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ynot1
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The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and...
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That answer would probably be speculative.Naty1 said:The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and eliminate its coordinate singularity. This work influenced the decisions of Roger Penrose and John Archibald Wheeler to accept the physical existence of event horizons and black holes.
But what does it mean??
Radiation escapes black holes and gravitons radiate.Tanelorn said:Originally Posted by JonDE
Maybe my confusion is because I think of it as a wave or particle (graviton), and I don't see how a graviton can escape when other particles cannot.
Originally Posted by Naty1
there are few if any 'particles' within a black hole.
Except for recent infalls, all are destroyed at the singularity.
Really? Check out http://www.theregister.co.uk/2010/11..._lead_results/ [Broken]
Originally Posted by Naty1
Hawking radiation is formed outside the horizon; Perhaps you mean infalling particles with negative energy combine with recent particles of positive energy...even that doesn't seem
likely ...how would one catch up with the other, or slow down, to affect annihilation...?
Incoming particles would collide with the quark-gluon plasma
Originally Posted by Naty1
The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and eliminate its coordinate singularity. This work influenced the decisions of Roger Penrose and John Archibald Wheeler to accept the physical existence of event horizons and black holes.
But what does it mean??
That answer would probably be speculative.
Originally Posted by Drakkith
Universe21, spacetime most certainly exists everywhere in the universe. And we don't know that gravity DOESN'T have a force carrier, we simply haven't been able to find one yet.
looks like whatever force carrier gravity has would be the same as that for light if they both propagate at the same speed.
Sorry page not found. Try http://www.physorg.com/news/2010-11-physicists-black-hole-plasma-lab.htmlNaty1 said:Where does that reference say ANYTHING about plasmas within black holes?
Lots of sources on google but I'm not sure about peer review. Sorry.Naty1 said:Please provide a peer reviewed source that discusses plasnmas within a black hole.
ynot1 said:looks like whatever force carrier gravity has would be the same as that for light if they both propagate at the same speed.
I'd say there is a difference. Gravitons would have infinite wavelength.Naty1 said:ynot
Looks like WHAT? You mean that the quanta of the gravitational force and electromagnetic force are identical?)
No, there are 4 gauge bosons. Since gravitons and photons both travel at the speed of light, I'd say a graviton would be a special form of a photon.Naty1 said:Are you implying that all massless particles are identical??
Seems silly if there is none.Naty1 said:If so, please provide a peer reviewed source. (PS: there is none)
The same would be true for an observer a finite distance away from the event horizon (i.e. not in an 'ideal' position).Naty1 said:This has been discussed before and I am not positive, but what I concluded from conflicting posts is that such an 'infinite' time is an 'ideal' perspective from infinity in flat spacetime...in our real universe, such a frame does not exist...so dilation IS extended but not infinite.
If it were, how could we observe ANY black hole??
Gravitons would not have infinite wavelength; and they are not a special form of photon (for example, photons are spin 1, where-as gravitons would need-be spin 2). Avoid overly speculative posts in accordance with the PF guidelines.ynot1 said:I'd say there is a difference. Gravitons would have infinite wavelength.
No, there are 4 gauge bosons. Since gravitons and photons both travel at the speed of light, I'd say a graviton would be a special form of a photon.
Naty1 said:Originally Posted by Naty1
The simplest kink exhibited an easily understood event horizon that led him to recognize the one in the Schwarzschild metric and eliminate its coordinate singularity. This work influenced the decisions of Roger Penrose and John Archibald Wheeler to accept the physical existence of event horizons and black holes.
But what does it mean??
ynot1 said:That answer would probably be speculative.
I notice you included your question inside of your quote. I was referring to the meaning, not the work. Sorry for the misunderstanding.Naty1 said:ynot
So you consider Finkelstein's work and subsequent years of acceptance by physicsts
'speculative'?...Can you provide a peer reviewed source
drawing such a radical conclusion.
So would a graviton have a wavelength? Or would that just be speculation.zhermes said:Gravitons would not have infinite wavelength; and they are not a special form of photon (for example, photons are spin 1, where-as gravitons would need-be spin 2). Avoid overly speculative posts in accordance with the PF guidelines.
ynot1 said:So would a graviton have a wavelength? Or would that just be speculation.
zhermes said:Gravitons would not have infinite wavelength; and they are not a special form of photon (for example, photons are spin 1, where-as gravitons would need-be spin 2). Avoid overly speculative posts in accordance with the PF guidelines.
I don't think a graviton has a finite wavelength, I was referring to the quote about gravitons would not have an infinite wavelenth. So I I'm wondering how you might go about finding the wavelength of a graviton, if there is such a thing. I'd think if there was a way we would have found one by now.Drakkith said:I'm assuming you are referring to the fact that a photon is an EM wave and has a particular wavelength, and comparing a graviton to it? I am unsure about whether or not a graviton is a gravitational wave like how a photon is an EM wave.
ynot1 said:I don't think a graviton has a finite wavelength, I was referring to the quote about gravitons would not have an infinite wavelenth. So I I'm wondering how you might go about finding the wavelength of a graviton, if there is such a thing. I'd think if there was a way we would have found one by now.
So I'm wondering how you might go about finding the wavelength of a graviton, if there is such a thing. I'd think if there was a way we would have found one by now.
Unambiguous detection of individual gravitons, though not prohibited by any fundamental law, is impossible with any physically reasonable detector.[12] The reason is the extremely low cross section for the interaction of gravitons with matter. ...
However, experiments to detect gravitational waves, which may be viewed as coherent states of many gravitons, are underway (e.g., LIGO and VIRGO). Although these experiments cannot detect individual gravitons, they might provide information about certain properties of the graviton...
I am unsure about whether or not a graviton is a gravitational wave like how a photon is an EM wave.
Gravitons and renormalization
When describing graviton interactions, the classical theory (i.e., the tree diagrams) and semiclassical corrections (one-loop diagrams) behave normally, but Feynman diagrams with two (or more) loops lead to ultraviolet divergences; that is, infinite results that cannot be removed because the quantized general relativity is not renormalizable, unlike quantum electrodynamics. That is, the usual ways physicists calculate the probability that a particle will emit or absorb a graviton give nonsensical answers and the theory loses its predictive power. These problems, together with some conceptual puzzles, led many physicists to believe that a theory more complete than just general relativity must regulate the behavior near the Planck scale.
Presumably a graviton would have a wavelength just like a photon does. It would be more appropriate to talk about the wavelength of the gravitational wave, and the energy of the graviton.ynot1 said:So would a graviton have a wavelength? Or would that just be speculation.
Phyzguy:
We really use the word photon to describe two things. On the one hand, we refer to a photon as being an elementary excitation of the EM field, which has a definite: energy, wavelength, and frequency. These photons are the eigenstates of the EM field, and extend to +/- infinity.
On the other hand, we also use the word photon to refer to the wave packet emitted by an atom when it drops from one energy level to another. But this latter photon is not an energy eigenstate. It does not have a definite frequency, because the atom is not in the upper and lower energy states for an infinite time, so there is a time uncertainty which leads to an energy uncertainty. So the wave packet contains a range of frequencies, and multiple measurements of its energy would lead to a distribution of probable values. Because there is a range of frequencies and wavelengths, the wave packet is also bounded in space and time. The "size" of the wave packet (let's say the duration in time) depends on how long the atom is undisturbed. If the atom is in a very undisturbed environment, with a long time between collisions, then the wave packet is very sharp, with a long duration (Delta-t), and a small distribution of energies (Delta-E). If the atom is in an environment where collisions are frequent, then the wave packet is more spread out, with a short duration (Delta-t), and a broad distribution of energies (Delta-E).
Originally Posted by Naty1
Where does that reference say ANYTHING about plasmas within black holes?
Sorry page not found. Try http://www.physorg.com/news/2010-11-...lasma-lab.html [Broken]
Interesting. So plasmas are created outside the event horizon.Naty1 said:What the described experiments are doing is reproducing the high energies [used to create plasmas] OUTSIDE black holes as matter is accelerated towards the horizon of a black hole.]
So black holes would never evaporate. I see.Naty1 said:[Any jets of matter and radiation 'emitted' from a black hole are accelerated out from the external accretion disk, not the interior of the black hole.]
I recall something about the frequency of the gravitational radiation from a binary star would be twice its rotational frequency. So I guess we could go from there to calculate its wavelength.zhermes said:Presumably a graviton would have a wavelength just like a photon does. It would be more appropriate to talk about the wavelength of the gravitational wave, and the energy of the graviton.
ynot1 said:Except for Hawing radiation I don't believe gravity does escape from a black hole. Note if too much gravity escapes the black hole it seems it wouldn't be a black hole anymore.
Particles are created outside of the event horizon. Not necessarily plasmas---which do often exist outside black-holes.ynot1 said:Interesting. So plasmas are created outside the event horizon.So black holes would never evaporate. I see.
That is exactly correct.ynot1 said:I recall something about the frequency of the gravitational radiation from a binary star would be twice its rotational frequency. So I guess we could go from there to calculate its wavelength.
Light and gravity travel at the same speed because they are both governed by the same fundamental force of nature, known as the speed of light, or c. This speed is a fundamental constant and is the maximum speed at which any form of energy or information can travel through space.
The speed of light, c, was first measured by the Danish astronomer Ole Rømer in the late 17th century. Later, in the early 20th century, Albert Einstein's theory of general relativity predicted that the speed of gravity would also be equal to the speed of light. This has been confirmed through numerous experiments and observations.
The fact that light and gravity travel at the same speed is crucial for understanding the fabric of our universe and how it functions. It also helps us to accurately measure distances and make predictions about the behavior of objects in space.
No, light and gravity are not the same thing. Light is a form of electromagnetic radiation, while gravity is a fundamental force of nature. The fact that they travel at the same speed is a result of their interactions with the fabric of space-time.
It is possible that there could be other forces or particles that travel at the speed of light, but currently, there is no evidence to support this. The speed of light is a fundamental constant and any new discoveries would need to be consistent with this speed.