Steve Giddings, Theoretical Physicist; Professor, Department of Physics, University of California, Santa Barbara: "For the 2014 Edge Question, I wrote that apparently our fundamental concept of spacetime is ready for retirement, and it needs to be replaced by a more basic quantum structure. There are multiple reasons for this."
What scientific idea is ready for retirement? Steve Giddings: "Spacetime. Physics has always been regarded as playing out on an underlying stage of space and time. Special relativity joined these into spacetime... (...) The apparent need to retire classical spacetime as a fundamental concept is profound..."
Can special relativity's spacetime be retired without retiring at least one of Einstein's 1905 postulates? Einsteinians?
Pentcho Valev
Thomas Howard Ray replied on Jan. 4, 2016 @ 13:02 GMT
Akinbo,
The times are
relative .
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John R. Cox replied on Jan. 4, 2016 @ 21:45 GMT
Tom,
at least you're doing better than me. I haven't even gotten a nibble and I've got my light-weight tackle of symmetrical spin axial of precession all rigged with a selection of Mr. Wiggly baits, fan casting the orthogonal intersection of three complex planes... and nothin' from the school of Sheephead bottom feeding on QM's prediction of pentaquarks without a rationale of what actually adding the spin characteristics of two additional quarks onto which planes will cause the precession to do. It will get wobbly again. o,o,o,o,@S^0 jrc
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Akinbo Ojo replied on Jan. 5, 2016 @ 09:13 GMT
Happy new year Steve Dufourny.
@ Tom, you will make a good politician. "The times are
relative", relative to what?
Let me repeat the question: (As seen by an observer/ experimenter), Which of two clocks in uniform relative motion (say 100m/s) does the special theory require to work more slowly?
@ Pentcho, before you accuse me falsely concerning, "there is no such thing as a false postulate", what is the meaning of 'postulate'? Postulate is a mere statement not requiring contradiction directly. Its contradiction or falsity can only be indirect by finding that its predictions are untrue. In that sense, constant speed of light is a postulate, it is its predictions that can be used to attack it not the statement itself which remains what it is, an assumption.
Anyway, I don't want to get embroiled in how words are used.
Regards,
Akinbo
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Thomas Howard Ray replied on Jan. 5, 2016 @ 15:58 GMT
Thomas Howard Ray replied on Jan. 5, 2016 @ 16:24 GMT
Akinbo,
While Pentcho struggles to explain the theory of optics without a speed of light constant, let me revive a post of mine from 2013, in this thread:
I find interesting:
"One proposal being studied describes black holes and their environments as a network of Hilbert spaces (a Hilbert space for any quantum mechanical system defines all possible states that the system can...
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Akinbo,
While Pentcho struggles to explain the theory of optics without a speed of light constant, let me revive a post of mine from 2013, in this thread:
I find interesting:
"One proposal being studied describes black holes and their environments as a network of Hilbert spaces (a Hilbert space for any quantum mechanical system defines all possible states that the system can be in). In the conventional picture of a black hole, locality prevents the Hilbert space of the interior of the black hole from influencing the Hilbert space of the exterior of the black hole."
For good reason. The quantum configuration space according to Bell's result cannot be mapped onto physical space without a nonlocal model. Therefore, quantum configuration space in the Hilbert space behind the event horizon is assumed simply connected and local, while the Hilbert space outside the event horizon has to be assumed multiply connected and nonlocal. If it seems paradoxical that simply connected space adjoining multiply connected space is not itself multiply connected -- that's because it *is* a paradox. Either the interior quantum configuration space maps nonlocally to the exterior space -- or the exterior space outside the event horizon is simply connected, not multiply conected, and all the space inside and outside the black hole horizon is simply connected.
Giddings chooses nonlocality to resolve the paradox. Does he have to? If one accepts the Hilbert space model of quantum configuration space, there is no way out; the choice is singular and correct.
In the continuous functions of quantum field theory, though, locality is everywhere. The Hilbert space doesn't work to preserve locality except as Giddings has described it: constrained by the boundary of a black hole event horizon. Giddings thinks he has found a way out. The article continues:
"In Giddings' model, however, the Hilbert spaces can exchange information. This allows a black hole to slowly evaporate, but not before it has dumped the information contained within into the environment."
Problem is, this does not resolve the paradox -- "the environment," the space outside the event horizon, is nonlocal. So the mathematical model is accurate; the quantum configuration space of the black hole interior maps onto physical space with a nonlocal model, consistent with Bell's result. There's a catch:
A physical observer sufficiently far from the event horizon has no concept of "fast" or "slow" information leakage. All she sees is on the 2-dimension surface of the event horizon, and those events are suspended in time, not dynamic, with no exchange of information between events inside and outside the horizon.
The article continues:
"The idea is that local quantum field theory can be derived as an approximation of this more fundamental underlying structure, in the same way that non-relativistic Newtonian physics can be derived from relativistic Einsteinian physics."
Except that quantum field theory is everywhere local, not bounded by anything except the speed of light, and nothing physical. It's also inaccurate that non-relativistic Newtonian physics derives from Einstein relativity -- Einstein's relativity is an extension of Newton's physics as Newton is an extension of Galilean relativity. There's no discontinuity, no gap where relativity doesn't apply.
Giddings seems aware of the conundrum, and is willing to eject spacetime from the physics canon: "Spacetime is doomed." If it is, Giddings' model doesn't do the job. The paradox created by the discontinuous dumping of information from the assumed local, simply connected quantum-configured black hole into the classical simply connected space outside the horizon, tells us at least three things:
1. There is no boundary between the quantum configuration space of the black hole, and "the environment." (All the space is simply connected.)
2. If the quantum configuration space cannot map onto the physical space without a nonlocal model, as Bell's result avers, the quantum configuration space behind the black hole event horizon is not local and not simply connected.
3. Nonlocality -- not spacetime -- is doomed.
Spacetime and quantum field theory nicely coexist with a continuum of Euclidean space, generalized to n-dimension topology. We simply don't need assumptions of Hilbert spaces and nonlocality.
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Akinbo Ojo replied on Jan. 6, 2016 @ 15:17 GMT
Tom,
I have read your post. Most of the concepts are preferred by the mathematically inclined like yourself. Concepts like nonlocality, spacetime, etc. The only statement that made most sense to me was where you said there can be no exchange of information between events inside and outside the horizon. This I agree with because based on the classical model, nothing can escape from a black hole. To me the Hawking process (whereby two particles are formed and one falls into the hole, while the other escapes) leading to black hole evaporation is flawed.
Concerning your answers to the questions I asked -
A: Which of two clocks in uniform relative motion does the special theory require to work more slowly? Do you have an answer to this?
T: The times are
relativeA: "The times are relative", relative to what?
T:
The speed of lightThe impression this gives is that times of the two clocks are relative to the speed of light. That is, whether a clock works more slowly or faster than another is relative to the speed of light. That means, the speed of light affects the rate of clocks in different ways and is not the same to every clock. I thought the speed of light was absolute and the same to all observers according to SR?
In any case, your answer that the times are relative to the speed of light avoids telling us which of the two clocks runs more slowly.
Akinbo
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Thomas Howard Ray replied on Jan. 6, 2016 @ 15:59 GMT
Akinbo, this is so painful to explain to people like you and Pentcho who are convinced that something is amiss -- but where?
"In any case, your answer that the times are relative to the speed of light avoids telling us which of the two clocks runs more slowly."
All motion is
relative to the speed of light. The speed of light is
absolute. No observer frame is
privileged. Given these three facts, it should be obvious that each observer perceives the other's clock running slowly, so demonstrating that there
no absolute time.I'll issue you the same challenge as Pentcho. Try explaining refraction without a constant finite speed of light -- then extrapolate that result from Newtonian physics to relativity at the speed of light limit.
If a clock is a rest relative to an observer, it is the moving clock which runs more slowly (time dilation). Because all motion is relative, however, an observer in a moving frame of reference is entitled to say that the at-rest observer's clock runs more slowly.
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John R. Cox replied on Jan. 6, 2016 @ 16:25 GMT
Tom,
I should be focusing on personal responsibilities right now, but am also seeing better what you are wrapping up in the topological package of spherical v. cubical space. It may help Akinbo to recognize what Hamilton apparently had, That 4 equal axes do not have to intersect for three to be mutually perpendicular inside a cube and that as time and space both exist on each of the 4 then motion is that fourth axial choice of direction. Inside R3, all 4 must intersect, and wherein "Ding-Dong the which is dead." jrc
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John R. Cox replied on Jan. 6, 2016 @ 19:27 GMT
Akinbo,
In Topology the length of an axis goes from 0 to 1, in R3 and R4 the axis of the same lengths intersect making an origin of 0 and going out to o.5 + or -.
In a topological sphere the 4 intersect at a mutual scalar value of o.5 and it is only initial choice of direction of which ends are 0. In R3, if the 4th axis is motion, then time exists outside the sphere and you will keep seeking which clock should move slower. In R4, the fourth axis is going to have the same dilemma seeking which direction is motion. In topological space, the 4 axes can define both a cube and a sphere because they can, but don't have to, intersect; where in R3 and R4 they must intersect and limited to light velocity only 3 orthogonal axis can and must intersect with the midpoints of the sides. Topologically; the initial choice of orthogonal direction is analogous to choice of 'right hand rule' of electromagnetic induction or its negative polar vector of 'left hand rule' which the Bell theorem mistakes for a simple polar vector. I really gotta stop dwelling on this but have reached a pleasing step on my learning curve, yet have to concentrate on necessities. Try looking at your world like the spacetime you experience IS 'mostly' flat, but dwell in that topological cube of non-intersecting axes. Your motion doesn't have to intersection with any absolutely defined mutually perpendicular axis. HNY - jrc
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Georgina Woodward replied on Jan. 6, 2016 @ 22:55 GMT
Hi Akinbo,
I hope this will be helpful. The observer observers the other's clock either by receipt of light, and so it is seen, or by receipt of a time signal send from the clock whether sent by radio or other kind of EM wave. It will travel to the recipient at the speed of light. It is a category error to assume the output of the signal IS the other's material clock.( It is unconventional to say so but it is self evident to me from considering this matter from the perspective of sensory perception.) Both observers are generating an 'idea' of the other's clock from the received signal and their 'ideas' will have reciprocal delay if they are stationary relative to each other or travelling so that they are not accelerating. Absolute time does not pertain to what is seen. You told me yourself that Newton was well aware of that fact.
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Thomas Howard Ray replied on Jan. 7, 2016 @ 01:38 GMT
Georgina, you couldn't be more wrong. There is nothing in special relativity that requires personal interpretation. Einstein would have found that abhorrent.
The theory " is contained entirely within the postulates."
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Georgina Woodward replied on Jan. 7, 2016 @ 02:08 GMT
Tom ,
What Einstein would think about my explanation is of no concern to me. He is dead and so unlikely to be troubled by it. The human observers that I included to keep things simple could be replaced by inorganic detectors that would receive the objective information and could instead output the reciprocally delayed time measurements. I was not faithfully reiterating Einstein's work but explaining how there can be reciprocal slowing of observed time for both observers, which is the issue Akinbo asked about. Just repeating -it is relative- does not help someone to 'get' why it must be so. Why it must be so is not because of the notions of external space-time, "fields of clocks", absence of absolute time but simply as I have explained. A scientific theory shouldn't be a straight jacket that prevents original thought on the subject.
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Thomas Howard Ray replied on Jan. 7, 2016 @ 02:48 GMT
"I was not faithfully reiterating Einstein's work but explaining how there can be reciprocal slowing of observed time for both observers ..."
That's why you got it wrong.
"Just repeating -it is relative- does not help someone to 'get' why it must be so."
Because there is no 'why' to it. That there is no privileged reference frame explains a physical phenomenon reconciled in a mathematical model (Lorentz transformation). Remember what I said about the independence of model and phenomenon?
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Georgina Woodward replied on Jan. 7, 2016 @ 03:14 GMT
Tom,
I did not get it wrong.I explained why it is that two observers can both see the other's clock slowed compared to his own. That is what was puzzling Akinbo. You are talking about a particular representation. 'There is no privileged reference frame' is terminology that applies if you are going to use reference frames for the explanation,which comes from thinking about how time is distributed, and that comes from Einstein thinking about clock time co-ordination. The fields of clocks giving different reference frames are not real but an explanatory device for co-ordination of time signals over distance.I am only talking about the real phenomenon of EM signal transmission not the imaginary external distribution of time.
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Thomas Howard Ray replied on Jan. 7, 2016 @ 03:25 GMT
"The fields of clocks giving different reference frames are not real but an explanatory device for co-ordination of time signals over distance."
Georgina, they are absolutely real. Space cannot be measured independently of time.
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Georgina Woodward replied on Jan. 7, 2016 @ 03:30 GMT
P.S. Are you saying that once a phenomenon has been 'reconciled in a mathematical model' no one is permitted to say why it happens except by reference to that model?
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John R. Cox replied on Jan. 7, 2016 @ 04:03 GMT
It's a clock, you don't have good enough eyes to see a clock one second away.
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Thomas Howard Ray replied on Jan. 7, 2016 @ 04:06 GMT
Georgina Woodward replied on Jan. 7, 2016 @ 04:12 GMT
Tom,
Space-time is not space. Space-time is constructed from signal receipt, it comes 'into being' as the output of those signals. That is a physical phenomenon that does not have to involve human observers. Space-time is not the EM radiation in space, that only has the potential to become a space-time output. As space-time only comes into being upon receipt of the signals the (field)clocks measuring time in space-time are imaginary.
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Georgina Woodward replied on Jan. 7, 2016 @ 04:34 GMT
John, Tom
seeing the clock was optimistic : ) I did talk about radio signals or other EM signal. It could be a TV signal that is seen. Anything else amuse, bemuse or annoy you John?
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Georgina Woodward replied on Jan. 7, 2016 @ 05:01 GMT
John,
By the way, I left a reply to Akinbo explaining why there can not be a return to Newtonian time on "New Podcast: Shifty Neutrinos Win Big, a Cosmic Test for Time, Existential Risk, & "Thunderbirds" Meets Quantum Physics". I'm letting you know about that as you were supporting his criticism.
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Eckard Blumschein replied on Jan. 7, 2016 @ 05:57 GMT
Pentcho, Tom,
The essence of SR is encrypted within what Einstein himself called the seeming contradiction between his two postulates. I prefer seeing SR more obviously and originally anchored within Einstein's silly Poincaré synchronization.
Tom wrote: "an observer in a moving frame of reference is entitled to say that the at-rest observer's clock runs more slowly." If an observer is entitled to say something then he is a person, and as such he may define his own immediate surrounding (A) as moving relative to something (B) at rest. In principle, he may either attribute A to his car and B to the street or the other way round. The question how fast two identical stop clocks at these locations do run can be objectively decided with a joint measurement performed by persons who are not bound to the subjective attribution of rest either to car or street - provided these persons agreed on a reasonable symmetrical one-way synchronization.
I agree with Georgina on that Tom/Einstein made a "category error"-
Two-way synchronization has problems:
- It is asymmetrical while light propagates isotropically.
- I was ad hoc fabricated as to formally justify Lorentz' attempt to rescue the aether hypothesis after Michelson in 1881/1887 didn't confirm a assumed aether; it is therefore not trustworthy.
- It cannot be reasonably applied to any model of how light propagates, no matter whether as a corpuscle or as a wave.
- It led to many so far unresolved paradoxes.
++++
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Pentcho Valev replied on Jan. 7, 2016 @ 09:31 GMT
Eckard,
I agree with Tom that "the theory is contained entirely within the postulates". That is, Einstein's 1905 postulates predetermine the conclusions of SR, no matter what Einstein or anybody else has said.
Of course I still insist that one of the postulates is false and the theory should be discarded.
Pentcho Valev
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Georgina Woodward replied on Jan. 7, 2016 @ 11:02 GMT
Penthco,
I also agree that the way in which SR works is because of the way in which it is formulated. I thought it would be helpful to mention that there is no problem with reciprocal observed delay as that is what occurs as a mere consequence of non instantaneous signal transmission even without any reference to SR. There is no need to ask which clock is the slow one, they can both be seen to be slower. Reciprocal delay doesn't suddenly become counter-intuitive when put into SR unless one is thinking that what is observed is the clock itself (category error). Perhaps I should have also mentioned that each observer can consider them-self stationary and the other to be moving.A person in a moving car sees the pedestrian whizzing past, the pedestrian sees the person in the car whizzing past. That's also every day experience and not counter-intuitive.
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Akinbo Ojo replied on Jan. 7, 2016 @ 11:44 GMT
Hi All,
Tom, must you think using only mathematics?
And Georgina, on "...That is what was puzzling Akinbo", not really. The question was posed by one more respected than myself, but mathematical people like Tom either refuse to answer or get the straight forward question muddled up in so many twists and turns. I than Tom for at least volunteering an answer, although painfully as he himself says. Eckard's post contains common sense, which is more superior to mathematical sense and I repost: "...If an observer is entitled to say something then he is a person, and as such he may define his own immediate surrounding (A) as moving relative to something (B) at rest. In principle, he may either attribute A to his car and B to the street or the other way round. The question how fast two identical stop clocks at these locations do run can be objectively decided with a joint measurement performed by persons who are not bound to the subjective attribution of rest either to car or street..."
How can one "relative" clock measure another "relative" clock? Does that make any sense?
Anyway, I recommend Prof. Herbert Dingle's book, specially for Tom and JRC, and for any who have not read it:
Science at the Crossroads, you may go straight to pages 7 and 27.
Regards,
Akinbo
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Georgina Woodward replied on Jan. 7, 2016 @ 11:58 GMT
Akinbo,
Yes I see now you have re-posted the original question.(I was addressing your later comments to Tom.)
I would have said the -output from the received signal seen- by each observer is relative and can be compared to the time on his own near clock. It is not the clock substantial objects that are relative. Each near clock is showing what Einstein called Proper time.
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Georgina Woodward replied on Jan. 7, 2016 @ 12:02 GMT
Akinbo. P.S. I left a reply explaining why there can not be a return to Newtonian time on "New Podcast: Shifty Neutrinos Win Big, a Cosmic Test for Time, Existential Risk, & "Thunderbirds" Meets Quantum Physics"
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Thomas Howard Ray replied on Jan. 7, 2016 @ 15:22 GMT
Akinbo,
"Tom, must you think using only mathematics?"
I could, but then I would be just as confused and wrong as the rest of you.
It's important to understand that special relativity is a mathematically compete theory. You don't add or subtract anything from it without destroying it. Even Pentcho understands this.
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Thomas Howard Ray replied on Jan. 7, 2016 @ 17:30 GMT
Akinbo,
Now I understand the source of your confusion, in Dingle's long-discredited argument:
"According to the special theory of relativity, two similar docks, A and B, which are in uniform relative motion and in which no other differences exist of which the theory takes any account, work at different rates. The situation is therefore entirely symmetrical, from which it follows that if A works faster than B, B must work faster than A. Since this is impossible, the theory must be false." (p.27)
This is NOT what special relativity says. Two clocks sharing uniform motion are synchronized at the origin. This means that they work at the SAME rate. If one or the other leaves this frame of reference, the moving clock runs slower than its partner. When brought back to relative rest, there is no doubt about the asymmetry, because the moving clock will have lost time.
When not at relative rest, each observer is entitled to say that the other's clock is slow, because of their state of relative motion. But when at rest in uniform motion, there is a definite asymmetry.
Akinbo, you really need to steep yourself in the mainstream literature before you go off half-cocked. You even managed to quote Einstein out of context, so it's obvious you have not studied the literature.
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