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

tuppence wrote:
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.

No we don't. From beneath the EH, looking toward it, we see a
blue-shift.

[snip]

(That's some of my two-pence worth.)

It's not even worth two-pence.

Paul Cardinale

"Paul Cardinale" wrote in message
oups.com...

tuppence wrote:
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.

No we don't. From beneath the EH, looking toward it, we see a
blue-shift.

Good! would you give me an example of when you were beneath the event
horizon, looking at it from the inside, other than being an observer in this
universe, whatever that is. I guess I thought galaxies approaching it from
our viewpoint showed a red-shift. Hubble must have had it wrong.

[snip]

(That's some of my two-pence worth.)

It's not even worth two-pence.

Obviously, you have mistaken me for someone who gives a damn what you think
it's worth.

Paul Cardinale

"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.

Dirk Vdm

Tuppence comments below:

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

"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. I
believe that experimental evidence (Hubble's observation) shows a red shift.
Is that not correct?

Tuppence

"tuppence" wrote in message ...
Tuppence comments below:

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

"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


I
believe that experimental evidence (Hubble's observation) shows a red shift.
Is that not correct?

Tuppence

"Dirk Van de moortel" wrote in message
news

"tuppence" wrote in message ...

[snip]

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.

This should obviously be (1)


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

and this (2)
Sorry.

Dirk Vdm

Tuppence replies below:

"Dirk Van de moortel" wrote
in message news

"tuppence" wrote in message
...
Tuppence comments below:

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

"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. 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
believe that experimental evidence (Hubble's observation) shows a red
shift.
Is that not correct?

Tuppence

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

| wrote
| in message ...
|
| "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. 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.

A possible difference between that which we notice for our "local
bubble" of the Universe and a black hole is that our "local bubble's"
*now* is the event horizon. IOW, outside of a black hole we have a
"surface" that is somewhat physical. Inside a black hole the event
horizon is related to time because if inside, you will never be able to
find the "surface" related to being outside the hole. Now, what the
heck would be the math for that?

FrediFizzx

tuppence wrote:
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.

Yes. But remember when you say "the wavelength of the radiation becomes
infinite" that is referring to the wavelength we detect, not the
wavelength at which it was emitted.


Now, let's say we are inside the
black hole. The observable universe seems to fit that.

No it does not. Not even close.


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.

Not true. First, for matter to approach the event horizon it must do so
FROM OUTSIDE. Matter inside the event horizon is monotonically moving
further from the event horizon as its elapsed proper time increases.
Second, light emitted from any object near the event horizon will be
BLUESHIFTED to an observer inside the horizon.


Bottom line: yes there is an observational horizon in the universe
beyond which we cannot observe anything. But this is QUITE different
from the event horizon of a black hole.


Tom Roberts