Author Topic: EM Drive Developments - related to space flight applications - Thread 10  (Read 1635189 times)

Offline Rodal

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...So let's say it's more like a "brane theory" in your example but without the brane, superstring, supersymmetry and all the quantum stuff. Only general relativity. That's the main difference....
OK, but this argument in this thread page started by a quotation about someone arguing against Quantum Gravity, the main objection being about whether gravity can be quantized (about whether gravitons are real).  Because what string theory and other quantum gravity theories attempt to explain is the graviton.  So, to me people railing against string (M) theory and the graviton is similar to Ernst Mach railing against Einstein's theory of relativity and against the existence of atoms, a statement which he made, amazingly, in the 20th century:



Just substitute nowadays "string theory" for "relativity" and "gravitons" for "atoms" in Mach's statement, and it would read by a hypothetical 21st century of Mach:

Quote from: a hypothetical 21st century Mach
I can accept the  (M) theory of strings as little as I can accept the existence of gravitons


And the railing against unusual objects like strings and branes, compactified extra dimensions and the multiverse sounds like the railing against the concept of black holes and gravitational waves (both of which Einstein himself questioned at some points in his life).

And hopefully everybody will agree that Mach's statements against relativity and against atoms was proven wrong.

And similarly those that argued against the existence of black holes, the accelerated expansion of our Universe, and against the existence of gravitational waves were also proven wrong.

So keep an open mind as to whether gravitation will be quantizable, whether gravitons exist, and whether there are such things as compactified extra dimensions.
« Last Edit: 09/15/2017 06:33 pm by Rodal »

Offline flux_capacitor

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{…}So keep an open mind as to whether gravitation will be quantizable, whether gravitons exist, and whether there are such things as compactified extra dimensions.

Of course, we must stay opened to all scientific possibilities, if these theories are well constructed. Not oppose them, only disprove them, which is a different thing. If it can't be done with observations (Popper's falsifiability) due to the limitation of today's technology, verifying their fundamental mathematics and internal logic is a good start.

As for me, I hope gravity will be quantized!

Offline Space Ghost 1962

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(FWIW, WRT quantum gravity, consider To Solve the Biggest Mystery in Physics, Join Two Kinds of Law:)
Quote from: Robbert Dijkgraaf
Reductionism breaks the world into elementary building blocks. Emergence finds the simple laws that arise out of complexity. These two complementary ways of viewing the universe come together in modern theories of quantum gravity.

Offline RotoSequence

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...So let's say it's more like a "brane theory" in your example but without the brane, superstring, supersymmetry and all the quantum stuff. Only general relativity. That's the main difference....
OK, but this argument in this thread page started by a quotation about someone arguing against Quantum Gravity, the main objection being about whether gravity can be quantized (about whether gravitons are real).  Because what string theory and other quantum gravity theories attempt to explain is the graviton.  So, to me people railing against string (M) theory and the graviton is similar to Ernst Mach railing against Einstein's theory of relativity and against the existence of atoms, a statement which he made, amazingly, in the 20th century:



Just substitute nowadays "string theory" for "relativity" and "gravitons" for "atoms" in Mach's statement, and it would read by a hypothetical 21st century of Mach:

Quote from: a hypothetical 21st century Mach
I can accept the  (M) theory of strings as little as I can accept the existence of gravitons


And the railing against unusual objects like strings and branes, compactified extra dimensions and the multiverse sounds like the railing against the concept of black holes and gravitational waves (both of which Einstein himself questioned at some points in his life).

And hopefully everybody will agree that Mach's statements against relativity and against atoms was proven wrong.

And similarly those that argued against the existence of black holes, the accelerated expansion of our Universe, and against the existence of gravitational waves were also proven wrong.

So keep an open mind as to whether gravitation will be quantizable, whether gravitons exist, and whether there are such things as compactified extra dimensions.

I don't think it's fair to compare Mach's dismissal of atoms with today's critics of supersymmetric string theory. It's my understanding that the Large Hadron Collider has placed enough limits on the mass-energies of potential supersymmetric pair particles that Supersymmetry is starting to create more problems than it solves.  :-\
« Last Edit: 09/15/2017 07:38 pm by RotoSequence »

Offline Rodal

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...
I don't think it's fair to compare Mach's dismissal of atoms with today's critics of supersymmetric string theory. It's my understanding that the Large Hadron Collider has placed enough limits on the mass-energies of potential supersymmetric pair particles that Supersymmetry is starting to create more problems than it solves.  :-\

1) Supersymmetry does not necessarily equal (all possible versions of) string theory or M-theory

2) Non-existence of supersymmetry does not necessarily equal non-existence of gravitons


Mach's dismissal of atoms in the 20th century is indeed an embarrassing abomination that is indeed without comparison.  It says more about Mach's mind than about the state of science at that time (early 20th century).
« Last Edit: 09/15/2017 07:50 pm by Rodal »

Offline flux_capacitor

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I don't think it's fair to compare Mach's dismissal of atoms with today's critics of supersymmetric string theory. It's my understanding that the Large Hadron Collider has placed enough limits on the mass-energies of potential supersymmetric pair particles that Supersymmetry is starting to create more problems than it solves.  :-\

I share your thoughts about supersymmetry. This is not only with the LHC admittedly. The XENON-1T experiment (aimed to detect WIMPs, and especially the neutralino, the main supercandidate for cold dark matter of positive mass, according to the leading theory) which is rightly technologically dimensioned for that purpose, is a failure according to its lead scientists Elena Aprile who published her results by May 2017. These researchers are sinking into despair, according to specialized popular science magazines of my country: the hunt for WIMPs has ran for thirty years, without a single positive result.

However as Rodal said, other theories don't need supersymmetry. But SuSy was quite important for cosmology and particle physics, especially wrt to the CDM and the Higgs boson.

Offline RonM

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I don't think it's fair to compare Mach's dismissal of atoms with today's critics of supersymmetric string theory. It's my understanding that the Large Hadron Collider has placed enough limits on the mass-energies of potential supersymmetric pair particles that Supersymmetry is starting to create more problems than it solves.  :-\

1) Supersymmetry does not necessarily equal (all possible versions of) string theory or M-theory

2) Non-existence of supersymmetry does not necessarily equal non-existence of gravitons


Mach's dismissal of atoms in the 20th century is indeed an embarrassing abomination that is indeed without comparison.  It says more about Mach's mind than about the state of science at that time (early 20th century).

Things are not looking good for supersymmetry, but that doesn't mean M-theory is in trouble.

However, M-theory proponents need to make predictions that can be experimentally verified. The universe is what it is, not what we want it to be.

BTW, we are way off topic.

Offline Rodal

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...BTW, we are way off topic.
At least we are discussing issues that pertain to space science   ;)
« Last Edit: 09/15/2017 08:31 pm by Rodal »

Offline Mulletron

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Just had an idea for an experiment. It's a Cavendish experiment. It consists of two masses off the balance, and two identical EMdrives, one on each end of the balance. It's not necessarily a thrust experiment. It's to see if G is any different and whether or not it's dependent on orientation of the drives.

And I can feel the change in the wind right now - Rod Stewart

Online meberbs

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Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.
This issue was also discussed in scalar-tensor theories starting with Brans-Dicke, but all tests up to now have rather confirmed the universality (in spacetime, to other epochs) of G, and very much narrowed the range in which G could be possible to vary

Since I was referring to the PV Model of GR, where we use a refractive index. The "coordinate" speed of light is given by c/K. Force is an invariant so;

c4/G = (c/K)4/(G/K4)

So G is a variable dependent on the refractive index. In the experiments, they use the "local" frame where "c" is a constant and K=1. Under those conditions, they will not measure a change in G either. This is based on dimensional analysis.
Since you are stating that the coordinate speed of light is c/K, then you still need the universal constant c, which is equal to the proper speed of light (that thing you referenced as measured in the local frame), but also has fundamental meaning that extends beyond electromagnetic waves. The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

There are theories that examine what if constants such as G are not constant across spacetime, but as Rodal said, experiments (mostly astronomical observations I think) currently don't support this. (These theories have the constants themselves change as if some property of the vacuum, not just adjustments to the coordinate speed of light due to general relativistic effects that are calculated based on the constants.)

Offline WarpTech

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Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.
This issue was also discussed in scalar-tensor theories starting with Brans-Dicke, but all tests up to now have rather confirmed the universality (in spacetime, to other epochs) of G, and very much narrowed the range in which G could be possible to vary

Since I was referring to the PV Model of GR, where we use a refractive index. The "coordinate" speed of light is given by c/K. Force is an invariant so;

c4/G = (c/K)4/(G/K4)

So G is a variable dependent on the refractive index. In the experiments, they use the "local" frame where "c" is a constant and K=1. Under those conditions, they will not measure a change in G either. This is based on dimensional analysis.
Since you are stating that the coordinate speed of light is c/K, then you still need the universal constant c, which is equal to the proper speed of light (that thing you referenced as measured in the local frame), but also has fundamental meaning that extends beyond electromagnetic waves. The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

There are theories that examine what if constants such as G are not constant across spacetime, but as Rodal said, experiments (mostly astronomical observations I think) currently don't support this. (These theories have the constants themselves change as if some property of the vacuum, not just adjustments to the coordinate speed of light due to general relativistic effects that are calculated based on the constants.)

Until you at least read and understand Puthoff's papers on the PV Model of GR, not to mention Joe Depp's revisions and my extensions, don't confuse people here with your assumptions. You don't know or care to understand the model, and it shows.

Offline Mulletron

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Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.
This issue was also discussed in scalar-tensor theories starting with Brans-Dicke, but all tests up to now have rather confirmed the universality (in spacetime, to other epochs) of G, and very much narrowed the range in which G could be possible to vary

Since I was referring to the PV Model of GR, where we use a refractive index. The "coordinate" speed of light is given by c/K. Force is an invariant so;

c4/G = (c/K)4/(G/K4)

So G is a variable dependent on the refractive index. In the experiments, they use the "local" frame where "c" is a constant and K=1. Under those conditions, they will not measure a change in G either. This is based on dimensional analysis.
Since you are stating that the coordinate speed of light is c/K, then you still need the universal constant c, which is equal to the proper speed of light (that thing you referenced as measured in the local frame), but also has fundamental meaning that extends beyond electromagnetic waves. The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

There are theories that examine what if constants such as G are not constant across spacetime, but as Rodal said, experiments (mostly astronomical observations I think) currently don't support this. (These theories have the constants themselves change as if some property of the vacuum, not just adjustments to the coordinate speed of light due to general relativistic effects that are calculated based on the constants.)

Until you at least read and understand Puthoff's papers on the PV Model of GR, not to mention Joe Depp's revisions and my extensions, don't confuse people here with your assumptions. You don't know or care to understand the model, and it shows.

Come on guys, just listen to Q.

And I can feel the change in the wind right now - Rod Stewart

Online meberbs

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Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.
This issue was also discussed in scalar-tensor theories starting with Brans-Dicke, but all tests up to now have rather confirmed the universality (in spacetime, to other epochs) of G, and very much narrowed the range in which G could be possible to vary

Since I was referring to the PV Model of GR, where we use a refractive index. The "coordinate" speed of light is given by c/K. Force is an invariant so;

c4/G = (c/K)4/(G/K4)

So G is a variable dependent on the refractive index. In the experiments, they use the "local" frame where "c" is a constant and K=1. Under those conditions, they will not measure a change in G either. This is based on dimensional analysis.
Since you are stating that the coordinate speed of light is c/K, then you still need the universal constant c, which is equal to the proper speed of light (that thing you referenced as measured in the local frame), but also has fundamental meaning that extends beyond electromagnetic waves. The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

There are theories that examine what if constants such as G are not constant across spacetime, but as Rodal said, experiments (mostly astronomical observations I think) currently don't support this. (These theories have the constants themselves change as if some property of the vacuum, not just adjustments to the coordinate speed of light due to general relativistic effects that are calculated based on the constants.)

Until you at least read and understand Puthoff's papers on the PV Model of GR, not to mention Joe Depp's revisions and my extensions, don't confuse people here with your assumptions. You don't know or care to understand the model, and it shows.
What assumptions do you think I made? I only looked at what you said and showed that there seems to be a contradiction, which may just be you being too imprecise in what you refer to as the speed of light and represent with the variable c.

If there is an issue with what I said, then please clarify what that issue is.

Offline OnlyMe

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My thinking about G isn't unmotivated. This appears to be happening, and in a predictable way. The question is, why? This is worth time and effort. Such a small deviation. Perhaps it's possible to have large deviations? Are we already and just don't understand it? Definitely worth exploring. Interesting comments in the phys.org article about planetary orbital resonances.

https://www.richarddawkins.net/2015/04/why-do-measurements-of-the-gravitational-constant-vary-so-much/

https://m.phys.org/news/2015-04-gravitational-constant-vary.html

Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.

So what you are saying above is that in the PV Model c is not universally constant. I don't personally have an issue with that, but it seems even the suggestion would require some supporting argument.

Offline OnlyMe

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...
I don't think it's fair to compare Mach's dismissal of atoms with today's critics of supersymmetric string theory. It's my understanding that the Large Hadron Collider has placed enough limits on the mass-energies of potential supersymmetric pair particles that Supersymmetry is starting to create more problems than it solves.  :-\

1) Supersymmetry does not necessarily equal (all possible versions of) string theory or M-theory

2) Non-existence of supersymmetry does not necessarily equal non-existence of gravitons


Mach's dismissal of atoms in the 20th century is indeed an embarrassing abomination that is indeed without comparison.  It says more about Mach's mind than about the state of science at that time (early 20th century).

Two problems with the above;

As you mentioned there are more versions of string theory than there are theorists. So defending string theory is almost like saying at least one has to be correct... but even that is not a certainty. Even hunting quail with a shotgun, does not guarantee you will come home with dinner... None of this is said in defense or rejection, of string theory. Only an assertion that we can imagine more things than we find to be real and that mathematics is a language that can be used to describe both what is and what we imagine might be. There is just no way to test the validity in this case. Whether there ever will be is an entirely different sort of discussion.

As it concerns Mach and what he could and couldn't accept, your position does not take into account that he was what 40-41 when Einstein was born and died only 10-11 years after special relativity was first published. It is not hard to understand that both relativity and the concept of atoms, were perhaps just too big a leap or change from the world he understood, to accept... Both of my grandfathers were born in the 1800's. My paternal grandfather told stories of gunfights in the streets and more. He also sat on the couch next to me when we landed on the moon and tried to convince the family that it was just a Hollywood movie. He never did accept that anyone walked on the moon, let alone went there. I don't think you are being fair to Mach, in your use of his words in this argument. It doesn't reflect the full context of the times and limitations, the quote is taken from.

« Last Edit: 09/15/2017 11:28 pm by OnlyMe »

Offline RSE

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The problem with the view that
Quote
the black hole is under this view a bridge of limited spatial extension with no central singularity, linking two Minkowski spaces
is

1) proving the stability of such a bridge, which appears unstable unless it contains negative mass-energy

2) the existence of another space is reminiscent of bridges in M-theory's multiverse, there is no experimental proof to decide between different theories (because black holes are...black)

Sure, it all boils down to allow either:
- an imaginary time and pure imaginary lengths inside the black hole, "beyond the event horizon" (as usually done)
- or consider that the interior of such a solution is physically (an mathematically) real.

PS : You're right this is unstable, and such solution represents a transient, very short, ephemeral bridge in time.
where is the bridge going into? if it comes back into our own Universe, shouldn't it display the other end of the bridge as a white hole? If so why is there no experimental evidence of such white holes (which should be easier to detect than black holes).

If the bridge goes into another brane, then I don't understand why people would be so much against M-theory and its multiverse of different branes and prefer this theory instead, since both seem to agree on bridges to other branes .

One could claim there was one "white hole" in our universe. We called it "The Big Bang". Note the correlation between the unstable bridge, and the short period of "inflation" at the start of "The Big Bang".

(Try not to laugh too hard. . . )

Offline WarpTech

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The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

This is not true in the PV Model of GR. I've been telling you to read these papers for months, but instead you just assume you know what you're talking about. In this model, the coordinate speed is all that matters, the speed we get from the Metric coefficients for the speed of light when we have a light-like metric, ds2 = 0, and not from local measurements where K=1 "by definition". We use the frame of a distant observer, far from gravitational fields to determine what K is. In this reference frame, c/K is what is measured non-locally, it's not constant and neither is G, ε0 or μ0. Read the papers, you will learn something.

Offline WarpTech

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My thinking about G isn't unmotivated. This appears to be happening, and in a predictable way. The question is, why? This is worth time and effort. Such a small deviation. Perhaps it's possible to have large deviations? Are we already and just don't understand it? Definitely worth exploring. Interesting comments in the phys.org article about planetary orbital resonances.

https://www.richarddawkins.net/2015/04/why-do-measurements-of-the-gravitational-constant-vary-so-much/

https://m.phys.org/news/2015-04-gravitational-constant-vary.html

Using dimensional analysis along with how gravity affects M,L,T. The value of G is not a universal constant. In the PV Model of GR, it is G/c4 that is a universal constant.

So what you are saying above is that in the PV Model c is not universally constant. I don't personally have an issue with that, but it seems even the suggestion would require some supporting argument.

This was the most recent paper by H. E. Puthoff, published in JBIS:

https://www.researchgate.net/publication/223130116_Advanced_Space_Propulsion_Based_on_Vacuum_Spacetime_Metric_Engineering

This was the original work where all of the tests of GR are reproduced by the PV representation, published by Springer:
https://www.researchgate.net/publication/1978393_Polarizable-Vacuum_PV_representation_of_general_relativity

There are many, many more papers on the subject by other physicists and engineers as well. Just look them up.

« Last Edit: 09/16/2017 12:01 am by WarpTech »

Online meberbs

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The value c can't be a function of K because otherwise you get into a recursive c = c/K.

Since this value c is a constant, if you say that G/c^4 is constant, then G is a constant.

This is not true in the PV Model of GR.
You said that the coordinate speed of light is c/K. If you do not have a constant "c" then saying that the coordinate speed of light is c/K does not make sense.

The constant "c" could vary with space as well, but you have said "they use the "local" frame where "c" is a constant and K=1" which implies only the coordinate speed of light is varying in this theory and not the constant c that is used to calculate it.

If your issue is with the second sentence you quoted, then you just need to read that sentence again because it is very nearly tautological.
 
We use the frame of a distant observer, far from gravitational fields to determine what K is. In this reference frame, c/K is what is measured non-locally, it's not constant and neither is G, ε0 or μ0. Read the papers, you will learn something.
Yes, c/K, the coordinate speed of light is not constant, and variations in the coordinate speed of light are a well known part of GR. However, you did not say that G/(c/K)^4 = constant, you said that G/c^4 = constant. The first implies a variable G, the second does not. You could define something like "coordinate G" = G/K^4 and that would be variable, but G itself would still be a constant. I don't have to read any other paper to recognize contradictory statements.

This was the original work where all of the tests of GR are reproduced by the PV representation, published by Springer:
https://www.researchgate.net/publication/1978393_Polarizable-Vacuum_PV_representation_of_general_relativity
Except that is simply not true as shown by this more recent paper: https://arxiv.org/abs/astro-ph/0302273
Quote
The theory predicts a radiation power from a binary system that is 2/3 that predicted by GR, and so incompatible with observed orbital decay rate of PSR 1913 + 16.

Offline spupeng7

...So let's say it's more like a "brane theory" in your example but without the brane, superstring, supersymmetry and all the quantum stuff. Only general relativity. That's the main difference....
OK, but this argument in this thread page started by a quotation about someone arguing against Quantum Gravity, the main objection being about whether gravity can be quantized (about whether gravitons are real).  Because what string theory and other quantum gravity theories attempt to explain is the graviton.  So, to me people railing against string (M) theory and the graviton is similar to Ernst Mach railing against Einstein's theory of relativity and against the existence of atoms, a statement which he made, amazingly, in the 20th century:



Just substitute nowadays "string theory" for "relativity" and "gravitons" for "atoms" in Mach's statement, and it would read by a hypothetical 21st century of Mach:

Quote from: a hypothetical 21st century Mach
I can accept the  (M) theory of strings as little as I can accept the existence of gravitons


And the railing against unusual objects like strings and branes, compactified extra dimensions and the multiverse sounds like the railing against the concept of black holes and gravitational waves (both of which Einstein himself questioned at some points in his life).

And hopefully everybody will agree that Mach's statements against relativity and against atoms was proven wrong.

And similarly those that argued against the existence of black holes, the accelerated expansion of our Universe, and against the existence of gravitational waves were also proven wrong.

So keep an open mind as to whether gravitation will be quantizable, whether gravitons exist, and whether there are such things as compactified extra dimensions.

Dr Rodal,
I suspect we will all be proven to have simplistic notions of physical reality, given the passage of enough time. Mach's supersonic flow experiments were vital to the development of supersonic aerodynamics and rocketry. His pursuit of answers to questions raised by Newton's bucket is as relevant today as it ever was.
Optimism equals opportunity.

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