This should be a good topic considering Hawking's impending presentation. My basic question is this: Do the event horizons of Black Holes or their gravitational pulls come in different sizes and intensities? If all EM signals can not escape the event horizon of a back hole, but gravity "signals" do (whether that's the propogation of deformation of the time-space continuum, or if its a graviton), what does that say regarding the relation of gravity waves to EM waves (faster, more energy, just not affected by a nevent horizon <most likely>)?
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Re: Black Holes
Mon, February 28, 2005 - 8:04 PMNow this is a trick question. Classically, yes, event horizons come in different diameters, but with the same intensity. But because the event horizon is, by definition, the point where space is stretched infinitely and time slows to a stop, then it doesn't make a difference how big the event horizon is, I think. Hopefully somebody can work this out. Anyway, EM waves are not related to gravity except by how they interact. It's becoming more and more clear that the graviton is a fiction and gravity really is a warping of space-time caused by the existence of mass. -
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Re: Black Holes
Tue, March 8, 2005 - 8:46 PMI am an interested lay person in all this but...do new ideas in quantum geometry, ie a finite quanta of space/time complicate the idea of an event horizon? What happens to these proposed quanta of distance at this point? An if time and light stop at the horizon are there problems with the uncertainty principle? Are these photon's motion and location too described? As to the realitive strengths of event horizions they must seem, as you say, to all the same, fixed by definition and separation from observation. But inside, could there be a bundle of massive quarks with just a little less mass than necessary to further collapse into a "true" singularity or are some neutron stars really quark stars. Help? Time magazine said Brian Greene's new book is in paperback. -
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Re: Black Holes
Mon, March 21, 2005 - 11:39 PMYou bring up some good points.... Now I'm by no means no expert, but my gut tells me that since time slows to a stop at the event horizon, then just outside of it, yes, time would pass in ticks instead of seeming continuous, assuming time is quantized (I believe it must be). This might bring up some interesting phenomena. I don't think quantization of distance would be a factor since event horizons are huge and distance is stretched so far anyway. I don't think there would be any change in the uncertainty principle but it would still apply to any measurements being taken. -
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Re: Black Holes
Tue, March 22, 2005 - 7:34 AMNo expert here, either. But I have a problem with time being quantized. Time is an integral part of the geometry of space. Therefore, if time is quantized, then space itself must be also. I just can't see the geometry of space broken up into quantum.
Unless there is another weird wave/particle paradox working here, too. -
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Re: Black Holes
Sun, November 5, 2006 - 1:09 PMThere is no wave/particle paradox. This is a pet peeve of mine. People try to explain properties of quantum mechanical objects by making analogies to things we are familiar with through our own experience. This just ends up confusing people. Quantum objects behave the way the math says they do, which is like nothing you have ever seen. Quantum objects aren't "sometimes a particle, sometimes a wave". If you try to think of QM this way and use your intuition, it will lead you astray.
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Re: Black Holes
Sun, November 5, 2006 - 1:23 PMTime doesn't stop for an observer falling into the black hole. If you perform an experiment with sufficiently small spacetime dimensions, it should behave as if you did it in flat space (classically, anyway). I'm not sure what happens with Hawking radiation (the idea that one of a matched pair of "virtual" particles gets trapped by the hole, and the other pops into existance outside the event horizon).
I much more interested in the implications of quantized spacetime at the singularity of a black hole.
I'm not understanding your question about quarks and neutron stars. If there isn't enough mass, there is no event horizon. No event horizon means the forces between particles stop the collapse.
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Re: Black Holes
Sun, November 5, 2006 - 12:59 PM"space is stretched infinitely and time slows to a stop"
That's not actually true at the event horizon. It's sort of true at the singluarity at the middle of a black hole. For an object falling into the black hole, time moves merrily along like nothing's going on. For an observer at a distance, the object appears to take forever to pass the event horizon. Perhaps that's what you were thinking of? And no, it doesn't matter how big the event horizon is.
What is your basis for saying it's more and more clear that the graviton is a fiction?
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Re: Black Holes
Sun, November 5, 2006 - 12:52 PMI've never seen a solution for gravity waves propagating within a black hole, but I doubt they can escape, for a couple of reasons. First, gravity waves have energy density, so, like anything else, they are affected by gravity. Second, gravity waves follow geodesics just like everything else. One way to think of the event horizon is that spacetime is so warped that the only paths through it for objects traveling less than or at the speed of light is in toward the black hole.
Did you have some source that suggested gravity waves could escape? If so, I'd like to see it. -
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Re: Black Holes
Tue, June 12, 2007 - 8:26 PMThe reason I think time might be quantized is because the Heisenberg Uncertainty Principle contains a temporal component. Same thing with space. After all, there appears to be a quantum foam, which suggests that space might be quantized, why not a temporal foam? -
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Re: Quantizied Space and Time
Tue, June 19, 2007 - 9:19 PMIf you could keep subdividing time, then there would be an infinite amount of smaller units of it between any two moments. How could you ever get anywhere. The same would apply to space. If you could keep subdividing space, then there would be an infinite amount of smaller units of it between any two points.
Space and time need to be quantizied for our universe to make sence. -
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Re: Quantizied Space and Time
Wed, June 20, 2007 - 12:04 AMNot so. You're basically reformulating a version of one of Zeno's paradoxes. The fallacy is that an infinite sum can't have a finite value, which is not the case. This is not to say that space and time aren't quantized, just that the infinite subdivision argument does not prove they are. -
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Re: Quantizied Space and Time
Wed, June 20, 2007 - 8:42 AMYou are right.(as you tend to be) It is not a proof. In mathamatics a infinite sum can have a finite value.
I am in the group that believes space and time are quantized. I am in the much smaller group that believes infinity does not exist in the real world of our universe. All is quantized and finite. I know that these are beliefs without proof, yet.
I feel that quantum theory (everything in our universe is quantized and not continuous) may be our greatest discovery of all time. While not proven true, we have not found any exceptions (read as lots of evidence in support) or any evidence that it may not be true. I am hopeful that we will someday find the quantum units of space and time. -
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Re: Quantizied Space and Time
Thu, July 26, 2007 - 6:35 PMit's likely curry that 'proof' of the quantized nature of space and time are beyond our grasp since any quantizisation would imply limits on components withinthesystem... i'e human cognative abilities.
If our universe is quantized then soare we...... It's a 'belief'' I similarly share and wouldeven be so bold as to claim that the limit of this quantizisation is 43 ordersof magnitude;hence the smallest mesurabletimeframe is10-43 seconds and smallest known length is the quark (10-17m)... 43 orders of magnitude smaller than the largest unit, theuniverse at 10-25m.
I've been terming this as 'the limit of fracture'
if I'm correct then your assumption that the higgs bosson doesnot exist is alsocorrect.
similarly it is possible to provide a mathematical 'proof' of this limit but unfortunately not in the context of a message board.
regards
GM23
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Re: Black Holes
Wed, July 25, 2007 - 9:43 PMThere are only three values needed to describe any black hole - charge, spin, mass. The event horizon, or the radius of the black hole only depends on the mass of the black hole. Once you cross this radius, nothing can escape, not even light. On the inside of the event horizon, all black holes are the same - a singularity with infinite density and zero size (as far as we know). On the outside, you just have the normal gravitational field from an object with mass. The larger the mass of the black hole, the stronger the gravitational field - the force of gravity drops off as the usual 1/r^2. As for gravity waves and EM waves, well there is not a clear theory just yet, but gravity deforms space-time, where as light just travels through spacetime - they are fundamentally different. -
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Re: Black Holes
Thu, July 26, 2007 - 9:08 AMMy personal view would be:
"a singularity with infinite density and zero size (as far as we know)"
Here you have infinity being created when you divide by zero. I have thought that this is not allowed or likely to be real.
I find it unlikely that a singularity could have a size of zero. Without some unit of space how could it be part of our universe. With all that gravity, it is clearly part of our universe. Some quantum unit of space would be required, even if it was only one.
I would agree that black holes show gravity and light as very different from each other.
I am looking forward to CERN and maybe finding the higgs particle. It may give clues to gravity and how it is related to mass.
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Re: Black Holes
Thu, July 26, 2007 - 6:53 PMMy personal view would be:
"a singularity with infinite density and zero size (as far as we know)"
Here you have infinity being created when you divide by zero. I have thought that this is not allowed or likely to be real.
I find it unlikely that a singularity could have a size of zero. Without some unit of space how could it be part of our universe.
you above statement would be true if space actually requires space... but it may not
similarly the singularitydoesn't need to have much mass; just the 'impression' of mass in order to have an infinite density.
in order to generate 'virtual space' it doesn't need 'real space' just three numbers, 0-, 0, 0+. whilst I hate such analogies the space in which we are currently communicating (cyber) doesn't actually exist in 'real space' and just as the cyber world is a product of mathematics so may also be our universe........only this cyber world uses only 0 and 0+.......
regards
gm23
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Re: Black Holes
Sun, July 29, 2007 - 12:40 PM"I find it unlikely that a singularity could have a size of zero."
I don't think I've ever seen anyone claim that they knew what was really going on at the center of a black hole in the mainstream literature. Pretty much all you hear is that the laws of physics as we know them must break down. Know one I know has volunteered to go in to a black hole and check things out. ;) -
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Re: Black Holes
Mon, July 30, 2007 - 10:19 AMI know I am hanging by a thread here. I base my personal opinon, not on visits to any black holes, but on the idea that you are either in this universe or not.. With all that gravity black holes contain a lot of mass and are in our universe. I know that the math and physics can not get you there but it is just as valid for a singularity to have space as not. Could a singularity really have no space or time and still be part of our universe. Maybe, but I think it unlikely. If I get the chance to go, I'll let you know, though evidence would say that I'll never get back. -
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Re: Black Holes
Mon, July 30, 2007 - 11:53 AMI think the way to think about it is that the singularities that arise out of General Relativity are in the realm where the situation is so extreme we can be confident that straight GR no longer applies. They show up in the current best model (GR), but in cases where the model probably isn't appropriate.
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