Posted: 9/5/2011 3:53:36 AM EDT
| If there are such things as gravity waves, they are emitted from inside the event horizon of a black hole and they affect things outside of the event horizon. Does this mean that they can exceed the speed of light? |
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I do not know what is the propagation rate of gravity, but if it has one, then it leads to an interesting contradiction. Let's say that a gravity wave moves at 350,000 m/s.
As a black hole increases its mass, it increases the deflection of light waves around it. The event horizon gets bigger. What is inside the event horizon gains mass from the things taken into the hole. We understand this based on the theories. The event horizon expands as the mass increases. In theory, more mass means greater acceleration due to gravity. Eventually, the hole has enough mass to cause a gravitational acceleration equal to itself. If the acceleration becomes equal to the speed that the gravity wave propagates, the gravity wave can no longer propagate. There would be no Hawking Radiation. What happens to the black hole? It can no longer affect the world around it. There could be no more event horizon because the gravity can't escape the hole to bend light waves. The only way you would know that it was there would be if you ran directly into it. But it is a singularity; a point that does not really exist in a three or four dimensional map of the universe. It has no dimensions. You can't run into it. It isn't there. Where did it go? |
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What's the speed of light got to do with anything? Light is EM radiation. Gravity is, well NOT. Just what is the propagation rate of gravity, anyway? I saw some documentary that said Einstein (I think) calculated that gravity propagated at the speed of light, but I think the point of the entire movie was that he was wrong and gravity wasn't really a wave. Either way, gravity doesn't seem to act on gravity just like electromagnetic radiation doesn't act on electromagnetic radiation. They can add or subtract to each other when they intersect, however. |
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The simplest answer is, "We have no idea." There's a program called Einstein at Home that's currently searching for gravity waves by processing data from a number of sources. To date we haven't found anything. I am familiar with the lack of evidence for gravity waves. The concept has always bothered me. It violates Newton's third law. If this is possible, it also means there is a way to violate the conservation of energy. |
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From your link: The black hole event horizon is where normal matter (and forces) must exceed the speed of light in order to escape, and thus are trapped. The horizon is meaningless to a virtual particle with enough speed. This interpretation says that the gravity particles have a speed. If they have a speed, then there should be a gravitational attraction sufficient to overcome that speed. It indirectly addresses a question I've considered for several years, in my unique and amateurish fashion. If the universe is expanding, it may expand at more than the speed of light or less than the speed of light. We can not tell the difference because if space expands faster than light, we will never see the light from the edge of the universe. This is implied by the fact that the farther away an object is, the faster it seems to be receding. It is possible that part of the universe expands faster than light, and therefore we will never see it. But all of that implies that something controls the speed of the expansion. It is not infinite. Now I return to classical physics, specifically aerodynamics. Four forces act on an airplane. They are gravity and lift, thrust and drag. If the lift is insufficient to overcome gravity, the plane stays on the ground. In an imaginary world with air and no gravity, the plane goes up and down according to which way the wind blows. Likewise, the plane accelerates until the thrust of the engine is equal to the aerodynamic drag. In an imaginary world where you can create lift with no drag, the plane would accelerate until the engine stopped. The model of thrust and drag seems an apt comparison to the model of a universe that manifested itself from a single point in absolutely nothing. The universe expands. What controls the expansion? When the big bang happened, something made the universe expand at a rate that we can observe and measure. What is that thing? We believe there to be three fundamental forces that control the universe. This is horseshit, frankly, because it ignores time, but that's a subject for another thread. Meanwhile, the singularity that existed before the big bang must have had one hell of a gravitational field. The energy of the field became too much for the field to contain and it overcame the energy of the singularity, coalescing into matter, space, and forms of energy that we can perceive. Theoretical models fail at that point, which makes me wonder if gravitation played a role in controlling the expansion of the universe. If so, then it still does. It also affects time and it overpowers light. It may be the æther in a non-classical sense. |
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The simplest answer is, "We have no idea." There's a program called Einstein at Home that's currently searching for gravity waves by processing data from a number of sources. To date we haven't found anything. I am familiar with the lack of evidence for gravity waves. The concept has always bothered me. It violates Newton's third law. If this is possible, it also means there is a way to violate the conservation of energy. I'm in the camp that most laws are theories (referencing Newton's 3rd). Einstein @ Home is testing the thought that gravity waves do exist, however they've got nada so far. I do believe they've discovered 9 pulsars and 1 new black hole so far though. It'll be interesting to follow the project over the next few years to see if we find anything. Gravity waves shouldn't exist...but they might. That's exciting to me. |
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Now, gravitational "lensing" has been proven, correct? Why not gravity waves? Is this not the same or similar mechanism? Forgive my ignorance. Lensing appears around various objects. The trouble with gravity is that no one understands how it gets from one place to another. The obvious problem with a gravity wave is that it would not work according to Newton's third law of motion - for every action there is an equal and opposite reaction. If the sun sends out a gravity wave, it should recoil. The thing the wave hits should be pushed away. This does not happen, so gravity does not work in the classical sense. That article says that gravity waves propagate at the speed of light. If that's the case, how do they escape their own effect around a black hole? They think it works by quantum mechanics, but they can't make gravity fit into a theory that explains all the other stuff - quarks, photons, etc. They've been trying to detect a gravity wave for several years and the studies have not found any evidence. The lack of evidence may be an important clue, but the theory shows that a gravity wave would be extremely hard to detect. They may exist and we can't detect them with current technology. |
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Now, gravitational "lensing" has been proven, correct? Why not gravity waves? Is this not the same or similar mechanism? Forgive my ignorance. Lensing appears around various objects. The trouble with gravity is that no one understands how it gets from one place to another. The obvious problem with a gravity wave is that it would not work according to Newton's third law of motion - for every action there is an equal and opposite reaction. If the sun sends out a gravity wave, it should recoil. The thing the wave hits should be pushed away. This does not happen, so gravity does not work in the classical sense. That article says that gravity waves propagate at the speed of light. If that's the case, how do they escape their own effect around a black hole? They think it works by quantum mechanics, but they can't make gravity fit into a theory that explains all the other stuff - quarks, photons, etc. They've been trying to detect a gravity wave for several years and the studies have not found any evidence. The lack of evidence may be an important clue, but the theory shows that a gravity wave would be extremely hard to detect. They may exist and we can't detect them with current technology. Ok, which makes sense because it is the weak force. |
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If there are such things as gravity waves
Folks have been searching a long time and have yet to find one. They have been searching for a magnetic monopole also, with the same negative results. It does not mean they may not exist, but we have yet to find any effect that requires either. |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... That sounds kind of repulsive. |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... The field from the individual magnets still has curl and forms a closed loop. A monopole is just that, a single pole. Assuming it exists simplifies some things in antennas, like slot antenna design. That does not mean it exists, just that the expressions for the electric and magnetic fields for a slot become a pair similar to a dipole. |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... The field from the individual magnets still has curl and forms a closed loop. A monopole is just that, a single pole. Assuming it exists simplifies some things in antennas, like slot antenna design. That does not mean it exists, just that the expressions for the electric and magnetic fields for a slot become a pair similar to a dipole. So would the magnet ball have a "charge" or not? |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... The field from the individual magnets still has curl and forms a closed loop. A monopole is just that, a single pole. Assuming it exists simplifies some things in antennas, like slot antenna design. That does not mean it exists, just that the expressions for the electric and magnetic fields for a slot become a pair similar to a dipole. Magnetic monopoles exist. |
| Id say yes, If gravity works in the m or brain theory fashion. It is not a force tied to our "relative" time and space, it bounces in and out. I have not heard a theory of gravity that I like better,YET. Going by what we know as "fact" now, I Would say no. The problem is the laws of physics (on paper) breakdown in a black hole so its hard to say what really happens. |
Now that we have particles faster than the speed of light, why not gravity? 
Anyway, the last time I studied this in any depth (~3 years ago) we always assumed an object's gravitational force propagated at the speed of light. However, this rarely had any measurable outcome of situations because gravity is so (relatively) weak, the distances were huge, and the relative velocities made the change is gravity's vector essentially zero. At the subatomic level it's hard to really apply gravity universally because they still can't find the Higgs. 
That being said, I remember reading an article about using gravity "waves" to communicate, but that it would require an ability to oscillate massive amounts of mass much faster than practical. You're better off using that energy for "standard" EM communication. |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... The field from the individual magnets still has curl and forms a closed loop. A monopole is just that, a single pole. Assuming it exists simplifies some things in antennas, like slot antenna design. That does not mean it exists, just that the expressions for the electric and magnetic fields for a slot become a pair similar to a dipole. Magnetic monopoles exist. 'String theory' is useless since no predictions can be made based on it, and it cannot be proven to even exist. |
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They have been searching for a magnetic monopole also, with the same negative results. Since you mentioned it: What happens if you take a bunch of magnets (the rectangular kind) and glue them all in a sphere so that the south poles are all facing towards the center? Intuitively I would say you have a north-charged sphere, but I imagine someone has tried this already and it was not the case... The field from the individual magnets still has curl and forms a closed loop. A monopole is just that, a single pole. Assuming it exists simplifies some things in antennas, like slot antenna design. That does not mean it exists, just that the expressions for the electric and magnetic fields for a slot become a pair similar to a dipole. Magnetic monopoles exist. 'String theory' is useless since no predictions can be made based on it, and it cannot be proven to even exist. That statement has no bearing on the the article. Dirac strings =/= string theory strings. |