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Demonstrated FTL communication?
by
francesco nicoli
on 30 Dec, 2019 21:43
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For physicists among us: I am not sure i understand correctly, but does this paper just published on Nature Physics amounts to the first practical appliccation of FTL information transmission? It seems so, since entanglement should be unaffected by space and being instantaneous. If so, implications for space are huge...
https://www.bristol.ac.uk/news/2019/december/quantum-teleportation.html
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#1
by
meberbs
on 30 Dec, 2019 22:08
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No, quantum teleportation is not regular teleportation. The no-communication theorem proves that the apparently FTL quantum behavior can never, ever, allow FTL communication or transport. Any information or energy that is transmitted in such experiments transfers at most at light speed over a generally classical channel.
https://xkcd.com/465/
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#2
by
francesco nicoli
on 30 Dec, 2019 23:36
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Thanks! But then which regular channel is used in the article?
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#3
by
Mark K
on 30 Dec, 2019 23:46
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Thanks! But then which regular channel is used in the article?
Photons. They are entangling multiple photons at a source and measuring their states elsewhere. What is getting "teleported" is the entangled quantum state. That is, the probabilities of certain measurements will be exactly the same when done on these separated photons. But nothing went faster than the particles.
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#4
by
francesco nicoli
on 31 Dec, 2019 06:51
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Perfect, now is clearer. I would have a couple of more questions for my personal curiosity, if anyone is kind enough to provide a reply I will pm you
😊
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#5
by
edzieba
on 31 Dec, 2019 06:51
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To greatly simplify: An entangled photon pair will - when measured - have 'opposite' states. e.g. if you have two entangled photons, and you measure 'yours' to be 'up', then you will know that the other photon, whereever in the universe it is (e.g. several light-years away) will be 'down'. The problem is that you have no way to influence the result of your measurement: whether you measure 'your' photon as 'up' or 'down' is random and out of your control. You gain some instant knowledge of what the state of the other photon is, but no way to use that knowledge without transmitting some other data to the other photon, which then has to travel at the speed of light (negating any utility of your 'FTL' link).
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#6
by
francesco nicoli
on 31 Dec, 2019 07:57
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Perfect. But the fact that there has been an observation is information in its own, it seems to me?
Ipotyhesize you entangle two pairs of particles and you send two entangled "ends" to an arbitrarily far distance. Now if i understand you correctly, can't transmit information through two entangled particles themselves. But does "observing" an entangled particle produce any effect (no matter what, even if its content is ubdetermined) that is distinguishable from the state of an unobserved but still entangled particle? If so, it seems to me you could build a binary system that instantaneous? In our example, imagine these two entangled particles are sent away. Imagine that a convention was agreed beforehand that "observing" particle 1 would correspond to a 0, while "observing" particle 2 would correspond to a 1. If "the other side" can assess whether a specific particle has been observed (regardless of the results of the observation) and others have not, wouldn't that be a basis for a (one use) communication system?
(note: I am a professor of economoics not a physicist. This question kept me awake all night, which I spent reading, but obviously I stand to be corrected a million times...)
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#7
by
meberbs
on 31 Dec, 2019 08:23
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Perfect. But the fact that there has been an observation is information in its own, it seems to me?
Ipotyhesize you entangle two pairs of particles and you send two entangled "ends" to an arbitrarily far distance. Now if i understand you correctly, can't transmit information through two entangled particles themselves. But does "observing" an entangled particle produce any effect (no matter what, even if its content is ubdetermined) that is distinguishable from the state of an unobserved but still entangled particle?
The answer, like many things in quantum is both yes and no at the same time. Yes, there is something that happens when you measure one particle that changes something about the other particle in an FTL fashion (This is what tests of Bell's inequality show). No, this does not transmit any information whatsoever, and as I stated before, nothing you come up with, no matter how convoluted can bypass the no-communication theorem.
If so, it seems to me you could build a binary system that instantaneous? In our example, imagine these two entangled particles are sent away. Imagine that a convention was agreed beforehand that "observing" particle 1 would correspond to a 0, while "observing" particle 2 would correspond to a 1. If "the other side" can assess whether a specific particle has been observed (regardless of the results of the observation) and others have not, wouldn't that be a basis for a (one use) communication system?
See my previous statement that you can never, ever use quantum as the basis for such a system, and then stop losing sleep wondering if such a thing might be possible. Scientists much smarter than me have proven it to be impossible in the general case. On either end, all they would get is a bunch of random numbers that are indistinguishable from whether an observation had taken place on the other end or not. The "effect" of the measurement only shows up in the data when you look at the 2 sets of measurements side by side. That requires classical communication to bring those 2 data sets together, at which point the classical channel bringing the data sets together could just transmit the information you want. There is absolutely no way to tell whether a measurement was done on the other end using the data from just one side.
Quantum has myriad uses, it has applications for both new forms of scamgraphy, breaking some old forms, and solving some hard problems, but none of the uses are the magic teleportation and FTL that people think of when they see headlines without understanding the terminology. Quantum does not behave in the same way as anything people are used to, you have to throw out most of your intuition to understand it, and it takes a fairly in depth course on quantum mechanics to cover everything you would need to follow a correct explanation of what happens in situations like what the original linked article mentions.
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#8
by
edzieba
on 31 Dec, 2019 09:24
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But does "observing" an entangled particle produce any effect (no matter what, even if its content is ubdetermined) that is distinguishable from the state of an unobserved but still entangled particle
No.
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#9
by
RotoSequence
on 31 Dec, 2019 09:42
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But does "observing" an entangled particle produce any effect (no matter what, even if its content is ubdetermined) that is distinguishable from the state of an unobserved but still entangled particle
No.
Entanglement is invisible unless you have full knowledge of the entangled system, and that information has to be communicated classically.
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#10
by
francesco nicoli
on 31 Dec, 2019 14:36
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Okay, all clear! Thanks everyone for the time spent in explain things to a noob like me
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#11
by
aero
on 01 Jan, 2020 01:24
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So the question becomes, "Is entanglement repeatable?" If so, the details need only be communicated once classically and used forever after.
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#12
by
RonM
on 01 Jan, 2020 14:29
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So the question becomes, "Is entanglement repeatable?" If so, the details need only be communicated once classically and used forever after.
No, once a measurement is made the entanglement is broken.
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#13
by
freda
on 01 Jan, 2020 16:06
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I truly am no expert, but would like to ask if this is related in any way to the “glove” scenario (remembered from a physics book I read long ago). I bought a pair of gloves, sent one glove to Barbara and one glove to Sally. Barbara opened her box first, and saw a left-handed glove. Immediately, Sally’s glove in the other box must have turned into a right-handed glove. The observer says “Wow, how do we explain this? Did a FTL entanglement connect the two boxes? How did Sally’s glove know the state of Barbara’s glove, and know to become the opposite?” I apologize; I am sure I simplify and trivialize the whole aspect by that scenario, but sometimes it does pop into my mind.
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#14
by
edzieba
on 01 Jan, 2020 17:15
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I truly am no expert, but would like to ask if this is related in any way to the “glove” scenario (remembered from a physics book I read long ago). I bought a pair of gloves, sent one glove to Barbara and one glove to Sally. Barbara opened her box first, and saw a left-handed glove. Immediately, Sally’s glove in the other box must have turned into a right-handed glove. The observer says “Wow, how do we explain this? Did a FTL entanglement connect the two boxes? How did Sally’s glove know the state of Barbara’s glove, and know to become the opposite?” I apologize; I am sure I simplify and trivialize the whole aspect by that scenario, but sometimes it does pop into my mind.
To simplify, this comes down to the "Copenhagen" vs. "Many Worlds" interpretations of Quantum effects.
Under Copenhagen, the contents of the two boxes were simultaneously both left and right gloves ('superposition') for the entire time up until you measured the contents of one box, at which point the wave-function collapses and one box contains the left glove and the other the right glove. Under Many Worlds, on measuring one box the contents of the other box is the opposite, and both were always that value all along. At the point where the two boxes were 'entangled' and separated two universes were created, and when you measured a box that confirmed which of the two universes you are actually in.
From what I recall (not being a physicist) evidence points to Copenhagen being the correct interpretation as far as experimental results go, as it is possible to non-destructively measure some portions of a quantum state without affecting others (and no, this is delicate and does not enable FTL, it only works by very carefully designing the experiment such that you gain absolutely no information whatsoever about the property you are not measuring).
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#15
by
meberbs
on 01 Jan, 2020 21:11
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I truly am no expert, but would like to ask if this is related in any way to the “glove” scenario (remembered from a physics book I read long ago). I bought a pair of gloves, sent one glove to Barbara and one glove to Sally. Barbara opened her box first, and saw a left-handed glove. Immediately, Sally’s glove in the other box must have turned into a right-handed glove. The observer says “Wow, how do we explain this? Did a FTL entanglement connect the two boxes? How did Sally’s glove know the state of Barbara’s glove, and know to become the opposite?” I apologize; I am sure I simplify and trivialize the whole aspect by that scenario, but sometimes it does pop into my mind.
To simplify, this comes down to the "Copenhagen" vs. "Many Worlds" interpretations of Quantum effects.
Under Copenhagen, the contents of the two boxes were simultaneously both left and right gloves ('superposition') for the entire time up until you measured the contents of one box, at which point the wave-function collapses and one box contains the left glove and the other the right glove. Under Many Worlds, on measuring one box the contents of the other box is the opposite, and both were always that value all along. At the point where the two boxes were 'entangled' and separated two universes were created, and when you measured a box that confirmed which of the two universes you are actually in.
From what I recall (not being a physicist) evidence points to Copenhagen being the correct interpretation as far as experimental results go, as it is possible to non-destructively measure some portions of a quantum state without affecting others (and no, this is delicate and does not enable FTL, it only works by very carefully designing the experiment such that you gain absolutely no information whatsoever about the property you are not measuring).
You don't have the description not many worlds interpretation quite correct. What you described is a local hidden variable theory with the unnecessary addition of universe splitting. Local hidden variable theories have been disproven by experiment. As I understand what is usually meant by many worlds, the measureable results are experimentally indistinguishable from Copenhagen. The issue with your description is where you say the box always had the left handed glove. The splitting of the universe occurs upon measurement not upon entanglement. The specifics of the issue are subtle, and the gloves analogy simply fails to be sufficient to describe the Bell's inequality differences. The closest I can think of is that on one end the glove is turned 20% inside out before measurement, but that doesn't actually make sense of course, I don't actually know a good analogy, it is simply outside normal experience.
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#16
by
edzieba
on 02 Jan, 2020 11:18
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You're right, I was thinking of Hidden Variable.
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#17
by
JohnFornaro
on 14 Jan, 2020 14:36
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Perfect. But the fact that there has been an observation is information in its own, it seems to me?
Late to the party, but here's an analogy that might help. Paul Revere made his famous midnight ride on the basis of 'one if by land, two if by sea'; that is, one lantern or two lanterns in the church steeple would inform Revere of the direction of the British attack. Revere made a 'measurement" by counting the lanterns he saw. His compatriot in the church steeple deliberately lit one or two lanterns in order to convey information. The compatriot did not "measure" the number of lit lanterns, but rather lit the lanterns deliberately.
The difference between that scenario and your photon example, is that the measurement itself does not convey information even though the collapse of the wave function upon measurement gives the impression of causality.
A slightly different problem arises with the two gloves in two boxes analogy. Just because the sender didn't "measure" which glove, left or right, that he sent to Sally or Barbara, there is still but one glove in each box. The recipient's knowledge about the handedness of the glove in the box may be uncertain, but the content of the boxes is what it is and is not subject to change upon opening the box. If Sally or Barbara is to rely upon the handedness of the gloves either receives in order to start a course of purposeful action, say, marriage, the gloves need to be placed in the boxes with the intention of conveying information. Otherwise, it is just a coin flip.
The conveyance of useful information pre-supposes intention.
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#18
by
leovinus
on 14 Jan, 2020 16:20
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Slightly off-topic, but as the discussion above keeps mentioning the "measurement", you can find a recent, deeper discussion of quantum mechanics and the "measurement process" over here
in Section 2. I found insightful. YMMV.
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#19
by
meberbs
on 14 Jan, 2020 19:05
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Slightly off-topic, but as the discussion above keeps mentioning the "measurement", you can find a recent, deeper discussion of quantum mechanics and the "measurement process" over here in Section 2. I found insightful. YMMV.
Paper is not necessarily bad overall, but there are a couple issues that people should be aware of before basing opinions on it. Particularly in the pointed out section 2, it greatly oversimplifies the concept of a detector, ignoring that detectors are things that bridge a single quantum value to a macroscopic system. Contrary to what they claim, there is nothing that happens there in contradiction to the Schrodinger equation, they are just ignoring that the detector is made up of a large number of particles and does not have such a simple eigenstate (|Ψ1i + |Ψ2i)/√2 as something valid. Yes, this is an area of research for quantum because it is inherently extremely difficult to model such large systems in quantum.
The biggest problem in the paper in general is that they do not actually address one of there own points "But of course the point of seeking a theory from which to derive quantum mechanics is not to reproduce quantum mechanics, but to make predictions beyond that." They do not in fact make a single prediction beyond standard quantum, and their "experimental test" section mostly talks about difficulties coming up with a test, and simply suggests doing ever more careful experiments, but then says that if this doesn't yield anything new, it doesn't invalidate the theory because maybe different tests are needed. This is pretty much the definition of nonfalsifiable.
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#20
by
leovinus
on 14 Jan, 2020 21:36
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I believe we are in complete agreement on the importance of testable and falsifiable experiments for quantum mechanics. With respect to the paper, I believe the authors simply wanted to summarize their thoughts on a.o. the measurement problem, which is relevant here, and are well aware that someone else will have to come up with testable QM experiments which is probably for another thread.
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#21
by
JohnFornaro
on 15 Jan, 2020 12:09
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Slightly off-topic, but as the discussion above keeps mentioning the "measurement", you can find a recent, deeper discussion of quantum mechanics and the "measurement process" over here in Section 2. I found insightful. YMMV.
Thanks! Just now digging into this paper. First impression: Super-determinism is an argument for this universe being a simulation.
Bell, from the paper: "In this matter of causality it is a great inconvenience that the real world is given to us once only."
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#22
by
giulioprisco
on 04 Mar, 2020 07:38
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The quantum teleportation schemes devised so far rely on exchanging classical information via a secondary classical channel (slower than light). This doesn't rule out (imo) the possibility that quantum entanglement could be used for FTL messaging, but we are not there yet.
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#23
by
meberbs
on 04 Mar, 2020 14:24
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The quantum teleportation schemes devised so far rely on exchanging classical information via a secondary classical channel (slower than light). This doesn't rule out (imo) the possibility that quantum entanglement could be used for FTL messaging, but we are not there yet.
It is called the no- communication theorem, and it proves that if you want to transmit information, you need a classical channel. No FTL communication can be done in quantum, not now,and not ever, because it has been rigorously ruled out.
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#24
by
Bob Woods
on 05 Mar, 2020 07:48
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"... No FTL communication can be done in quantum, not now,and not ever, because it has been rigorously ruled out.
I think you need to proceed that statement with the qualifier of " Based on our current understanding of physics.."
This is, after all., the section for "NEW Physics for Space Technology."
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#25
by
RotoSequence
on 05 Mar, 2020 08:16
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"... No FTL communication can be done in quantum, not now,and not ever, because it has been rigorously ruled out.
I think you need to proceed that statement with the qualifier of " Based on our current understanding of physics.."
This is, after all., the section for "NEW Physics for Space Technology."
Since the universe has doggedly, persistently rebuffed our best efforts to communicate with entanglement - to the point that a photonic system will
communicate its state backwards in time just to prevent information from being transmitted, I wouldn't be getting my hopes up and using qualifiers like "yet."
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#26
by
meberbs
on 05 Mar, 2020 12:40
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"... No FTL communication can be done in quantum, not now,and not ever, because it has been rigorously ruled out.
I think you need to proceed that statement with the qualifier of " Based on our current understanding of physics.."
This is, after all., the section for "NEW Physics for Space Technology."
I do try to be careful with things like that, in this case I covered it by saying "in quantum" which is not new physics. Anything with FTL communication would no longer be quantum as we use the term today, since nothing in this thread actually includes a proposal of new physics this seems sufficient as a response.
As for the possibility of someone proposing new physics similar to this, see the post above this one, it is not a promising line of research.
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#27
by
giulioprisco
on 06 Mar, 2020 08:39
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The quantum teleportation schemes devised so far rely on exchanging classical information via a secondary classical channel (slower than light). This doesn't rule out (imo) the possibility that quantum entanglement could be used for FTL messaging, but we are not there yet.
It is called the no- communication theorem, and it proves that if you want to transmit information, you need a classical channel. No FTL communication can be done in quantum, not now,and not ever, because it has been rigorously ruled out.
According to many experts, you are right, but I prefer to be more open minded. Fundamental reality is non-local (this is not only a theoretical result of quantum physics but also a fact repeatedly confirmed in the lab), and perhaps we'll be able to exploit non-locality for communications. According to other experts, Lorentz invariance is not a feature of fundamental reality but an effective field feature manifested at the scales and energies that we have probed so far.
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#28
by
meberbs
on 06 Mar, 2020 16:14
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According to many experts, you are right, but I prefer to be more open minded.
As I said it is a theorem. Theorem means rigorous proof. You might as well be saying that you are "open-minded" about whether 2+2=4. It cannot be done in quantum, you would need something different and entirely new to get around the existing proof.
Fundamental reality is non-local (this is not only a theoretical result of quantum physics but also a fact repeatedly confirmed in the lab), and perhaps we'll be able to exploit non-locality for communications.
Nope, the experiments you seem to be referencing are Bell's inequality tests, which specifically exclude local hidden variables. This is more specific than saying it is "non-local" although that is one of the easier to understand remaining possibilities.
According to other experts, Lorentz invariance is not a feature of fundamental reality but an effective field feature manifested at the scales and energies that we have probed so far.
Yeah, time travel might just be possible, but if so, quantum mechanics as we know it does not allow it at any energy scale. GR theoretically does but so far only in impossible to create conditions. (You would need negative mass particles which are non-existent.)
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#29
by
Bob Woods
on 07 Mar, 2020 17:39
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Yeah, time travel might just be possible, but if so, quantum mechanics as we know it does not allow it at any energy scale. GR theoretically does but so far only in impossible to create conditions. (You would need negative mass particles which are non-existent.)
https://phys.org/news/2017-04-physicists-negative-mass.htmlNot sure if this experiment was refuted...
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#30
by
meberbs
on 07 Mar, 2020 18:00
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Yeah, time travel might just be possible, but if so, quantum mechanics as we know it does not allow it at any energy scale. GR theoretically does but so far only in impossible to create conditions. (You would need negative mass particles which are non-existent.)
https://phys.org/news/2017-04-physicists-negative-mass.html
Not sure if this experiment was refuted...
As usual, news articles about such things completely fail to capture the specifics. This has essentially nothing to do with the negative mass I referenced, and instead talks about a system with some interesting dynamics properties. It does not have true net negative energy, or curve space backwards. (Specifically, they mention "negative effective mass." Effective mass is a term that comes up in quantum mechanics, such as when all but a few states in a semiconductor are filled, the system is treated as if it has a small number of imaginary particles called holes, which have positive charge. This is simpler than directly considering the large number of electrons, and makes it easier to analyze some unintuitive effects such as the fact that a test of the Hall effect would indicate positive charge carriers, even though it is actually electrons moving around.)
When seeing ground breaking claims laid out like this to check if they really are what you think, ask yourself whether you see any statements in the article making it sound like they are a shoe in for the Nobel prize.
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#31
by
Hakasays
on 16 Mar, 2020 13:31
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#32
by
RotoSequence
on 17 Mar, 2020 02:13
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#33
by
Hakasays
on 17 Mar, 2020 13:31
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Interesting paper, but what's happened on that line of research in the eight years hence?
Very little, it would seem. It's likely they lack sufficient context from which extrapolate other possibilities/experiments.
In the modern context, wave propagation is usually determined as a singular constant C rather than the dual factors of electric permittivity and magnetic permeability of empty space.
I suspect they will have more success once they break 'light' down into its individual components.
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#34
by
RSE
on 27 Mar, 2020 14:43
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The previous post brings up the issue of – What is the maximum speed of light?
Before I get all the demands that the speed of light is a constant ( C ), one must note that the speed of light is a variable, depending on the density of the medium. The denser, the slower. This variability has been experimentally proven, over and over again.
However, starting in the late 1990's, fields have been created, with both negative permeability and negative permittivity, and later fields (of both types, ++ or –) that have a permeability and permittivity lower than that of a free vacuum. Totally artificial, but produces.
So the experimental question is – what would the speed of light be in a field with much lower permittivity and permeability than a free vacuum?
According to one of the boundary conditions of Maxwell's Equations, the speed should be much higher. (See the previous post's equation.)
I have yet to read of this experiment ever being done.
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#35
by
dustinthewind
on 28 Mar, 2020 05:02
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Interesting paper, but what's happened on that line of research in the eight years hence?
Very little, it would seem. It's likely they lack sufficient context from which extrapolate other possibilities/experiments.
In the modern context, wave propagation is usually determined as a singular constant C rather than the dual factors of electric permittivity and magnetic permeability of empty space.
I suspect they will have more success once they break 'light' down into its individual components.
I suspect there is something to this. Locally the universe conspires to give us the impression when we locally measure the speed of light that it is constant but non locally it is not constant. The very nature gravitational lensing is that light is bent by both time and space can be viewed as a non-local change in the speed of light. WarpTech used to bring up a paper linked to this that related to a non-local change in the speed of light via a polarized vacuum. One of the names was Harold Puthoff.
https://en.wikipedia.org/wiki/Polarizable_vacuumSo light slows near a gravitational well. I began to view this in one dimension where a gravitational well is a dip in potential. An object falling into a potential falls to a lower energy state but in this lower energy state time will tick slower and space physically shrinks. Objects want to fall to the lower energy state via pressure or gravity. The funny thing is you can kind of see this curvature in one dimension as a second dimension which represents the transition of space to a lower energy state inducing curvature so space does curve. This change in slope induces what appears to be a local relative change in velocity or acceleration. If we have 2 dimensions for every dimension of space this makes 6 dimensions. This is why an object can become relativistically flat as one of its dimensions can rotate into a time like dimension. In fact an object falling into an orbit around a black hole can effectively become one dimensional if it orbits at the speed of light and resides near the event horizion. then it becomes flat in 2 dimensions leaving only length. The orbit velocity is perpendicular to the gravitational horizion so the relativistic pancaking happens in 2 perpendicular dimensions.
So we can see this reduction in potential of space around matter which is gravity. However when merging black holes brake against space time, they transfers their kinetic energy to space time. The problem is a gravitational wave represents more potential energy in space time so it resides at a higher potential. Visualizing this it appears a gravity waves should be gravitationally repulsive at very large energy densities as radiation is repulsive to an electric charge that generates it or absorbs. On a large scale I suspect this is responsible for einsteins negative cosmological constant or dark energy and possibly dark matter - energy residing in space time in the voids that is gravitationally repulsive. This is like inflated space time where the plank length would be larger and the speed of light would be non-locally faster than c. If we look at air or some dielectrics heating them speeds up velocities of sound or signals from changing dielectric properties. Ill give you an example.
google books
Qualitative differences between linear and nonlinear waves
Some characteristic of nonlinear wave motion can be described in general terms.
...
The distincitive feature of nonlinear waves, however concerns disturbances or discontinuities whichare not necessarily small. In linear waves motion any initial discontinuity across a surface is preserved as a discontinuity and propagated with sound speed. Nonlinear wave motion behaves in a different manner: Suppose there is an initial discontinuity between two regions of different pressures, densities, and flow velocities. Then there are the following alternative possibilities: either the initial discontinuity is resolved immediately and the disturbance, while propagated, becomes continuous, or the initial discontinuity is propagated through one or two shock fronts, advancing not at sonic but at supersonic speed relative to the medium.
Another example is
Predicted properties of quantum non-equilibrium
Valentini showed that his expansion of the De Broglie–Bohm theory would allow “signal nonlocality” for non-equilibrium cases in which {\displaystyle \rho (x,y,z,t)}\rho (x,y,z,t) ≠{\displaystyle |\psi (x,y,z,t)|^{2}}|\psi (x,y,z,t)|^{2},[3][4] thereby violating the assumption that signals cannot travel faster than the speed of light.
Valentini furthermore showed that an ensemble of particles with known wave function and known nonequilibrium distribution could be used to perform, on another system, measurements that violate the uncertainty principle.[7]
These predictions differ from predictions that would result from approaching the same physical situation by means of the Copenhagen interpretation and therefore would in principle make the predictions of this theory accessible to experimental study. As it is unknown whether or how quantum non-equilibrium states can be produced, it is difficult or impossible to perform such experiments.
However, also the hypothesis of quantum non-equilibrium Big Bang gives rise to quantitative predictions for nonequilibrium deviations from quantum theory which appear to be more easily accessible to observation.[8]
You see the big bang would be gravitationally repulsive and expanded the universe faster than light.
Now you might wonder if there are any examples in space time where such a signal has possibly been seen to exist. There is one I suspect. Some might be skeptical of him but I think he might be legit.
Eugene Podkletnov particurlarly his gravity impulse generator which he charges capacitors to millions of volts and discharges them through super condutors. Low electron density means the electrons reach rediculous velocities and accelerations in superconductors and I think possibly interact with space time generating high energy dense gravity waves which travel at ftl ~66c as of his claims. see video at 19 minutes. I don't think they actually are faster than light non-locally. If you inflate the plank length and increase time nonlocally you increase c and this probably has an effect on the non-local electric permittivity and magnetic permeability of free space changing the non-local speed of c.
Technically such a wave would reduce your effective mass. The opposite of gravity. Be gravitationally repulsive which Eugene does seem to claim indirectly and travel ftl so I suspect he may be telling the truth as it seems to fit the puzzle. Negative mass effects are necessary for warp drives. I suspect you would surf the wave, passing it through your ship making you mas-less, instantly reaching c locally while exceeding c non-locally. There would have to be some way to disengage but your time slowing down should be countered by the wave which is negative mass and speeds up time - opposite of gravity via mass.
I think this article might simply be that some ions are being accelerated to nonlocal FTL by a gravity wave from a highly energetic explosion. Later the wave dissipates. You get your reverse signal.
https://www.sciencealert.com/faster-than-light-speeds-could-be-the-reason-why-gamma-ray-bursts-seem-to-go-backwards-in-time/ampThis might all also be related to super cavitation which is used to push torpedos to high speeds in water.
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#36
by
meberbs
on 14 Apr, 2020 04:15
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Interesting paper, but what's happened on that line of research in the eight years hence?
Very little, it would seem. It's likely they lack sufficient context from which extrapolate other possibilities/experiments.
In the modern context, wave propagation is usually determined as a singular constant C rather than the dual factors of electric permittivity and magnetic permeability of empty space.
I suspect they will have more success once they break 'light' down into its individual components.
Your final statement is nonsensical. You cannot separate the electric and magnetic fields. They are a single thing, the electromagnetic field, they transform together as a tensor in special relativity.
The answer therefore seems more like that it is an abandoned dead end.
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#37
by
meberbs
on 14 Apr, 2020 04:25
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The previous post brings up the issue of – What is the maximum speed of light?
Before I get all the demands that the speed of light is a constant ( C ), one must note that the speed of light is a variable, depending on the density of the medium. The denser, the slower. This variability has been experimentally proven, over and over again.
No, you are confusing 2 distinct things, the speed of light in vacuum, which is a universal constant, and the speed of electromagnetic wave propagation in a material, which is completely irrelevant to this thread. See this video below if you want additional explanation:
However, starting in the late 1990's, fields have been created, with both negative permeability and negative permittivity, and later fields (of both types, ++ or –) that have a permeability and permittivity lower than that of a free vacuum. Totally artificial, but produces.
So the experimental question is – what would the speed of light be in a field with much lower permittivity and permeability than a free vacuum?
According to one of the boundary conditions of Maxwell's Equations, the speed should be much higher. (See the previous post's equation.)
I have yet to read of this experiment ever being done.
Metamaterials with negative index of refraction and such are cool, but that is just bending light in special ways (and it is essentially always frequency dependent.) Anything about propagation speeds faster than the vacuum speed of light in a material is some form of illusion. The meaningful velocity that energy and information travels at (usually the group velocity) will always within the universal constant c. Anything faster than that (such as a phase velocity in typical cases) will just be an illusion, just like a shadow or the point of a laser beam can move arbitrarily fast as long as it is being cast far enough away from the source.
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#38
by
meberbs
on 14 Apr, 2020 04:49
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Interesting paper, but what's happened on that line of research in the eight years hence?
Very little, it would seem. It's likely they lack sufficient context from which extrapolate other possibilities/experiments.
In the modern context, wave propagation is usually determined as a singular constant C rather than the dual factors of electric permittivity and magnetic permeability of empty space.
I suspect they will have more success once they break 'light' down into its individual components.
I suspect there is something to this. Locally the universe conspires to give us the impression when we locally measure the speed of light that it is constant but non locally it is not constant. The very nature gravitational lensing is that light is bent by both time and space can be viewed as a non-local change in the speed of light. WarpTech used to bring up a paper linked to this that related to a non-local change in the speed of light via a polarized vacuum. One of the names was Harold Puthoff.
No, see my above post on why this is based on a misunderstanding. (That is at least a common enough misunderstanding, but your post goes much much farther than that) The bringing in GR is just an irrelevant change in topic, Gravitational time dilation is very real, but is not a change in the fundamental constant. And check out the wiki page on
Puthoff, he was involved with scientology and pseudoscience experiments on psychic powers. He is not someone you reference to lend credibility to an idea.
The rest of your post is a bunch of non-sequiters and logical leaps that aren't even worth discussing since you have repeatedly demonstrated your lack of interest in actually learning what the words you use mean.
This might all also be related to super cavitation which is used to push torpedos to high speeds in water.
This final sentence gives a good summary of how completely irrelevant your statements are. There is simply nothing that could possibly relate supercavitating torpedoes to the subject of this thread and if you think there is, you have very deep misunderstandings of fundamental aspects of the physics under discussion, and you need to go try to learn it from scratch after abandoning your preconceived notions.
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#39
by
RSE
on 17 Apr, 2020 17:17
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Mberbs, I don't agree with either your interpretation or the the video's interpretation. I would like to explain, in detail what I am trying to get across.
Point 1. Causality does not exist for a massless particle. A massless particle travels at C, according to the Lorenz transformation, and General Relativity, correct? At if it is traveling at C, time (t) = 0, according to its reference frame, correct? (And without time, there is no way to define distance, as well. Therefore no space, either.)
For duration to exist, t must be > 0. otherwise you have no duration. And for causality to exist, one has to have a sequence of durations (in a particular order). (which is the definition of causality).
So what we think of spacetime is only defined by, and measured by, particles with mass. Now, at C = infinity, there would be no spacetime for massed particles, as well. As the video pointed out, at C = infinity, the universe as we know it would not exist.
This leads to point 2.
Point 2. Is C necessarily a fixed constant? Certainly, quantum vacuum seems to be a constant across space and time, as massed particles are affected by it, but can the underlying quantum be manipulated in any way? If so, what happens to C?
To me, this is an absolutely valid question. One of the boundary conditions of Maxwell's Equations defines C in terms of permeability and permittivity of a vacuum. If those factors can be manipulated, even for a narrow band of electromagnetic frequencies, then measuring C through a field with a modified (lowered) permeability and permittivity would be a valid and important experiment.
Now it might be an expanded group velocity, or it might actually be a faster C without a wildly spread group velocity. This would not destroy the Lorenz transformation, merely expanding it by substituting the Maxwell's Equations boundary condition for C where C is located in the Lorenz transformation. Relativity and the Universe as we know it would merely be a subset of a larger physics, just like Newtonian mechanics is a subset of Relativity.
We now have the experimental method to test this possibility. Look in the box and find out.
Theory should never be used as a reason to not do an experiment.
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#40
by
meberbs
on 17 Apr, 2020 18:00
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Mberbs, I don't agree with either your interpretation or the the video's interpretation. I would like to explain, in detail what I am trying to get across.
This is not "interpretation" what I and the video say are what physics says. Your previous discussion is simply wrong. You are confusing 2 different things with different definitions. The local propagation of electromagnetic waves is not the universal constant c by definition. Measuring one does not tell you the other.
Point 1. Causality does not exist for a massless particle.
Untrue, you are effectively making the mistake of trying to do calculations in a frame travelling at c, which is simply invalid due to it being a divide by 0 error. When looking at any real frame there is a clear cause and effect including for the emission and absorption of light. Any limit approaching c (the way you deal with divide by 0 errors) will preserve this.
This leads to point 2.
Point 1 is wrong, so nothing leads to point 2.
Now it might be an expanded group velocity, or it might actually be a faster C without a wildly spread group velocity. This would not destroy the Lorenz transformation, merely expanding it by substituting the Maxwell's Equations boundary condition for C where C is located in the Lorenz transformation. Relativity and the Universe as we know it would merely be a subset of a larger physics, just like Newtonian mechanics is a subset of Relativity.
We now have the experimental method to test this possibility. Look in the box and find out.
Theory should never be used as a reason to not do an experiment.
You have not actually described an experiment. You are just asserting that 2 things with different definitions are the same. There have been many, many experiments showing that electromagnetic waves propagate differently in different materials even extreme values, yet spacetime around these materials does not magically warp as you imply should happen. It doesn't even make sense to substitute the local propagation velocity of light into the Lorentz transformation since there is no definition for frequency in the context of Lorentz transformations.
As for an actual experiment that is trivial to perform that proves your entire concept to be nonsense, drop to balls with significantly different permittivities and observe them fall at the same rate. The Einstein field equations show have the gravitational constant in the form of G/c^4. It would be impossible not to notice the effect if the local propagation of electromagnetic waves had anything whatsoever to do with the universal constant c.
There is a such thing as variable speed of light theories, but they have literally nothing to do with anything you are talking about and have their own set of problems.
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#41
by
JohnFornaro
on 18 Apr, 2020 15:56
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The previous post brings up the issue of – What is the maximum speed of light?
Before I get all the demands that the speed of light is a constant ( C ), one must note that the speed of light is a variable, depending on the density of the medium. The denser, the slower. This variability has been experimentally proven, over and over again.
No, you are confusing 2 distinct things, the speed of light in vacuum, which is a universal constant, and the speed of electromagnetic wave propagation in a material, which is completely irrelevant to this thread.
Yeah. But.
My understanding is that the various measurements of c with increasing accuracy have varied over the years and that they are not trending towards a specific value.
Is this evidence for the variable speed of light theory? [VSL]
https://en.wikipedia.org/wiki/Variable_speed_of_lightEinstein: "The principle of the constancy of the speed of light can be kept only when one restricts oneself to space-time regions of constant gravitational potential."
He went on to conclude that c is constant when gravity does not have to be considered. But doesn't gravity have to be considered in ALL frames of reference?
I have no idea how a possible non-constant value of c would tie into these various proposals for propellantless rocketry.
A criticism of VSL from the oracle:
"Specifically regarding VSL, if the SI meter definition was reverted to its pre-1960 definition as a length on a prototype bar (making it possible for the measure of c to change), then a conceivable change in c (the reciprocal of the amount of time taken for light to travel this prototype length) could be more fundamentally interpreted as a change in the dimensionless ratio of the meter prototype to the Planck length or as the dimensionless ratio of the SI second to the Planck time or a change in both. If the number of atoms making up the meter prototype remains unchanged (as it should for a stable prototype), then a perceived change in the value of c would be the consequence of the more fundamental change in the dimensionless ratio of the Planck length to the sizes of atoms or to the Bohr radius or, alternatively, as the dimensionless ratio of the Planck time to the period of a particular caesium-133 radiation or both."
Are we all swelling and shrinking and speeding up and slowing down at the same rate? How could we tell?
Sheesh.
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#42
by
meberbs
on 18 Apr, 2020 18:43
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The previous post brings up the issue of – What is the maximum speed of light?
Before I get all the demands that the speed of light is a constant ( C ), one must note that the speed of light is a variable, depending on the density of the medium. The denser, the slower. This variability has been experimentally proven, over and over again.
No, you are confusing 2 distinct things, the speed of light in vacuum, which is a universal constant, and the speed of electromagnetic wave propagation in a material, which is completely irrelevant to this thread.
Yeah. But.
My understanding is that the various measurements of c with increasing accuracy have varied over the years and that they are not trending towards a specific value.
Is this evidence for the variable speed of light theory? [VSL]
https://en.wikipedia.org/wiki/Variable_speed_of_light
As I mentioned at the end of my post VSL is a thing, but it is fundamentally different than what was discussed above. I am not sure what you are referring to with measurements of the speed of light changing with time, but since 1983, that is literally impossible by definition. (More on that below)
Einstein: "The principle of the constancy of the speed of light can be kept only when one restricts oneself to space-time regions of constant gravitational potential."
He went on to conclude that c is constant when gravity does not have to be considered. But doesn't gravity have to be considered in ALL frames of reference?
I don't fully trust that article on this, some of the quotes seem to be mixing different claims. It certainly leaves out the fact that in the end, GR uses the speed of light as a constant. You can only do meaningful measurements in a local sense in GR, distant measurements give you different apparent results, but that is more like an illusion where you aren't measuring the right thing.
I have no idea how a possible non-constant value of c would tie into these various proposals for propellantless rocketry.
Doesn't matter since this is an FTL comms thread not a propellantless thread.
Are we all swelling and shrinking and speeding up and slowing down at the same rate? How could we tell?
Sheesh.
And this is the biggest problem with VSL theories, you have to be extremely careful with defining what is actually changing, probably a dimensionless ratio between some independently measurable things. As I mention above the speed of light is fixed under current definitions, it would be the effective length of a meter or duration of a second that would change. But even with other defitions of the meter like a fixed rod, you have to consider did the bond spacing change between atoms in the material due to changes in atomic size, but that could be due to changes in the electron mass.
Honestly real VSL theories break my brain when I try to sort them out, and while I think that it is good to question the assumptions of constant fundamental constants with time in the universe, the experimental data shows at least a reasonable amount of consistency. I haven't seen a good source reviewing a VSL theory in depth accounting for the complications and implications and comparing to astronomical data. I get the impression that this is because no one has come up with a good way to define a consistent VSL theory (possibly due to the brain breaking nature of it.)
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#43
by
JohnFornaro
on 18 Apr, 2020 22:06
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... Honestly real VSL theories break my brain when I try to sort them out ...
Thanks very much for your comments.
From:
https://www.phys.ksu.edu/personal/rprice/SpeedofLight.pdf"The speed of light was measured using the Foucault method of reflecting a beam of light from a rotating mirror to a fixed mirror and back creating two separate reflected beams with an angular displacement that is related to the time that was required for the light beam to travel a given distance to the fixed mirror. By taking measurements relating the displacement of the two light beams and the angular speed of the rotating mirror, the speed of light was found to be (3.09±0.204)x108 m/s, which is within 2.7% of the defined value for the speed of light."
2.7% is pretty dang far off.
From:
https://www.livescience.com/29111-speed-of-light-not-constant.htmlOn 04-27-2013. Which I know ain't the best source. But still.
"Speed of Light May Not Be Constant, Physicists Say"
"Cosmic vacuum and light speed
"The first [paper], by lead author Marcel Urban of the Université du Paris-Sud, looks at the cosmic vacuum, which is often assumed to be empty space. The laws of quantum physics, which govern subatomic particles and all things very small, say that the vacuum of space is actually full of fundamental particles like quarks, called "virtual" particles. These matter particles, which are always paired up with their appropriate antiparticle counterpart, pop into existence and almost immediately collide. When matter and antimatter particles touch, they annihilate each other.
"Photons of light, as they fly through space, are captured and re-emitted by these virtual particles. Urban and his colleagues propose that the energies of these particles — specifically the amount of charge they carry — affect the speed of light. Since the amount of energy a particle will have at the time a photon hits it will be essentially random, the effect on how fast photons move should vary too.
"The second paper proposes a different mechanism but comes to the same conclusion that light speed changes. In that case, Gerd Leuchs and Luis Sánchez-Soto, from the Max Planck Institute for the Physics of Light in Erlangen, Germany, say that the number of species of elementary particle that exist in the universe may be what makes the speed of light what it is. ...
"Leuchs and Sanchez-Soto say that there should be, by their calculations, on the order of 100 'species' of particle that have charges. The current law governing particle physics, the Standard Model, identifies nine: the electron, muon, tauon, the six kinds of quark, photons and the W-boson."
Conspicuously missing are morons and peons. But still, these blokes seem to be saying that the speed of light varies; get used to it.
I don't want to get too sidetracked, but these people touch on permittivity as do you above. TBF, a skeptic of VSL, said that he "wasn't confident about the mathematical techniques used, and that it seemed in both cases the scientists weren't applying the mathematical tools in the way that most would."
And it is the math where I give up. I have to dig further to find the variable speeds of light that I've run across.
Thanx again for your commentary.
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#44
by
cdebuhr
on 18 Apr, 2020 22:12
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speed of light was found to be (3.09±0.204)x108 m/s, which is within 2.7% of the defined value for the speed of light."
2.7% is pretty dang far off.
No. It isn't. You've got to look at the error bar on their measurement (the ±0.204 part). The established value of c is completely consistent with their measured value within the limits of its stated uncertainty.
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#45
by
meberbs
on 18 Apr, 2020 22:57
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2.7% is pretty dang far off.
As stated above, with experimental uncertainty of >6%, it is pretty much dead on.
From:
https://www.livescience.com/29111-speed-of-light-not-constant.html
I agree we are probably getting sidetracked, so just a brief comment.
The first one of these doesn't even make sense to me, as it is explained in the article it just seems fundamentally inconsistent. The second one doesn't even sound like a variable speed of light, but an alternate quantum explanation of where the speed of light comes from, but since it adds in a bunch of particles we have no evidence for, it feels like it brings up more issues than it solves.
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#46
by
JohnFornaro
on 19 Apr, 2020 13:22
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2.7% is pretty dang far off.
As stated above, with experimental uncertainty of >6%, it is pretty much dead on.
Went back to article and took a closer read. Missed that. Thanks.
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#47
by
RSE
on 19 Apr, 2020 15:57
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Mberbs, I don't agree with either your interpretation or the the video's interpretation. I would like to explain, in detail what I am trying to get across.
This is not "interpretation" what I and the video say are what physics says. Your previous discussion is simply wrong. You are confusing 2 different things with different definitions. The local propagation of electromagnetic waves is not the universal constant c by definition. Measuring one does not tell you the other.
Point 1. Causality does not exist for a massless particle.
Untrue, you are effectively making the mistake of trying to do calculations in a frame travelling at c, which is simply invalid due to it being a divide by 0 error. When looking at any real frame there is a clear cause and effect including for the emission and absorption of light. Any limit approaching c (the way you deal with divide by 0 errors) will preserve this.
This leads to point 2.
Point 1 is wrong, so nothing leads to point 2.
Now it might be an expanded group velocity, or it might actually be a faster C without a wildly spread group velocity. This would not destroy the Lorenz transformation, merely expanding it by substituting the Maxwell's Equations boundary condition for C where C is located in the Lorenz transformation. Relativity and the Universe as we know it would merely be a subset of a larger physics, just like Newtonian mechanics is a subset of Relativity.
We now have the experimental method to test this possibility. Look in the box and find out.
Theory should never be used as a reason to not do an experiment.
You have not actually described an experiment. You are just asserting that 2 things with different definitions are the same. There have been many, many experiments showing that electromagnetic waves propagate differently in different materials even extreme values, yet spacetime around these materials does not magically warp as you imply should happen. It doesn't even make sense to substitute the local propagation velocity of light into the Lorentz transformation since there is no definition for frequency in the context of Lorentz transformations.
As for an actual experiment that is trivial to perform that proves your entire concept to be nonsense, drop to balls with significantly different permittivities and observe them fall at the same rate. The Einstein field equations show have the gravitational constant in the form of G/c^4. It would be impossible not to notice the effect if the local propagation of electromagnetic waves had anything whatsoever to do with the universal constant c.
There is a such thing as variable speed of light theories, but they have literally nothing to do with anything you are talking about and have their own set of problems.
Since you posit the point #1 is false, could you answer the following questions.
According to relativity, all reference frames are locally valid. So a sealed reference frame travelling at .999
C, would perceive the same physics as one remaining at rest. Only to an external observer would there be differences. (Or do I have this wrong?)
So....
From the reference frame of a photon (a massless particle travelling at
C,
not from the reference frame of an external observer of said particle, how would time be measured? According to the Lorenz transformation, at
C, time should go to 0, in that reference frame. That is not a divide by 0 error, that is an asymptotic approach to zero, with 0 being reached at
C, which can only be reached by a massless particle.
So please explain how time is measured in a photon's reference frame.
How is duration measured in that reference frame.
And how changes in wavelength measured in that reference frame.
Not in an external observer's reference frame, but the photon's reference frame.
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#48
by
meberbs
on 19 Apr, 2020 17:52
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According to relativity, all reference frames are locally valid. So a sealed reference frame travelling at .999 C, would perceive the same physics as one remaining at rest. Only to an external observer would there be differences. (Or do I have this wrong?)
This is fine, but you then extend this to a hypothetical reference frame at c, but that is nonsensical, you cannot have a valid reference frame moving at c.
From the reference frame of a photon (a massless particle travelling at C, not from the reference frame of an external observer of said particle, how would time be measured? According to the Lorenz transformation, at C, time should go to 0, in that reference frame. That is not a divide by 0 error, that is an asymptotic approach to zero, with 0 being reached at C, which can only be reached by a massless particle.
Asserting that such a reference frame exists is a divide by 0 error. to transform into that reference frame you need to multiply by the Lorentz factor 1/sqrt(1-v^2/c^2) when v = c, this reduces to 1/(1-1) = <error: divide by zero>
Really this question is backwards, you are the one asserting that such a reference frame is anything other than a math error, so you are the one who has to answer impossible questions like how you measure time in that frame to assert that "time should go to 0, in that reference frame."
So please explain how time is measured in a photon's reference frame.
How is duration measured in that reference frame.
And how changes in wavelength measured in that reference frame.
None of these are measured in the reference frame of a photon, because such a reference frame makes no sense. Both space and time collapse from the divide by 0 error. You cannot do meaningful calculations in that frame because you effectively lose a dimension as space collapses in the direction of travel, and so even if you take all of the limits correctly to get a transformation in that frame, you lose information like "which side of that wall am I on" and you can never get to meaningful answers or meaningfully transfor back into an actually useful frame. That is why divide by 0 is simply an error.
Not in an external observer's reference frame, but the photon's reference frame.
I am running out of ways to say this, again, that is not a valid frame. If you want to assert otherwise, you need to demonstrate how to do calculations in that frame. Trying to ask me to show your work for you is backwards.
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#49
by
RSE
on 19 Apr, 2020 20:31
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According to relativity, all reference frames are locally valid. So a sealed reference frame travelling at .999 C, would perceive the same physics as one remaining at rest. Only to an external observer would there be differences. (Or do I have this wrong?)
This is fine, but you then extend this to a hypothetical reference frame at c, but that is nonsensical, you cannot have a valid reference frame moving at c.
From the reference frame of a photon (a massless particle travelling at C, not from the reference frame of an external observer of said particle, how would time be measured? According to the Lorenz transformation, at C, time should go to 0, in that reference frame. That is not a divide by 0 error, that is an asymptotic approach to zero, with 0 being reached at C, which can only be reached by a massless particle.
Asserting that such a reference frame exists is a divide by 0 error. to transform into that reference frame you need to multiply by the Lorentz factor 1/sqrt(1-v^2/c^2) when v = c, this reduces to 1/(1-1) = <error: divide by zero>
Really this question is backwards, you are the one asserting that such a reference frame is anything other than a math error, so you are the one who has to answer impossible questions like how you measure time in that frame to assert that "time should go to 0, in that reference frame."
So please explain how time is measured in a photon's reference frame.
How is duration measured in that reference frame.
And how changes in wavelength measured in that reference frame.
None of these are measured in the reference frame of a photon, because such a reference frame makes no sense. Both space and time collapse from the divide by 0 error. You cannot do meaningful calculations in that frame because you effectively lose a dimension as space collapses in the direction of travel, and so even if you take all of the limits correctly to get a transformation in that frame, you lose information like "which side of that wall am I on" and you can never get to meaningful answers or meaningfully transfor back into an actually useful frame. That is why divide by 0 is simply an error.
Not in an external observer's reference frame, but the photon's reference frame.
I am running out of ways to say this, again, that is not a valid frame. If you want to assert otherwise, you need to demonstrate how to do calculations in that frame. Trying to ask me to show your work for you is backwards.
Mberbs, photons
exist. They are real (as we understand reality), and have a set of properties. We measure them. As such, they have a frame of reference. It is not an inertial frame, because they have no mass, but a frame nonetheless. (A non-inertial frame, one might say.) And the implication of the Lorenz transformation implies that as you approach
C as a limit, mass goes to infinity and time goes to 0. I state that photons, having no mass, are inherently at that limit. so time in their frame should be at 0. (With everything that t=0 implies.)
Since you state this is not right, describe the frame and what it is - to a photon. What I hear from is is that, in essence, photon don't exist. (They can't be accounted for in your frame description, so they aren't real. )
If they are, provide an explanation of what the universe would look like to a photon.
(I feel like I'm arguing the difference between a null set and zero.)
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#50
by
meberbs
on 19 Apr, 2020 21:27
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Mberbs, photons exist. They are real (as we understand reality), and have a set of properties. We measure them.
Yes they do, and I have never claimed otherwise. They travel (in vacuum) at exactly the speed of light in every reference frame that makes sense. This is one more
As such, they have a frame of reference.
No, just because something exists does not mean it makes sense to describe reality in a reference frame co-moving with it.
It is not an inertial frame, because they have no mass, but a frame nonetheless. (A non-inertial frame, one might say.)
Have you just never actually opened a physics book? An inertial frame is one that is not accelerating. Since a frame moving with a relative velocity of c would have constant velocity, it would be inertial if it made any sense to talk about.
And the implication of the Lorenz transformation implies that as you approach C as a limit, mass goes to infinity and time goes to 0. I state that photons, having no mass, are inherently at that limit. so time in their frame should be at 0. (With everything that t=0 implies.)
How can time go to 0 when you are multiplying it by a number approaching infinity?
Look at the first equation here:
https://en.wikipedia.org/wiki/Lorentz_transformationYou seem to be confusing time with delta time, and not defining exactly what difference you are taking. (And infinity minus infinity, is undefined just like the division by 0 you used to get the infinities.)
Since you state this is not right, describe the frame and what it is - to a photon. What I hear from is is that, in essence, photon don't exist. (They can't be accounted for in your frame description, so they aren't real. )
Read what I wrote. I have never said anything remotely similar to what you assert that I did. Photons exist in any valid frame, in an invalid frame, logic doesn't work. I can't do calculations in an invalid frame. I repeatedly asked you to provide a way of doing calculations in a speed of light frame if you were to continue insisting one exists, and you simply and rudely have ignored that, instead repeating meaningless assertions that plainly contradict the math of frame transformations.
If they are, provide an explanation of what the universe would look like to a photon.
I already did and you ignored it, because you don't like the answer.
(I feel like I'm arguing the difference between a null set and zero.)
Zero is a number, the null set is the lack of any number. The set of all meaningful reference frames travelling at c is null, yet you keep trying to pull numbers out of this empty set. It simply doesn't work. What result do you get when you roll all of the dice from an empty bag? The question is simply wrong because the action "roll dice" can't be performed.
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#51
by
RSE
on 19 Apr, 2020 21:28
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On the PBS imbed you included eariler, at around 9:30, the spokeman points out that at C = infinity, there is no mass (correct) and therefore no spacetime. which is consistent with the concept that for massless particles, there is no spacetime, from their frame of reference, regardless of the value of C. (At C = infinity, there is no other reference frame other than the massless frame.
E=MC*C
E/MC = C
If C = infinity, then M = 0 (Or if one prefers, as C approached infinity as a limit, M must approach 0 as a limit.)
E/0 = infinity
Infinity = infinity
Q.E.D.
(Our computers can't handle it, but the math is clear. A/B, as B approaches 0, A approaches infinity as a limit for both.)
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#52
by
meberbs
on 19 Apr, 2020 21:56
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On the PBS imbed you included eariler, at around 9:30, the spokeman points out that at C = infinity, there is no mass (correct) and therefore no spacetime. which is consistent with the concept that for massless particles, there is no spacetime, from their frame of reference, regardless of the value of C. (At C = infinity, there is no other reference frame other than the massless frame.
They are discussing a hypothetical alternate universe to consider the implications, not the real one where c is finite. Your extrapolations from there miss the entire point.
E/MC = C
If C = infinity, then M = 0 (Or if one prefers, as C approached infinity as a limit, M must approach 0 as a limit.)
E/0 = infinity
Meaningless, multiple infinities on either side of the equation, and you are taking the M*C, asserting randomly that M is 0, and then nonsensically claiming that 0* infinity is 0, but the rule "anything times 0 is 0" cancels with "anything time infinity is infinity" and no meaningful result can be determined. This is taught along with limits in any basic calculus class.
Infinity = infinity
Q.E.D.
(Our computers can't handle it, but the math is clear. A/B, as B approaches 0, A approaches infinity as a limit for both.)
Infinity does not equal infinity, for example, see :
https://en.wikipedia.org/wiki/Cardinality_of_the_continuumWhen you do such math, the result is nonsensical. For demonstration see below*
let 2 variables, a and b both equal 1. Since they are equal, the following equations are clearly true:
b^2 = a*b
a^2 = a^2
subtracting you get:
a^2-b^2 = a^2 - a*b
factoring you get:
(a+b)*(a-b) = a*(a-b)
therefore you can clearly see that a+b = a *****
Plugging in the original values, you get 2 = 1.
Clearly this is gibberish. It is equivalent to what you keep doing though. That step with all of the asterisks is arrived at by dividing by zero, because (a-b) = 0. When you divide by zero you have abandoned logic. Whether a computer can handle this is irrelevant. Any conclusions after that point is meaningless, and ending with infinity = infinity is simply the same thing. Again, there is a such thing as limits, but to use them right you have to do things carefully, and they don't strictly mean that the result you get is the value at that limit. There are cases where this is decidedly not true.
*Slightly modified from the book Zero: The Biography of a Dangerous Idea by Charles Seife, The book goes on to prove that Winston Churchill is a carrot.
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#53
by
RSE
on 19 Apr, 2020 22:24
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Mberbs, you are sounding like a theologian defending the faith, not a scientist.
The "alternate universe" is merely taking the relativity mathematics and analysing all possible aspects. Changing values to see what the mathematics imply. They imply that if all particles were massless, there would be no spacetime, as we know it, because there would be no time, no duration, and no causality, implying no space as well.
So, does this apply to massless particles (wavicles, if you prefer), which travel at C, where C is a finite value? An absolutely valid question to ask. It seems consistent with the existing mathematics.
If not, please provide me with the math describing how and why duration exists for a photon, that is consistent with that "alternate universe".
In other words, why times passes for a photon, if it does, and how would it be measured, in its own "perspective", not that of an outside observer.
This is a building block that must be settled before any oher discussion can be contemplated.
So far, you have refused to deal with this subject, other than hurl insults.
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#54
by
meberbs
on 19 Apr, 2020 22:47
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Mberbs,
Once is an accident, twice starts sounding like an insult, check your spelling.
you are sounding like a theologian defending the faith, not a scientist.
So you ran out of logic and resort to insults now?
The "alternate universe" is merely taking the relativity mathematics and analysing all possible aspects. Changing values to see what the mathematics imply. They imply that if all particles were massless, there would be no spacetime, as we know it, because there would be no time, no duration, and no causality, implying no space as well.
You are missing the point, if the universal constants were significantly different, then the universe would look significantly different, but that is not the case, so these conclusions do not apply to the real world.
So, does this apply to massless particles (wavicles, if you prefer), which travel at C, where C is a finite value? An absolutely valid question to ask. It seems consistent with the existing mathematics.
Again, read my previous posts. I already provided the equations that show that your assertions are inconsistent.
If not, please provide me with the math describing how and why duration exists for a photon, that is consistent with that "alternate universe".
Math consistent with an imaginary universe does not in general provide any utility in the real world.
In other words, why times passes for a photon, if it does, and how would it be measured, in its own "perspective", not that of an outside observer.
You cannot meaningfully measure things from the perspective of a photon, as I have said a dozen times. If you want to assert otherwise, the burden of proof is on you.
This is a building block that must be settled before any oher discussion can be contemplated.
In other words you refuse to even consider the possibility that your statements are inherently wrong and illogical, and you not only refuse to admit that, but rather than providing any kind of counterargument, you insist that I defend your position for you.
So far, you have refused to deal with this subject, other than hurl insults.
You are the one who has refused to respond to a single thing I have said, who has misrepresented what I said, and you are now lying, claiming that I have hurled insults when I have done no such thing. (And if you think that pointing out that you don't understand the math you are discussing by providing specifics of exactly where you are wrong with a worked out example is somehow an insult, then you can only blame yourself for the implications of refusing to accept your own mistakes.)
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#55
by
RSE
on 20 Apr, 2020 14:21
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Meberbs, you want me to address your questions. I will only do it one at a time, starting with the most basic question. Otherwise, the discussion will get snarled between issues.
From various posts, starting with #40.
Untrue, you are effectively making the mistake of trying to do calculations in a frame travelling at c, which is simply invalid due to it being a divide by 0 error. When looking at any real frame there is a clear cause and effect including for the emission and absorption of light. Any limit approaching c (the way you deal with divide by 0 errors) will preserve this.
This is fine, but you then extend this to a hypothetical reference frame at c, but that is nonsensical, you cannot have a valid reference frame moving at c.
Asserting that such a reference frame exists is a divide by 0 error. to transform into that reference frame you need to multiply by the Lorentz factor 1/sqrt(1-v^2/c^2) when v = c, this reduces to 1/(1-1) = <error: divide by zero>
In response, I will go into detail to show where I disagree with you.
In mathematics, infinity is an accepted concept. It crops up in lots of places. A simple example: how many real number exist between whole numbers 1 and 2? Answer – an infinite number. One can find examples in all sorts of places in mathematics.
So, assuming we are in agreement so far, I bring up the next major piece of mathematics, the concept of a limit. It is the bedrock of Calculus. For example, the area under a curve. (A traditional example) It can't be directly calculated numerically. The concept was to make a rectangle of a portion of the area and calculate that, which is determinate, and to do that for the entire curve in question. Sum all the individual rectangles, and you have an approximate answer. The more rectangles you use, the closer to the exact answer you get. If you had an infinite (that concept again) number of rectangles, you would get the exact answer. So, the concept of limit was used. As the number of rectangles approach infinity, as a limit, the value of the area under the curve approaches the correct answer. Calculus is the mathematics that uses this concept to get the correct answer.
Now, assuming we are still in agreement at this point, we get to the question at hand - divide by zero.
You keep insisting it is an error. It is not – in mathematics. Let me explain.
For any two numbers, if one divides one by the other (the numerator divided by the denominator) you get an result. What happens with the special case of 0 as the denominator? Well, as the denominator gets smaller, the result get larger. So, I bring in the concept of a limit. As the denominator approaches zero, as a limit, the result approaches infinitely large as a limit. Therefore, by using the concepts of Calculus, I say the dividing a number by 0 gives infinity for an answer. Now, infinity cannot be used for numerical calculations, but that does not make it wrong or unreal – or an error. Now from a determinate numerical perspective (which is how our computers function), this is defined as an error, but that is due to the limitation of tool(s), not a mathematical reality.
If we can agree in this then I can go onto the next question.
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#56
by
meberbs
on 20 Apr, 2020 16:13
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In response, I will go into detail to show where I disagree with you.
In mathematics, infinity is an accepted concept. It crops up in lots of places. A simple example: how many real number exist between whole numbers 1 and 2? Answer – an infinite number. One can find examples in all sorts of places in mathematics.
So, assuming we are in agreement so far, I bring up the next major piece of mathematics, the concept of a limit. It is the bedrock of Calculus. For example, the area under a curve. (A traditional example) It can't be directly calculated numerically. The concept was to make a rectangle of a portion of the area and calculate that, which is determinate, and to do that for the entire curve in question. Sum all the individual rectangles, and you have an approximate answer. The more rectangles you use, the closer to the exact answer you get. If you had an infinite (that concept again) number of rectangles, you would get the exact answer. So, the concept of limit was used. As the number of rectangles approach infinity, as a limit, the value of the area under the curve approaches the correct answer. Calculus is the mathematics that uses this concept to get the correct answer.
There is nothing explicitly wrong with any of this, except you leave out extremely important details. some of which I have already explained.
Importantly, there is not a single concept of "infinity" which seems to be an unstated assumption in your description here. just as there are infinite numbers between 1 ans 2, there are also infinite integers. There are infinite positive integers, yet the set of all integers is clearly larger than the set of positive integers by an infinite amount, yet it is still possible to create a 1 to 1 mapping between them, which is why you have to be very careful when working with infinities, or implications of this will result in nonsensical answers. To continue on this, there are more numbers between 1 and 2 than there are integers, this however is a qualitatively different infinity, as no mapping is possible with the lesser infinity of integers.
Also important is that infinity is only defined in mathematics in special situations where all of the caveats of different concepts represented by "infinity" are controlled. The most typical is one that you mention: limits. Outside of limits, infinity loses its meaning, and becomes nonsense. Up until this point, you have simply avoided taking a formal limit of anything, jumping to simply nonsensical answers.
Now, assuming we are still in agreement at this point, we get to the question at hand - divide by zero.
You keep insisting it is an error. It is not – in mathematics. Let me explain.
For any two numbers, if one divides one by the other (the numerator divided by the denominator) you get an result. What happens with the special case of 0 as the denominator? Well, as the denominator gets smaller, the result get larger. So, I bring in the concept of a limit. As the denominator approaches zero, as a limit, the result approaches infinitely large as a limit. Therefore, by using the concepts of Calculus, I say the dividing a number by 0 gives infinity for an answer.
Not even kind of true. You are skipping all of the subtleties that I mention above.
Now, infinity cannot be used for numerical calculations, but that does not make it wrong or unreal – or an error. Now from a determinate numerical perspective (which is how our computers function), this is defined as an error, but that is due to the limitation of tool(s), not a mathematical reality.
No, it is mathematical reality. The simple "infinity" you claim as a result cannot further be used to do anything, because all of the subtlety is gone. In reality here are some actual uses of limits:
lim (x->0) 0/x = 0
lim (x->0) 1/x = inf
lim (x->0) sin(x)/x = 1
lim (x->0) x/x^2 = inf
lim (x->0) x^2/x = 0
In this simplified case 1/x and x/x^2 are equivalent, but if instead I had used 1/x^2 it would no longer be valid to compare the infinities.
I am familiar with working with infinities outside of the formal context of limits. I had a professor who liked to do things that would horrify mathematicians, but he was always careful to warn us that he was bending the rules, and only did so when the result happened to be valid, and the shortcut could help us gain a better understanding. For example he would write an equation like:
delta(t) = 1/(2*pi) integral (-inf to inf) e^(i*w*t) dw
where delta is the Dirac delta function. This is WRONG because the Dirac delta function contains an infinity. The Dirac delta is simply undefined except when it is inside an integral (as you mentioned an integral is a form of a limit which is why certain well-defined infinities can be contained there.) It however works for conceptual understanding, because it strips away some of the formalism that distracts from the point an in practice it would only be used within the context of an integral.
You have simply not demonstrated the comprehension required for this to be useful in this discussion, so I will have to insist that we keep things formal.
If we can agree in this then I can go onto the next question.
Or we could shortcut this, because I have already explained exactly where you are wrong, I had already linked you to an explanation for the different infinities, I have now written it out as plainly as possible myself. Considering that you didn't even stop to apologize for what I pointed out in my last post, I don't get the impression that there is a point conversing with you. The explanations to this point are more for the benefit of passing readers. Nothing you say in this post, even if it was perfect and not a setup to skip important subtleties, would be a foundation for your incorrect statements in previous posts such as:
-You ignored/denied the fact that the universal constant c and the local propagation velocity of electromagnetic waves have different definitions.
-You got the definition of an inertial frame wrong.
-You claim that time goes to 0 in a speed of light frame despite the transformation clearly saying otherwise (t' = gamma * (t-v*x/c^2) in the limit as v->c says: t' = inf*(t-x/c), which in most cases simply equals inf, though really it is just meaningless.
-You assert that there must be a valid way to describe the universe in a reference frame moving at c or photons could not exist. This is simply untrue, these 2 points are not logically connected.
Just about everything after the first bullet is a drift away from the thread topic anyway. I only had one "question" for you and that was for you to provide a consistent way to do calculations in a speed of light frame if you were going to insist that such a frame has any meaning. This really is rhetorical though, as it would be a fools errand. At best it may be possible to set up some careful limits and effectively do the calculations in a near c frame, since actually taking the limits causes things to collapse and information to be irretrievably lost. Such a setup would obviously just give the typical expected answers and not be insightful.
The rest of what I have said is simply pointing out errors you have made, and there really is no room to discuss. Most of the time it is a matter of literal definition, or of simple and straightforward math. These in general are not things that I have come up with entirely myself, but things that were originally come up with by people much, much smarter than me.
Seriously anything you have to say from this point is most likely covered by something I have already written, so rather than continuing this, please just re-read my posts, and only respond if there is a specific error in one of my posts you can point out. (Though it would help if you first stopped to admit that you are wrong about anything, even something irrelevant like the definition of an inertial frame.)
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#57
by
laszlo
on 20 Apr, 2020 16:31
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meberbs either has the patience of Job or is out of things to do in lockdown.
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#58
by
JohnFornaro
on 22 Apr, 2020 12:41
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meberbs either has the patience of Job or is out of things to do in lockdown.
For real. Plus, he can rattle off things like:
(t' = gamma * (t-v*x/c^2) in the limit as v->c says: t' = inf*(t-x/c)
Without, we assume, breaking out into a sweat. Personally, I do not understand his interlocutor's motives.
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#59
by
dustinthewind
on 23 Apr, 2020 17:52
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Interesting paper, but what's happened on that line of research in the eight years hence?
Very little, it would seem. It's likely they lack sufficient context from which extrapolate other possibilities/experiments.
In the modern context, wave propagation is usually determined as a singular constant C rather than the dual factors of electric permittivity and magnetic permeability of empty space.
I suspect they will have more success once they break 'light' down into its individual components.
I suspect there is something to this. Locally the universe conspires to give us the impression when we locally measure the speed of light that it is constant but non locally it is not constant. The very nature gravitational lensing is that light is bent by both time and space can be viewed as a non-local change in the speed of light. WarpTech used to bring up a paper linked to this that related to a non-local change in the speed of light via a polarized vacuum. One of the names was Harold Puthoff.
No, see my above post on why this is based on a misunderstanding. (That is at least a common enough misunderstanding, but your post goes much much farther than that) The bringing in GR is just an irrelevant change in topic, Gravitational time dilation is very real, but is not a change in the fundamental constant. And check out the wiki page on Puthoff, he was involved with scientology and pseudoscience experiments on psychic powers. He is not someone you reference to lend credibility to an idea.
The rest of your post is a bunch of non-sequiters and logical leaps that aren't even worth discussing since you have repeatedly demonstrated your lack of interest in actually learning what the words you use mean.
This might all also be related to super cavitation which is used to push torpedos to high speeds in water.
This final sentence gives a good summary of how completely irrelevant your statements are. There is simply nothing that could possibly relate supercavitating torpedoes to the subject of this thread and if you think there is, you have very deep misunderstandings of fundamental aspects of the physics under discussion, and you need to go try to learn it from scratch after abandoning your preconceived notions.
Your relevance is a matter of opinion. What's relevant to one person might be garbage to another. This means we obviously don't understand each other and I'm not sure that will change anytime soon. Even Einstein understood that there's a non-local change in the speed of light where locally the speed of light is constant. This is where the quote before somebody had something to say about Einstein mentioning the constancy of the speed of light in a constant gravitational acceleration, not a changing gravitational acceleration. If the gravitational acceleration changes the non-local speed of light changes but the local measured speed of light remains the same.
I don't care about Harolds Religion. I do care about the relevance of what his paper had to say about space time. Warptechs references him because it illustrates a point about general relativity. He mentions a non-local change in the speed of light. There are many other scientist who also point out the exact same thing. I don't judge people and everything they do based on their religion. rather I filter out what is useful and throw away what I don't find useful as should be done.
https://forum.nasaspaceflight.com/index.php?topic=19421.msg2062810#msg2062810what's really irrelevant is you bringing in the vsl variable speed of light concepts which probably indicate a change in the measured local speed of light which may change over the eons. the concept is just simple general relativity which also collapses into special relativity.
Now if you exist in a region where the non-local speed of light is slower than the rest of non-local speed of light then there is a possible non-local faster than the normal speed of the light. The speed of light can be defined as c equals 1 divided by the square root of the magnetic permeability times the electric permittivity or something like that. Go look it up if you want to nitpick.
In some materials when you modify the local dielectric it changes the speed of light in that material. SpaceTime is also like a dielectric then you can modify it to change the non local speed of light but in doing so you modify the physical matter so that it measures a constant speed of light.
I will try and make this simple
The reference to torpedo cavitation is about the same. you can move a torpedo faster through the gas bubble in the water then you can move the torpedo through the water.
There is another paper that was referenced that discusses extremely high energy waves in water in which the wave turns into a gas wave. I think this is related to shock physics and might relate to highly energetic gravitational waves moving through space-time. The gas wave can move faster than a sound wave moving through the water.
Surprise surprise it all relates to faster than light signals but also relates to faster-than-light propulsion by manipulating space time. This is why warptech referenced it in the alcubre warp drive section.
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#60
by
meberbs
on 23 Apr, 2020 18:44
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Your relevance is a matter of opinion. What's relevant one person might be garbage to another.
Threads have topics. You quite frequently post things that objectively have no relevance, and without even a single statement explaining why you think there would be relevance.
This means we obviously don't understand each other and I'm not sure that will change anytime soon.
The primary reason here is that you keep misusing terminology even after the correct definitions and terminology have been explained to you. If you insist on making up your own language where words have different meanings than what scientists use, then communication will remain impossible.
Even Einstein understood that there's a non-local change in the speed of light where is locally the speed of light is constant. This is where the quote before somebody had something to say about Einstein mentioning the constancy of the speed of light and a constant gravitational field not a changing gravitational acceleration. Big the gravitational field changes the non-local speed of light changes but the local speed of light remains the same.
You are again confusing things. Einstein probably looked at true variable speed of light theories but these didn't work out (I say probably, because wikipedia indicates that he did but the article is not well written and it is not relevant to confirm). In GR the speed of light is a universal constant, different apparent results when you measure measure things non-locally is essentially an illusion. It is true that that is what you measure, but what you measure is not what the speed of light is defined as, you are measuring something different.
I don't care about Harolds Religion. I do about care about the relevance of what his paper had to say about space time. Warptechs references him because it illustrates a point about general relativity.
No, he appears to reference him because he is unwilling to stick to reputable sources. Scientology is not a proper religion, but a cult. It has damaging, dangerous, and anti-science beliefs. If you look at the page I linked to, you will also see other evidence that Puthoff simply has done bad science.
He mentions a non-local change in the speed of light. There are many other scientist who also point out the exact same thing. I don't judge people and everything they do based on their religion. rather I filter out what useful and throw away what I don't find useful.
That last bit is basically cherry picking, and it is a great way to get results you want, rather than correct answers. Instead you should look at research done that actually follows the scientific method, and then not perform any cherry picking.
what's really irrelevant is you bringing in the vsl variable speed of light concepts which probably indicate a change in the measured local speed of light which may change over the eons. the concept is just simple general relativity which also collapses into special relativity.
No, VSL is an entirely different thing. The universal constant c is a universal constant in GR. VSL proposes that it is not a universal constant, however I have yet to see a VSL theory supported by data and rigorous analysis.
Now if you exist in a region where the non-local speed of light is slower than the rest of non-local speed of light then there is a possible non-local faster than the normal speed of the light.
This sentence is either incoherent or irrelevant. The number that matters is the universal constant c, which by definition is measured locally. If you go at sufficiently high relativistic speeds, you could only age a few weeks on a trip to alpha centauri. This does not mean that you traveled 50 times the speed of light. That might be your average "proper velocity" but proper velocity mixes reference frames, and is not what anyone means when they refer to FTL travel. Your talk of "non-local speed of light" is simply you adding unnecessary confusion. Non-local measurements of the speed of light means that you are mixing frames, just like "proper velocity" mixes frames. There are times where it can tell you something meaningful. It is simply irrelevant when the question is FTL travel.
The speed of light can be defined as c equals 1 divided by the square root of the magnetic permeability times the electric permittivity or something like that. Go look it up if you want to nitpick.
That is the propagation velocity of electromagnetic waves. In free space it will be equal to the universal constant c "speed of light" since photons are massless as far as we can tell. But this equivalence breaks down as soon as you add materials.
In some materials when you modify the local dielectric it changes the speed of light in that material. SpaceTime is also like a dielectric then you can modify it to change the non local speed of light but in doing so you modify the physical matter so that it measures a constant speed of light.
Again, this is not what has been measured in the lab. Electromagnetic waves travel slower than the speed of light when propagating through pretty much any medium, but the presence of such mediums has never affected the universal constant c itself in any experiment. (And there are many experiments where this would show up due to c being relevant to gravity in GR and the fine structure constant.)
I will try and make this simple
It is simple:
The speed of propagation of electromagnetic waves
and
The universal constant which limits how fast anything including energy, mass, and information can travel
are 2 separate concepts with separate definitions, and the first is only equal to the second in very special circumstances.
You keep complicating this by changing and mixing the definitions, and bringing in other irrelevant concepts such as "non-local speed of light" which you appear to have multiple distinct definitions for in just this one post.
The reference to torpedo cavitation is about the same. you can move a torpedo faster through the gas bubble in the water then you can move the torpedo through the water.
There is another paper that was referenced that discusses extremely high energy waves in water in which the wave turns into a gas wave. I think this is related to shock physics and might relate to highly energetic gravitational waves moving through space-time. The gas wave can move faster than a sound wave moving through the water.
"Has similar sounding words" is not a basis for 2 things being related. The physics of a shockwave in air or gas is dramatically different than the physics of gravitational waves. If you want to claim otherwise show the parallels using math. In particular the speed of sounds is not even close to comparable to the speed of light (the universal constant), which is an absolute and fundamental limit
Surprise surprise it all relates to faster than light signals.
Except what you said before this references nothing about FTL signals, this statement is a complete non-sequiter. Your logic appears to be "you can move faster than the speed of sound, so you therefore can move faster than the speed of light." This logic is simply invalid, since the speed of sound, and the universal constant c are fundamentally different, just as the propagation speed of electromagnetic waves is different than the universal constant c.
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#61
by
dustinthewind
on 24 Apr, 2020 02:07
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Your relevance is a matter of opinion. What's relevant one person might be garbage to another.
Threads have topics. You quite frequently post things that objectively have no relevance, and without even a single statement explaining why you think there would be relevance.
What you don't get via your inflexibility in understanding is that they all tie in together. Propellant-less propulsion ties into manipulating space time ties into the mach effect ties into the alcubiere warp drive, ties into non-local change in the speed of light in general relativity (which you don't seem to understand) and non-local faster than normal c is the negative mass needed to make ftl work while still not violating moving locally faster than light.
Scientists have made many inventions from simple fundamental concepts which means a single simple fundamental concept can have lots of applications. One subject can easily cross over into others but if they are connected then they are. Science does not flourish under strict limiting of individual freedom of thought as should be obvious and it doesn't seem relevant if you don't seem to understand it, but I can't seem to help that because you don't seem to get it.
Woodward understand the non-local change in the speed of light in General Relativity.
Inertia and propulsion in general relativity: a reply to rodal...
In special relativity c is a simple constant. In general relativity c becomes a “locally measured invariant” because although the same number for the magnitude of c is obtained in all local tests, the value of c in non-local tests may differ from the local value. The commonplace example of this behavior is the speed of light near the event horizon of a black hole—as determined by a distant observer—tending to zero as the horizon is approached by the light. While c is a locally measured invariant, and G may be too
...
Rodal’s justification for making his assertion about the potential seems to be that the large potential due to distant sources can be treated as a constant, so space and time derivatives of that part of the potential vanish. But no part of the potential involved in the interaction can be treated as constant. As we will see in the next section where the work of Carl Brans is discussed, the locally measured Newtonian potential is a “locally measured invariant”—like the vacuum speed of light—and since locally measured invariants have non-local values that may differ from the locally measured value, space and time derivatives of locally measured invariants do not in general vanish.
Even gravitomagnetism suggests a non-local change in the speed of light with circular motion.
This means we obviously don't understand each other and I'm not sure that will change anytime soon.
The primary reason here is that you keep misusing terminology even after the correct definitions and terminology have been explained to you. If you insist on making up your own language where words have different meanings than what scientists use, then communication will remain impossible.
you don't even specify the terminology your referring to. Just accusations. Not a lick of flexibility in understanding.
Even Einstein understood that there's a non-local change in the speed of light where is locally the speed of light is constant. This is where the quote before somebody had something to say about Einstein mentioning the constancy of the speed of light and a constant gravitational field not a changing gravitational acceleration. Big the gravitational field changes the non-local speed of light changes but the local speed of light remains the same.
You are again confusing things. Einstein probably looked at true variable speed of light theories but these didn't work out (I say probably, because wikipedia indicates that he did but the article is not well written and it is not relevant to confirm). In GR the speed of light is a universal constant, different apparent results when you measure measure things non-locally is essentially an illusion. It is true that that is what you measure, but what you measure is not what the speed of light is defined as, you are measuring something different.
See the below page which highlights absolute time and motion with respect to local space time as Galilean Space-Time allowing FTL
Although the one-way speed of light is not constant in general (ie. when expressed in an arbitrary reference frame), the mean-speed c of a round-trip is again constant [2], what is in accordance with all experiments (like Michelson-Morley a.s.o.). It should be emphasized again that there has been no experiment which determined the one-way speed of light [3], since this would require the possibility of synchronizing physical clocks by some other means than finite-speed signals. Thus, in fact, some "experimental proof" of the constancy of the one-way speed of light has not been given so far.
***
Although non-local effects are a constituent of quantum mechanics, most physicists still believe in the validity of special relativity, because EPR-like effects have not allowed to transmit information at superluminal speeds so far. Yet, EPR-correlations remain a mystery if local realism is assumed to be valid. Therefore, the possibility of superluminal communication (and thus FTL travel) has been acknowledged by various authors, eg.
...
Some Arguments in Favour of Absolute Time
...
Second, it is well known that one can define a universal time, which appears in cosmological models. For instance, general relativity leads one to the Robertson-Walker metric [11], which describes the long-range structure of our universe:
...
Which is the real space-time structure? Both Galilean space-time and Minkowski space-time have appeared to be valid physical concepts. However, the absolute generality of relativistic covariance is set into doubt by the following arguments:
The time evolution of a quantum mechanical state has no covariant representation, because the "measurement process" cannot be described in a relativistically invariant manner.
EPR-like effects seem to indicate non-local (superluminal) processes.
It is impossible to construct a quantum time observable, so that no covariant 4-position operator exists.
From a cosmological perspective the existence of a preferred reference frame appears to be natural.
It has been argued that a solution to these incompatibilities could be the reintroduction of absolute time to physics. Thus, the concept of Galilean Space-Time might be the correct one after all. Incidentally, there are active research groups trying to experimentally detect the existence of a preferred reference frame in this context.
...
Conclusion: If our universe has a Newtonian background, ie. if there is an absolute time underlying the space-time continuum, then there is no threat on causality by superluminal processes, because time travel and its paradoxes are excluded a priori. And thus, within this framework, faster-than-light travel is possible, at least in principle.
I also argue it solves the twin paradox problem and leaves a changing non-local speed of light.
Sorry but I don't have the time to bother with the rest of this right now.
I don't care about Harolds Religion. I do about care about the relevance of what his paper had to say about space time. Warptechs references him because it illustrates a point about general relativity.
No, he appears to reference him because he is unwilling to stick to reputable sources. Scientology is not a proper religion, but a cult. It has damaging, dangerous, and anti-science beliefs. If you look at the page I linked to, you will also see other evidence that Puthoff simply has done bad science.
He mentions a non-local change in the speed of light. There are many other scientist who also point out the exact same thing. I don't judge people and everything they do based on their religion. rather I filter out what useful and throw away what I don't find useful.
That last bit is basically cherry picking, and it is a great way to get results you want, rather than correct answers. Instead you should look at research done that actually follows the scientific method, and then not perform any cherry picking.
what's really irrelevant is you bringing in the vsl variable speed of light concepts which probably indicate a change in the measured local speed of light which may change over the eons. the concept is just simple general relativity which also collapses into special relativity.
No, VSL is an entirely different thing. The universal constant c is a universal constant in GR. VSL proposes that it is not a universal constant, however I have yet to see a VSL theory supported by data and rigorous analysis.
Now if you exist in a region where the non-local speed of light is slower than the rest of non-local speed of light then there is a possible non-local faster than the normal speed of the light.
This sentence is either incoherent or irrelevant. The number that matters is the universal constant c, which by definition is measured locally. If you go at sufficiently high relativistic speeds, you could only age a few weeks on a trip to alpha centauri. This does not mean that you traveled 50 times the speed of light. That might be your average "proper velocity" but proper velocity mixes reference frames, and is not what anyone means when they refer to FTL travel. Your talk of "non-local speed of light" is simply you adding unnecessary confusion. Non-local measurements of the speed of light means that you are mixing frames, just like "proper velocity" mixes frames. There are times where it can tell you something meaningful. It is simply irrelevant when the question is FTL travel.
The speed of light can be defined as c equals 1 divided by the square root of the magnetic permeability times the electric permittivity or something like that. Go look it up if you want to nitpick.
That is the propagation velocity of electromagnetic waves. In free space it will be equal to the universal constant c "speed of light" since photons are massless as far as we can tell. But this equivalence breaks down as soon as you add materials.
In some materials when you modify the local dielectric it changes the speed of light in that material. SpaceTime is also like a dielectric then you can modify it to change the non local speed of light but in doing so you modify the physical matter so that it measures a constant speed of light.
Again, this is not what has been measured in the lab. Electromagnetic waves travel slower than the speed of light when propagating through pretty much any medium, but the presence of such mediums has never affected the universal constant c itself in any experiment. (And there are many experiments where this would show up due to c being relevant to gravity in GR and the fine structure constant.)
I will try and make this simple
It is simple:
The speed of propagation of electromagnetic waves
and
The universal constant which limits how fast anything including energy, mass, and information can travel
are 2 separate concepts with separate definitions, and the first is only equal to the second in very special circumstances.
You keep complicating this by changing and mixing the definitions, and bringing in other irrelevant concepts such as "non-local speed of light" which you appear to have multiple distinct definitions for in just this one post.
The reference to torpedo cavitation is about the same. you can move a torpedo faster through the gas bubble in the water then you can move the torpedo through the water.
There is another paper that was referenced that discusses extremely high energy waves in water in which the wave turns into a gas wave. I think this is related to shock physics and might relate to highly energetic gravitational waves moving through space-time. The gas wave can move faster than a sound wave moving through the water.
"Has similar sounding words" is not a basis for 2 things being related. The physics of a shockwave in air or gas is dramatically different than the physics of gravitational waves. If you want to claim otherwise show the parallels using math. In particular the speed of sounds is not even close to comparable to the speed of light (the universal constant), which is an absolute and fundamental limit
Surprise surprise it all relates to faster than light signals.
Except what you said before this references nothing about FTL signals, this statement is a complete non-sequiter. Your logic appears to be "you can move faster than the speed of sound, so you therefore can move faster than the speed of light." This logic is simply invalid, since the speed of sound, and the universal constant c are fundamentally different, just as the propagation speed of electromagnetic waves is different than the universal constant c.
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#62
by
meberbs
on 24 Apr, 2020 06:41
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Skipping the first part since it is baseless ad hominem, nonsensical statements that demonstrating misunderstandings of GR on your part, and a diversion into talk of Woodward including equating something based on sound math and standard GR (the Alcubierre drive) with his flawed theory, which isn't based on standard GR. Why Woodward's statements in general are wrong should be and has been covered in the relevant thread.
This means we obviously don't understand each other and I'm not sure that will change anytime soon.
The primary reason here is that you keep misusing terminology even after the correct definitions and terminology have been explained to you. If you insist on making up your own language where words have different meanings than what scientists use, then communication will remain impossible.
you don't even specify the terminology your referring to. Just accusations. Not a lick of flexibility in understanding.
Could you please actually read my post? (Even if you don't reply to everything at least read it rather than claiming I don't say something that I do.) I gave specific definitions on the differences between the universal constant c, and the speed of electromagnetic wave propagation. I also pointed out that you seemed to use "non-local speed of light" to mean multiple different things. And clarified that such measurements (for whichever definition of non-local speed of light you pick) are never what people mean when they refer to FTL, with an example for clarification.
In the past (but irrelevant right now) a common example has been your misuse of the term "effective mass" I have explained that one to you a number of times, and you have never acknowledged it.
Changing what words mean every other sentence as you do is not "flexibility" it simply prevents meaningful communication.
See the below page which highlights absolute time and motion with respect to local space time as Galilean Space-Time allowing FTL
It has been long since demonstrated that the predictions of special relativity which differ from Galilean relativity hold true (time dilation, etc.) This means that the whole page is a big compare and contrast between 2 things when we already know which one is right.
The link provides misleading information, avoiding saying the actual conclusions of several things to give the appearance of a question. For example it insists on assuming "local realism" and discussing the relevant implications, when the Bell's inequality tests have disproven local realism. This does not point to contradictions in the theory like they claim but to the falsehood of their assumption. While quantum gravity is a problem as they say, nothing else in the page is discussing GR, and QED combines special relativity and quantum perfectly well.
I also argue it solves the twin paradox problem and leaves a changing non-local speed of light.
There is no paradox in the "twin paradox" it is an unfortunately misleading name (and called a paradox because people who don't understand special relativity and do the calculations wrong think there is a paradox). The resolution to it can be determined by simply applying relativity correctly, you don't actually need GR. In the standard situation, one twin accelerates mid way through to turn around and meet up with the other. It is this acceleration that differentiates the 2 and makes that twin younger.
Before making assertions about which of us doesn't understand relativity, try doing a search on this and learning something:
https://www.scientificamerican.com/article/how-does-relativity-theor/(Note that while it calls pointing to the acceleration "misleading" it is the acceleration which differentiates the 2 which they do agree with , since "leaving a reference frame" is done by accelerating. They are correct though that it is not the act of acceleration that directly causes the difference in age.)
There is a thread somewhere about resolutions to FTL paradoxes. There are basically 2 options that were come up with and I am not convinced they are actually different in practice. The basic one is that if there is a basic underlying universal reference frame, and all FTL is always forward in time in that frame, which is what your link seems to suggest. However, it does not provide any test for the existence of such a frame. All existing experimental data matches with relativity. If there were a universal frame that means there would be a way to measure your velocity relative to it, such as the Michelson-Morley experiment attempted to do. Not only has no such frame been found but no one even has a testable hypothesis proposing one that is actually consistent with existing experimental data.
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#63
by
dustinthewind
on 07 May, 2020 15:37
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I stand corrected in thinking that vsl theories were related to light changing over the eons. Must have been something else I read. I was correct that even Einstein understood the non-local variability in the speed of light however. It was Einstein that was formulating the vsl theory of the speed of light in 1911.
https://en.m.wikipedia.org/wiki/Variable_speed_of_lightEinstein's updated proposals (1905–1915)Edit
Albert Einstein went through several versions of light speed theory between 1905 and 1915, eventually concluding that light speed is constant when gravity does not have to be considered[5] but that the speed of light cannot be constant in a gravitational field with variable strength.
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#64
by
meberbs
on 07 May, 2020 16:47
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I stand corrected in thinking that vsl theories were related to light changing over the eons. Must have been something else I read. I was correct that even Einstein understood the non-local variability in the speed of light however. It was Einstein that was formulating the vsl theory of the speed of light in 1911.
In none of your previous posts that I can tell did you claim that VSL is the speed of light changing over time (and I don't know what just "light" changing over time would even mean), you instead made incorrect conflations of VSL with effects such as time dilation in GR. The true constant c changing over time would be a true VSL theory. You appear to still be asserting the same thing you were before about "non-local" things, without defining how exactly something can be measured non-locally.
Your excerpt from wikipedia leaves out important context that I already addressed:
You are again confusing things. Einstein probably looked at true variable speed of light theories but these didn't work out (I say probably, because wikipedia indicates that he did but the article is not well written and it is not relevant to confirm). In GR the speed of light is a universal constant, different apparent results when you measure measure things non-locally is essentially an illusion. It is true that that is what you measure, but what you measure is not what the speed of light is defined as, you are measuring something different.
And to emphasize it again: That wikipedia article is poorly written, especially around that part. I can't be bothered to do the research required to properly re-write it, but it at least has the main point that any attempt Einstein made at VSL theory did not match experimental data.
