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#1760 by Bob012345 on 20 Sep, 2017 18:33
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This test rig will prove CofE and CofM is not violated
How exactly are you going to show that conservation of momentum is not violated?
The only ways to do this are for either the device to not move, or for you to demonstrate that there is some form of exhaust.
Which is really the bigger problem for you, that TT thinks momentum is conserved in a working EMDrive, a position professor Woodward appeared to hold until recently, or if a proven force exists without an exhaust showing momentum isn't conserved (at least locally)? Personally, I didn't mind Woodward's old position. Either way would lead to energy devices with greater output than input.
Please cite a source for your unsourced claim thatQuotemomentum is conserved in a working EMDrive, a position professor Woodward appeared to hold until recently
The paper I read from him in the Journal of the British Interplanetary Society was actually arguing against White's QV theory for the EM Drive.
http://www.jbis.org.uk/paper.php?p=2016.69.331
please cite a source where he commented about <<a working EMDrive>>. Are you suggesting that he previously stated that a working EM Drive would conserve momentum and now he states that a working EM Drive would not conserve momentum? I am sure he would say that conservation of momentum has to be satisfied before, now and in the future.
Sorry, I didn't meant to imply prof. Woodward said there was "a working EMDrive" that was sloppy sentence construction. I meant if there was a working propellent less propulsion device. I have professor Woodward's paper to the effect that he believed momentum and energy were conserved locally. It seems to me TT's position and prof. Woodward's position, each for their respective candidate propellent less devices were similar. That's all I meant. And I got the first part about prof. Woodward's position change from a post by Paul March a few weeks ago in the Woodward Effect forum msg. 976. I'll be disappointed if the members of the team now disagree about what prof. Woodward's position really is. Besides, I got that also from the slide published with the names of the whole NIAC team on it.
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#1761 by Rodal on 20 Sep, 2017 18:37
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Hi. I think we should keep Mach Effect related discussions on their own thread, until there is enough evidence that Emdrive exists and that it could be explained as a extended GR/Mach effect phenomenon.
I don't see why a well reasoned discussion of Machian explanations (based on experiments and theory) for the EM Drive would be prevented in this thread. If people (not me!) think that there is an extra-Machian effect not present in General Relativity that is responsible for acceleration of the EM Drive they should be allowed to discuss that, just as much as they are allowed to discuss any other explanation: Shawyer's explanation, Minotti's explanation, McCulloch's explanation. There is no such thing as a thread for "Mach Effects in the EM Drive" or about "Unruh effects in the EM Drive" or about "Newtonian effects in the EM Drive", or about "General Relativity effects in the EM Drive", or about "Quantum Mechanics effects in the EM Drive" nor do I think there should be when people are still debating whether the experiments are an artifact and if not what is responsible.
Mods have been patient with us so far, but let's not over-stress that good disposition.
All that has happened here is that some have asserted an extra-Machian effect (not present in GR) explanation and I have been asking them to cite experiments showing such extra-Machian effect (not already present in GR). The reason being, that all the experiments I am aware of (since Shapiro all the way to Gravity Probe B) that have looked for such extra-Machian effects have failed to find any such effect not already present in General Relativity. Maybe somebody will find such an experiment. Maybe the assertions will fall off on their own. Just like it happens with all the other explanations. We are all curious to find out what could explain what is claimed by Shawyer and others. -
#1762 by Rodal on 20 Sep, 2017 18:58
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..Sorry, ..
Perhaps the discussion you are referring to was about energy conservation issues in GR under dynamic conditions, see these fine points, which occur for example when trying to localize the energy in gravitational waves: https://physics.stackexchange.com/questions/35431/is-the-law-of-conservation-of-energy-still-valid, but I can't speak for other people. My opinions are only my own
In any case, in this thread we should only speak about the EM Drive, not about other, different, devices. -
#1763 by Bob012345 on 20 Sep, 2017 19:24
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..Sorry, ..
Perhaps the discussion you are referring to was about energy conservation issues in GR under dynamic conditions, see these fine points, which occur for example when trying to localize the energy in gravitational waves: https://physics.stackexchange.com/questions/35431/is-the-law-of-conservation-of-energy-still-valid, but I can't speak for other people. My opinions are only my own
In any case, in this thread we should only speak about the EM Drive, not about other, different, devices.
Thanks, I'm pretty clear. But I certainly hope you agree with the slide I referenced that has your name on it.
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#1764 by M.LeBel on 20 Sep, 2017 19:59
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The CoM is an empirical law, a description. Kick (precise) some object in space (no additional forces) and it will keep going with proper mv. We must understand that the reason it keeps going (inertia) is not because it read the CoM law (or Newton’s) ! It keeps going for other unknown factors (not empirical-Newton-GR etc.) but because of some pilot wave or something specifically associated with the object. It is not inconceivable that we may recreate some such “pilot wave” (or whatever) in the emDrive device, later requiring an adjustment or extension to the CoM.
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#1765 by wicoe on 20 Sep, 2017 20:20
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The CoM is an empirical law, a description. Kick (precise) some object in space (no additional forces) and it will keep going with proper mv. We must understand that the reason it keeps going (inertia) is not because it read the CoM law (or Newton’s) ! It keeps going for other unknown factors (not empirical-Newton-GR etc.) but because of some pilot wave or something specifically associated with the object. It is not inconceivable that we may recreate some such “pilot wave” (or whatever) in the emDrive device, later requiring an adjustment or extension to the CoM.
Actually, CoM/CoE are not just empirical laws, they follow from one of the most fundamental symmetries of physics (i.e. that the same physical process exhibits the same outcomes regardless of place and time - refer to Noether's theorem). -
#1766 by tchernik on 20 Sep, 2017 20:52
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I don't see why a well reasoned discussion of Machian explanations (based on experiments and theory) for the EM Drive would be prevented in this thread. If people (not me!) think that there is an extra-Machian effect not present in General Relativity that is responsible for acceleration of the EM Drive they should be allowed to discuss that, just as much as they are allowed to discuss any other explanation: Shawyer's explanation, Minotti's explanation, McCulloch's explanation. There is no such thing as a thread for "Mach Effects in the EM Drive" or about "Unruh effects in the EM Drive" or about "Newtonian effects in the EM Drive", or about "General Relativity effects in the EM Drive", or about "Quantum Mechanics effects in the EM Drive" nor do I think there should be when people are still debating whether the experiments are an artifact and if not what is responsible.
All that has happened here is that some have asserted an extra-Machian effect (not present in GR) explanation and I have been asking them to cite experiments showing such extra-Machian effect (not already present in GR). The reason being, that all the experiments I am aware of (since Shapiro all the way to Gravity Probe B) that have looked for such extra-Machian effects have failed to find any such effect not already present in General Relativity. Maybe somebody will find such an experiment. Maybe the assertions will fall off on their own. Just like it happens with all the other explanations. We are all curious to find out what could explain what is claimed by Shawyer and others.
OK, I get it. GR/Machian effects for explaining the Emdrive could very well be on topic, the same as the other explanations as long as there is no definitive answer to the actual existence, or lack thereof, of the Emdrive and to its internal functioning.
My concern here is: do the mods see it that way? or are we losing focus? -
#1767 by Monomorphic on 20 Sep, 2017 21:31
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I was able to pick up the ISO 10 spindle oil today locally and it works just as anticipated. The viscosity seems right between antifreeze and soybean oil.
Here is a dual calibration pulse to see how repeatable they are. Eyeballing it, I would say the pendulum is now just below critically damped.
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#1768 by Rodal on 20 Sep, 2017 21:44
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I was able to pick up the ISO 10 spindle oil today locally and it works just as anticipated. The viscosity seems right between antifreeze and soybean oil.
What is the rationale to conduct the test with damping high enough such that it is critically damped?
Here is a dual calibration pulse to see how repeatable they are. Eyeballing it, I would say the pendulum is now critically damped.
Wouldn't it be better to run it underdamped?
* most microNewton thrust measurement torsional pendulum measurements are done with an underdamped pendulum
* the critically damped condition is at the edge of a different solution to the differential equation of motion of the torsional pendulum. Wouldn't it be better to be definitely on the underdamped side (for the whole range of temperatures that you may encounter during testing) such that the solution to the equation of motion display always the same type of solution? If you run critically damped at today's temperature, the pendulum may exhibit overdamped conditions at a colder temperature tomorrow, and underdamped conditions at a hotter temperature the day after tomorrow. Ideally one would run always at the same temperature, hence same damping, but given that assuring perfect temperature control is impossible, wouldn't it be better to be on the underdamped side for all temperatures?
Following quotes are from: http://hpepl.ae.gatech.edu/sites/default/files/Journal_Articles/JPP%20V33%20No3%20MayJune2017_ThrustMeasurement.pdf
hat tip to Mr. Peter's great post https://forum.nasaspaceflight.com/index.php?topic=42978.msg1725093#msg1725093
CalTech's "Recommended Practice for Thrust Measurement in Electric Propulsion Testing"QuoteAs noted previously, the thrust stand sensitivity can vary with
frequency for dynamic thrust loads. To achieve a flat response for
relevant thrust input frequencies, the stand should be designed to be
underdamped with a damping ratio of ∼0.5–0.6 and a natural
frequency much higher than the input frequencies. High natural
frequencies can be achieved with high stiffness or a low moment of
inertia. Of these strategies, decreasing the moment of inertia is
preferred; otherwise, sensitivity (which scales inversely with
stiffness) will be sacrificed for a flat response. The amplification in
response near the resonant frequency has been exploited in at least
one design [4] to increase sensitivity. In this approach, a pulsed
thruster was fired every half-period at the natural frequency of a
minimally damped torsional thrust stand in order to amplify the
amplitude of the stand oscillation and achieve sub-micronewton
sensitivityQuotethe maximum
overshoot, and the settling time ts (the time required for the variations
around the steady-state value to drop to within 2% of that value).
Figures 2 and 3 illustrate the effect of damping ratio on these
parameters. A damping ratio of 0.4 ≤ ζ ≤ 0.8 generally gives a good
step response. For this range, ts 4∕ζωnQuote. Thrust stands used in
impulse measurements are typically underdamped pendulums that
are allowed to oscillate at their natural frequency after an impulse
perturbationQuoteThe known calibration impulse will perturb the natural motion of
the stand and cause it to ring or oscillate at its natural frequency.
Figure 14 shows a plot of LVDT voltage as a function of time for a
torsional balance that has experienced an impulsive perturbation. The
impulse causes the stand to deflect with an initial velocityΔx_0 and a
maximum range of travel, defined as the difference between the first
peak and the first valley in the oscillatory response. These parameters
can be estimated by fitting a damped sinusoid (for underdamped
pendulums) to the data.QuoteThe known calibration impulse will perturb the natural motion of
the stand and cause it to ring or oscillate at its natural frequency.
Figure 14 shows a plot of LVDT voltage as a function of time for a
torsional balance that has experienced an impulsive perturbation. The
impulse causes the stand to deflect with an initial velocityΔx_0 and a
maximum range of travel, defined as the difference between the first
peak and the first valley in the oscillatory response. These parameters
can be estimated by fitting a damped sinusoid (for underdamped
pendulums) to the data.
Others in this thread have previously argued for critically damped and overdamped measurement systems, but I have found such argumentation unconvincing in the final analysis. -
#1769 by Monomorphic on 20 Sep, 2017 21:51
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What is the rationale to conduct the test with damping such that it is critically damped?
Wouldn't it be better to run it underdamped?
The only rationale is this is the first test with the new dampening fluid. It is just chance that this test ended up being just under critically-damped. I can adjust the dampening paddle to get underdamped now if desired.
With regard to temperature, I do plan on trying to conduct all tests at as close to the same temperature as possible. Part of the advantage of waiting until October is it will be cooler. It is easier for me to control the temperature in the workshop during cooler weather as all I need is a space heater. -
#1770 by M.LeBel on 20 Sep, 2017 21:53
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The CoM is an empirical law, a description. Kick (precise) some object in space (no additional forces) and it will keep going with proper mv. We must understand that the reason it keeps going (inertia) is not because it read the CoM law (or Newton’s) ! It keeps going for other unknown factors (not empirical-Newton-GR etc.) but because of some pilot wave or something specifically associated with the object. It is not inconceivable that we may recreate some such “pilot wave” (or whatever) in the emDrive device, later requiring an adjustment or extension to the CoM.
Actually, CoM/CoE are not just empirical laws, they follow from one of the most fundamental symmetries of physics (i.e. that the same physical process exhibits the same outcomes regardless of place and time - refer to Noether's theorem).
- Actually, CoM and CoE came before Noether’s theorem (So, inspired from, re-derived but not follow)
- “fundamental symmetries of physics”. Still, physics is empirical. (based on experience)
- If my “not inconceivable” was clearly and absolutely wrong for everyone, both meberbs and Rodal would have been long gone from this thread. (not a proof, but some indication)
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#1771 by Rodal on 20 Sep, 2017 22:47
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Back then I calculated the damping ratios based on your previous runs.What is the rationale to conduct the test with damping such that it is critically damped?
Wouldn't it be better to run it underdamped?
The only rational is this is the first test with the new dampening fluid. It is just chance that this test ended up being just under critically-damped. I can adjust the dampening paddle to get underdamped now if desired.
With regard to temperature, I do plan on trying to conduct all tests at as close to the same temperature as possible. Part of the advantage of waiting until October is it will be cooler. It is easier for me to control the temperature in the workshop during cooler weather as all I need is a space heater.
Do you recall what damping ratio did I previously calculate you had at that time (when you were using SeeShell's antifreeze)?
Notice that the CalTech authors recommend 0.4 ≤ ζ ≤ 0.8 or 0.5 ≤ ζ ≤ 0.6 as ideal:
CalTech's "Recommended Practice for Thrust Measurement in Electric Propulsion Testing"QuoteAs noted previously, the thrust stand sensitivity can vary with
frequency for dynamic thrust loads. To achieve a flat response for
relevant thrust input frequencies, the stand should be designed to be
underdamped with a damping ratio of ∼0.5–0.6 and a natural
frequency much higher than the input frequencies. High natural
frequencies can be achieved with high stiffness or a low moment of
inertia. Of these strategies, decreasing the moment of inertia is
preferred; otherwise, sensitivity (which scales inversely with
stiffness) will be sacrificed for a flat response. The amplification in
response near the resonant frequency has been exploited in at least
one design [4] to increase sensitivity. In this approach, a pulsed
thruster was fired every half-period at the natural frequency of a
minimally damped torsional thrust stand in order to amplify the
amplitude of the stand oscillation and achieve sub-micronewton
sensitivityQuotethe maximum
overshoot, and the settling time ts (the time required for the variations
around the steady-state value to drop to within 2% of that value).
Figures 2 and 3 illustrate the effect of damping ratio on these
parameters. A damping ratio of 0.4 ≤ ζ ≤ 0.8 generally gives a good
step response. For this range, ts 4∕ζωn -
#1772 by Mr. Peter on 20 Sep, 2017 23:27
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Do you recall what damping ratio did I previously calculate you had at that time (when you were using SeeShell's antifreeze)?
Dr. Rodal,
It was ζ =0.23 afair
https://forum.nasaspaceflight.com/index.php?topic=41732.msg1648589#msg1648589
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#1773 by Monomorphic on 20 Sep, 2017 23:45
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Do you recall what damping ratio did I previously calculate you had at that time (when you were using SeeShell's antifreeze)?
Dr. Rodal,
It was ζ =0.23 afair
https://forum.nasaspaceflight.com/index.php?topic=41732.msg1648589#msg1648589
Yes, ~0.2 is what I recall as well. I'm glad CalTech recommends more damping. ζ =0.22 was very loose. It was hard to keep the noise level down because of the electronics. With 0.4 ≤ ζ ≤ 0.8, noise levels will be easier to mitigate. -
#1774 by spupeng7 on 21 Sep, 2017 01:33
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4) Time is a property of matter and the space it exists within is a human (animal) construct which depends upon a point perspective.A differential in the rate of time is gravity (quote from Unruh, posted n times already).
A lot of interesting comments, LeBel, but it may be incorrect gravity, whether a force or observation, is an outcome of time's variation. It depends on the nature and limits of space's distortion (note: I separated time) and if gravity exists. Here's a handful of options;
1) Time and space are the same, placing the same bounds on space's distortion as time. In the absence of matter, space will expand and time will advance at a constant and will slow to near zero in presence of abundant mass. This definition prevents space from contracting, only limiting its expansion, and thus gravity must be an actual force - One locked to the local rate of spacetime, defined by mass's presence. note: it'd also mean our universe isn't cyclical, but a one-off.
2) Time and space are aspects of one system called spacetime. But while time expands at a rate from near zero to one, space can expand or contract at rates between one and -one. Both time and space's distortion is again dependent on mass and again returns to "one" in mass's absence. It can thus be stated gravity is only an observation of spacetime's distortion due to mass.
3) Time is a dimension and space an unrelated, decreasing field. Again, time and space are retarded by mass, but space would not return to expansion in mass's absence. The rate of space's expansion decreases with time, but appears otherwise (aka: dark energy) due to the geometry of the universe. Gravity is again an observation of space's contraction due to mass while time is separately, but similarly effected - thus there is no relation between time and gravity other than appearance. -
#1775 by spupeng7 on 21 Sep, 2017 02:13
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...
So you think that the explanation for the EM Drive is something in Mach's principle that is not present in Einstein's General Relativity (GR), you ignore all the tests (starting with Shapiro and ending with Gravity Probe B) that have conclusively shown no such extra-Mach-effect,
Rodal,
the flaw in GR is quantum mechanics. Why is this so hard for you to accept? GR relies on the assumption that mass has inertia, due to some undefined internal mechanism, without any explanation as to why that inertia varies with the degree of time dilation that it exists within relative to the greater universe. The experiment that calls GR into question is the emdrive itself, which defies explanation within GR.
...
I ask you for experimental proof
and your experimental proof for this extra-Mach effect being responsible for the EM Drive experimental claim is....the EM Drive experiment itself?
And you wonder why I find unacceptable the claim that there are extra-Mach effects not present in GR?
----
And you say that this extra-Mach effect, not present in GR, is what,...quantum mechanics?
Mach, the man that could not even accept the existence atoms, you find responsible for... quantum mechanic effects?
https://www.nasa.gov/mission_pages/gpb/gpb_results.html
Rodal,
you attack the person (Mach) not the idea. But no, I have no 'time' for quantum mechanics, I think it mostly a delusion born of the point perspective the weakness of which has already been made clear by Einstein.
What I think is that the photon is a bandwagon fallacy, a contrived solution made necessary by the inability of folk, including Einstein, to take in the notion that time is complex. By 'time is complex' I mean that time is not and cannot be linear when it runs at different rates in different places, and that the only math which encompasses the truth of this situation is that time has a complex conjugate. The combination of real time (whose rate never varies at any point even when that point is in motion) and its complex conjugate, is the structure of time which allows energy to move by the mechanisms we understand to be 'photons'. Emission and absorption being at locations coincident in complex time. Difficult to visualize but worth the effort.
Then again, I believe the complex conjugate to be a fundamental component of all mathematics because it arises naturally in all analysis starting with the quadratic equation. The coincidence which allows absorption of a quantum to be an intimate and immediate part of its emission, can only exist in complex time and I can find no other explanation which satisfies all the experimental evidence.
So, good Dr Rodal, must I confess my curiosity. If the emdrive does eventually provide us with abundant thrust, what will be your explanation? -
#1776 by Rodal on 21 Sep, 2017 02:25
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...you attack the person (Mach) not the idea...
spupeng, The Mach Principle states that the distant stars are responsible for inertia. It is not a statement about quantum mechanics. Your statement that saying this implies an attack on Mach is unfair, as he never accepted even the existence of the atom, much less quantum mechanics (which had not even seen Schrödinger and Heissenberg by the time Mach passed away in 1916). Give Mach credit for inspiring Einstein and for his work in supersonic flow instead. Asking for experimental proof of a Principle is also not attacking anybody.
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#1777 by ThinkerX on 21 Sep, 2017 05:15
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...you attack the person (Mach) not the idea...
spupeng, The Mach Principle states that the distant stars are responsible for inertia. It is not a statement about quantum mechanics. Your statement that saying this implies an attack on Mach is unfair, as he never accepted even the existence of the atom, much less quantum mechanics (which had not even seen Schrödinger and Heissenberg by the time Mach passed away in 1916). Give Mach credit for inspiring Einstein and for his work in supersonic flow instead. Asking for experimental proof of a Principle is also not attacking anybody.
Doctor Rodal - I thought you'd authored a mathematical paper that supported (?) the Woodward/Mach Drive/Effect, and possibly (?) linked it with the EM Drive. Apologies, memory is a bit hazy.
I also seem to remember you being involved with some sort of NASA side (?) program involving Woodward/Mach Drive or effect. -
#1778 by Rodal on 21 Sep, 2017 12:29
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.. I thought you'd authored a mathematical paper that supported (?) the Woodward/Mach Drive/Effect, and possibly (?) linked it with the EM Drive. Apologies, memory is a bit hazy.
* it is well-known that Einstein recognized Mach as one of his main sources of inspiration
I also seem to remember you being involved with some sort of NASA side (?) program involving Woodward/Mach Drive or effect.
* what constitutes Mach's principle is subjective because Mach was very vague and did not formulate it mathematically. Bondi (an expert in general relativity that supported steady-state cosmology) co-authored a well known paper that defines 10 possible interpretations of Mach's principle.
* Einstein recognized his theory of General Relativity does not incorporate all possible interpretations of Mach's principle, only some of them.
* none of these versions of Mach's principle deals with quantum mechanics. Mach died in 1916, before Quantum Mechanics (Schrodinger , Heissenberg, etc.) was fully developed.
* Sciama wrote his paper (1953) at the time that Sciama himself describes as before the revolution in astronomy: a time in which there were no astronomical measurements of cosmic background radiation, neutron stars, black holes, dark mass, dark energy etc.
* In the late 1950's to early 1960's there were many theories (Brans-Dicke prominent among them) that claimed extra-Machian effects not present in General Relativity.
* Starting with Shapiro at MIT there have been up to now a large number of investigations of all such extra-Machian effects
* all measurements, including the recent Gravity Probe B reveals the complete absence of any such extra-Machian effects. All measurements are in complete agreement with Einstein's general relativity
* what we are discussing is whether there are any super-Machian effects not present in General Relativity. All measurements so far reveal there is no such thing
* A couple of years after Sciama, Davidson showed in a paper that the theory that was described by Sciama already existed: it is called Einstein's general relativity.
* as far as me linking any of this to the EM Drive I have posted Internet links to Montillet's work in this thread as Montillet's work pertains to the EM Drive. I am not Montillet. Montillet is in Switzerland, I am in the USA. My opinions are my own.
* the gravitational term dependent on the second time derivative of variable mass density can be shown to exist in Einstein's general relativity. I do not claim the existence of any extra-Machian effect not present in general relativity.
* to those that claim extra-Machian effects that are absent in general relativity I have asked them to explain what these effects are and what experimental evidence exists for such effects and how such existence can be compatible with our cosmological measurements. -
#1779 by flux_capacitor on 21 Sep, 2017 12:38
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.. I thought you'd authored a mathematical paper that supported (?) the Woodward/Mach Drive/Effect, and possibly (?) linked it with the EM Drive. Apologies, memory is a bit hazy.
* it is well-known that Einstein recognized Mach as one of his main sources of inspiration
I also seem to remember you being involved with some sort of NASA side (?) program involving Woodward/Mach Drive or effect.
* what constitutes Mach's principle is subjective because Mach was very vague and did not formulate it mathematically. Bondi (and expert in general relativity) co-authored a well known paper that defines 10 possible interpretations of Mach's principle. Einstein recognized his theory of General Relativity does not incorporate all possible interpretations of Mach's principle, only some of them.
* Sciama wrote his paper (1953) at the time that Sciama himself describes as before the revolution in astronomy: a time in which there was no cosmic background radiation, neutron stars, black holes, dark mass, dark energy etc.
* In the late 1950's to early 1960's there were many theories (Brans-Dicke prominent among them) that claimed extra-Machian effects not present in General Relativity.
* Starting with Shapiro at MIT there have been up to now a large number of investigations of all such extra-Machian effects
* all measurements, including the recent Gravity Probe B reveals the complete absence of any such extra-Machian effects. All measurements are in complete agreement with Einstein's general relativity
* what we are discussing is whether there are any super-Machian effects not present in General Relativity. All measurements so far reveal there is no such thing
* A couple of years after Sciama, Davidson showed in a paper that the theory that was described by Sciama already existed: it is called Einstein's general relativity.
* as far as me linking any of this to the EM Drive I have posted links to Montillet's work. Montillet is not using any extra-Machian effects
* the gravitational term dependent on the second time derivative of variable mass density can be shown to exist in Einstein's general relativity
As you say, there are several interpretations of Mach's principle. The "lightest" one is to say that the inertia of a body is dependent of the other masses around, involving nothing more than gravitation. The "strong" Mach's principle on the other hand, as advocated by Jim Woodward (see my previous post where I cite him and where his specific view on that subject is made evident) – as well as Fred Hoyle and Jayant Narlikar with their own theory of gravity, and now Heidi Fearn with the Gravitational Absorber Theory derived from it – implies that inertia of bodies comes from all the masses in the entire universe instantaneously interacting with each others, through retarded/advanced waves. This "strong Mach's principle" is a view that must be ADDED to general relativity (i.e. the addition of some kind of Wheeler-Feynman radiative field applied to gravity) in order to make the instantaneity of gravitational interaction possible, i.e. a gravitational interaction source of inertia that is not limited to the speed limit c of "plain vanilla" general relativity.
What is your own view on Mach's principle, among all the possibilities it suggests?
