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#4120 by rfmwguy on 03 Aug, 2016 13:55
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#4121 by Gilbertdrive on 03 Aug, 2016 13:58
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... I did not see an unified way of naming the part of the acceleration that can be locally measured. I would like to call it subjective acceleration, because it is felt from the viewpoint of the accelerating subject.
The General Relativity is the best point of view to adress this subject.
...
Only a body which follows a geodesic of the space-time will experience no acceleration. This is the so-called "free-fall" situation. Geodesics of the space time are geometric trajectories imposed by the energy/momentum content of the universe. For a body following a geodesic the gravity does not exist anymore.
Anybody on earth by opposition will experience acceleration (mainly our weight imposed on us by the earth gravitation) as he is prevented to follow the local geodesic by the reaction force of the ground on which he stands.
I agree. Also there is still the need for having a specifical term for distinguing the acceleration due to gravity,and the acceleration locally experienced, that can be measured by an accelerometer.
A stone free falling is still considered as accelerating in an earth referential for GR.
I have now found the official term used in General Relativity. It is Proper Acceleration, and it correspond to that I named subjective acceleration, due to my ignoring...
https://en.wikipedia.org/wiki/Proper_acceleration
If an acceleration was needed for the Emdrive to be in motor mode, only proper acceleration would matter, or it would be highly illogical
Proper acceleration is experienced on earth, but mainly vertically. In fact, that is the constant part of the proper acceleration that gives the definition or local verticallity
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#4122 by Gilbertdrive on 03 Aug, 2016 14:19
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I can see how that applies to automobile propulsion. If the car is not moving the engine can't do any work accelerating the car. And if the car is stopped the brakes don't convert kinetic energy into heat. Am I getting this right?
If you stop the car on an incline, the brakes still are applying a force. The brakes can't do work when the car is not moving though, which is only because the car has a special rest frame (the road). There is no special frame that could apply to the EMDrive.
The engine can do work when the car is in a stopped position, otherwise you couldn't start moving. It can also apply a force while doing no work if the car is pointed uphill and you balance the engine output to match gravity when the car is stopped. Alternatively the same engine setting would be doing work if the car had an initial velocity uphill. (It would climb with constant velocity, gaining gravitational potential energy)
This shows why TheTraveller's claims are not consistent with reality. A device such as a motor can produce a force, but external factors determine whether or not that force does any work. TheTraveller is proposing that the EMDrive magically knows the difference between these situations and suddenly stops applying a force in one of them. This probably stems from Shawyer's strange abuses and misuses of terminology in that paper he keeps linking.
I agree on Shawyer's strange abuses and misuses of terminology in that paper. I also agree that this result would be very strange, and is not correctly motivated for now.
But, if the acceleration that matter is the proper acceleration, yes, it is not physically impossible that it is a parameter for a motor.
For example, classical liquid fuel motors need proper acceleration to correctly work, so that the propellant is at the bottom of the tank. On many rockets, after stage separation, another propulsion system is used seconds before the ignition of the next stage. So, the lack of proper acceleration is a true parameter, that can not be denied by a general theorem.
But, in the case of the Emdrive, I do not see why this parameter would play. There is no propellant that can freely move inside.
Also, in your example of the car that rests on an incline, the car is experiencing a proper acceleration, in the direction of it's normal course, due to the reaction of the road, and the earth gravity. So it is not an example of a non proper accelerating device
Anyway, if we were believing Shaywer theory about motor mode, an incline of less that one degree should give enough proper acceleration for the Emdrive to work. (Believing is the right word, because that is what The Traveller asks us to do
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#4123 by Mezzenile on 03 Aug, 2016 14:24
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I have now found the official term used in General Relativity. It is Proper Acceleration, and it correspond to that I named subjective acceleration, due to my ...
A famous situation where an accelerometer onboard an object will detect no measurable acceleration is the case of interplanetary probes which execute "fly by" manoeuvers with planets to increase their speed at no propergol cost. From the earth you can see clearly the probe gaining a large amount of speed allowing it to escape Sun attraction and onboard the probe there is no acceleration detected (no inertial force on the occupants by opposition to what happen in an accelerating car). In fact the situation is similar to a free fall on the earth from a tower, but here we are too accustomed to it to be surprised .
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#4124 by Monomorphic on 03 Aug, 2016 19:53
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Draft enclosure complete. Noise from air currents completely eliminated. At first I thought a "tap" test would be impossible with the torsional pendulum enclosed. Then I remembered the magnetron contains magnets. I brought a large permanent magnet near the plexiglass and was able to impart minute forces onto the pendulum. I'm pretty sure I will be able to measure forces of ~10 μN or less and hope to test its maximum sensitivity tonight.
This test was performed with the HVAC and CPU fan running, plus me walking around in the room. I used 0.25" plexiglass for the front windows.
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#4125 by Bob Woods on 03 Aug, 2016 20:04
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Draft enclosure complete. Noise from air currents completely eliminated. At first I thought a "tap" test would be impossible with the torsional pendulum enclosed. Then I remembered the magnetron contains magnets. I brought a large permanent magnet near the plexiglass and was able to impart minute forces onto the pendulum. I'm pretty sure I will be able to measure forces of ~10 μN or less and hope to test its maximum sensitivity tonight.
This test was performed with the HVAC and CPU fan running, plus me walking around in the room. I used 0.25" plexiglass for the front windows.
Nice! Will you put a temp sensor above the wedge to detect air temp change above the wedge? Might be able to estimate some thermal lift characteristics. -
#4126 by Monomorphic on 03 Aug, 2016 20:40
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Nice! Will you put a temp sensor above the wedge to detect air temp change above the wedge? Might be able to estimate some thermal lift characteristics.
I don't see any reason why not. I will also still be able to use the IR camera since plexiglass is infrared transmitting. -
#4127 by AnalogMan on 03 Aug, 2016 22:00
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Nice! Will you put a temp sensor above the wedge to detect air temp change above the wedge? Might be able to estimate some thermal lift characteristics.
I don't see any reason why not. I will also still be able to use the IR camera since plexiglass is infrared transmitting.
I think you'll find that plexiglass will not transmit the long wavelength IR radiation (8-12 µm) that thermal cameras use - as a check I just tried mine with a 2.5 mm thick sheet and I could not see my hand through it. -
#4128 by otlski on 04 Aug, 2016 01:31
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Yes, there is a difference between the near infrared (NIR) and the thermal wavelengths. Acrylic stops passing at 2000 nm.
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#4129 by mwvp on 04 Aug, 2016 04:02
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...EmDrive force is only produced when the frustum reference frame experiences acceleration. Initial accelerative force on the frustum needs to be external.
Negative inertial resistance?
The paper Shell referred: "Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator" by Reed, and references in it to R.C. Jennison, and John A. Macken, “The Universe is Only SpaceTime”, (www.onlyspacetime.com) are interesting.
Very interesting.
Thanks so much Shells! One of the best references ever. -
#4130 by SeeShells on 04 Aug, 2016 13:22
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You're quite welcome. It's so intense, I'm re-reading much of this a second time. I'm waiting for for more parts to arrive this week and getting ready for winter in these parts so it's catch up time, review and reabsorb this last year's work....EmDrive force is only produced when the frustum reference frame experiences acceleration. Initial accelerative force on the frustum needs to be external.
Negative inertial resistance?
The paper Shell referred: "Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator" by Reed, and references in it to R.C. Jennison, and John A. Macken, “The Universe is Only SpaceTime”, (www.onlyspacetime.com) are interesting.
Very interesting.
Thanks so much Shells! One of the best references ever.
Shell -
#4131 by rfmwguy on 04 Aug, 2016 15:27
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1701A Special Announcement: https://www.reddit.com/r/QThruster/comments/4w50bk/1701a_emdrive_testing_completed_for_2016/
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#4132 by tchernik on 04 Aug, 2016 17:17
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You're quite welcome. It's so intense, I'm re-reading much of this a second time. I'm waiting for for more parts to arrive this week and getting ready for winter in these parts so it's catch up time, review and reabsorb this last year's work....EmDrive force is only produced when the frustum reference frame experiences acceleration. Initial accelerative force on the frustum needs to be external.
Negative inertial resistance?
The paper Shell referred: "Confinement of Light: Standing Wave Transformations in a Phase-Locked Resonator" by Reed, and references in it to R.C. Jennison, and John A. Macken, “The Universe is Only SpaceTime”, (www.onlyspacetime.com) are interesting.
Very interesting.
Thanks so much Shells! One of the best references ever.
Shell
I agree this and R.C. Jennison's papers (from the late 70s/early 80s) are astounding. They can perfectly be 'the' explanation of why the Emdrive (a photon resonator) could actually work.
They are so amazing in their implications in fact, that I wonder why they didn't received more attention so far.
I don't believe in conspiracies, though (messy things that break apart as easily as a house of cards the more people is involved) but I certainly believe in the irresistible power of human stupidity, against which even the gods themselves fight in vain.
Proverbial treasures may be buried in the works done even several decades ago, and they don't receive attention because there simply isn't enough people (and attention) to give to them.
It's that or they have been refuted, but I have yet to see any contrarian response about these papers. -
#4133 by meberbs on 05 Aug, 2016 05:53
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...
I was surprised that I couldn't find any significant response to the theory presented on http://www.onlyspacetime.com/
Proverbial treasures may be buried in the works done even several decades ago, and they don't receive attention because there simply isn't enough people (and attention) to give to them.
It's that or they have been refuted, but I have yet to see any contrarian response about these papers.
I have not read through much of it (and don't have time to do more), but I can fill in the gap and provide a response to some of it.
First of all, on the front page of the website, the author states:QuoteThe standard model has so many component parts that it is difficult to state a specific number.
The standard model has 12 fundamental particles which have anti-particles, 4 gauge bosons (sub-variations include 2 W's and 8 gluons) and the Higgs boson. They are defined by just 19 independent parameters, with 7 more needed in the extension of the standard model to allow for neutrino oscillations. Those are specific numbers. Scientists try to and wish they could simplify and reduce the number of parameters, but they haven't found a way given the complexity of the universe.
He says early on (Chapter 4):QuoteIf the assumption is wrong, the error should be quickly evident.
This is a true statement, I jumped to chapter 12, because I knew that was likely to be where issues with this proposal are most evident. It turns out I made a good guess.QuoteThis chapter lumps together several difficult subjects not previously covered. These include bonds, the ψ function, quarks, gluons, the weak force and neutrinos. Most of these are not clearly understood in mainstream physics. This vagueness prevents plausibility calculations to test the spacetime model involving these subjects. For example, quarks do not exist in isolation, so their properties are always partly hidden.
The first statement that these are not understood is simply false. While many of these are non-intuitive, and there are some things we don't know yet because we haven't built sufficiently sensitive instruments, there is a lot that we do know, and has been rigorously verified by experiment.
For example, he goes on:QuotePerhaps the most shocking conclusion is that the spacetime based model in its current state of development does not need gluons.
Gluons have been experimentally shown to exist, and were predicted by theory before their initial detection. Predictive power is one of the most useful parts of a physical theory. If his theory says there are no gluons, then it is wrong.
In general this chapter contains a lot of him describing standard physics and either saying "this model agrees" with no work to show that it does, or saying "this doesn't make sense, but this model doesn't predict that" (even though experiments show it to be true). He spends a bunch of time describing how binding energy works with most forces, and is consistent with his model. He then gets to the strong force which behaves differently and says "it doesn't make sense for this to behave differently, so here is why my model predicts it to be different" This is simply a logical fallacy, there is no reason to believe it wouldn't be unique, and experiments show that the strong force behaves in a non-intuitive manner.
One example of where he simply demonstrates ignorance of what he is talking about:QuoteWhy does the force start at zero and increase with distance? This is “explained” by physicists postulating that as the quarks are separated, the gluons form “flux tubes” and this concentration actually increases the force of attraction even though the distance is increasing. What is the physics behind this concept? What supplies the force to constrain the size of the flux tubes?
Gluons have charge themselves. In developing this theory, he seems to have given up on the concept of there being an attractive force, so he doesn't see that the color charges on the gluons that make up the flux tubes means the gluons making up the tubes would themselves be attracted to each other, constraining them.
He also accuses the standard model of treating quarks as point particles, and states how nonsensical the infinite mass density is. The problem with his statement is that quantum mechanics does not allow point particles, because particles are waves as well and subject to the uncertainty principle. While many calculations use point particles for simplicity, when relative scales allow it, his statement about the standard model is simply incorrect.
______
I could go on more, but it really doesn't seem worth it. I believe that some of our modern problems in physics will only be solved by taking a radical orthogonal view of things, so researching ideas like this is useful. For example, general relativity and quantum electrodynamics are simply formulated in different ways. At least one will probably have to be reformulated into some equivalent theory before they can be unified. At the same time though, you have to know what standard physics says about things, so that you can make sure your theory matches with what is already known. This is hard, because if you don't know enough physics, and start guessing at theories, you will almost certainly have significant flaws in your theory. On the other hand, by the time you learn enough physics to have a chance at a reasonable theory, you will have seen so much of the current formulations, it will be difficult to come up with a novel way of approaching the problem.
For an experienced physicist (moreso than me), reading some of this theory with the right mindset might help them think of a novel way of approaching things. For someone who isn't already an expert, they should probably not read this, because it mixes in too many falsehoods. I caught many, but I am sure there are some I didn't notice, since I am not an expert in all of the relevant fields discussed. -
#4134 by CorvusCorax on 05 Aug, 2016 06:05
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If a proper acceleration were required for the EM drive to produce thrust, for in spave application you'd need a propellant-less source of acceleration.
( especially should the thrust force provided by the frustum be a factor of said acceleration and very small, you'd need a large acceleration without expending propellant. )
If this indeed were a requirement, it could be met by spinning the vehicle around an axis that imparts centripetal acceleration across an apropriate axis.
Worst case, if the axis have to be parallel, you'd have to pulse the EM drive in sync with its rotation to get thrust in the desired direction. If its perpendicular, you could operate continuously.
Either way this should still work in orbit, shouldn't it?
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#4135 by Gilbertdrive on 05 Aug, 2016 09:18
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If a proper acceleration were required for the EM drive to produce thrust, for in spave application you'd need a propellant-less source of acceleration.
( especially should the thrust force provided by the frustum be a factor of said acceleration and very small, you'd need a large acceleration without expending propellant. )
If this indeed were a requirement, it could be met by spinning the vehicle around an axis that imparts centripetal acceleration across an apropriate axis.
Worst case, if the axis have to be parallel, you'd have to pulse the EM drive in sync with its rotation to get thrust in the desired direction. If its perpendicular, you could operate continuously.
Either way this should still work in orbit, shouldn't it?
I agree.
If I correctly understand, the proper acceleration has to be in the axis of the frustrum, a perpendicular acceleration, in the Shawyer model, should not work.
In a spinning ship, the axis of the frustrum just has to have a small angle relative to the axis of the ship, so there is a small proper acceleration in the axis of the frustrum.
And, once the frustrum is running, it's orientation can be changed to align the axis of the frustrum and the axis of the ship. Except is the acceleration provided by the frustrum to the ship is not enough to meet the proper acceleration requirement.
But, without providing us how much proper acceleration is required, the "acceleration needed theory" is still very vague. -
#4136 by JaimeZX on 05 Aug, 2016 12:41
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In fact the situation is similar to a free fall on the earth from a tower, but here we are too accustomed to it to be surprised
I would be very surprised if I found myself falling from a tower. .
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#4137 by Monomorphic on 05 Aug, 2016 14:47
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Now this is a high voltage probe. Arcing vaporized the tip of my previous smaller probe. I think the cat is a little concerned.
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#4138 by SeeShells on 05 Aug, 2016 15:25
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Over the last year I've read over 600 papers, countless online educational videos and writings on anything relating to this project. In almost every case I've found where the writer(s) have fudged facts, test results or downright guessed at something , even presenting it as a truism....
I was surprised that I couldn't find any significant response to the theory presented on http://www.onlyspacetime.com/
Proverbial treasures may be buried in the works done even several decades ago, and they don't receive attention because there simply isn't enough people (and attention) to give to them.
It's that or they have been refuted, but I have yet to see any contrarian response about these papers.
<sorry sniped a little>
For an experienced physicist (moreso than me), reading some of this theory with the right mindset might help them think of a novel way of approaching things. For someone who isn't already an expert, they should probably not read this, because it mixes in too many falsehoods. I caught many, but I am sure there are some I didn't notice, since I am not an expert in all of the relevant fields discussed.
The thing I've had to do (and by no means am I even close to you or, many here in depth of understanding) is try to not take all of it to heart and question everything I read, watch or hear.
Reviewing John Macken's "The Universe is Only Spacetime", you're right he did take a different look and approach this blending problem of the 2 great houses of thought. In trying to describe the box of reality everything must work in and that's spacetime, this was somewhat unique and even thought provoking.
I'm not a physicist but just an old girl engineer and my no means am I in the same class like so many here, but I'm trying to improve and learn. Thank you meberbs for helping.
Shell
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#4139 by SeeShells on 05 Aug, 2016 15:29
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Now this is a high voltage probe. Arcing vaporized the tip of my previous smaller probe. I think the cat is a little concerned.
OMG it's so big!
I also fried out the cheap one I got online and either I'm going to build one of buy another.
Shell
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