the
wavelength
of its radiation will become infinite. So, we can't observe it beyond
that
from the inside. So, whether we are inside or outside the
Schwarzschild
barrier, we see the same thing happening as something approaches the
barrier. (That's some of my two-pence worth.)

Actually, no. In the Schwarzschild metric the time t of
the global reference frame is the "time at infinity", or in
practice "the time for a sufficiently far away observer".
The business of "slowing down of time" near the event
horizon arrises when you compare this "far-away time"
with the proper time of clocks near the event horizon.
But the closer you yourself (the observer) are near the
black hole, the less the clocks near the horizon seem
"to run slower than your clock". Ultimately, imagine
yourself falling into the hole, together with the clock.
In that case you obvioulsy would see nothing strange
about the clock.
When you are inside the hole, falling to the center, you
would use another metric and you would not be using
far-away time anymore. When comparing your time with
clocks on the outside, even near the event horizon, you
would find that the outside clocks are "running fast" and
that incoming light would be blue shifted.

Ok, thanks, but I'm not comparing my clocks with clocks on the outside.
I'm
looking at matter approaching the Schwarzschild surface from the inside.

That is an ambiguous sentence

(1) Are you on the outside, looking at matter that approaches
the horizon from the inside?
or
(2) Are you on the inside, looking at matter that approaches
the horizon from the outside?

In case (2), with the Schwarzschild black hole, motion inside
the event horizon can never be radially outward. Everything
goes to the center. Nothing can approach the horizon from
the inside.

In case (1), reread and think carefully about my previous reply.
It has the complete answer.

Dirk Vdm

Ok, thanks, and I'll go away and re-read and re-think some more. But I
believe that in case (2) is where the general relativistic theory of
gravitation breaks down. Once you get inside the black hole it's somewhat
like a Maxwellian distribution of motion, and things don't attract to the
center.

Quite on the contrary. On the inside your 'distance' to the
center decreases the same way as our time on the outside
increases. That's what the model says anyway. No one
has ever been there and came back to describe it of course.

Dirk Vdm

Things seem very uniform and isotropic. You don't get infinite
energy of attraction to a point. I believe we have experimental evidence of
that, because we are in a black hole that is thought of as the observable
universe. The numbers seem to verify that. And, after all, science is about
numbers and observations. If you have an experimental example of viewing
incoming radiation from outside a black hole, please refer it to me.
Otherwise, I am skeptical.

"tuppence" wrote in message
...
If we observe, from the outside, matter falling into a black hole its time
gets slower and slower, or the wavelength of radiation it emits gets longer
and longer ... until it gets to the surface described by the Schwarzschild
radius, where the wavelength of the radiation becomes infinite, and then we
can no longer observe it from the outside. Now, let's say we are inside the
black hole. The observable universe seems to fit that. If we take the
Schwarzschild formula

R = (2GM)/c^2

it fits the observable universe quite well. So, now as we look towards the
surface described by R from the inside, we see the same thing happening. As
matter gets closer and closer to this surface, its time gets slower and
slower and the wavelength of its radiation gets longer and longer. It
appears that when the matter reaches R its time will stop and the wavelength
of its radiation will become infinite. So, we can't observe it beyond that
from the inside. So, whether we are inside or outside the Schwarzschild
barrier, we see the same thing happening as something approaches the
barrier. (That's some of my two-pence worth.)

Tuppence

dr
No, thanks for two-pence worth here's my one pennyworth {:-) from the
inside the frequency get shorter as the EMR moves to the event horizon from
the inside.
--
Dr *** time/length/energy
http://home.freeuk.com/paulps/
Some updates the turnips are coming
up nicely. Ooh ah.{:-)

Dr *** wrote:
from the
inside the frequency get shorter as the EMR moves to the event horizon from
the inside.

It is not possible for any timelike or null trajectory to approach the
horizon of a black hole from inside. Inside a Schwarzschild black hole
the singularity is always in the future and the horizon is always in the
past.

[Using the usual Schwarzschild coordinates, in the region r2M,
the time coordinate is r and the future is in the -d/dr
direction. The singularity is at r=0. This is QUITE different
from naive expectations....]


Tom Roberts

"tuppence" wrote in message
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Tuppence replies below:

"Dirk Van de moortel" wrote
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"tuppence" wrote in message
...
Tuppence comments below:

"Dirk Van de moortel"
wrote
in message ...

"tuppence" wrote in message
...
snip
Ok, thanks, and I'll go away and re-read and re-think some more. But I
believe that in case (2) is where the general relativistic theory of
gravitation breaks down. Once you get inside the black hole it's somewhat
like a Maxwellian distribution of motion, and things don't attract to the
center. Things seem very uniform and isotropic. You don't get infinite
energy of attraction to a point. I believe we have experimental evidence of
that, because we are in a black hole that is thought of as the observable
universe. The numbers seem to verify that. And, after all, science is about
numbers and observations. If you have an experimental example of viewing
incoming radiation from outside a black hole, please refer it to me.
Otherwise, I am skeptical.

Tuppence

I tend to agree with you but it may be a case of position so that very near
the EH from the inside you get a blue shift because in that case you have
the total mass of our cosmos behind you and you are in a gradient with in
front being zero mass and the other end also being zero mass but with the
total mass of the cosmos in between you in that direction.
So from decreasing density you get blue shift light and from within
increased density you get red shift. I very much suspect that the blue
shifted light coming from the outside is the same blue shifted light you
would see coming from the inside of the centre of mass of our cosmos but I
have never been quick enough to watch both places at the same time.{:-) I
guess from the pov of any beings of the density of a BH our cosmos would
seem non-existent and their time rate would be so slow that our cosmos will
have come and gone before they find the toilet paper. Move out to a quicker
lifestyle or in to a real drag.{:-)
--
Dr *** time/length/energy
http://home.freeuk.com/paulps/
Some updates the turnips are coming
up nicely. Ooh ah.{:-)

"Tom Roberts" wrote in message
...
Dr *** wrote:
from the
inside the frequency get shorter as the EMR moves to the event horizon
from
the inside.
tr
It is not possible for any timelike or null trajectory to approach the
horizon of a black hole from inside. Inside a Schwarzschild black hole
the singularity is always in the future and the horizon is always in the
past.
dr
I disagree, although I should have written the observed frequency of
incoming radiation from the pov of an observer approaching the EH from the
inside is blue shifted. The horizon for this observer is always in the
future and the main body of the hole is in the past due to the density
gradient decreasing to the horizon.
tr
[Using the usual Schwarzschild coordinates, in the region r2M,
the time coordinate is r and the future is in the -d/dr
direction. The singularity is at r=0. This is QUITE different
from naive expectations....]

Tom Roberts

dr
Have you considered that your math may be naive and your comprehension
incomplete.?
--
Dr *** time/length/energy
http://home.freeuk.com/paulps/
Some updates the turnips are coming
up nicely. Ooh ah.{:-)