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#400 by Rodal on 19 Dec, 2015 17:31
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The recent discussion in several posts, justifying unpredictable EM Drive experimental measurements of force on the use of a magnetron runs completely and diametrically opposed to what Paul March (NASA) wrote threads ago: that perhaps the orders of magnitude higher forces claimed in reports by Yang and Shawyer were due to their use of magnetrons while NASA was measuring orders of magnitude smaller forces because NASA was not using magnetrons.
Paul March then argued that perhaps it was precisely what is now being described as "bad": the frequency modulation and phase modulation of magnetrons, that could be responsible for the "better" orders of magnitude higher experimental forces claimed by Yang and Shawyer. Paul also discussed that NASA was going to perform experiments with a magnetron on a teeter-totter balance to see whether such an experimental device would result in experimental values close to what Yang and Shawyer claims.
No attempt to reconcile these conflicting, diametrically opposed viewpoints is made in these recent posts, which do not discuss what was presented previously by Paul March concerning frequency and phase modulation of magnetrons. Perhaps because several people that are posting now where not posting at the time that Paul March was having those discussions and may be unaware of such diametrically opposed viewpoints ? .
Discussions about "frequency locking" should take into account that there isn't a fixed frequency of resonance for an electromagnetic cavity that is simultaneously induction heated and hence getting hotter and hence expanding due to thermal expansion and hence changing its natural frequency as it gets hotter. The natural frequency is changing with time. This was part of the reason why frequency modulation was argued previously as being benefitial. The other argument by Paul March was based on computer modeling at NASA using their "Quantum Vacuum" model.
The fact that now, the complete opposite is being discussed in these pages: that frequency modulation and phase modulation of magnetrons is actually "bad" and that what one may want is "locking" to a particular resonant frequency shows how unsettled is such EM Drive experimentation and analysis. I hope that we will hear soon from NASA and TU Dresden to clarify this state of affairs
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#401 by zen-in on 19 Dec, 2015 17:33
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Take a dead magnetron, core it out, stuff it with resistors or a electric dryer's heating element, and replace for the active one. If you dissipate the same heat, the same way, you've got a adequate "heat dummy" to do a difference with.
I think this is a great idea. Another option would be to mount a high Wattage halogen light, such as a projector bulb in an Aluminum box with cooling fins mounted to it. The Wattage doesn't have to be as high as the magnetron. This dummy heat load can be used to characterize the response of the measuring device (balance or torsion pendulum) to heat excitation. Run a series of tests at different power levels, plotting the thrust signature due to heating. This will reveal any non-linearities and can be used to predict how much of the system response is from heating when a magnetron is powered up.
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#402 by OnlyMe on 19 Dec, 2015 18:02
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It is remarkable that the recent discussion in several posts, justifying unpredictable EM Drive experimental measurements of force on the use of a magnetron runs completely and diametrically opposed to what Paul March (NASA) wrote threads ago: that perhaps the orders of magnitude higher forces claimed in reports by Yang and Shawyer were due to their use of magnetrons while NASA was measuring orders of magnitude smaller forces because NASA was not using magnetrons.
Paul March then argued that perhaps it was precisely what is now being described as "bad": the frequency modulation and phase modulation of magnetrons, that could be responsible for the "better" orders of magnitude higher experimental forces claimed by Yang and Shawyer. Paul also discussed that NASA was going to perform experiments with a magnetron on a teeter-totter balance to see whether such an experimental device would result in experimental values close to what Yang and Shawyer claims.
No attempt to reconcile these conflicting, diametrically opposed viewpoints is made in these recent posts, which ignore what was presented previously by Paul March concerning frequency and phase modulation of magnetrons. Perhaps because several people that are posting now where not posting at the time that Paul March was having those discussions and may be unaware of such diametrically opposed viewpoints ? .
Discussion about "frequency locking" apparently ignore that there isn't a fixed frequency of resonance for an electromagnetic cavity that is simultaneously induction heated and hence getting hotter and hence expanding due to thermal expansion and hence changing its natural frequency as it gets hotter. The natural frequency is changing with time. This was part of the reason why frequency modulation was argued previously as being benefitial. The other argument by Paul March was based on computer modeling at NASA using their "Quantum Vacuum" model.
The fact that now, the complete opposite is being discussed in these pages: that frequency modulation and phase modulation of magnetrons is actually "bad" and that what one may want is "locking" to a particular resonant frequency shows how unsettled is such EM Drive experimentation and analysis. I hope that we will hear soon from NASA and TU Dresden to clarify this state of affairs
For my part, I did read Paul March's comments you refer to, at least some of them. They seemed to, even as you reference them, to be speculation. Until Eagleworks is able to provide further test results we cannot know, if they were nothing more than speculation or subsequently supported by experiment.
Until someone, who is conducting experiments, gets to a place where they can share more information, all anyone.., not conducting experiments can do, is speculate.
And I agree, it would be nice to see something published or even more DIY results. In both cases we just have to wait until the processes and circumstances, that delay and slow down the release or accumulation of data, resolve theirselves.
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#403 by ThereIWas3 on 19 Dec, 2015 18:12
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I was under the impression that Shawyer did not use a magnetron, but used a signal generator and a TWT amplifier. This setup appears in diagrams for his 3.85 GHz "Flight Thruster".
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#404 by OnlyMe on 19 Dec, 2015 18:19
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I was under the impression that Shawyer did not use a magnetron, but used a signal generator and a TWT amplifier. This setup appears in diagrams for his 3.85 GHz "Flight Thruster".
I can't say for certain at this point but I believe his earlier builds did use a magnetron. At the risk of insighting more controversy, Shawyer is not providing detail..., I think the move to a signal generator was to address requests to supply power to the frustum via coax.., instead of directly from a magnetron via waveguide...
More speculation on my part.., without hunting back through the discussion for fragments of comments. -
#405 by Rodal on 19 Dec, 2015 18:30
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I was under the impression that Shawyer did not use a magnetron, but used a signal generator and a TWT amplifier. This setup appears in diagrams for his 3.85 GHz "Flight Thruster".
He did use a magnetron on other earlier tests according to posts in earlier threads.
Tests conducted at 2.45 GHz:
SPR Ltd, R. Shawyer, Experimental
SPR Ltd, R. Shawyer, Demonstration
NOTE: But Shawyer used waveguide feeding of the RF. Waveguides are better at promoting a given polarization of the fields (as opposed to just connecting the magnetron directly to the EM Drive cavity), as well shown by the Meep runs with dual symmetric waveguide feeding exciting the TE mode.
For the Flight Thruster project he went a different route,including a completely different frequency: 3.85 GHz, which meant no magnetron (commercial magnetrons are usually available at 2.45 GHz). A magnetron with a resonant frequency of 3.85 GHz would have to be specially desinged (as it would imply a non-standard magnetron cavity dimension).
Take a gander at:
http://emdrive.wiki/Experimental_Results -
#406 by OnlyMe on 19 Dec, 2015 18:39
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It is remarkable that the recent discussion in several posts, justifying unpredictable EM Drive experimental measurements of force on the use of a magnetron runs completely and diametrically opposed to what Paul March (NASA) wrote threads ago: that perhaps the orders of magnitude higher forces claimed in reports by Yang and Shawyer were due to their use of magnetrons while NASA was measuring orders of magnitude smaller forces because NASA was not using magnetrons.
This is a question dumb or not...
Paul March then argued that perhaps it was precisely what is now being described as "bad": the frequency modulation and phase modulation of magnetrons, that could be responsible for the "better" orders of magnitude higher experimental forces claimed by Yang and Shawyer. Paul also discussed that NASA was going to perform experiments with a magnetron on a teeter-totter balance to see whether such an experimental device would result in experimental values close to what Yang and Shawyer claims.
No attempt to reconcile these conflicting, diametrically opposed viewpoints is made in these recent posts, which do not discuss what was presented previously by Paul March concerning frequency and phase modulation of magnetrons. Perhaps because several people that are posting now where not posting at the time that Paul March was having those discussions and may be unaware of such diametrically opposed viewpoints ? .
Discussion about "frequency locking" apparently ignore that there isn't a fixed frequency of resonance for an electromagnetic cavity that is simultaneously induction heated and hence getting hotter and hence expanding due to thermal expansion and hence changing its natural frequency as it gets hotter. The natural frequency is changing with time. This was part of the reason why frequency modulation was argued previously as being benefitial. The other argument by Paul March was based on computer modeling at NASA using their "Quantum Vacuum" model.
The fact that now, the complete opposite is being discussed in these pages: that frequency modulation and phase modulation of magnetrons is actually "bad" and that what one may want is "locking" to a particular resonant frequency shows how unsettled is such EM Drive experimentation and analysis. I hope that we will hear soon from NASA and TU Dresden to clarify this state of affairs
Earlier I mentioned using a thermal insulating casting material to form a box around a frustum and reduce the effects of thermal turbulence.
The question I have here is, would forming the frustum parts from a copper sheet, just thick enough to make forming the tapered cavity workable, and then casting an exterior layer of essentially low thermal conductive ridged material, help to minimize the thermal distortion of the frustum enough to be useful.
The specific product I was looking at as reference is,
Kast-O-lite 26 LI Insulating Castable Refractory: This material has a thermal conductivity of 4.0 btu-in/hr-F-ft^2 at 2000 degrees F.
Suppliers web link is, http://www.hightemptools.com/castablerefractory.html.
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#407 by rq3 on 19 Dec, 2015 20:01
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It is remarkable that the recent discussion in several posts, justifying unpredictable EM Drive experimental measurements of force on the use of a magnetron runs completely and diametrically opposed to what Paul March (NASA) wrote threads ago: that perhaps the orders of magnitude higher forces claimed in reports by Yang and Shawyer were due to their use of magnetrons while NASA was measuring orders of magnitude smaller forces because NASA was not using magnetrons.
Paul March then argued that perhaps it was precisely what is now being described as "bad": the frequency modulation and phase modulation of magnetrons, that could be responsible for the "better" orders of magnitude higher experimental forces claimed by Yang and Shawyer. Paul also discussed that NASA was going to perform experiments with a magnetron on a teeter-totter balance to see whether such an experimental device would result in experimental values close to what Yang and Shawyer claims.
No attempt to reconcile these conflicting, diametrically opposed viewpoints is made in these recent posts, which do not discuss what was presented previously by Paul March concerning frequency and phase modulation of magnetrons. Perhaps because several people that are posting now where not posting at the time that Paul March was having those discussions and may be unaware of such diametrically opposed viewpoints ? .
Discussions about "frequency locking" apparently ignore that there isn't a fixed frequency of resonance for an electromagnetic cavity that is simultaneously induction heated and hence getting hotter and hence expanding due to thermal expansion and hence changing its natural frequency as it gets hotter. The natural frequency is changing with time. This was part of the reason why frequency modulation was argued previously as being benefitial. The other argument by Paul March was based on computer modeling at NASA using their "Quantum Vacuum" model.
The fact that now, the complete opposite is being discussed in these pages: that frequency modulation and phase modulation of magnetrons is actually "bad" and that what one may want is "locking" to a particular resonant frequency shows how unsettled is such EM Drive experimentation and analysis. I hope that we will hear soon from NASA and TU Dresden to clarify this state of affairs
These reasons are exactly why I have always advocated the use of a phase lockable synthesizer and amplifier. Most lab quality frequency synthesizers are arbitrarily modulatable in phase, frequency, and amplitude. They can easily emulate a magnetron, while a magnetron can only be a magnetron.
Having phase lock capability allows one to play games like automatically tune the synthesizer for lowest frustum VSWR or greatest return loss, given a sample of the microwave input presented to the frustum, or reflected from the frustum. This can even compensate for "de-tuning" from thermal effects, etc.
I think I mentioned back in thread 3 that puffing microwaves from an oven magnetron into a sealed copper funnel will probably only lead to, "well that didn't work, now what?" There are few variables under the control of the experimenter with the magnetron get-up. Shaving copper to micrometric precision to chase a magnetron is an exercise in futility. If you don't get thrust, you'll have no idea why. If you DO get thrust, you'll have no idea why. -
#408 by Emmett Brown on 19 Dec, 2015 20:26
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Sorry for the lack of posts, busy time of year...
Does anyone have a COMSOL (5.0) model of a frustum available to share? I'm just learning the S/W and this would help me so I don't model it incorrectly being a noob.
I've got some progress on my build. Endplates are now bolted to the frustum flange. Experimented with a simple magnetic damping setup on the test platform so it settles quicker before running a test. Trivial setup - magnet and copper plate, actually worked quite well, drastically reduced the settling time.
Planning on placement of magnetron injection. I broke down and ordered the MiniVNA Tiny - that's going to hurt the Canadian wallet (our dollar is horrible right now).
Basically, next step is to simulate in S/W and test cavity with VNA (when it arrives). Although I'm sure I'll get impatient and try the maggie on an endplate since it's easy to do...
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#409 by A_M_Swallow on 19 Dec, 2015 22:01
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Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil
Moving equipment across international borders can cause a few bureaucratic problems. Such as import licenses, export licenses and no longer a tourist. -
#410 by frobnicat on 19 Dec, 2015 22:05
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...
3. OnlyMe at post 196 on dark matter/energy
The courses I took on general relativity and cosmology are now over 34 years ago, so it's fair to say I'm eager to avoid a detailed debate with someone more current!
I acknowledge what you say about dark energy being an extra term in GR equations, not a balancing item for conservation of energy. However, consider this: dark energy implies (so I read) an energy density for the vacuum, and a total energy which changes as the universe expands. If the theory including dark energy has the total energy of the universe conserved, it's very hard to see how the same observed dynamical behaviour is consistent with the conservation of energy in the Universe absent dark energy. In that sense, dark energy is a balancing item for CoE.
I realize the topic might be conceptually slippery, and I may be wrong. I'd be interested in any response.
R.
Maybe this short entry level article by Lubos Motl (and the following answers to some comments) can feed your thoughts :
http://motls.blogspot.fr/2010/08/why-and-how-energy-is-not-conserved-in.html
From what I get (not much), energy is not conserved on cosmological time scales (on the order of billion years) because at such scales the "background" is not invariant under time translations. So there is no problem with Noether theorem that the concept of "conserved total energy" gets slippery and drifts away. But there is also no hope of practical consequences at our mundane scales (in time and in space).
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#411 by OnlyMe on 19 Dec, 2015 22:07
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Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil
Moving equipment across international borders can cause a few bureaucratic problems. Such as import licenses, export licenses and no longer a tourist.
If it works getting it won't be the problem... Getting it back? -
#412 by rfmwguy on 19 Dec, 2015 22:21
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Sorry for the lack of posts, busy time of year...
Nice metalwork...simpliist injection is endplate. I had resonance at central large dia injection. Shell has side. There are no blueprints you must follow, so enjoy experimenting yourself. The minivna was well worth it imho.
Does anyone have a COMSOL (5.0) model of a frustum available to share? I'm just learning the S/W and this would help me so I don't model it incorrectly being a noob.
I've got some progress on my build. Endplates are now bolted to the frustum flange. Experimented with a simple magnetic damping setup on the test platform so it settles quicker before running a test. Trivial setup - magnet and copper plate, actually worked quite well, drastically reduced the settling time.
Planning on placement of magnetron injection. I broke down and ordered the MiniVNA Tiny - that's going to hurt the Canadian wallet (our dollar is horrible right now).
Basically, next step is to simulate in S/W and test cavity with VNA (when it arrives). Although I'm sure I'll get impatient and try the maggie on an endplate since it's easy to do...
Now to the next step...the testing. Just like frustum design, there are no blueprints. Do torsional, do balance beam...whatever you want. Each has pluses and minuses.
Here's what I've learned in the past year...no one has proposed the perfect build nor experiment. This includes people on both sides of the issue. Whether they think it's unworthy, beneath their dignity or beyond their capabilities to put an entire build and test together, is irrelevant.
This is your build, your test and for you to enjoy and hopefully share. North America now has about 3 or 4 serious, private builders...welcome to the edge of known physics where many are fearful to tread.
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#413 by Kenjee on 20 Dec, 2015 00:02
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I hope you don't mind my attempts
So, mineral oil for coolant, measuring displacement. -
#414 by R.W. Keyes on 20 Dec, 2015 00:38
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Always liked Caesar's Palace. Wife likes the shopping.
Make it March 2016 or later & I'll bring along my S band spherical end plate thruster on the rotary test rig. It is designed to travel.
Phil
Moving equipment across international borders can cause a few bureaucratic problems. Such as import licenses, export licenses and no longer a tourist.
If it works getting it won't be the problem... Getting it back?
This is something I don't know much about, I am sorry to say. Surely there is good precedent? emdrive isn't under ITAR I trust. -
#415 by ThereIWas3 on 20 Dec, 2015 00:50
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Not until it works.
Shipping problems are one reason I favor Hangouts. Plus Everyone stays in their own lab where they can move a webcam around real equipment, share screens, etc, yet still see each other. With no travel or hotel costs. -
#416 by SteveD on 20 Dec, 2015 02:56
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Sorry for the lack of posts, busy time of year...
Does anyone have a COMSOL (5.0) model of a frustum available to share? I'm just learning the S/W and this would help me so I don't model it incorrectly being a noob.
I've got some progress on my build. Endplates are now bolted to the frustum flange. Experimented with a simple magnetic damping setup on the test platform so it settles quicker before running a test. Trivial setup - magnet and copper plate, actually worked quite well, drastically reduced the settling time.
Planning on placement of magnetron injection. I broke down and ordered the MiniVNA Tiny - that's going to hurt the Canadian wallet (our dollar is horrible right now).
Basically, next step is to simulate in S/W and test cavity with VNA (when it arrives). Although I'm sure I'll get impatient and try the maggie on an endplate since it's easy to do...
Contact TheTraveller, he thought there might be some special issues with oxidation in your build. -
#417 by transistorboy32 on 20 Dec, 2015 08:02
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SeeShells,
First off, thanks for all the work you've done and info you've shared so far. I'm continually impressed by all the little things you've thought to design into your setup.
From what I can tell from your posts, your main force measurement device is a Weighmax W-HD200 (200g max, 0.01g resolution) digital scale, correct? Will you be using any other instruments/devices for force measurement? If not, how do you plan on synchronizing the recording of the scale display with other datasets such as magnetron on/off or frustum temperature logs, etc.? I am reminded of the extra manual sync step needed to visually/acoustically match rfmwguy's video timestamp/real-timestamp and mag on/off hum noise. If you're planning on using another force-measurement/acquisition system then you can disregard the remainder of this post.
To remedy the issue of manually linking scale display video with other data in your tests, I'd suggest using a different measurement device which has the ability to save data to a file for later review/processing. This can take the form of a computer (or Raspberry Pi, as you're planning to use) with a DAQ-type device and force sensor. Alternatively, if there is concern that using a non-RTOS might introduce unpredictable sampling delay errors from the various inputs into the final dataset (in the case that any generated force might be a fast transient when the RF is first switched on, and thus a low-sampling rate will miss, or unpredictable sample delays will mis-represent this critical information), a microcontroller with microSD card interface could be used which could be programmed with calculable sampling delays.
I have purchased & taken apart one of the same model W-HD200 scales (See attached picture. Note I've removed the LCD and bent up the backlight to see underneath) to see if there is any data output interface. Unfortunately it doesn't look like there is. The main IC is unfortunately a glob top and is thus unidentifiable. Due to this, the characteristics of the scale (such as internal sample rate, temperature drift error, etc.) are unknown and will make error analysis attempts difficult.
Since accurate measurement of force is of the utmost importance, I'd suggest using a load cell and amp/DAQ with well-documented characteristics. I also note that the scale in question uses a 300g max load cell (as can be seen on the green label on the side). I'd suggest using a 100g load cell, as the reduced full-scale range would be reduced by a factor of three, and as such the accuracy should proportionally increase by a factor of three (as more of the full-scale output voltage will be utilized). As glennfish estimated in his post (http://forum.nasaspaceflight.com/index.php?topic=39004.msg1459170#msg1459170), total force probably won't exceed 1N (~100g). In my non-extensive search, it seems as though any load cells with a max capacity <100g are prohibitively expensive (like $600+). Therefore it seems like 100g cells have the best performance-to-price ratio. For example, this 100g load cell (http://www.phidgets.com/products.php?product_id=3139) or others on eBay look like they'd work, they're generally <$10, and have included performance characteristics which will allow for system error analysis.
As far as amplifiers/ADCs, the ADS1232REF evaluation module (http://www.ti.com/tool/ads1232ref) from TI looks like one of the best options. The HX711 is another chip commonly used for this purpose, however the datasheet is not as extensive and it has worse RMS input noise by at least a factor of two. The ADS1232REF uses a 24-bit ADC with a full datasheet, the eval board has been designed specifically for load cell measurements, it provides a small LCD display, programmable MSP430 microcontroller, USB interface, and costs about $50. It looks like the LCD might only display raw ADC values when using the USB interface rather than scaled weight values in common units (as it would in Scale mode, see the user manual: http://www.ti.com/lit/ug/sbau120b/sbau120b.pdf), but the acquired raw data could easily be scaled on the computer to output weight/force units. It looks like it has the ability to act as a COM port on the computer, and therefore it would be pretty easy to write software to interface and save data. Alternatively, it is possible to re-program the on-board MSP430 and probably trivial to add functionality to output scaled data (vs. raw data) via USB/UART. It should be possible to tap into the MSP430's UART signals directly (between it and the USB<->UART conversion chip on the board) and send data directly to another microcontroller logging data to a microSD or flash chip, which would reduce the sample-timing errors discussed above (due to the non-RTOS running on the host computer, if such errors turn out to be non-negligible).
According to various data which can be found in the ADS1232 datasheet (http://www.ti.com/lit/ds/sbas350f/sbas350f.pdf), I estimate the evaluation board should be capable of 42.3uN (micro-Newton) resolution (about 2x better than that of the Weighmax scale), using the aforementioned 100g load cell, with a sample-rate of 80 per second (resolution approximately doubles @ 10SPS - a trade-off to consider). The estimated force resolutions are based on "noise-free bits" and could be improved via averaging, although of course this would lessen the overall sample-rate proportionally.
TL;DR: Shell, I suggest you implement a force-measurement method using devices which are well-characterized for error-analysis purposes, and which provide data in a format that can be automatically saved to a file for fine-detailed analysis (rather than manually reading values from a scale display off a video).
Back to lurking...
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#418 by rfmwguy on 20 Dec, 2015 13:01
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Tangential alert - read something interesting and thought I would share it. Seems it applies to many things on the edge of known physics...just like the emdrive projects:
My answer was “Falsifiability.” More of a philosophical idea than a scientific one, but an idea that is bandied about by lazy scientists far more than it is invoked by careful philosophers. Thinking sensibly about the demarcation problem between science and non-science, especially these days, requires a bit more nuance than that.
Modern physics stretches into realms far removed from everyday experience, and sometimes the connection to experiment becomes tenuous at best. String theory and other approaches to quantum gravity involve phenomena that are likely to manifest themselves only at energies enormously higher than anything we have access to here on Earth. The cosmological multiverse and the many-worlds interpretation of quantum mechanics posit other realms that are impossible for us to access directly. Some scientists, leaning on Popper, have suggested that these theories are non-scientific because they are not falsifiable.
The truth is the opposite. Whether or not we can observe them directly, the entities involved in these theories are either real or they are not. Refusing to contemplate their possible existence on the grounds of some a priori principle, even though they might play a crucial role in how the world works, is as non-scientific as it gets.
- author unknown
Edit - found the complete article and author...sean carroll of caltech: https://edge.org/response-detail/25322
In an apparent case of scientific bipolarity, this same author casually dismisses the emdrive based on the singular belief that it violates Conservation of Momentum: http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/
While I have no doubt of this gentleman's credentials, I would suggest he follow his own philosophy
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#419 by Rodal on 20 Dec, 2015 15:03
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Tangential alert - read something interesting and thought I would share it. Seems it applies to many things on the edge of known physics...just like the emdrive projects:
My answer was “Falsifiability.” More of a philosophical idea than a scientific one, but an idea that is bandied about by lazy scientists far more than it is invoked by careful philosophers. Thinking sensibly about the demarcation problem between science and non-science, especially these days, requires a bit more nuance than that.
Modern physics stretches into realms far removed from everyday experience, and sometimes the connection to experiment becomes tenuous at best. String theory and other approaches to quantum gravity involve phenomena that are likely to manifest themselves only at energies enormously higher than anything we have access to here on Earth. The cosmological multiverse and the many-worlds interpretation of quantum mechanics posit other realms that are impossible for us to access directly. Some scientists, leaning on Popper, have suggested that these theories are non-scientific because they are not falsifiable.
The truth is the opposite. Whether or not we can observe them directly, the entities involved in these theories are either real or they are not. Refusing to contemplate their possible existence on the grounds of some a priori principle, even though they might play a crucial role in how the world works, is as non-scientific as it gets.
- author unknown
Edit - found the complete article and author...sean carroll of caltech: https://edge.org/response-detail/25322
In an apparent case of scientific bipolarity, this same author casually dismisses the emdrive based on the singular belief that it violates Conservation of Momentum: http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/
While I have no doubt of this gentleman's credentials, I would suggest he follow his own philosophy
Sean Carroll received his PhD in astronomy and astrophysics in 1993 from Harvard University. He worked as an assistant professor at the University of Chicago until 2006 when he was denied tenure. Sean Carroll is now a research professor in the Department of Physics at the California Institute of Technology.
While I wrote a dissenting comment on his blog, and I still stand behind my comments http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/ , I don't think that he can be accused of "scientific bipolarity" or of not following his own philosophy.
The 'theories" of both the originator of the EM Drive (Shawyer) and the person who has claimed the largest experimentally measured thrust forces (Yang) clearly violate conservation of momentum. That is a fact that cannot be denied, and therefore Caroll is completely correct in this respect. Although Shawyer and Yang claim that their theories do not violate conservation of momentum, it is straightforward to show that their theories are mathematically inconsistent.
Carroll cannot be accused of bipolarity, because String Theory (unlike the EM Drive "theories") is a fully self-consistent theory, and the mathematical physics backing String Theory is supported by (arguably) the best mathematical physicists of the last decades (Edward Witten, etc.). The criticism against String theory is made on a completely different basis than the criticism against the EM Drive: it has to do with the fact that at the present time it is not possible to falsify String Theory experimentally. On the other hand, it is undeniable that all the theories that have been advanced so far for the EM Drive are fully falsifiable from an experimental viewpoint.
If Do-It-Yourself practitioners do not believe that the EM Drive is falsifiable why would they be performing their experiments ?
One would assume the complete opposite: that DIY practitioners not only think that the EM Drive theories can be falsified, but that EM Drive theories are so easy to falsify that they think that they can even be falsified at one's own home, on a relatively small budget, and that's why they engage in DIY of the EM Drive.
