How can gravity escape a black hole?

[modest]

Continued from this post.

Originally Posted by Pluto

G'day Modest.

Yes I agree with you along that logic.

But!

How can gravity escape a black hole if its speed is C?

This is a very good question.

In general relativity, gravity is the curvature of spacetime. While changes in the fabric of spacetime are theorized to travel at c, I don’t believe there is any real need for information regarding the mass of the singularity to travel out of the event horizon. Spacetime is curved and sloping from the singularity out to objects beyond. That curvature is what tells objects outside the event horizon where and how to move. The curvature is already there and doesn't need to travel across the event horizon.

In quantum mechanics the situation is very much different. There is currently no verified theory of gravity in QM, but some aspects are easy to guess. All forces in quantum mechanics are mediated by particles. For example, electric charge and the Coulomb force is mediated by the exchange of virtual photons. Gravity would be mediated by gravitons. So, in a theory of quantum gravity, a graviton would need to escape a black hole in order to communicate the force of gravity to the rest of the universe. Does this mean a graviton needs to travel faster than c in order to do this? I think so.

Does this present a problem for quantum gravity? I don’t think so. Gravitons would be virtual particles and I think virtual particles are allowed to travel faster than light. Someone more familiar with QM can correct me if I’m wrong, but I think gravitons:

1. would need to travel faster than c to leave a black hole and affect distant objects gravitationally
2. can travel faster than c because they’re virtual.

~modest

[Pluto]

G'day from the land of ozzz

Modest I agree with you,,,,,,,,darn against my aim to argue.

I like your opinion on this paper. By memory I think you have commented on this in the past.

Is faster-than-light propagation allowed by the laws of physics?
Is faster-than-light propagation allowed by the laws of physics? (a primer on Lorentzian relativity)

Abstract. As the relativity of motion is taught today, Einstein’s special relativity has been observationally confirmed so often that there is no longer reason to doubt it. However, the chief competitor theory known as Lorentzian relativity has passed those same observational tests. Whether surpassing the speed of light in classical physics will be routinely possible or not depends critically on which of these models is correct. Recent experimental evidence for faster-than-light force propagation is fully consistent with Lorentzian relativity, but is a test that special relativity cannot pass.

Table 1. Overview and comparison of SR and LR.

In summary, Table 1 shows the major features of and differences between the two competing theories for the relativity of motion, Einstein special relativity and Lorentzian relativity. Experiments have now decided in favor of the interpretations in the last column.

==================================================

also

Kopeikin and the Speed of Gravity
Kopeikin and the speed of gravity

"The speed of gravity"

Abstract. New findings were announced on 2003/01/08 by S. Kopeikin, claiming to have measured the "speed of gravity" and finding it essentially equal to the speed of light. These findings are invalid by both experimental and theoretical standards because the quantity measured was already known to propagate at the speed of light. The hyped claims therefore do a disservice to science in general and the advancement of physics in particular because the announced findings do not represent the meaning of the actual experimental results and cannot possibly represent the physical quantity heretofore called "the speed of gravity", which has already been proved by six experiments to propagate much faster than light, perhaps billions of times faster. Several mainstream relativists have also stated their disagreement that the experiment really measured what it claimed to measure.

==============================================

Now I have to read further on and try to understand.

I should have taken up tennis.

[Tormod]

An interesting aspect of this idea (that black holes could trap gravity) is that it would, at least in theory, make it possible to create gravity blocking devices. Goodbye rockets!

[Pluto]

G'day from the land of ozzz

Thinking out loud past thunder dome. What do you think of this logic.

For a black hole to trap gravity it would need to go into ultra ultra dense graviton matter. In this state the graviton becomes part of the SOUP and would not be able to escape.

In normal so called Black holes the common matter traps its own kind.

Maybe I'm wrong,,,,,,,,,just a thought.

[freeztar]

Originally Posted by Pluto

G'day from the land of ozzz

Thinking out loud past thunder dome. What do you think of this logic.

For a black hole to trap gravity it would need to go into ultra ultra dense graviton matter. In this state the graviton becomes part of the SOUP and would not be able to escape.

In normal so called Black holes the common matter traps its own kind.

Maybe I'm wrong,,,,,,,,,just a thought.

This is a very interesting thread guys.

Pluto, I'm no expert (not even close), but it seems a bit unintuitive, imho, to talk about gravitons not being able to escape gravity. In other words, it seems paradoxical.

If the gravitons coalesced at the "soup"/singularity/what have you, wouldn't that suggest a "runaway" effect, gravitationally? Why wouldn't the event horizons of supermassive black holes be very, very small with your idea?

[Pluto]

G'day from the land of ozzzzz

freeztar said

If the gravitons coalesced at the "soup"/singularity/what have you, wouldn't that suggest a "runaway" effect, gravitationally? Why wouldn't the event horizons of supermassive black holes be very, very small with your idea?

Theoretically yes, in reality no.

Theoretically the sun if it was preon particles it would have a dia of 1 mm. About Thats 10^35 kg/m3

What prevents black holes from growing bigger and bigger?

How big can a black hole grow?
How big can a black hole grow? - space - 03 September 2008 - New Scientist Space

If 50 billion sun massses is the limit of black holes. What is the mechanism that trims their mass down.

The subatomic particles such a quarks or what ever form a plasma soup. We know that plasma has a double layer property and can create z-pinch of these layers. In so doing the ultra dense plasma can use its own internal forces and create a jet and eject matter in a protective electromagnetic field deep into space.
Jet sizes are dertemined by their surrounding, our sun , Neutron stars, pulsars, magnetars and varies forms and sizes of black holes.

This logic is disputed by most.
Why? Because of this satement.
Nothing can escape a black hole.
This statement has prevented other options in the past.

I'd rather treat the black hole as a compact body and apply the properties of plasma.

[Pluto]

G'day from the land of ozzzzzzzz

I came across this link, it maybe of interest

[gr-qc/9709011] Bounding the mass of the graviton using gravitional-wave observations of inspiralling compact binaries

Bounding the mass of the graviton using gravitional-wave observations of inspiralling compact binaries

Authors: Clifford M. Will (Washington University, St. Louis)
(Submitted on 4 Sep 1997)

Abstract: If gravitation is propagated by a massive field, then the velocity of gravitational waves (gravitons) will depend upon their frequency and the effective Newtonian potential will have a Yukawa form. In the case of inspiralling compact binaries, gravitational waves emitted at low frequency early in the inspiral will travel slightly slower than those emitted at high frequency later, modifying the phase evolution of the observed inspiral gravitational waveform, similar to that caused by post-Newtonian corrections to quadrupole phasing. Matched filtering of the waveforms can bound such frequency-dependent variations in propagation speed, and thereby bound the graviton mass. The bound depends on the mass of the source and on noise characteristics of the detector, but is independent of the distance to the source, except for weak cosmological redshift effects. For observations of stellar-mass compact inspiral using ground-based interferometers of the LIGO/VIRGO type, the bound on the graviton Compton wavelength is of the order of $6 \times 10^{12}$ km, about double that from solar-system tests of Yukawa modifications of Newtonian gravity. For observations of super-massive black hole binary inspiral at cosmological distances using the proposed laser interferometer space antenna (LISA), the bound can be as large as $6 \times 10^{16}$ km. This is three orders of magnitude weaker than model-dependent bounds from galactic cluster dynamics.

Still reading through it.

[Jay-qu]

Thinking about gravitons can get you a bit mixed up because no one knows if the graviton exists or not. Our current theories just dont cut it. If we can quantise gravity and attribute a guage boson to the gravitational force, it would be known as the graviton and if that occurs we expect the graviton to be massless. But that doesnt ensure it can escape a black hole - as a photon is massless and cannot escape.

The question becomes, if the graviton is the communicator of the gravitational force, then with what are we communicating? I think there are two ways of looking at it. One, you exchange bosons with the object directly, or two, instead you exchange particles with the local spacetime, where the curvature defines the type of interaction that occurs.

[ughaibu]

One of the irreversibility problems in physics is that of wave propagation, one could moot the possibility that gravity is such a reverse wave phenomenon and converges on mass rather than originating from it.

[lawcat]

Originally Posted by ughaibu

One of the irreversibility problems in physics is that of wave propagation, one could moot the possibility that gravity is such a reverse wave phenomenon and converges on mass rather than originating from it.

Yes, and that would be consistent, at least in theory, with the Special relativity and quantum gravity--which would deem general relativity a bad theory. I agree with the logic of your point of view.