Quote from: Von NeumannThe sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work."Method in the Physical Sciences", in The Unity of Knowledge (1955), ed. L. G. Leary (Doubleday & Co., New York), p. 157
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
The key take away from the light in a box page was the red shift/blue shift. The same thing is presented by Shawyer. Also the theory paper presented (see Colbert) explains precisely how momentum is conserved. There is no free/cheap momentum. Asserting there are conservation issues /while at the same time not understanding the interaction doesn't make sense. That's like passing legislation governing the use of time travel and warp drive before they become real. Just speculation. You just have to read the paper.
I think this explains how Emdrive can never go over unity.http://usersguidetotheuniverse.com/?p=2865
Quote from: Mulletron on 02/20/2015 04:13 pmThe key take away from the light in a box page was the red shift/blue shift. The same thing is presented by Shawyer. Also the theory paper presented (see Colbert) explains precisely how momentum is conserved. There is no free/cheap momentum. Asserting there are conservation issues /while at the same time not understanding the interaction doesn't make sense. That's like passing legislation governing the use of time travel and warp drive before they become real. Just speculation. You just have to read the paper.What paper ? Colbert ? Where ?Not trying to be obtuse here but you'll have to connect the dots for me (and for some other readers I guess)... still not understanding how this is supposed to make an energy generating scheme to fail (under the assumption that an emdrive could give 1N of thrust when fed 1kW microwave power for instance). Some doppler shift is supposed to modifie the thrust/power ratio when emdrive is accelerated ? Does it pertain to accelerations vectors orthogonal to the axis of the frustum (as would be the case for a frustum mounted on a flywheel) ? Does it pertain to arbitrarily low accelerations (as the proposed device would work at, say, fixed tangential velocity V=2 km/s, acc=V˛/R so by extending the radius, radial acceleration can be made arbitrarily low) ? Does it pertain to an emdrive that is not accelerating, that is on straight trajectory, at constant velocity and thrusting at constant force that is pulling a tether that is rotating an electric generator ?I'm not saying there is conservation issue, I'm concerned about consistency of a phenomenological model that's implied when mission profiles are proposed, this model is very simple : at a given microwave power there is a given thrust. Thrust=f(Power). Not Thrust=f(Power, Velocity wrt?, Acceleration, ...?) Granted, this model is speculative, but within this speculation it is not a speculation to state that the same effect used to accelerate a spacecraft can be used in a system that generates energy. It is not logical to operate under this assumption to devise mission profiles and not to devise unlimited energy generators.From your previous remark :Quote from: Mulletron on 02/20/2015 11:09 amI think this explains how Emdrive can never go over unity.http://usersguidetotheuniverse.com/?p=2865So you seem to think that "Emdrive can never go over unity", isn't it a bit speculative at this stage ? Regardless of why, that would imply that you consider that the Emdrive can't be used to accelerate a spacecraft at constant thrust/power ratio. What would be the proposed Thrust=f(Power, Velocity wrt?, Acceleration, ...?)To be clear, I'm not trying to make a case that emdrive makes apparent energy conservation breaking and that therefore it must be bogus. If the effect is bogus or not is decided by experience, not by armchair physicists. But armchair physicist is legitimate to foretell that if effect is not bogus for space flight application (thrusting for deltaV) then it is not bogus for energy generation : the two situations can be made undistinguishable from the point of view of the device. This is a package. Take both or leave both. Otherwise makes the claims appear not serious. Just saying. For the later (energy generation) limitation on material makes the idea practical around 1N/kW above 1km/s speed (wrt local energy harvesting frame). So maybe the effect proves possible but not at such levels and that "prevents" the practical energy generation potential of the package. But even 50µN/50W is already enough to apparently break energy conservation, if not practically, at least in some physically possible setup.
“The law that entropy always increases, holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell's equations—then so much the worse for Maxwell's equations. If it is found to be contradicted by observation—well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics, I can give you no hope; there is nothing for it but to collapse in deepest humiliation.” Sir Arthur Eddington (The Nature of the Physical World, 1915)
What is the end goal of this line of reasoning?
Does the model presented with the mission profile, potentially lead to a situation where the EmDrive could be used as an over Unity power generator? Maybe.
But lets for arguments sake agree that it does. What use is this information?
I ask this question because if anything is clear from the discussions in this thread and the reported results to date. We only have a few rough guestimates at what is going on within the EmDrive. To prove or disprove the over unity power generation assertion you would need to completely characterize everything that is going on in the system. Right now the most we know is that when we pump EM into the cavity we get some thrust. We don't know beyond a reasonable doubt where the thrust is actually coming from. We don't know what we are actually interacting with. Now there are probably a whole lot of potential consequences of this research if it holds up to experimental scrutiny. But right now, the one thing I could probably guarantee, is that there will be a subset of those potential consequences that will not be possible once we have a better understanding of what is ACTUALLY happening.
On the flip side, should the researchers be allowed to propose mission profiles that could potentially not pan out due to a fundamental lack of understanding of what is actually going on? Maybe. Though from my perspective I think I am willing to give the primary investigators some leeway in painting a picture of what could be possible. As long as they assume the responsibility of dealing with the fall out if their vision is never realized.
Last topic for the night for me. Someone on this list asked if one could extract energy from the QV. If the QV is GRT space-time, and space-time is the cosmological gravitational field that is created by all the causally connected mass/energy in our section of the universe, then we live in a high pressure sea of gravitational energy. Now if the QV energy state is degradable and locally changeable, then one can posit the possibility of a thermodynamic energy conversion cycle that can extract energy from a pressure difference created in this QV media relative to the QV background average pressure, with a net decrease in this universal gravitational pressure or temperature reflective of the amount of energy so extracted. And try to remember that gravitational energy is negative energy. I'll leave the rest to you folks to draw your own conclusions from what this might mean...Best, Paul March
Entropically speaking, are there any other shapes for which we can write an analytic dispersion relation ?And where did I leave my Gunn diode oscillator ?
I think that frobnicat is simply saying thatIF there is a system (any system) that generate a given thrust when it's fed a given electrical power (with no other parameters affecting the thrust) THEN it can be used to generate power, at least theoretically.
This implication doesn't necessitate knowledge of quantum physics, it's simply basic physics.
The interesting question is then "Is EMdrive a system that generate a given thrust when it's fed a given electrical power?"If it is, we can generate power with EMdrive. It is an useful information: it means that, since free energy doesn't exist, we take this energy from somewhere.If it isn't, knowing which parameters affect the thrust will probably give us some insight into how EMdrive generate thrust.(as usual, if we assume that the thrust is not an artefact)
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?
....I also would like to understand to why the curved bottoms of Shawyer's new test rig "makes more sense" , from microwave resonance point of view?....
..What would be the implications of fe, using a paraboloid (or a hyperboloid) ?http://mathworld.wolfram.com/Paraboloid.htmlA paraboloid has a natural focal point, which probably would create an ever higher H-field intensity, as far as the resonance patterns go?...
Quote from: Flyby on 02/20/2015 11:35 pmFinding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?...I think it's from Shawyer and improperly attributed to Juan Yang on some other web sites: http://emdrive.com/flightprogramme.htmlSomeone should ask Roger Shawyer directly about the Chinese version (especially the dimensions of the cavity). He knows a lot about it, since he went there to speak with Juan Yang and give her some advice.
Finding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?...
Quote from: flux_capacitor on 02/20/2015 11:52 pmQuote from: Flyby on 02/20/2015 11:35 pmFinding pictures of shawyer's test device(s) is not that hard, but can any1 actually confirm that this is the Chinese truncated cone? or is it completely unrelated?...I think it's from Shawyer and improperly attributed to Juan Yang on some other web sites: http://emdrive.com/flightprogramme.htmlSomeone should ask Roger Shawyer directly about the Chinese version (especially the dimensions of the cavity). He knows a lot about it, since he went there to speak with Juan Yang and give her some advice.Yes, that Shawyer's Flight Thruster development programme. A 3.85GHz thruster weighing 2.92 Kg,.http://emdrive.com/flightprogramme.htmlI don't recall estimated dimensions for it. If anybody estimated the dimensions, @aero is the most likely one to have done it.
The photo is a bit blurry and that makes estimating a bit challenging, and there are lens distortions to the photo, but nothing too major. If the concrete block happened to be a common standard size, which of course is no given, then the dimensions would roughly be: