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#100 by Rodal on 01 Jun, 2017 16:42
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FYI: https://arxiv.org/pdf/1607.03118.pdf
Thank you, Notsosureofit. The fact that entropy of bodies attracted by gravitation can increase purely due to dynamic movement of the bodies (without friction or other forms of dissipation being present) is something that escapes many people's attention.
Entropy theorems in classical mechanics, general relativity, and the gravitational
two-body problem
(Dated: August 30, 2016)
"In classical Hamiltonian theories, entropy may be understood either as a statistical property of
canonical systems, or as a mechanical property, that is, as a monotonic function of the phase space
along trajectories. In classical mechanics, there are theorems which have been proposed for proving
the non-existence of entropy in the latter sense. We explicate, clarify and extend the proofs of these
theorems to some standard matter (scalar and electromagnetic) field theories in curved spacetime,
and then we show why these proofs fail in general relativity; due to properties of the gravitational
Hamiltonian and phase space measures, the second law of thermodynamics holds. As a concrete
application, we focus on the consequences of these results for the gravitational two-body problem,
and in particular, we prove the non-compactness of the phase space of perturbed SchwarzschildDroste
spacetimes. We thus identify the lack of recurring orbits in phase space as a distinct sign of
dissipation and hence entropy production."
Note: It is the existence of recurring "orbits" in "free energy" arguments that gives me reason to dismiss them out of hand.
Perhaps one way to visualize this is to think about the 3 body problem, and the N- body problem. It is only under certain conditions, for some finite amount of time (albeit a very long time compared with life) that one can have low-entropy solutions: stable elliptical orbits of planets around the Sun, stable orbits of moons around planets. Over the long-term the stability of these planets and these moons will be perturbed and they will cease to be stable, for example the planets falling into the Sun or a moon escaping a planet (thus entropy will increase). The range of dynamic solutions that are stable decreases with the number of gravitational bodies involved. Therefore, for example, in the Hoyle-Narlikar model, inertia of a body is conferred by the gravitational effect of all the other bodies in the Universe. If one fluctuates the energy in a body at a frequency omega, a small fluctuating mass density will result (Woodward's hypothesis) and if one rectifies this fluctuation by superposing another fluctuation at a superharmonic 2 omega, then an acceleration of the center of mass can occur due to the shift in the center of mass. The momentum and energy associated with this acceleration is balanced by the (infinitesimally small in comparison) change in momentum and energy of the rest of the bodies in the universe (responsible for conferring the inertial mass to the object). What the paper you mentioned shows, is that this (infinitesimally small) change in momentum and energy of the rest of the bodies in the universe must be accompanied by an increase in entropy of the universe. This must follow, because as one perturbs the dynamic equilibrium of N bodies in gravitation, the entropy of the universe must increase.
This increase in entropy of the universe due to dynamic perturbation of the motion of the N bodies, is not due to any friction (any such frictional losses are in addition to this effect) but due to the fact that gravitation of many bodies is a dynamically unstable problem. (We are fooled by thinking about the stability of planets and moons, and satellites: we also have to think about the whole range of possible motions that lead to instability and hence to a dynamic configuration that is less orderly and hence has increased entropy).
Thus, there are at least two kinds of entropy being ignored by those maintaining that there is boundless free-energy to be extracted: the entropy of the Machian drive (as entropy of a material being vibrated increases, due to dissipation of heat) and the entropy of the universe also must increase (as shown in the paper you posted). There is no free lunch.
If the EM Drive is not an experimental artifact and its acceleration is somehow due to general relativity, these entropy (2nd law) constraints must also operate: thus they pertain to the "overunity problem" frequently discussed, and the acceleration that would be possible and under what range of motions (along a geodesic vs. circular motion as in what is frequently hypothesized would be used to generate electricity).
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#101 by tchernik on 01 Jun, 2017 17:09
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Perhaps one way to visualize this is to think about the 3 body problem, and the N- body problem. It is only under certain conditions, for some finite amount of time (albeit a very long time compared with life) that one can have low-entropy solutions: stable elliptical orbits of planets around the Sun, stable orbits of moons around planets. Over the long-term the stability of these planets and these moons will be perturbed and they will cease to be stable, for example the planets falling into the Sun or a moon escaping a planet (thus entropy will increase). The range of dynamic solutions that are stable decreases with the number of gravitational bodies involved. Therefore, for example, in the Hoyle-Narlikar model, inertia of a body is conferred by the gravitational effect of all the other bodies in the Universe. If one fluctuates the energy in a body at a frequency omega, a small fluctuating mass density will result (Woodward's hypothesis) and if one rectifies this fluctuation by superposing another fluctuation at a superharmonic 2 omega, then an acceleration of the center of mass can occur due to the shift in the center of mass. The momentum and energy associated with this acceleration is balanced by the (infinitesimally small in comparison) change in momentum and energy of the rest of the bodies in the universe (responsible for conferring the inertial mass to the object). What the paper you mentioned shows, is that this (infinitesimally small) change in momentum and energy of the rest of the bodies in the universe must be accompanied by an increase in entropy of the universe. This must follow, because as one perturbs the dynamic equilibrium of N bodies in gravitation, the entropy of the universe must increase.
This increase in entropy of the universe due to dynamic perturbation of the motion of the N bodies, is not due to any friction (any such frictional losses are in addition to this effect) but due to the fact that gravitation of many bodies is a dynamically unstable problem. (We are fooled by thinking about the stability of planets and moons, and satellites: we also have to think about the whole range of possible motions that lead to instability and hence to a dynamic configuration that is less orderly and hence has increased entropy).
Thus, there are at least two kinds of entropy being ignored by those maintaining that there is boundless free-energy to be extracted: the entropy of the Machian drive (as entropy of a material being vibrated increases, due to dissipation of heat) and the entropy of the universe also must increase (as shown in the paper you posted). There is no free lunch.
If the EM Drive is not an experimental artifact and its acceleration is somehow due to general relativity, these entropy (2nd law) constraints must also operate: thus they pertain to the "overunity problem" frequently discussed, and the acceleration that would be possible and under what range of motions (along a geodesic vs. circular motion as in what is frequently hypothesized would be used to generate electricity).
Very good and clear explanation for the lay person.
If I understand well, and if the MEGA/Emdrive thrusters have any kind of physical validity, then they could be indeed used for getting useful thrust and speeds (e.g. for space ships), seemingly getting more energy in the form of kinetic energy than the one we spend on making them active.
Because the energy making them move is not from the energy we used to catalyze the reactions actually making them move. It comes from the distant part of the cosmos these systems are inextricably linked to, like everything else.
But the universal accounting book remains balanced and with an ever growing entropy. We are simply taking energy from the distant bodies of the universe, in infinitesimal amounts but very measurable at the local level, which is the one we are interested in. -
#102 by Rodal on 01 Jun, 2017 17:46
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Re: Ricci tensor & Einstein tensor. Having finally located my notes, one can quickly show that Rμν=0 ⇔ Gμν=0
Yes, that is completely true. The interesting thing is that the Ricci tensor being zero somewhere, sometime, Rμν = 0 does not necessarily mean that spacetime is flat (for 4D spacetime). Therefore Gμν=0 does not necessarily mean that spacetime is flat either. In 4D spacetime Rμν = 0 does not at all mean that Rαβμν = 0 .
By definition, Rμν= Gμν +½(gμνR) Rμν=0 ⇒R=0⇒Rμν= Gμν⇒Gμν=0
But the trace of the Einstein tensor is G=-R So Gμν=0 ⇒G=0⇒R=0⇒Rμν= Gμν⇒Rμν=0
I can say this with some feeling as a guy who calculated the tensor in detail in a free-space solution before the slap-the-forehead moment...
It is the Riemann curvature tensor Rαβμν (which is a 4th rank tensor, as opposed to the Ricci tensor Rμν which is only second rank) that completely defines the curvature. Thus General Relativity is interesting because one can have zero mass and a zero source of energy in a region in 4D spacetime, therefore Ricci tensor Rμν = 0 and yet the Riemann curvature tensor Rαβμν may have non-zero components. One can have gravitational waves that carry momentum and energy in a given region of spacetime without that region in spacetime needing to contain mass or energy sources. (This in contrast with charge in electrodynamics, where a source of charge is always needed, as photons do not carry charge). -
#103 by Notsosureofit on 01 Jun, 2017 17:52
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Thank you, Notsosureofit. The fact that entropy of bodies attracted by gravitation can increase purely due to dynamic movement of the bodies (without friction or other forms of dissipation being present) is something that escapes many people's attention.
Note: It is the existence of recurring "orbits" in "free energy" arguments that gives me reason to dismiss them out of hand.
I should add that my reasoning came not from GR, but from the "Hamiltonian" radars that I worked on in the 60's, where only the "entropic" components of the solutions were of interest. -
#104 by dustinthewind on 01 Jun, 2017 19:26
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One can have gravitational waves that carry momentum and energy in a given region of spacetime without that region in spacetime needing to contain mass or energy sources. (This in contrast with charge in electrodynamics, where a source of charge is always needed, as photons do not carry charge).
Something interesting to consider is an electronic positron annihilation. The source of the charge after annihilation no longer exists. The light could be considered to Cary the remaining mass and charge of the annihilated e-p pair.
The electric field of light possibly being low level disturbance of vacuum e-p pair virtual particles. So while they have zero charge it may actually be negative plus positive. Reversing the light wave recreates the charges.
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#105 by R.W. Keyes on 01 Jun, 2017 22:37
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True, 2,4 Ghz is an ISM band.
https://en.wikipedia.org/wiki/ISM_band. But there are others. I have an Amateur Radio license and could legally use those bands, but there are other legal requirements which may make such a plan untenable.
I understand the problems with heat and drift of magnetrons, but there was a paper posted here some time ago which detailed ways of stabilizing them. Stable enough? Maybe not.People seem to like 2.4 Ghz because of the availability of magnetrons for it, but there's a lot of RF noise in that band. Magnetrons seem to be dismissed because of their noisiness (even if there are ways to stabilize them, does it matter at experimenter's power levels?)
I like 2.45Ghz as that frequency band is unlicensed and therefore safe to leak into. I would hate to have the FCC call as those fines are quite substantial.
Magnetrons also require cooling to keep the frequency stable. If it is not actively cooled, then runaway thermal heating causes the frequency to drift lower, eventually damaging the magnetron. The frequency drift makes holding resonance very difficult and active cooling makes precise measurements very difficult. -
#106 by WarpTech on 01 Jun, 2017 23:13
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Hi Guys
Normally I lurk and enjoy the show, but I spotted this pertinent preprint on the arXiv today:
Theoretical calculation of the fine-structure constant and the permittivity of the vacuumQuoteLight traveling through the vacuum interacts with virtual particles similarly to the way that light traveling through a dielectric interacts with ordinary matter. And just as the permittivity of a dielectric can be calculated, the permittivity ϵ0 of the vacuum can be calculated, yielding an equation for the fine-structure constant α. The most important contributions to the value of α arise from interactions in the vacuum of photons with virtual, bound states of charged lepton-antilepton pairs. Considering only these contributions, the fully screened α≅1/139
.
An intriguing suggestion at the end is that considering the vacuum in this manner allows for a variable speed of light in the very early universe. But the fact that the Fine Structure Constant can be computed from assuming the vacuum is filled with virtual positronium (some ~10^39 per cubic metre) does lend some credence to Harold White's suggestions about how EM-Drives and kin *might* work.
I haven't sat down and compared them yet, but this sounds very similar to Marcel Urban, et. al.'s paper:
The quantum vacuum as the origin of the speed of light - 2013
https://link.springer.com/article/10.1140%2Fepjd%2Fe2013-30578-7
If anyone has the time to compare them, please keep me in the loop.
Thanks!
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#107 by dustinthewind on 02 Jun, 2017 03:36
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Hi Guys
Normally I lurk and enjoy the show, but I spotted this pertinent preprint on the arXiv today:
Theoretical calculation of the fine-structure constant and the permittivity of the vacuumQuoteLight traveling through the vacuum interacts with virtual particles similarly to the way that light traveling through a dielectric interacts with ordinary matter. And just as the permittivity of a dielectric can be calculated, the permittivity ϵ0 of the vacuum can be calculated, yielding an equation for the fine-structure constant α. The most important contributions to the value of α arise from interactions in the vacuum of photons with virtual, bound states of charged lepton-antilepton pairs. Considering only these contributions, the fully screened α≅1/139
.
An intriguing suggestion at the end is that considering the vacuum in this manner allows for a variable speed of light in the very early universe. But the fact that the Fine Structure Constant can be computed from assuming the vacuum is filled with virtual positronium (some ~10^39 per cubic metre) does lend some credence to Harold White's suggestions about how EM-Drives and kin *might* work.
I haven't sat down and compared them yet, but this sounds very similar to Marcel Urban, et. al.'s paper:
The quantum vacuum as the origin of the speed of light - 2013
https://link.springer.com/article/10.1140%2Fepjd%2Fe2013-30578-7
If anyone has the time to compare them, please keep me in the loop.
Thanks!
The vacuum pairs I suspect can not reach a zero temperature state. As a result the vacuum should actually possess some form of average mass/energy, on a large scale.
If we push against light resulting in a 2nd order Doppler shift (change in frame) might this also have an effect on accelerating or changing the frame of such vacuum pairs? -
#108 by spupeng7 on 02 Jun, 2017 04:37
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It's good to know they do good work in Guernsey C. I.
They used to. I have done a few years there as a farm laborer/gardener (which is good for the blood) but all they do is banking now...
must confess to some workshop envy
:J -
#109 by qraal on 02 Jun, 2017 09:26
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Hi
I seem to remember that preprint too...
The quantum vacuum as the origin of the speed of lightQuoteWe show that the vacuum permeability and permittivity may originate from the magnetization and the polarization of continuously appearing and disappearing fermion pairs. We then show that if we simply model the propagation of the photon in vacuum as a series of transient captures within these ephemeral pairs, we can derive a finite photon velocity. Requiring that this velocity is equal to the speed of light constrains our model of vacuum. Within this approach, the propagation of a photon is a statistical process at scales much larger than the Planck scale. Therefore we expect its time of flight to fluctuate. We propose an experimental test of this prediction.
Thanks for the lead. Will have a read too.Hi Guys
Normally I lurk and enjoy the show, but I spotted this pertinent preprint on the arXiv today:
Theoretical calculation of the fine-structure constant and the permittivity of the vacuum
An intriguing suggestion at the end is that considering the vacuum in this manner allows for a variable speed of light in the very early universe. But the fact that the Fine Structure Constant can be computed from assuming the vacuum is filled with virtual positronium (some ~10^39 per cubic metre) does lend some credence to Harold White's suggestions about how EM-Drives and kin *might* work.
I haven't sat down and compared them yet, but this sounds very similar to Marcel Urban, et. al.'s paper:
The quantum vacuum as the origin of the speed of light - 2013
https://link.springer.com/article/10.1140%2Fepjd%2Fe2013-30578-7
If anyone has the time to compare them, please keep me in the loop.
Thanks! -
#110 by Paul Howard on 02 Jun, 2017 20:47
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So we're years on and I assume this magical device hasn't been proven still? Still a chance or do we send this to the room that has the anti-gravity machine that's collecting dust?
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#111 by Stormbringer on 02 Jun, 2017 21:17
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So we're years on and I assume this magical device hasn't been proven still? Still a chance or do we send this to the room that has the anti-gravity machine that's collecting dust?
actually the effect is still anomalous but the signal is there. what hasn't happened despite everybody trying to do it is explain why it is there. or what spurious source of the signal is responsible. Also several sources of error have been eliminated or greatly reduced. Now correct me if i am wrong but i thought the scientific method involved a null hypothesis which (despite the years you have mentioned) has not been validated. Or contra-wise the experimental hypothesis has not been falsed.
In fact; current evidence points to the contrary of the null hypothesis. The experimenters have accounted for several proposed mundane sources of error by identifying potential sources of error/ spurious signals and designing the protocols and equipment to negate or to be able to filter them out of the data. The anomalous signal remains despite this effort.
That is the current status of the experiments. They are ongoing. It is premature to try to consign the effect to the dustbin.
EDIT: Besides the antigravity machine is not in some room collecting dust. My star cruiser's engineers run a clean engine room and it is inspected on a daily basis. -
#112 by tchernik on 02 Jun, 2017 21:34
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That is the current status of the experiments. They are ongoing. It is premature to try to consign the effect to the dustbin.
...
It is taking longer than most people expected to get it confirmed/refuted, but IMO, the theoretical body and experimental work surrounding the Emdrive is much better than it ever was. But it seems like it will take several years more to achieve a conclusion.
This is a shocker for many, given our natural urgency to see if this has any truth behind it, but science is a slow deliberate process that takes years and sometimes decades.
Prof. Woodward has been doing something like this since the mid nineties, carefully gathering evidence and theoretical works and it is just now that his research received some institutional attention outside of the inner circle.
The Emdrive broke through into public attention in 2006 (even if Mr. Shawyer had been working on it since several years before), so it's slightly more than 10 years since anyone else than Mr. shawyer heard about it. -
#113 by rq3 on 02 Jun, 2017 23:27
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So we're years on and I assume this magical device hasn't been proven still? Still a chance or do we send this to the room that has the anti-gravity machine that's collecting dust?
Patience, Grasshopper
. From memory, it took 7 years for polywater to be declared "not an actual thing". Lots of folks are spending a phenomenal amount of time, money, and effort to pick this signal out of the noise, and there is phenomenal science being done here.
The other "weird science" I personally follow is LENR (Low Energy Nuclear Reactions, AKA cold fusion). That apparently is also an area where something seems to be going on, but no-one can get a "recipe" type handle on it, because it violates what we think we know.
Theory and experiment tend to leap-frog each other. We're all in the middle of a leap. It's a matter of time and co-operation to determine whether the frog goes splat, or keeps soaring.
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#114 by SeeShells on 03 Jun, 2017 00:30
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Everyone needs a playpen.It's good to know they do good work in Guernsey C. I.
They used to. I have done a few years there as a farm laborer/gardener (which is good for the blood) but all they do is banking now...
must confess to some workshop envy
:J
My Very Best,
Shell -
#115 by WarpTech on 03 Jun, 2017 03:57
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Hi
I seem to remember that preprint too...
The quantum vacuum as the origin of the speed of lightQuoteWe show that the vacuum permeability and permittivity may originate from the magnetization and the polarization of continuously appearing and disappearing fermion pairs. We then show that if we simply model the propagation of the photon in vacuum as a series of transient captures within these ephemeral pairs, we can derive a finite photon velocity. Requiring that this velocity is equal to the speed of light constrains our model of vacuum. Within this approach, the propagation of a photon is a statistical process at scales much larger than the Planck scale. Therefore we expect its time of flight to fluctuate. We propose an experimental test of this prediction.
Thanks for the lead. Will have a read too.Hi Guys
Normally I lurk and enjoy the show, but I spotted this pertinent preprint on the arXiv today:
Theoretical calculation of the fine-structure constant and the permittivity of the vacuum
An intriguing suggestion at the end is that considering the vacuum in this manner allows for a variable speed of light in the very early universe. But the fact that the Fine Structure Constant can be computed from assuming the vacuum is filled with virtual positronium (some ~10^39 per cubic metre) does lend some credence to Harold White's suggestions about how EM-Drives and kin *might* work.
I haven't sat down and compared them yet, but this sounds very similar to Marcel Urban, et. al.'s paper:
The quantum vacuum as the origin of the speed of light - 2013
https://link.springer.com/article/10.1140%2Fepjd%2Fe2013-30578-7
If anyone has the time to compare them, please keep me in the loop.
Thanks!
I wrote to the authors regarding their work vs the work of Dr Fern and Prof. Woodward, recently published in JBIS. Because their claim that there are 1.11 x 1039 parapositronium "on mass shell" atoms per cubic meter, results in a cubic meter of empty spacing having an instantaneous rest mass of over 2 million metric tons.
I'm looking forward to a response.
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#116 by hyperplanck on 03 Jun, 2017 04:42
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What is often over looked by those wanting to degrade those involved in em drive research and discussion is in the context of the long term future. Long distance space propulsion through nuclear reactions may not be the wisest or most feasible propulsion. Not only is it a danger to crew and launch missions but it is not an easily found fuel and a complicated design, with many 'possible fail points' in the system where as in the EM drive you can charge batteries off of a lot of materials and interactions and its fairly simple. A low fail, simplistic design is crucial in space travel. Things that can't be fixed, cannot be allowed to break down. Ion propulsion is stymied in fuel by Xenon and Solar sails are too weak or flimsy, while functional regenerative materials will take another decade at least to even be operable, and that doesn't mean they will even work. Yet I don't see people and the media going around such that, "people researching quantum field theory of solar sails are delusional." Most physicists that I see attack the EM drive are usually indoctrinated by academic peer pressure to disregard everything, or simply don't know any better about the research being done.
"The scientific (mind) does not aim at an immediate result. They do not expect that their advanced ideas will be readily taken up. Their work is like that of the planter - for the future. Their duty is to lay the foundation for those who are to come, and point the way." - Tesla
Quantum mechanics and field theory in cavities is a very complicated scenario with a large array of phenomena. If you look at fusion cavity research it is probably some of the most complex interactions to be solved through physics. More than particle interactions and the big bang computations because they are under no pressure to extract energy from their experiments reactions.
So you could almost assimilate em drive research to be as difficult and as complicated as fusion research in many instances, and especially considering the economic environment. ITER, and CERN receive billions. It is easy to attack those who don't have exuberant funding. Though large funding is not always equal to good science. In fact I think the smaller fusion experiments will gain more headway in the long term as far as discovery.
What we are discovering and will discover through this research may not formulate in the way you thought it would. Science has a funny way of discovering other things and inventions while trying to solve some unrelated problem such as all the 1000's of inventions nasa indirectly has made while flying rockets and people around the Earth.
In critical terms the low 'm newton' thrust needs to be increased by a factor of 10 to be able to overcome GEO correct? As well as a stabilization ability as I believe it will have sporadic tilt. So to me, rather than directing money to an inflight experiment, or building more em drives; developing a more detailed simulation model with an ability to alter various characteristics and physics formulas with the intent of increasing thrust and stabilization with an increase of detailed interactions would be an objective worth alternative consideration before you build. IMHO.
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#117 by Star One on 03 Jun, 2017 06:39
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Some things just take a long time to prove or disprove. Look at how long LIGO took to produce results, it's my understanding that even with Einstein on their side so to speak many weren't sure if it would ever produce any results.
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#118 by SeeShells on 03 Jun, 2017 13:46
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My take on the time for results.
On the surface this looks like a simple thing to do. Something you should be able to pick up at your local supermarket.
1 can of microwaves
1 antenna
1 table
Box of sensors
Spaghetti-O-wires
Box of Lucky Charms
1 theory recipe (sold out of theory this week)
Mix all ingredients thoroughly (without the theory recipe) and. bake, heat, chill, let stand, or boil. Sadly you end up with something your dog won't eat because they were out of recipes.
On the surface this looks easy to do but it's not. The drive is relative easy to build all things considered.
Although it's very easy to get this silly thing to fail.
To do this right and prove without a shadow of doubt will take time and small calculated steps. Maybe someone will get lucky and hit it with a first time build, but don't count on it, as one missed ingredient and it will fail.
When I get discouraged and ready to throw in the towel I come back here to recharge and get a dose of enthusiasm. I thank you all for that.
My Very Best,
Shell -
#119 by Bob Woods on 03 Jun, 2017 21:06
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If you check your closet and the anti-gravity machine is dust free, you may want to continue to experiment.
. From memory, it took 7 years for polywater to be declared "not an actual thing". Lots of folks are spending a phenomenal amount of time, money, and effort to pick this signal out of the noise, and there is phenomenal science being done here.