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#480
by
93143
on 13 Sep, 2014 01:21
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No, it's the part where the weak force is involved that confuses me. I have Woodward's book; he's talking about gravity waves. Something about quadrupole radiation with the rest of the universe as part of the system. And as far as I know there is no universally accepted theory that couples gravity with any of the other forces.
Perhaps you could explain a little, rather than just assuming I already know all this and am being deliberately obtuse?
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#481
by
Rodal
on 13 Sep, 2014 01:33
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At the time that Wheeler and Feynman conceived their theory (late 1940's) not much was known about the Weak Force. We are here 70 years later, with all kinds of experimental results including the Weak Force's arrow of time, and its role in radiation.
Yes, you are correct that we don't have a Unified theory of Gravitation and Quantum Gravity. And yes, Dr. Woodward can have a theory that uses Wheeler Feynman absorber theory (although Feynman himself abandoned that theory) and ignore the Weak Force if he likes. I would prefer to consider present theories that are compatible with present experimental knowledge, including the Weak Force, and that explain known phenomena in a more unified way than it was possible in the 1940's.
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#482
by
93143
on 13 Sep, 2014 01:35
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Does the weak force have anything to do with gravity waves specifically? Because that's what Woodward is talking about. He's not talking about the Wheeler-Feynman theory in electrodynamics; he's repurposing the concept for gravity.
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#483
by
Rodal
on 13 Sep, 2014 01:46
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Sorry, I don't understand this statement <<Does the weak force have anything to do with gravity waves specifically? Because that's what Woodward is talking about. He's not talking about the Wheeler-Feynman theory in electrodynamics; he's repurposing the concept for gravity.>>.
Please explain how this works: does Dr. Woodward end up with gravity waves that travel at infinite speed?
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#484
by
93143
on 13 Sep, 2014 02:01
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Of course not. The whole point of the advanced/retarded wave concept in W-F is that you can get instantaneous action at a distance without breaking causality; no momentum or energy or information need travel faster than c.
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#485
by
Rodal
on 13 Sep, 2014 02:07
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<<the advanced/retarded wave concept in W-F is that you can get instantaneous action at a distance without breaking causality>>
We disagree:
instantaneous action at a distance means an infinite speed
and yes, Wheeler-Feynman absorber theory is well-known to break causality. Both Wheeler and Feynman admitted this. Feynman wrote about this in at least one of his books.
Now, 70 years later, after Feynman dropped the W-F theory long ago, we have at least 3 arrows of time:
1) The cosmological arrow of time: from the order of the Big Bang, through Inflation through Dark Energy accelerating expansion (this last one unknown at the time of W-F).
2) The 2nd law of Thermodynamics arrow of time in the macro world we inhabit.
3) The Weak Force arrow of time at the Quantum Mechanics level (not well understood at the time of W-F theory).
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#486
by
Rodal
on 13 Sep, 2014 02:21
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<< I have Woodward's book; he's talking about gravity waves. Something about quadrupole radiation with the rest of the universe as part of the system.>>
I don't have any of Dr. Woodward's books. I only read some of his papers. My statement concerning radiation was entirely based on his video. Thank you for explaining that he meant quadrupole radiation. Therefore what he meant was the radiation of the gravity waves, and he didn't mean anything to do with actual particle radiation --therefore nothing to with the Weak Force in that sense, I agree.
Still I make my argument regarding the three arrows of time, and what we have learnt during the last 70 years since W-F, Dark-Energy accelerating expansion involvement for the Cosmological arrow of time and the Weak Force for the Quantum Mechanics arrow of time.
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#487
by
Rodal
on 13 Sep, 2014 02:32
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You can disregard the Quantum Mechanics (Weak Force) arrow of time, and the 2nd law of Thermodynamics arrow of time (both at your own peril), concerning a theory of inertia and gravitation. I would rather not disregard them.
But I don't understand how you or Dr. Woodward can disregard the Cosmological arrow of time.
And it is strange to consider a General Relativity theory where one divorces completely from the Quantum Mechanics arrow of time (the Weak Force), but postulates that gravitational waves travel effectively with infinite speed, as with "action at a distance" (a concept only known in Quantum Mechanics entanglement).
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#488
by
cuddihy
on 13 Sep, 2014 02:33
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Goat Guy: no page of calculations are required for a prima facie rejection of the premise.
Any scheme that requires mass-energy input to the object to equal the change in the object(s) mass-energy is by definition a normal rocket, not 'propellantless'.
'Propellantless', whether Woodward or EM or whatever *assumes* less mass-energy required to be input to the rocket than the rocket gains during this process. Period.
So argue the premise is rediculous all you want. But the calculation of difference between input and change doesn't add anything.
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#489
by
93143
on 13 Sep, 2014 02:41
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instantaneous action at a distance means an infinite speed
Are you sure you know what Wheeler-Feynman absorber theory actually says? 'Cause I was pretty sure I understood the gist of it, and what you've said here is wrong according to my understanding. Nothing in the theory travels faster than
c, and that remains true in Woodward's gravinertial version.
Still I make my argument regarding the three arrows of time
I don't find this a strong argument. The only one of those three that seems potentially relevant is the cosmological one, but it's a bit circular (unless I've misunderstood it) and doesn't seem to bear on the nature of fundamental physical interactions.
Basically, just because some things are time-asymmetric doesn't mean all things are. You yourself stated that the weak force is the only one of the four forces that seems to be, which as far as I can tell leaves the door pretty wide open for what Woodward is describing...
I'm not saying he's right. But I don't think you've made much of a case for saying he must necessarily be wrong.
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#490
by
Rodal
on 13 Sep, 2014 02:52
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instantaneous action at a distance means an infinite speed
Are you sure you know what Wheeler-Feynman absorber theory actually says? 'Cause I was pretty sure I understood the gist of it, and what you've said here is wrong according to my understanding. Nothing in the theory travels faster than c, and that remains true in Woodward's gravinertial version.
The statement is absolutely correct on the first count.
Instantaneous action at a distance means an INFINITE speed, in any theory, not just W-F theory. The only proviso you could make would be to involve Quantum Mechanics here all of a sudden and claim that instantaneous is restricted to the Planck time
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#491
by
93143
on 13 Sep, 2014 03:00
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I was using the phrase in the context of W-F theory, where (if I'm not greatly mistaken) it means something other than what it seems to mean on its face.
As far as I can tell, the idea is basically that a particle that does something feels the reaction from other particles instantaneously, but the other particles actually react at time t0+r/c. This is where the reversed-time waves come in - the initial action resulted in a normal retarded wave, which propagated at c, and the other particles on receiving this wave produced an advanced wave in response which traveled back in time to converge at the point of initial action.
In the context of M-E, it would mean that the thruster feels the effect of the distant matter reacting to its operation instantaneously, but the distant matter doesn't actually react for billions of years.
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#492
by
Rodal
on 13 Sep, 2014 03:03
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I have not seen Dr. Woodward's "re-purposing" of W-F for gravitational waves. If Dr. Woodward's formulation results in a causal gravitational wave, then it canNOT be "instantaneous action at a distance". But that is NOT what Dr. Woodward answered in the video.
Do you claim that Dr. Woodward misspoke in the video? Or that Dr. Woodward meant that instantaneous action is not an infinite speed? How long a period of time is instantaneous according to Dr. Woodward?
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#493
by
aceshigh
on 13 Sep, 2014 03:05
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I think we are only missing Dr Woodward and Dr White themselves in this topic right now
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#494
by
Rodal
on 13 Sep, 2014 03:06
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<<the thruster feels the effect of the distant matter reacting to its operation instantaneously>>
Well instantaneous means an Infinite speed. How does the thruster "feel" the effect of distant matter instantaneously? Does the thruster have a special means of feeling that is traveling through wormholes and not through spacetime?
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#495
by
Rodal
on 13 Sep, 2014 03:09
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Does the thruster have a special means of feeling distant matter that is traveling through ANOTHER DIMENSION, one of the infinitesimally small extra dimensions of string theory and it is wormholing through that extra dimension and hence avoiding normal spacetime?
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#496
by
Rodal
on 13 Sep, 2014 03:11
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Actually, one of Dr. White's papers invoked a string theory manifold with 1 extra dimension (3+1), having 4 space dimensions...But I haven't seen anything by Dr. Woodward invoking extra dimensions...
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#497
by
Rodal
on 13 Sep, 2014 03:16
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The "Chung-Freese" metric with 3+1 dimensions.... NO experimental evidence whatsoever for that. But you are free to consider it if you like. I would rather consider a Cosmological arrow of time myself, I think that there is much more evidence for that...
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#498
by
Rodal
on 13 Sep, 2014 03:22
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And to be fair to Dr. White, he only invoked the Chung-Freese 3+1 metric to see how far he could push the warp field drive concept. I don't fault him for that, it was an interesting exercise.
Dr. White did not invoke the Chung-Freese 3+1 to justify action at a distance.
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#499
by
93143
on 13 Sep, 2014 03:36
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Perhaps you should slow down and read my whole post a little more carefully.
There is no instantaneous communication. There is an instantaneous reaction that results from communication forward and then backward in time, at c. The distant matter does not feel the interaction at the same time the thruster does.
[NB for anyone reading this: this is not the result Woodward derived. It is an explanation he brought in afterward to make sense of the implications of his result, and does not have to be accepted in order to take his experimentation or even his Mach-effect equation seriously.]
