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| Slinkey |
 Posted: Tue Dec 25, 2007 4:47 am Post subject: The Paradoxical Nature of Black Holes |
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To me black holes represent a paradox within science.
The thing that is the paradox to me is as follows:
1. An outside observer watching something fall into a black hole would never see it cross the event horizon.
2. Black holes evaporate through Hawking radiation.
Conclusion:
If you watch something fall into a black hole for long enough the black hole will evaporate before the "something" crosses the event horizon.
According to theory this is not so. The "something", from it's perspective, would enter the black hole.
I beg to differ: I submit that if you fell into a black hole (and could survive the tidal forces) that the event horizon would be unreachable as it would fall away from you as you fall towards it.
For me, the key here is the time warp suggested by theory to exist at the event horizon. It is an infinite time warp to all outside observers and therefore would take an infinite amount of time to traverse. As a black hole evaporates there is not an infinite amount of time available and thus the black hole would cease to exist before you reach the event horizon.
Personally, I don't think there are black holes and they are a curiosity of general relativity that is holding us back from unifying quantum mechanics and GR. Because we seek to create a quantum black hole the theory will never make sense or be fruitful. We need to move away from this curiosity to unify physics.
What we think are black holes at the center of galaxies are, in my estimation, something else that we are yet to discover and not until QM and GR are unified.
cheers
Slinkey |
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| (Q) |
| Posted: Tue Dec 25, 2007 9:25 am Post subject: Re: The Paradoxical Nature of Black Holes |
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| Slinkey wrote: |
I beg to differ: I submit that if you fell into a black hole (and could survive the tidal forces) that the event horizon would be unreachable as it would fall away from you as you fall towards it. |
That makes no sense. Once you're moving on a geodesic bound for the center of the object, you WILL reach the event horizon. In GR, it is the object that accelerates up towards the free-falling object, not accelerate away from it.
| Quote: |
| For me, the key here is the time warp suggested by theory to exist at the event horizon. It is an infinite time warp to all outside observers and therefore would take an infinite amount of time to traverse. As a black hole evaporates there is not an infinite amount of time available and thus the black hole would cease to exist before you reach the event horizon. |
No, you would reach and pass the event horizon, however an outside observer would simply see you disappear as the light reflected from you shifts off the scale.
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| Personally, I don't think there are black holes and they are a curiosity of general relativity that is holding us back from unifying quantum mechanics and GR. Because we seek to create a quantum black hole the theory will never make sense or be fruitful. We need to move away from this curiosity to unify physics. |
No, GR is NOT holding us back.
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| What we think are black holes at the center of galaxies are, in my estimation, something else that we are yet to discover and not until QM and GR are unified. |
Perhaps that may occur, but it does not suggest GR is the problem.
_________________
I may have no understanding of the current theory of evolution. But that's because science keeps changing it. A few weeks ago I read in the newspaper that it had once again been adjusted & just the other day I discovered a new book called "The New Theory of Evolution" ~~Steven Titchenell : W.V.B.I.G. President. |
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| Slinkey |
| Posted: Tue Dec 25, 2007 1:42 pm Post subject: |
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| That makes no sense. Once you're moving on a geodesic bound for the center of the object, you WILL reach the event horizon. In GR, it is the object that accelerates up towards the free-falling object, not accelerate away from it. |
I couldn't think of another way of saying it but let me try to expland below.
Let's discuss the event horizon (EH). The EH is not a physical entity. It is the point around a black hole (BH) that marks the spot where time dilation becomes infinite due to gravity. It also marks the spot where any object falling into the BH will be accelerated to light speed.
According to special relativity when an object is moving relative to yourself it shortens in the direction of its movement. At c the equations of SR imply that an object would have no length at c.
Now lets translate this to GR. As an object accelerates towards the EH of a BH it would appear to shorten in the direction of its movement. At the EH it would reach c and therefore no longer have any length in the direction of it's movement. But it is not only the object that has shrunk to zero thickness. At this point everything would be shrunk to zero thickness including space.
How long does it take something of zero thickness to traverse no space? Well, from our perspective at a fixed distance from the EH - forever.
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| No, you would reach and pass the event horizon, however an outside observer would simply see you disappear as the light reflected from you shifts off the scale. |
Of course, my argument is not taking this into account light coming from near the EH of a BH will be redshifted (and infinitely redshifted at the EH) so for the purposes of this discussion let's ingore this effect and assume we can see it. Would we ever see it cross the EH? No. It would appear to move towards the EH at an ever decreasing velocity. ie. we would see it getting closer and closer but never see it reach.
If the black holes is evaporating due to Hawking radiation it will not exist forever. Therefore if we watch long enough we will see the BH evaporate before we see the object cross the EH.
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| No, GR is NOT holding us back. |
That's not what I said actually. I am saying that when we try to join GR and QM we try, as one of our tests of our new theories, to create BHs from the new equations. I'm saying that we might be wrong in using this as a test and it could be holding us back. It would be interesting to see theories that do not need to allow for a BH and how close they are to reality.
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| Perhaps that may occur, but it does not suggest GR is the problem. |
My perspective is the solutions that allow for black holes may be misleading us.
On a final and related note let's look at SR again. A spaceship is accelerating at 10m/s^2. When do we see it reach light speed? What about from the perspective of the spaceship?
cheers
Slinkey |
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| Posted: Tue Dec 25, 2007 5:53 pm Post subject: |
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| Slinkey wrote: |
According to special relativity when an object is moving relative to yourself it shortens in the direction of its movement. At c the equations of SR imply that an object would have no length at c. |
SR is a subset of GR and is not used with accelerated frames, hence your explanation is moot.[/quote]
_________________
I may have no understanding of the current theory of evolution. But that's because science keeps changing it. A few weeks ago I read in the newspaper that it had once again been adjusted & just the other day I discovered a new book called "The New Theory of Evolution" ~~Steven Titchenell : W.V.B.I.G. President. |
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| Slinkey |
| Posted: Wed Dec 26, 2007 6:06 am Post subject: |
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| SR is a subset of GR and is not used with accelerated frames, hence your explanation is moot. |
Errr, incorrect. You can do accelerations with SR.
cheers
Slinkey |
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| Posted: Wed Dec 26, 2007 9:28 am Post subject: |
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| Slinkey wrote: |
| Quote: |
| SR is a subset of GR and is not used with accelerated frames, hence your explanation is moot. |
Errr, incorrect. You can do accelerations with SR.
cheers
Slinkey |
But, not when the accelerations are in curved space-time, ONLY flat space-time. Space-time in and around black holes is curved.
_________________
I may have no understanding of the current theory of evolution. But that's because science keeps changing it. A few weeks ago I read in the newspaper that it had once again been adjusted & just the other day I discovered a new book called "The New Theory of Evolution" ~~Steven Titchenell : W.V.B.I.G. President. |
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| Slinkey |
| Posted: Wed Dec 26, 2007 1:53 pm Post subject: |
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| But, not when the accelerations are in curved space-time, ONLY flat space-time. Space-time in and around black holes is curved. |
Acceleration is curved spacetime. Ref: Einstein.
cheers
Slinkey |
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| Slinkey |
| Posted: Wed Dec 26, 2007 2:06 pm Post subject: |
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I want to add another thought experiment to this discussion.
We are hovering at a fixed distance from a BH. We have to accelerate at 1g to stay at this fixed distance. We open the cargo bay door on the underside of our spaceship and drop a clock. The clock accelerates towards the BH under the influence of gravity. After 10 seconds we cut the spaceship's engines and also start accelerating towards the BH directly behind the clock.
Given that no outside observers can see anything cross the EH (and ignoring redshifting of light and tidal forces for now) how can we ever cross the event horizon ourselves?
cheers
Slinkey |
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| Posted: Thu Dec 27, 2007 1:04 pm Post subject: |
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| Slinkey wrote: |
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| But, not when the accelerations are in curved space-time, ONLY flat space-time. Space-time in and around black holes is curved. |
Acceleration is curved spacetime. Ref: Einstein. |
I don't recall Einstein ever saying that acceleration IS curved spacetime.
_________________
I may have no understanding of the current theory of evolution. But that's because science keeps changing it. A few weeks ago I read in the newspaper that it had once again been adjusted & just the other day I discovered a new book called "The New Theory of Evolution" ~~Steven Titchenell : W.V.B.I.G. President. |
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| KALSTER |
| Posted: Fri Dec 28, 2007 1:50 am Post subject: |
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| Let's discuss the event horizon (EH). The EH is not a physical entity. It is the point around a black hole (BH) that marks the spot where time dilation becomes infinite due to gravity. It also marks the spot where any object falling into the BH will be accelerated to light speed. |
Huh? Am I missing something here? This isn't correct , is it? As far as I understand it, an EH is nothing more than the distance from the centre of gravity at which the escape velocity is => C. You would not be accelerated to C before you reach it.
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| Slinkey |
| Posted: Fri Dec 28, 2007 2:11 am Post subject: |
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| I don't recall Einstein ever saying that acceleration IS curved spacetime. |
Einstein stated that acceleration is indistinguishable gravity - gravity is acceleration. If I was hovering a foot above the earth's surface I would feel 1g - acceleration due to gravity. This would be indistinguishable from me accelerating my rocket at 1g in a flat spacetime.
To state that using SR is invalid because it is a subset of GR is like saying the fur of a brown fox is some colour other than brown when it isn't attached to the fox.
The results of SR are valid within GR otherwise it could not be a subset of GR. You might want to brush up on your set theory. SR is used in the special case of flat spacetime and it shows how acceleration warps flat spacetime. If it did not there would be no effect.
If I was accelerating across space I would be able to detect effects and these effects would be due to my acceleration.
If I fell towards a black hole I would be able to detect effects and these effects would be due to my acceleration.
In both cases the effects would be the same and indistinguishable.
It is therefore a viable conclusion to state that acceleration is curved spacetime.
Unless of course you're claiming that SR describes a different effect from GR, or are you claiming they display the same effects but by different means?
In the meantime you could always address the second thought experiment, or even the first. Or is it that you are ill-equiped to defeat my argument and thus want to discuss quotes of Einstein instead?
I don't mean to be rude but the best argument I've had back is that SR doesn't apply because it's a subset of GR which is ludicrous.
cheers
Slinkey |
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| Slinkey |
| Posted: Fri Dec 28, 2007 2:17 am Post subject: |
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| Huh? Am I missing something here? This isn't correct , is it? As far as I understand it, an EH is nothing more than the distance from the centre of gravity at which the escape velocity is => C. You would not be accelerated to C before you reach it. |
You'll get no argument from me as that's what I said. The EH is the point at which you would be accelerated to c.
cheers
Slinkey |
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| KALSTER |
| Posted: Fri Dec 28, 2007 4:39 am Post subject: |
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| Slinkey wrote: |
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| Huh? Am I missing something here? This isn't correct , is it? As far as I understand it, an EH is nothing more than the distance from the centre of gravity at which the escape velocity is => C. You would not be accelerated to C before you reach it. |
You'll get no argument from me as that's what I said. The EH is the point at which you would be accelerated to c.
cheers
Slinkey |
Ok then. But is that not the only difference between being just over the event horizon, that you could never go back? To be able to accelerate to C, an infinite resultant force needs to apply to an object, which does not exist just on the other side of the EH. The gravitational force would approach infinity as you go nearer to the singularity, but would only reach epic proportions when you are quite close to it, not at the distance of the EH.
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| KALSTER |
| Posted: Fri Dec 28, 2007 4:45 am Post subject: |
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| It is therefore a viable conclusion to state that acceleration is curved spacetime |
I think what Einstein was saying, is that what we know as gravity, is actually acceleration caused by the curvature of space-time. So one could say gravity = acceleration as a result of space-time curvature, but not acceleration = space-time curvature. Kind of like: All apples are fruit, but not all fruit are apples.
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| (Q) |
| Posted: Fri Dec 28, 2007 7:15 am Post subject: |
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| Slinkey wrote: |
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| I don't recall Einstein ever saying that acceleration IS curved spacetime. |
Einstein stated that acceleration is indistinguishable gravity - gravity is acceleration. If I was hovering a foot above the earth's surface I would feel 1g - acceleration due to gravity. This would be indistinguishable from me accelerating my rocket at 1g in a flat spacetime. |
Ah, so Einstein DID NOT say acceleration IS curved spacetime. That was either a lie or you're just confused.
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| To state that using SR is invalid because it is a subset of GR is like saying the fur of a brown fox is some colour other than brown when it isn't attached to the fox. |
More confusion on your part.
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| The results of SR are valid within GR otherwise it could not be a subset of GR. You might want to brush up on your set theory. SR is used in the special case of flat spacetime and it shows how acceleration warps flat spacetime. If it did not there would be no effect. |
And here's what I said, but you said I was wrong:
"But, not when the accelerations are in curved space-time, ONLY flat space-time."
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If I was accelerating across space I would be able to detect effects and these effects would be due to my acceleration.
If I fell towards a black hole I would be able to detect effects and these effects would be due to my acceleration.
In both cases the effects would be the same and indistinguishable.
It is therefore a viable conclusion to state that acceleration is curved spacetime. |
The conclusion is incorrect. Acceleration is curved spacetime ONLY with gravity.
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Unless of course you're claiming that SR describes a different effect from GR, or are you claiming they display the same effects but by different means?
In the meantime you could always address the second thought experiment, or even the first. Or is it that you are ill-equiped to defeat my argument and thus want to discuss quotes of Einstein instead?
I don't mean to be rude but the best argument I've had back is that SR doesn't apply because it's a subset of GR which is ludicrous. |
That wasn't the argument. You only use SR by introducing Minkowskian spacetime, ie. FLAT, which doesn't correspond to the spacetime in and around a black hole; ie. CURVED.
_________________
I may have no understanding of the current theory of evolution. But that's because science keeps changing it. A few weeks ago I read in the newspaper that it had once again been adjusted & just the other day I discovered a new book called "The New Theory of Evolution" ~~Steven Titchenell : W.V.B.I.G. President. |
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