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#540 by SteveD on 22 Dec, 2015 05:11
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There are two spacecrafts involved in this concept. While there was only one spacecraft involved in the discussion by Frobnicat. Take a gander at what happens to the other spacecraft and you will then understand how energy and momentum is conserved in this concept, and why it does not make sense (for energy and momentum conservation) to take a look at only one of the two spacecrafts without taking into account what happens to the other. And why it does not make sense to associate the EM Drive with this concept, as the EM Drive is conceived as one undivided engine instead of two spacecrafts becoming further and further apart from each other.
Hold on. Momentum is conserved. I 100% agree on that. But isn't the issue here with conservation of energy. I believe the argument is that constant power, creating constant thrust will -- with sufficient time -- result in the total kinetic energy in the system going over unity. Absent some of the Baeisms, here is a diagram of a recycling photon rocket.
Now, I think we've established that in a photon rocket, the over unity only takes place at a speed greater than c. These equations would seem to imply that if you can bounce the photon once, the point of over unity becomes less than c. Now you have two spacecraft that are gaining constant acceleration with (the same amount !!) of constant power. The problem is multiplied. Of course, it need not be two proper spacecraft. You could have one that is ejecting mirrors with light pressure as a "reaction mass." Momentum is conserved, but it seems to me that two spacecraft moving apart lack a readily apparent source of power to solve the energy problem.
It would seem that bouncing around photons causes a problem that would only occur in a photon rocket moving faster than c to appear at a slower speed. In effect, the "fuel efficiency" has become high enough that we are having a CoE problem.
It, intuitively, strikes me that this is not a problem that a chemical rocket is going to face. I remember reading somewhere that one of the deep space Ion Engine probes (I think it was New Horizons but might have been Dawn), had an unexpectedly large amount of propellant left over after accelerating. I wonder if this might have bearing on the matter at hand. -
#541 by SeeShells on 22 Dec, 2015 05:37
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Sir I just can't do that with a set frequency magnetron. 2.47GHz is what I have to work with.So one large error is being overlooked here. That is the difference between power input, resonance density, and force output. Even if we don't assume that resonance creates thrust this is still just as relevant because resonance is an easy way to measure accumulated power.
How would you design an experiment to test for this?
What do we know about the elasticity of a linear function? That it is nonlinearly varying over the course of a straight line.
That is to say that if thrust power output is a linear function of resonance power, this still wouldn't make thrust a linear function of power input. If you have 1000 photons bouncing in a cavity (let's assume perfect reflectors, and that we aren't even extracting work from their momenta), it takes 100 photons to scale the power of resonance up by 10%. To scale resonance power up another 10% will require 110 photons, which is nonconstant returns to thrust from input power.
Because other forms of thrust do not work by accumulating resonance of thrust energy, I think some of the calculations being done here are mistaken. Note again, this should be true even if resonance is not the creator of thrust but an indicator of energy density.
If he's saying what I think he's saying, apply power at different frequencies. The lower the frequency the more photons. I've got a spreadsheet that can suggest some frequencies that might have better results than others.
Shell -
#542 by oliverio on 22 Dec, 2015 08:28
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Sir I just can't do that with a set frequency magnetron. 2.47GHz is what I have to work with.So one large error is being overlooked here. That is the difference between power input, resonance density, and force output. Even if we don't assume that resonance creates thrust this is still just as relevant because resonance is an easy way to measure accumulated power.
How would you design an experiment to test for this?
What do we know about the elasticity of a linear function? That it is nonlinearly varying over the course of a straight line.
That is to say that if thrust power output is a linear function of resonance power, this still wouldn't make thrust a linear function of power input. If you have 1000 photons bouncing in a cavity (let's assume perfect reflectors, and that we aren't even extracting work from their momenta), it takes 100 photons to scale the power of resonance up by 10%. To scale resonance power up another 10% will require 110 photons, which is nonconstant returns to thrust from input power.
Because other forms of thrust do not work by accumulating resonance of thrust energy, I think some of the calculations being done here are mistaken. Note again, this should be true even if resonance is not the creator of thrust but an indicator of energy density.
If he's saying what I think he's saying, apply power at different frequencies. The lower the frequency the more photons. I've got a spreadsheet that can suggest some frequencies that might have better results than others.
Shell
On the topic of how to test this, I am not sure. To be honest that's a question for a smarter mind than I. It seems to me, however, that thrust must be some function of how much total power is accumulated in the drive. Given the nature of resonance this isn't something that can be just "scaled up." If we discover that thrust is a function of total photons in resonance (i.e. the field intensity of the standing photonic wave), a few things do come to mind.
Namely:
Let y=Y(x) represent photons in resonance, where x is power input;
Let z=Z(y) represent the magnitude of the thrust vector, which is presumably a function of photons in resonance;
The derivative of y is the incremental change in resonance given marginal increases of power input;
The second derivative of this quantity describes the change in resonance efficiency over varying power input.
The derivative of z represents the incremental change in thrust given marginal changes in resonance energy.
The second derivative here will be acceleration w.r.t. the function y?
So thrust varies as Z(Y(x)) in this hypothetical; the over-unity point of this theoretical drive is relative to the derivative of Z with regards to X. Or the second derivative of this quantity? My mathematical weaknesses are showing through. The point is, though, if we can get some data we should be able to figure out if I am right. My gut tells me that no system gets constant returns to power, and my gut also tells me that you can get more work out of a photon than a photon rocket-- so given all that, my gut tells me that if the EMDrive works as promised, it will work with the same sort of scaling that any engine does, such that you can't pull energy out of it.
(Presumably, figure out a stable way to measure how many photons are in resonance, which will not have a constant power relationship. Then, vary this accordingly [on this part I am not clear how one might do so] and track whether or not the thrust scales at some predictable level with photons in resonance, not with power input.) -
#543 by frobnicat on 22 Dec, 2015 09:13
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Frobnicat, I can follow your synopsis a bit, then I go into theory tilt mode. Frame dragging/reference is a bit hard to visualize but thanks for your efforts and detailed reply. Hardware and software design...I can do. Theoretical physics, uhhhh, best left to braintrusts like yourself.
In a sentence or two, assuming the emdrive force is real, what is it?
If by "real" you mean really useful thrust for spaceflight, given the energy (and center of mass) issues frankly I don't see what it could be. The "would be phenomenology" of a working Emdrive (the consequences) imply either the use of tachyons (roughly speaking, outputting energetic debt), or an incoming energy flow. Tachyons have problems with causality (probably don't exist, or need people in the future to send backward in time to us, focusing emdrive experiments!), and if such energy reserve existed in deep space as to allow the excess power needed to run 1N/kW at typical velocities 10km/s, harvested from a package less than 1m² cross section, then the required densities of field/medium X would have measurable gravitational effects (i.e. would be higher than dark matter, for which we already know there isn't quite enough even if it interacted with microwaves like crazy). So we'd need ubiquitous space permeating field/medium X dense enough in energy, and yet not gravitating (as that would be excluded by high precision astronomical measurement aimed at dark matter). Energy tends to gravitate, except may be "dark energy"... But there also the energy/pressure densities (of dark energy) are known to be too low (in the galaxy lower than dark matter).
Hey, I'm not skeptic for the pleasure of it... But please remember that I'm only a Newtonian guy with a pinch of SR.
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#544 by TheUberOverLord on 22 Dec, 2015 09:15
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What constitutes violations of CoE ("Conservation of Energy") and/or CoM ("Conservation of Momentum")?
The reason why so many people have said the em-drive violates conservation of energy is really quite simple. One central claim of the em-drive is that the force it produces is constant and requires only a constant input of energy. If you plotted the energy that was input over time it would be a straight line with a positive slope; ie EI = kt, where k = the input energy/ Sec. The constant force, F, produces a constant acceleration, a = F/M, where M = the mass being accelerated (em-drive + hypothetical space ship, lol). Since the velocity, V, after time t is: V = a*t the velocity increases linearly. However the kinetic energy with respect to time is a square function, EK = MV2/2. It wouldn't take very long for the kinetic energy curve to achieve a higher value than the input energy curve. Where does this excess energy come from?
Then why are some saying that for the EM Drive to do what it maybe doing, would in fact need to violate CoE and/or CoM to do so?Edit: One more analogy. Please don't lump this one with the one above unless it justifies it.
If this bulb was placed free-floating in space and completely sealed would/could it create thrust as photons were spinning it's sails ("Like man swimming in space can and could")? If so, is that also a violation of Coe and/or CoM?
Again, if not? Then why are some saying that for the EM Drive to do what it maybe doing, would in fact need to violate CoE and/or CoM to do so?
Don
If the radiometer was free-floating in space it would just spin the way it does on Earth; maybe a lot faster because of a looser bearing, brighter sunlight and better heat radiation into the coldness of space. But it wouldn't move by itself. There might be some recoil of the glass envelope due to the movement of air molecules inside it. That recoil would just be a spin in the opposite direction of the glass envelope.The paddles are inside the glass envelope so they aren't providing any propulsion. It is not sunlight reflecting off the paddles that makes the radiometer spin.
Sure would like to see a radiometer tested in free-floating space to see what the ("Actual") results are of an experiment like that would be. Would be cheap to do when compared to many other space experiments. Removing any need for words like "Might" or "Maybe". Depending on the amount of "Recoil" one can and could call that a form of thrust, even when caused by an initial or continued internal force. Since if that internal force was stopped, then there would not be the same, if any external thrust. Not saying that any thrust created by that internal force would be large. But still wondering if it would be completely zero?
My other question in the same post, was asking if a solar sail was enclosed in a transparent cage of glass or plastic in space. Using it's own lights to create the actual photons that hit the solar sail or using photons produced by a star. Would it still be able to create an external thrust? Or because the solar sail was enclosed now, whatever thrust was possible without that enclosure would now be gone as in zero possible external thrust? Yet the transparent enclosure was still allowing photons to reach that solar sail ("In the case of using photons produced by a star"). Would one source of the photons still be able to cause thrust and the other not? In my mind, it's more or less similar to the same principal as the radiometer analogy. If thrust can't be created from an internal confined force ("Even caused by external photons produced by a star") that can be transferred externally as thrust. Yet that same solar sail could produce thrust by internal or external photons when not confined in a transparent cage of glass or plastic.
Better said. Can something be pushed in a direction externally, from the "results" of a internally confined force, in some cases, or is that considered impossible in all ways?
By no means am I trying to be sarcastic. But I can't help but always think of a statement that Mark Twain once made that even applies to many theorems, to this day:
"There are three kinds of lies: lies, damned lies, and statistics."
My point is, that when it comes to theories. Time and time again. It has been shown that changes are made from time to time. If one does not allow oneself to "Think out of the box" then many theorems would have remained as is. Which in the end would not advance knowledge.
Of course there comes a time where one has to admit that there is enough evidence that "The sun does not revolve around the earth". But personally, I think it's safe to say that at the moment that conclusion can't be reached with that level of certainty for EM Drive like concepts.
Maybe I am being "Too open minded" but closed minds don't make changes to currently accepted theorems they work within them because they refuse to "Work outside the box".
What I find as somewhat humorous is that when Cosmic Background Radiation, or the Microwave Background was found at distances too far to have gotten to some places that the speed of light allows. AKA as the “horizon problem”. To better try to explain that. Some say that "Well, in the past light/radiation/heat may have been able to move faster than it can today or could in the future" AKA "Cosmic inflation". Which some accept as a reasonable solution to the violations, of current theorems:
http://www.physicsoftheuniverse.com/topics_bigbang_inflation.html
Yet I don't think any current builders of EM Drives are trying to make up final theorems on why or how the EM Drive might work. But instead, are trying to prove it can or does by producing experimental results vs. trying to simple create "Special Circumstances" on why EM Drives could possibly work.
Don -
#545 by Notsosureofit on 22 Dec, 2015 09:55
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So the question is then what effect has that on the possible force generation in the frustum?
Unless we are breaking relativity, and/or emdrive is sailing/dragging on some preferred rest frame aether, "absolute velocity" should have none.
But what effect will acceleration have on an asymmetric, dissipative and dispersive high-Q energized cavity near cutoff?
see: http://emdrive.wiki/@notsosureofit_Hypothesis
That by itself still requires that the entropy of the enclosed system increases with acceleration. At this point I have convinced myself that that is so. In a cylindrical cavity the entropy of the wavefunction is maximized at free fall. The effect of acceleration is to induce a gravitational dispersion and lower the entropy. In a tapered (dispersive) cavity the effect of acceleration in a direction which reduces the dispersion, increases the entropy of the enclosed wavefunction. The classical case (photon gas) is valid for wavelengths which are much shorter than the cavity dimension (ie very high number mode structures). You can see this behavior in the chart as frequency increases.
[ I spent way too much time trying to use the photon gas model when I should have remembered that Van Allen and Caravillano wrote a paper on the spherical harmonic modes of the earth-ionosphere system in '62 (?). Esp. as I wrote the Fortran program to do those calculations for them ! ]
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#546 by Rodal on 22 Dec, 2015 11:48
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There are no controversial physics either in photon rockets (inlcuding Bae's) or ion engines.
There are two spacecrafts involved in this concept. While there was only one spacecraft involved in the discussion by Frobnicat. Take a gander at what happens to the other spacecraft and you will then understand how energy and momentum is conserved in this concept, and why it does not make sense (for energy and momentum conservation) to take a look at only one of the two spacecrafts without taking into account what happens to the other. And why it does not make sense to associate the EM Drive with this concept, as the EM Drive is conceived as one undivided engine instead of two spacecrafts becoming further and further apart from each other.
Hold on. Momentum is conserved. I 100% agree on that. But isn't the issue here with conservation of energy. I believe the argument is that constant power, creating constant thrust will -- with sufficient time -- result in the total kinetic energy in the system going over unity. Absent some of the Baeisms, here is a diagram of a recycling photon rocket.
...
Now, I think we've established that in a photon rocket, the over unity only takes place at a speed greater than c. These equations would seem to imply that if you can bounce the photon once, the point of over unity becomes less than c. Now you have two spacecraft that are gaining constant acceleration with (the same amount !!) of constant power. The problem is multiplied. Of course, it need not be two proper spacecraft. You could have one that is ejecting mirrors with light pressure as a "reaction mass." Momentum is conserved, but it seems to me that two spacecraft moving apart lack a readily apparent source of power to solve the energy problem.
It would seem that bouncing around photons causes a problem that would only occur in a photon rocket moving faster than c to appear at a slower speed. In effect, the "fuel efficiency" has become high enough that we are having a CoE problem.
It, intuitively, strikes me that this is not a problem that a chemical rocket is going to face. I remember reading somewhere that one of the deep space Ion Engine probes (I think it was New Horizons but might have been Dawn), had an unexpectedly large amount of propellant left over after accelerating. I wonder if this might have bearing on the matter at hand.
Both momentum and energy are conserved in Bae's concept. It cannot be used as a perpetual motion device.
There are no mysteries of energy conservation with ion engines either. Momentum and energy are also conserved in ion engines, which have been successfully tested since the 1960's and are well understood by aerospace engineers (they have been taught at MIT's Department of Aeronautics and Astronautics since the 1950's).
Having more propellant than someone may have predicted left after accelerating does not constitute an energy conservation mystery any more than your car having more fuel left after accelerating than what you predicted. The problem is with the faulty assumptions employed in the prediction of propellant consumption (including orbital mechanics gravity assist maneuver calculations, that are very dependent on precise knowledge of actual motion and any resistance met in close by slingshot around gravitational bodies), and the problem is not with the ion engine going over unity. There is no such thing as ion engines or photon rockets going over unity.
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#547 by Rodal on 22 Dec, 2015 12:35
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So the question is then what effect has that on the possible force generation in the frustum?
Unless we are breaking relativity, and/or emdrive is sailing/dragging on some preferred rest frame aether, "absolute velocity" should have none.
But what effect will acceleration have on an asymmetric, dissipative and dispersive high-Q energized cavity near cutoff?
see: http://emdrive.wiki/@notsosureofit_Hypothesis
That by itself still requires that the entropy of the enclosed system increases with acceleration. At this point I have convinced myself that that is so. In a cylindrical cavity the entropy of the wavefunction is maximized at free fall. The effect of acceleration is to induce a gravitational dispersion and lower the entropy. In a tapered (dispersive) cavity the effect of acceleration in a direction which reduces the dispersion, increases the entropy of the enclosed wavefunction. The classical case (photon gas) is valid for wavelengths which are much shorter than the cavity dimension (ie very high number mode structures). You can see this behavior in the chart as frequency increases.
[ I spent way too much time trying to use the photon gas model when I should have remembered that Van Allen and Caravillano wrote a paper on the spherical harmonic modes of the earth-ionosphere system in '62 (?). Esp. as I wrote the Fortran program to do those calculations for them ! ]
<< In a tapered (dispersive) cavity the effect of acceleration in a direction which reduces the dispersion, increases the entropy of the enclosed wavefunction. >>
Does this theory show a decrease of the quality of resonance (Q) concomitant with the increase in entropy of the enclosed wavefunction and reduction of dispersion accompanying acceleration ? -
#548 by Notsosureofit on 22 Dec, 2015 12:41
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<< In a tapered (dispersive) cavity the effect of acceleration in a direction which reduces the dispersion, increases the entropy of the enclosed wavefunction. >>
Does this theory show a decrease of the quality of resonance (Q) concomitant with the increase in entropy of the enclosed wavefunction and reduction of dispersion accompanying acceleration ?
Good question ! That should also increase the entropy, but I only looked at the uniformity of the distribution of energy within the cavity. I'll see what I can figure. -
#549 by Flyby on 22 Dec, 2015 12:56
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....
My oh my...seems i inadvertently opened another can of worms with my questions/public pondering.
Scientist are (more often than not) not the intellectual ayatollahs you apparently think they are. They are trained to jump from one framework to another, so adding another framework is not something I would believe they are afraid of... Anyway :
.....
No, I'm not perceiving scientifically trained persons as ayatollahs....
I do not reside in the camp of the anti-establishment movement that finger points knowledgeable ppl as being elitist. No sir.. I have an university degree myself and an above average interest in what happens on the scientific scene...
Science isn't Chinese for me, but more like Swedish... i recognize the letters, some words here and there, but, admittedly, the overall context of the more advanced topics eludes me.
Although the calculus behind physics can be intimidating , I personally don't feel intimidated by it. It is just a different world we live in, a consequence of a choice in life we made many years ago...
I am fully aware to where my situation is in this type of theoretical discussion. I'll probably have to reread your answer several times before i can grasp what you've put forward.
But my ignorance is both my weakness and strength, as I dare ask questions that more knowledgeable people might not ask, as I don't feel constraints of making a fool of myself.
I am asking questions so i can understand the bigger picture, so, i want to thank you, frobnicat, for taking the time and explaining your vision.
But there seems to be so many different visions and opinions on this EMdrive matter, all with their own degree of credibility...and that keeps me asking even more questions...
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#550 by meberbs on 22 Dec, 2015 13:09
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Hold on. Momentum is conserved. I 100% agree on that. But isn't the issue here with conservation of energy. I believe the argument is that constant power, creating constant thrust will -- with sufficient time -- result in the total kinetic energy in the system going over unity. Absent some of the Baeisms, here is a diagram of a recycling photon rocket.
...
Now, I think we've established that in a photon rocket, the over unity only takes place at a speed greater than c. These equations would seem to imply that if you can bounce the photon once, the point of over unity becomes less than c. Now you have two spacecraft that are gaining constant acceleration with (the same amount !!) of constant power. The problem is multiplied. Of course, it need not be two proper spacecraft. You could have one that is ejecting mirrors with light pressure as a "reaction mass." Momentum is conserved, but it seems to me that two spacecraft moving apart lack a readily apparent source of power to solve the energy problem.
It would seem that bouncing around photons causes a problem that would only occur in a photon rocket moving faster than c to appear at a slower speed. In effect, the "fuel efficiency" has become high enough that we are having a CoE problem.
...
I might have missed it, but I don't think anyone responded with the "simple" answer to this. The energy imparted to the mirrors as their velocity increases comes from the redshift of the photons. I worked out some of the math in this post on how even an initially stationary mirror with finite mass will slightly redshift a photon reflected off of it. COE remains unbroken. -
#551 by TheTraveller on 22 Dec, 2015 13:14
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rfmwguy... You still have that picture of the maggie that you modified for your VNA scan, could you post it again?
Thanks,
Shell
Shell,
This is the best image I could find in his image archive.
Phil
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#552 by rfmwguy on 22 Dec, 2015 13:23
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I think Frobnicat was speaking to me about my nonconformist style of challenging authority (I was a child of the late 60s ya know) Anyway, Its ingrained in me to push back on things like scientific authority in the same manner they push back on edgy theories. Tit for tat, so to speak.....
My oh my...seems i inadvertently opened another can of worms with my questions/public pondering.
Scientist are (more often than not) not the intellectual ayatollahs you apparently think they are. They are trained to jump from one framework to another, so adding another framework is not something I would believe they are afraid of... Anyway :
.....
No, I'm not perceiving scientifically trained persons as ayatollahs....
I do not reside in the camp of the anti-establishment movement that finger points knowledgeable ppl as being elitist. No sir.. I have an university degree myself and an above average interest in what happens on the scientific scene...
Science isn't Chinese for me, but more like Swedish... i recognize the letters, some words here and there, but, admittedly, the overall context of the more advanced topics eludes me.
Although the calculus behind physics can be intimidating , I personally don't feel intimidated by it. It is just a different world we live in, a consequence of a choice in life we made many years ago...
I am fully aware to where my situation is in this type of theoretical discussion. I'll probably have to reread your answer several times before i can grasp what you've put forward.
But my ignorance is both my weakness and strength, as I dare ask questions that more knowledgeable people might not ask, as I don't feel constraints of making a fool of myself.
I am asking questions so i can understand the bigger picture, so, i want to thank you, frobnicat, for taking the time and explaining your vision.
But there seems to be so many different visions and opinions on this EMdrive matter, all with their own degree of credibility...and that keeps me asking even more questions...
Psychologically speaking (another area I'm fascinated with) think its beneficial not to simply roll over and accept dogma. Its actually a skeptic's skeptical point of view if that makes sense (probably doesn't and that's OK).
Sooo, bottom line is it was me frobni was speaking to and it was regarding my skeptic2 attitude sometimes. Not to worry, I'll get over it
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#553 by rfmwguy on 22 Dec, 2015 13:36
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Thanks Phil...beat me to the punch...BTW thanks for setting up my image archive link in your group. I use it to find my own stuffrfmwguy... You still have that picture of the maggie that you modified for your VNA scan, could you post it again?
Thanks,
Shell
Shell,
This is the best image I could find in his image archive.
Phil
Shell, the cut on the brass tube (mag body) should be about 3/8 of an inch or less from the end. Longer that that and you'll cut into the meat of the cavities. Also, don't cut too deep on the side wall and damage the brass strip feeding the radome.
Doing this again, I'd probably drill a hole into the side, adjacent to the brass strip, solder the braid on the outside and insert the dielectric insulator through the hole and solder the center conductor directly to the brass strip. That way, you could solder an endplate onto the open end of the vna radome probe for a cleaner looking assembly.
p.s. (wait for it) take a pic of your finished probe assembly
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#554 by Rodal on 22 Dec, 2015 13:46
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...
The hard sciences like mathematics and physics are the furthest removed from "dogma".
Psychologically speaking (another area I'm fascinated with) think its beneficial not to simply roll over and accept dogma. Its actually a skeptic's skeptical point of view if that makes sense (probably doesn't and that's OK).
...
On the contrary, dogma is associated with religion, politics, law, legislation, sociology, etc., and not with mathematical physics.
What are called "laws" in Physics are not dogmatic laws, they are mathematical statements that are derived mathematically under well defined assumptions (*). They are not concepts that people learn dogmatically (they are not like laws that a lawyer has to learn as dogmatically passed by a Legislature).
Skepticism is better directed at EM Drive assertions contradicted by experimental evidence (such as those by Shawyer) than at consistent physical concepts like conservation of momentum and conservation of energy that are so far supported by all the experimental evidence and that have been successful at bringing humanity into the Space Age.
Dogma is a somebody dogmatically asserting (because he says so) inconsistent, obviously wrong statements that are contradicted by experimental evidence, like "a frustum of a cone cavity excited by a spherical wave experiences no radiation pressure on the lateral surfaces of the frustum", or that "a closed cavity resonance is governed by the same cut-off frequency condition as an open waveguide", or that "the EM Drive experiences self-acceleration due to electromagnetism as explained by Classical Physics (Maxwell's laws and SR) and such self-acceleration is consistent with conservation of momentum and Newton's laws."
______
(*) Of course, no consistent system of axioms whose theorems can be listed by an "effective procedure" (i.e., any sort of algorithm) is capable of proving all truths. Also, Newtonian physics was modified by General Relativity and Quantum Mechanics to extend to the very large and the very small dimensions, but the consistency of Newtonian Physics for its range of validity remains unadultered and used to this date. -
#555 by rfmwguy on 22 Dec, 2015 14:14
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Except, I take no issue with CoE/M at all, as I believe most builders do as well. I would take issue with dogma not being applicable to mathematical physics. So often, I have read "show me the math" as if it was the only genesis to scientific discovery. I do not believe it is, necessarily....
The hard sciences like mathematics and physics are the furthest removed from "dogma".
Psychologically speaking (another area I'm fascinated with) think its beneficial not to simply roll over and accept dogma. Its actually a skeptic's skeptical point of view if that makes sense (probably doesn't and that's OK).
...
On the contrary, dogma is associated with religion, politics, sociology, etc., and not with mathematical physics.
Skepticism is better directed at EM Drive wild and inconsistent assertions (such as those by Shawyer) than at consistent physical concepts like conservation of momentum and conservation of energy that are so far supported by all the experimental evidence and that have been successful at bringing humanity into the Space Age.
My opinion (only) is that serious math can come before or after experimentation, as evidenced by Goddard and his rocket experiments (and many others). Elegant? No. But who cares except perhaps institutional authorities dependent upon math equations first, experiments second. That is OK as well. Hey, who am I to pretend I'm a dissertation supervisor?
See Doc, I told you I am a non-conformist
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#556 by frobnicat on 22 Dec, 2015 14:15
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So the question is then what effect has that on the possible force generation in the frustum?
Unless we are breaking relativity, and/or emdrive is sailing/dragging on some preferred rest frame aether, "absolute velocity" should have none.
But what effect will acceleration have on an asymmetric, dissipative and dispersive high-Q energized cavity near cutoff?
Classically (special relativity only) the only effect having photons bouncing around inside a box is an added apparent mass of E/c², where E is the stored energy (in the form of "bound" electromagnetic energy flying inside). There have been various discussions around Q, but I think it's a safe bet to say that in a "typical" frustum fed at 1kW E is less than 1J, that is about 10-17 kg. of added apparent mass (inertial and gravitating). Being dissipative and dispersive, near cutoff somewhere inside shall make no difference in this regard : when all those specifics have been summarized as resulting to a certain Q value, that will give a stored_bound E for a given power input (at given frequency) and this tiny bound E equivalent mass is the only thing that will make a loaded cavity differ from an unloaded cavity as seen from the outside (+ it's radiating away waste heat). Obviously this equivalent mass is just the same as that lost by the battery to pump up an unloaded cavity to loaded state, so in principle we are just transferring a tiny tiny mass from one place to another (which is of very limited interest in terms of propulsion) before letting it bleed away at less than photon rocket efficiency. Again, classically. That's why so many classically trained people look at the concept and just think "huh ?" before turning to other more serious business.
But I see notsosureofit has a less trivial take on that...
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#557 by Rodal on 22 Dec, 2015 14:22
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Except, I take no issue with CoE/M at all, as I believe most builders do as well. I would take issue with dogma not being applicable to mathematical physics. So often, I have read "show me the math" as if it was the only genesis to scientific discovery. I do not believe it is, necessarily....
The hard sciences like mathematics and physics are the furthest removed from "dogma".
Psychologically speaking (another area I'm fascinated with) think its beneficial not to simply roll over and accept dogma. Its actually a skeptic's skeptical point of view if that makes sense (probably doesn't and that's OK).
...
On the contrary, dogma is associated with religion, politics, sociology, etc., and not with mathematical physics.
Skepticism is better directed at EM Drive wild and inconsistent assertions (such as those by Shawyer) than at consistent physical concepts like conservation of momentum and conservation of energy that are so far supported by all the experimental evidence and that have been successful at bringing humanity into the Space Age.
My opinion (only) is that serious math can come before or after experimentation, as evidenced by Goddard and his rocket experiments (and many others). Elegant? No. But who cares except perhaps institutional authorities dependent upon math equations first, experiments second. That is OK as well. Hey, who am I to pretend I'm a dissertation supervisor?
See Doc, I told you I am a non-conformist
Goddard received a Ph.D. in physics in 1911 (this at a time when in US Universities, many Professors did not have a PhD). Goddard would be one of the last persons I would associate with rejection of mathematical physics ! Much on the contrary!
The practical use of Goddard's experiments was indeed discussed mathematically by Goddard himself, and most importantly before Goddard by pioneers like Konstantin Tsiolkovsky. Goddard in his elegant experiments and mathematical discussions, rather than rejecting existing mathematical physics, embraced mathematical physics !
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#558 by Paul451 on 22 Dec, 2015 14:27
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Sooo, consider the possibility that [the EMDrive] is manipulating/focusing/expelling/attracting/interacting with XEM...a natural condition of the universe, perhaps part of the theory of an ever-expanding universe...a driving force...lets even say it could be the new LHC particle, call it unicorn dust...doesn't matter for this thought experiment.
Suppose a natural condition, a zero frame of reference, of which we are never a part of (as we fly thru the cosmos) does exist and somehow we are putting on the brakes, attaching to it/countering it/repelling it, whatever...
Are we really at an over-unity, CoM/E violating condition?
If the EMDrive is acting as say a dark matter parachute, then no. There's no issue with over-unity.
It would be a "free energy machine" in the sense that a solar panel or wind turbine is. But not in the sense of reversing entropy and injecting free energy into the universe. It would merely (!) be reducing the velocity difference between Earth and the dark matter flow, converting it (ultimately) into low quality waste heat while extracting useful work.
However, as frobnicat noted, the required energy density is... demanding. Given that it, by definition, has remained hidden until now in spite of the number of people looking very very carefully at the mass/energy balances of astronomical and cosmic systems.
Which also means that Shawyer/et al invented a device based on a misunderstanding of electromagnatism and general relativity, that somehow accidentally stumbled into a completely different phenomena that would be the most revolutionary thing in physics since some guy¹ rubbed two dry sticks together and noticed they were getting hot.
¹ Ugg, U. Anomalous heat from resonant movement against desiccated high lignin content fibres. Actual Nature, 1, 16-17.
However, many of the proposed explanations don't work like that. Precisely because they require the system to "know" it's "absolute" velocity. Which is as big a physics-impossibility/breakthrough as violating CoE. Invoking something that would utterly rewrite physics in order to explain away something that requires the rewriting of physics... not sure what they're trying to save. Embrace the magic.how much stranger is this than the big bang when all the matter and energy in the universe simply appeared out of nothingness...
Yeah, but that was considered kind of a big deal at the time. -
#559 by TheTraveller on 22 Dec, 2015 14:35
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See Doc, I told you I am a non-conformist
Ditto.
As Paul March said here some time ago.
"Follow the Data, Theory be Damned".
