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Author Topic: Can the escape velocity of a mass ever exceed c?  (Read 3216 times)

Offline jeffreyH

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Can the escape velocity of a mass ever exceed c?
« on: 07/04/2014 02:50:51 »
I personally have come to the conclusion that any mass has to obey one proposed law. That is that neither the density or size of a mass can exceed the point where the required escape velocity equals c. I would like more views on this.


 

Offline Bored chemist

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #1 on: 07/04/2014 09:48:51 »
There is fairly good evidence that you are wrong.
Black holes are objects whose escape velocity exceeds c.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #2 on: 07/04/2014 10:24:08 »
There is fairly good evidence that you are wrong.
Black holes are objects whose escape velocity exceeds c.

Yet we cannot directly measure a black hole. The theory states that c is exceeded but what actual evidence is there? I have looked at mass-energy density and what I found was that as the size of a black hole increases the mass-energy density per volume decreases. I would actually like someone else to double check this result as at the time I did the work I expected a consistent density behind the event horizon. By that I mean as the mass compresses to exactly within the horizon. I took a range of mass sizes and for each calculated the Schwarzschild radius. Using this I then calculated the density per cubic volume for each mass. This is when I discovered the drop in density. Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole.
 

Offline Bored chemist

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #3 on: 07/04/2014 10:41:19 »
"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?
 

Offline evan_au

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #4 on: 07/04/2014 12:00:24 »
Quote: "as the size of a black hole increases the mass-energy density per volume decreases"
A table of theoretical black hole sizes supports the idea that more massive (ie larger radius) black holes have lower density.
See: http://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters

Mathematically, the cause is that:
- the radius of the event horizon increases in proportion to the mass,
- but the volume of the black hole increases as the cube of the mass.
- hence the density decreases as the square of the mass.

This leads to the paradoxical result that a stellar mass black hole would kill you by spaghettification if you got too close, but a much larger galactic black hole would not.

Quote: "neither the density or size of a mass can exceed the point where the required escape velocity equals c"
The event horizon is the surface within which the escape velocity exceeds c. If the mass of a black hole were lower, the escape velocity would still exceed c, but at a proportionately smaller radius.

From our current understanding, we will never be able to see into the region where the speed of light (theoretically) exceeds c, but at least we should be able to peer down to regions where the escape velocity approaches c.

Astronomers are hoping to get some more hints about our galactic hole over the next few months and years.
See: http://esciencenews.com/articles/2014/04/04/watching.a.black.hole.gobble.a.gas.cloud
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #5 on: 07/04/2014 12:48:02 »
Quote: "as the size of a black hole increases the mass-energy density per volume decreases"
A table of theoretical black hole sizes supports the idea that more massive (ie larger radius) black holes have lower density.
See: http://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters

Mathematically, the cause is that:
- the radius of the event horizon increases in proportion to the mass,
- but the volume of the black hole increases as the cube of the mass.
- hence the density decreases as the square of the mass.

This leads to the paradoxical result that a stellar mass black hole would kill you by spaghettification if you got too close, but a much larger galactic black hole would not.

Quote: "neither the density or size of a mass can exceed the point where the required escape velocity equals c"
The event horizon is the surface within which the escape velocity exceeds c. If the mass of a black hole were lower, the escape velocity would still exceed c, but at a proportionately smaller radius.

From our current understanding, we will never be able to see into the region where the speed of light (theoretically) exceeds c, but at least we should be able to peer down to regions where the escape velocity approaches c.

Astronomers are hoping to get some more hints about our galactic hole over the next few months and years.
See: http://esciencenews.com/articles/2014/04/04/watching.a.black.hole.gobble.a.gas.cloud

I may well be wrong on the fact that c cannot be exceeded. I have had to change my mind on other assumptions. What raised the issue was the method of calculating G assuming G=C^2 when calculating a Planck mass for use in deriving G. This scaling of the values links c to G in an unexpected way.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #6 on: 07/04/2014 12:50:11 »
"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
 

Offline Bored chemist

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #7 on: 07/04/2014 17:26:25 »
"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
Or, they may not.
And the fact that black holes exists shows that they don't.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #8 on: 07/04/2014 21:36:18 »
"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
Or, they may not.
And the fact that black holes exists shows that they don't.

Yes, or they may not. We need a proper understanding of gravity to determine the outcome. This has been an informative debate. Thanks for the feedback.
 

Offline Bored chemist

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #9 on: 08/04/2014 21:04:19 »

"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
Or, they may not.
And the fact that black holes exists shows that they don't.

Yes, or they may not. We need a proper understanding of gravity to determine the outcome. This has been an informative debate. Thanks for the feedback.

Re.
"We need a proper understanding of gravity to determine the outcome. "
Not really.
We can just look at black holes, see that they exist (and are black) and conclude that light can't escape from them.
The mechanism by which gravity works doesn't affect the outcome.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #10 on: 08/04/2014 21:27:53 »

"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
Or, they may not.
And the fact that black holes exists shows that they don't.

Yes, or they may not. We need a proper understanding of gravity to determine the outcome. This has been an informative debate. Thanks for the feedback.

Re.
"We need a proper understanding of gravity to determine the outcome. "
Not really.
We can just look at black holes, see that they exist (and are black) and conclude that light can't escape from them.
The mechanism by which gravity works doesn't affect the outcome.

It depends upon how far the wavelength would be shifted. If a photon is having to match its own speed just to escape how long would the wavelength be? Would it even be detectable? It would simply look .... black. The one thing that is probably in favour of your argument is that the Schwarzschild radius of the Planck mass is two Planck lengths and not one. At one Planck length light would escape as it travels one Planck length in one Planck time so gravity would have no time to react.

As an addendum to this post, if gravity waves travel at c, then does the actual energy of the gravity have be greater than the energy of the photon to stop it. At two Planck lengths would there be enough energy to stop light? If we knew this relationship of Rs to gravitational energy we may find some limits on black hole sizes.
« Last Edit: 09/04/2014 11:04:04 by jeffreyH »
 

Offline JP

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #11 on: 09/04/2014 01:09:41 »
Jeffrey, please stop promoting your own theory about gravitational feedback in this forum.  Please keep posts on that to new theories and posts on more mainstream topics (or questions about those topics) here.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #12 on: 09/04/2014 10:55:51 »
Jeffrey, please stop promoting your own theory about gravitational feedback in this forum.  Please keep posts on that to new theories and posts on more mainstream topics (or questions about those topics) here.

Sorry JP. I have removed the offending sentences. It is not my aim to promote a personal theory. I am just thinking about it a lot at the moment.
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #13 on: 09/04/2014 11:12:00 »

"The theory states that c is exceeded but what actual evidence is there? "
The colour.
"Ultimately this lower density will reach a point where a large enough gas cloud contained within a particular area could form a black hole."
Why would that be a problem?

The problem arises when considering a gas cloud compressing to a singularity. The inverse square law and the distance between individual particles may prohibit this.
Or, they may not.
And the fact that black holes exists shows that they don't.

Yes, or they may not. We need a proper understanding of gravity to determine the outcome. This has been an informative debate. Thanks for the feedback.

Re.
"We need a proper understanding of gravity to determine the outcome. "
Not really.
We can just look at black holes, see that they exist (and are black) and conclude that light can't escape from them.
The mechanism by which gravity works doesn't affect the outcome.

You are exactly right when you say "The mechanism by which gravity works doesn't affect the outcome." I really like these forum discussions because it makes you think in different ways about the problem. Yes black holes are black because light can't escape.
 

Offline JP

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #14 on: 09/04/2014 15:25:06 »
I've moved your posts about calculating G to New Theories, Jeffrey, as they're well outside of accepted methods.  If you want to discuss them or ask questions about your methodology, that's the place to do it!  (Feel free to re-title the new thread to something more appropriate by clicking "modify" on your first post).
 

Offline jeffreyH

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #15 on: 09/04/2014 16:35:10 »
I've moved your posts about calculating G to New Theories, Jeffrey, as they're well outside of accepted methods.  If you want to discuss them or ask questions about your methodology, that's the place to do it!  (Feel free to re-title the new thread to something more appropriate by clicking "modify" on your first post).

That's fine. It is outside the norm. Thanks for letting me know.
 

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Re: Can the escape velocity of a mass ever exceed c?
« Reply #15 on: 09/04/2014 16:35:10 »

 

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